Motorola M12 Oncore User Manual

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M12
User’s Guide
Supplement
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M12 Oncore
1. Product Specifications
2. Basic Description
3. Mechanical
4. Environmental
5. Electrical
6. RF Characteristics of Receiver
7. RF Requirements for Antenna
8. Performance
9. Features
10. Serial I/O Messages
11. Receiver/Controller Command Descriptions
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Receiver Architecture • 12 parallel channels
• L1 1575.42 MHz
• C/A code (1.023 MHz chip rate)
• Code pluscarrier tracking (carrier aided tracking)
Tracking Capability • 12 simultaneous satellites Dynamics • Velocity: 515 m/s(1000 knots); >515 m/sat altitudes < 18,000 m
• Acceleration: 4 g
• Jerk: 5 m/s
3
• Vibration: 7.7G per MilitaryStandard 810E
Acquisition Time • <15 s typical TTFF - Hot (current almanac, position, time, ephemeris) (Time To FirstFix, TTFF) • <45 s typical TTFF - Warm (current almanac, position and time)
• <70 s typical TTFF - Cold (No stored information)
• <1.0 s internal reacquisition
Positioning Accuracy • 100 meters 2dRMS with SA asper DoD specification
• Less than 25 meters, SEP withoutSA Timing Accuracy(1PPS) • < 500 ns with SA on Datum • WGS-84
• One user definable datum I/O Messages • Latitude, longitude, height, velocity, heading, time
• Motorola binary protocol at 9600 baud
• NMEA 0183 at 4800 baud (GGA, GLL, GSA, GSV, RMC, VTG, ZDA)
• Software selectable outputrate (continuousor poll)
• 3 V digital logic interface
• Second COM portfor RTCM input Power Requirements • 2.8 to 3.2 Vdc; 50 mVp-p ripple (max) "Keep-Alive" BATT Power • Externa l 1.8 Vdcto 3.2 Vdc, 5µA (typical@2.7 Vdc@ +25°C) Power Consumption • <0.225 W @ 3 V without antenna
Dimensions • 40.0 x60.0 x10.0 mm [1.57 x2.36 x0.39 in.] Weight • Receiver 25 g (0.9 oz.) Connectors • Power/Data: 10 pin (2x5) unshrouded male header on 0.050 inch
centers (available in rightangle or straight configuration)
• RF: right angle MMCX female (subminiature snap-on) Antenna • Active micro strip patch Antenna Module
• Powered byReceiver Module atselectable 3 or 5 V Antenna to Receiver • Single coaxial cable with 6 dB maximum lossatL1 (active antenna)
Interconnection • Antenna Sense Circuit
• Antenna gain range 10 - 26 dB Operating Temperature • -40˚C to +85˚C Storage Temperature • -40˚ to 105˚C Humidity • 95% over dry bulb range of +38˚C to+85˚C Altitude • 18,000 m (60,000 ft.) maximum
• > 18,000 m (60,000 ft.) for velocities < 515m/s (1000 knots) Standard Features • Motorola DGPScorrectionsat 9600 baud on COM port one
• RTCM SC-104 input Type 1 and Type 9 messages for DGPSat
2400, 4800 or 9600 baud on COM porttwo
• NMEA 0183 output
• Inverse DGPSsupport Optional features • Lithium battery backup
General
Characteristics
Performance
Characteristics
Serial
Communication
Electrical
Characteristics
Environmental Characteristics
Miscellaneous
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2. Basic Description

2.1 Receiver architecture

Channels 12 parallel
Frequency 1575.42 MHz
Code C/A
Tracking Carrier aided

2.2 Description

The highly integrated single board GPS receiver module is optimized specifically for automotive
applications. The GPS receiver tracks the NAVSTAR GPS constellation of satellites. The satellite
signals received by an active antenna are tracked with 12 parallel channels of L1, C/A code then
downconverted to an IF frequency and digitally processed to obtain a full navigation solution of
position, velocity, time and heading. The solution is then sent over the serial link via the 10-pin
connector.
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3. Mechanical

3.1 Mechanical Drawings

3.1.1 M12 Oncore with right angle power/data connector
3.1.2 M12 Oncore with straight power/data connector
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3.2 Size

Dimensions 40.0 x 60.0 x 10.0 mm

3.3 Weight < 25 g

3.4 Connectors

Power/Data Straight: Samtec, FW-05-03-L-D-156-156, 10-pin
Right Angle: Samtec, ASP62522-01-M, 10-pin
Antenna RF Sub-miniature MMCX connector type

4. Environmental

4.1 Temperature

Operating -40°C to +85°C
Storage -40°C to +105°C

4.2 Relative humidity

Operating 95% over dry bulb range of +38°C to +85°C

4.3 Vibration 0.04 G

2
/Hz, 20 Hz to 1000 Hz
7.7 G per Military Standard 810E

5. Electrical

5.1 Pin Outputs

Pin # Signal Description
1 TTL TXD1 Transmit 3 V logic
2 TTL RXD1 Receive 3 V logic
3 +3.0 V PWR +3 V regulated main power
4 1 PPS One pulse per second signal
5 GROUND Ground (receiver)
6 BATTERY Externally applied backup power (1.8 to 3.2 V)
7 Reserved Not currently used
8 RTCM IN RTCM input only
9 ANTENNA VOLTAGE 3 V or 5 V antenna input voltage
10 Reserved Not currently used
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5.2 Main power

Voltage 2.8 to 3.2 Vdc regulated
50 mV maximum peak-to-peak ripple
Power 0.225 W maximum (without antenna)

5.3 Backup power

Voltage 1.8 V to 3.2 V
Current 5 mA typical @ 2.7 V
Retention Backup power retains date, time, position, satellite data,
oscillator learning table and operating mode

5.4 Antenna feed power out of RF connector

Voltage 2.7 V to 3.2 V over current range for 3 V antenna
Current 15 mA to 80 mA
Flags set in serial data when limits exceeded

5.5 1PPS signal definition

Level 0 V to 3 V
Time mark Rising edge
Width 200 ms typical

5.6 Serial I/O signal definition

Levels 0 V to 3 V, active low
Baud rate 9600 (Motorola Binary)
4800 (NMEA)
Parity None
Data bits 8
Start/stop bits 1

6. RF Characteristics of Receiver

6.1 Dynamic range 27 dB

6.2 Saturation -110 dBm

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7. RF Requirements for Antenna

7.1 General

Frequency 1575.42 MHz (L1)
Bandwidth ± 1.023 MHz
Polarization Right hand circular
Impedance 50

7.2 Gain requirement 16 dB to 30 dB (at receiver input)

7.3 Gain Pattern +0 dBic minimum at zenith

-10 dBic minimum at 0° elevation

7.4 Noise figure 1.8 dB typical

2.2 dB maximum

7.5 VSWR 1.5:1 typical

2.5:1 maximum

7.6 Axial ratio 3 dB typical at zenith

6 dB maximum at zenith

7.7 1 dB compression point -14 dBm typical (at antenna output)

7.8 3 dB frequency bandwidth 45 MHz maximum

7.9 25 dB frequency rejection ± 95 MHz

7.10 Ground plane 15 x 15 cm recommended

7.11 Power

Voltage 2.8 V to 3.2 V, or 4.75 V to 5.25 V
3.0 V typical, or 5.0 V typical
Current 15 mA typical
25 mA maximum

7.12 Temperature

Operating -40°C to +85°C
Storage -40°C to +100°C
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8. Performance

8.1 Accuracy

Position 25 m SEP without SA
100 m 2DRMS (95%) with SA
1 to 5 m typical in differential mode
Altitude 156 m RMS (95%)
Velocity 0.02 m/s without SA
Time pulse UTC ± 500 ns with SA on

8.2 Dynamic limits

Velocity 515 m/s maximum at altitudes > 18000 m
Altitude -1000 m minimum
18000 m maximum at velocities > 515 m/s
Acceleration 4 G maximum
Jerk 5 m/s
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maximum

8.3 Startup time (TTFF)

Hot (date, time, position, almanac, ephemeris) 15 s
Warm (date, time, position, almanac, olt) 45 s
Cold (no stored information) 70 s

8.4 Reacquisition time

After 60 s obstruction 3.5 s
Internal < 1.0 s

8.5 RFI

Jamming resistance Resistant to narrow band CW jamming at the
receiver input of +20dBm at less than 1525
MHz and greater than 1625 MHz for loss of lock with a signal input of –130 dBm
Burnout protection Protected from damage by RF signals at
frequencies100 MHz or more from L1 with received power up to 1 W at the antenna

8.6 EMI

Radiated Complies with Class B, Part 15 of FCC rules
Conducted Complies with European CE requirements
Tested to IEC 801-4 spec for fast transients at 500 V, 5/50 ns, 5 kHz
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9. Features

9.1 Differential operation

Motorola binary corrections on TTL RXD1 (pin 2) at 9600 baud
RTCM SC-104 Type 1 and Type 9 corrections on TTL RXD2 (pin 8) at 2400 or 9600 baud

9.2 NMEA 0183 output

NMEA 0183 Output on TTL TX1 at 4800 baud
Messages supported GGA, GLL, GSA, GSV, RMC, VTG, ZDA

9.3 User definable datum

One user definable datum may be defined using the @@Ap command. The default datum is WGS-84.

9.4 Antenna sense circuit

The M12 Oncore receiver is capable of detecting the presence of an antenna. The receiver utilizes an antenna sense circuit, which can detect under current (open) and over current (shorted or exceeding maximum limit) conditions. The status of the antenna circuit is reported in the Position/Status/Data Message (@@Ha), the Short Position Message (@@Hb) and the Self-Test Message (@@Ia).
The antenna sense circuit is useful for verifying that the antenna is properly connected to the receiver and is drawing the proper amount of current. The antenna sense status should be checked after installation and monitored regularly.
Undercurrent indication < 8 mA
Overcurrent indication > 80 mA

9.5 Real time clock

The real-time clock (RTC) is a standard feature on the M12 Oncore. It is used to minimize the time to first fix (TTFF). The date and time will be retained in the RTC if battery backup power is applied when main power is off.
The user has two options regarding time initialization:
1) Set the date and time BEFORE the receiver acquires any satellites
2) Let the receiver automatically set the date and time AFTER acquiring the first satellite
Note: The date and time cannot be manually set while the receiver is tracking satellites.
Without battery backup, the receiver will start-up with a default time of 12:00:00. To obtain a faster time to first fix, the time, date and GMT offset should be initialized if both the main power and battery backup power have been disconnected.
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10. Serial I/O Messages

10.1 Solution

Update rate 1 Hz maximum (Selectable 1/s – 1/255s)
Latency < 1 s
Reported Position, velocity, time, satellite status, receiver status,
antenna status
Reference WGS-84 or user defined datum

10.2 Resolution

Latitude/longitude 1 milliarcsecond
Height 0.01 m
Velocity 0.01 m/s
Heading 0.1°
Time 1 ns

10.3 Solution quality indicators

Receiver status 3D, 2D, propagation, acquisition
Geometry HDOP when in 2D mode
PDOP when in 3D mode
Satellite status C/No (dB)
Flag indicating satellite tracking status
Flag indicating satellite is used in solution

10.4 Initialization

Startup mode Acquisition based on information available
Battery backup provided No initialization required
No battery backup Receiver will be in default condition, entering date, time,
position and almanac will speed up acquisition process
Default condition No serial messages active unless there is a power-on self-
test failure

10.5 RTCM Commands

The M12 Oncore accepts RTCM SC-104 Type 1 and Type 9 messages. The messages are input on the second communications port (pin 8) at a user selectable baud rate of 2400, 4800 or 9600. The RTCM messages are buffered and processed independently from the primary communications port.
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10.6 Motorola binary I/O command list

Motorola binary commands can be used to initialize, configure, control and monitor the GPS receiver. The Motorola binary commands are supported on the primary communications port at 9600 baud. The commands supported by the M12 Oncore are listed in the table below, and detailed command descriptions are provided in alphabetical order by binary command on subsequent pages.
Function Description Binary Controller Supplement
Command Command Page #
Satellite Set Mask Angle @@Ag mask 14 Receiver Satellite Ignore List @@Am ignore 16 Setup Select Datum @@Ao datum 18 Setup Set User Datum @@Ap udatum 20 Setup Atmospheric Correction Mode @@Aq ion 22 1PPS Position-Hold Position @@As php 24 Setup Altitude-Hold Height @@Au ahp 26 Time Time Mode @@Aw utc 28 1PPS 1PPS Cable Delay @@Az ppsdelay 30 Position Position Lock Parameters @@AM lockp 32 Setup Velocity Filter @@AN filter 34 Setup RTCM Port Mode @@AO p2baud 36 Position Position Filter Select @@AQ pfilter 38 Position Position Lock Select @@AS locke 40 Satellite Visible Satellite Status @@Bb vis 42 Almanac Almanac Status @@Bd alm 44 Almanac Almanac Data Output @@Be almout 46 Ephemeris Ephemeris Data Input @@Bf ephin 48 Almanac Almanac Data Input @@Cb almin 50 Time UTC Offset Status @@Bo utcoff 52 Receiver UTC/Ionospheric Data Output @@Bp utcion 54 DGPS Pseudorange Correction Input @@Ce n/a 56 Receiver Set-to-Defaults @@Cf default 58 NMEA Switch to NMEA @@Ci ioformat 60 Receiver Receiver ID @@Cj id 62 Receiver UTC/Ionospheric Data Input @@Co n/a 64 Position ASCII Position Message @@Eq as8 66 Position Combined Position @@Ga compo 68 Time Combined Time @@Gb comtim 70 1PPS 1PPS Control @@Gc ppscon 72 Position Position Control @@Gd holdcon 74 Time Leap Second Status @@Gj leap12 76 Setup ID Tag @@Gk vin 78 Position Position/Status/Data Message (12Ch) @@Ha ps12 80 Position Short Position Message (12Ch) @@Hb psd 86 Setup Self-Test Message (12Ch) @@Ia selftest12 90 Receiver System Power-On Failure @@Sz n/a 92
NMEA NMEA Messages n/a n/a 94-109
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SATELLITE MASK ANGLE
The GPS receiver will attempt to track satellites for which the elevation angle is greater than the satellite mask angle. This parameter allows the user to control the elevation angle that was used for this decision.
Range: 0 to 89 degrees Default value: 0 degrees
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SATELLITE MASK ANGLE
Motorola Binary Format
• Poll current mask angle:
@@AgxC<CR><LF>
x 1 out of range byte $ff C checksum Message length: 8 bytes
• Change current mask angle:
@@AgdC<CR><LF>
d degrees 0 .. 89 C checksum Message length: 8 bytes
• To either command:
@@AgdC<CR><LF>
d degrees 0 .. 89 C checksum Message length: 8 bytes
Input Command
Response Message
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SATELLITE IGNORE LIST
It is useful to have the flexibility to delete particular satellite identification numbers (SVIDs) from the selection process. The GPS receiver includes, in its list of satellites to track, all satellites that are healthy and in the almanac. The user can elect to ignore particular satellites in the almanac by issuing an Ignore Satellite Command. In addition, the user can restore any previously ignored satellite IDs by issuing an Include Satellite Command. This command also affects the satellite Alert-Planning settings. Satellites that have been removed by this command are not included in the produced Alert-Planning output. The user may notice a delay between issuing this command and the actual removal or inclusion of particular satellites.
Default value: All satellite SVIDs included.
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Response Message
Input Command SATELLITE IGNORE LIST
Motorola Binary Format
Send Current Satellite Ignore List:
@@AmxxxxxC<CR><LF>
xxxxx 5 bytes all hex 00 C checksum Message Length: 12 bytes
• Change Satellite Ignore List:
@@AmkssssC<CR><LF>
k 00 fixed binary constant ssss 32 bit binary field. Each bit represents one SVID.
(msb = SVID 32, lsb = SVID 1)
1 = Ignore
0 = Include C checksum Message Length: 12 bytes
To either command:
@@AmkssssC<CR><LF>
k 00 fixed binary constant ssss 32 bit binary field. Each bit represents one SVID.
(msb = SVID 32, lsb = SVID 1)
1 = Ignore
0 = Include C checksum Message Length: 12 bytes
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SELECT DATUM
The GPS receiver has one predefined datum in its internal memory and one user definable datum. The datums are referenced by an ID number. The predefined datum is number 49 and the user defined datum is number 50. The user instructs the GPS receiver which datum to use by sending the Select Datum command. The command contains the ID number of the desired datum and the GPS receiver returns the response message which gives the user the ability to validate that the input command was accepted. The user can instruct the GPS receiver to use the user defined datum by sending the Select Datum command set to 50.
Default datum: WGS-84 (ID code 49)
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SELECT DATUM
Motorola Binary Format
• Poll current datum ID code:
@@AoxC<CR><LF>
x 1 out of range byte $ff C checksum Message length: 8 bytes
• Change current datum ID code:
@@AodC<CR><LF>
d datum ID 49 or 50 C checksum Message length: 8 bytes
• To either command:
@@ApdsssffiiffffxxyyzzC<CR><LF>
d datum ID 49 or 50 sssff semi-major axis (m)
sss integer part 6,000,000 .. 7,000,000 ff fractional part 0 .. 999 (0.0 .. 0.999)
iiffff inverse flattening
ii integer part 285 .. 305
ffff fractional part 0 .. 999,999,999 (0.0 .. 0.999999999) xx delta X (0.1 m) -32,768 .. 32,767 (-3276.8 .. 3276.7) yy delta Y (0.1 m) -32,768 .. 32,767 (-3276.8 .. 3276.7) zz delta Z (0.1 m) -32,768 .. 32,767 (-3276.8 .. 3276.7) C checksum Message length: 25 bytes
Input Command
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Response Message
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SET USER DATUM
The GPS receiver has one user defined datum stored as ID number 50. The User Datum command allows the user to define the constants used for a custom datum.
A datum is defined by a semi-major axis, an inverse flattening constant, and an offset from the center of mass of the earth given as delta-X, delta-Y, and delta-Z parameters.
Default values: WGS-84 parameters
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SET USER DATUM
Motorola Binary Format
• Poll current user defined datum parameters:
@@ApdxxxxxxxxxxxxxxxxxC<CR><LF>
d desired user datum 50 xxxxxxxxxxxxxxxxx 17 bytes all hex 00 C checksum Message length: 25 bytes
• Change current user defined datum parameters:
@@ApdsssffiiffffxxyyzzC<CR><LF>
d datum ID 50 sssff semi-major axis (m)
sss integer part 6,000,000 .. 7,000,000
ff fractional part 0 .. 999 (0.0 .. 0.999) iiffff inverse flattening
ii integer part 285 .. 305
ffff fractional part 0 .. 999,999,999 (0.0 .. 0.999999999) xx delta X (0.1 m) -32,768 .. 32,767 (-3276.8 .. 3276.7) yy delta Y (0.1 m) -32,768 .. 32,767 (-3276.8 .. 3276.7) zz delta Z (0.1 m) -32,768 .. 32,767 (-3276.8 .. 3276.7) C checksum Message length: 25 bytes
• To either command:
@@ApdsssffiiffffxxyyzzC<CR><LF>
d datum ID 50 sssff semi-major axis (m)
sss integer part 6,000,000 .. 7,000,000 ff fractional part 0 .. 999 (0.0 .. 0.999)
iiffff inverse flattening
ii integer part 285 .. 305
ffff fractional part 0 .. 999,999,999 (0.0 .. 0.999999999) xx delta X (0.1 m) -32,768 .. 32,767 (-3276.8 .. 3276.7) yy delta Y (0.1 m) -32,768 .. 32,767 (-3276.8 .. 3276.7) zz delta Z (0.1 m) -32,768 .. 32,767 (-3276.8 .. 3276.7) C checksum Message length: 25 bytes
Input Command
Response Message
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ATMOSPHERIC CORRECTION MODE
The user has the flexibility of turning the GPS ionospheric and/or tropospheric correction models on or off. The models do a reasonable job of taking out the range error induced by the earth’s ionosphere and troposphere by using algorithms and parameters transmitted to the users by the satellites. For some applications, such as differential systems, the atmospheric models should be disabled since the differential corrections include the atmospheric errors.
Default modes: Ionospheric model enabled
Tropospheric model disabled
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ATMOSPHERIC CORRECTION MODE
Motorola Binary Format
• Poll current Atmospheric Correction Mode:
@@AqxC<CR><LF>
x 1 out of range byte $ff C checksum Message length: 8 bytes
• Change current Atmospheric Correction Mode:
@@AqsC<CR><LF>
s selection 0 = both models disabled
1 = ionospheric model only enabled 2 = tropospheric model only enabled
3 = both models enabled C checksum Message length: 8 bytes
• To either command:
@@AqsC<CR><LF>
s selection 0 = both models disabled
1 = ionospheric model only enabled
2 = tropospheric model only enabled
3 = both models enabled C checksum Message length: 8 bytes
Input Command
Response Message
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POSITION-HOLD POSITION
The user can specify receiver coordinates for timing applications to increase the timing accuracy. This command is used to enter the position to be held. Note that this command will only be executed if the Position Control (@@Gd) position hold is disabled. The position to be held is specified in the same units and referenced to the same datum (WGS 84) as the initial position coordinates of latitude, longitude and height (to the same resolution). The height parameter is referenced to the GPS reference ellipsoid. Note that all three parameters must be specified. The valid ranges of each parameter are the same as those specified in the Combined Position Message (@@Ga).
Default values: Latitude = 0° (Equator)
Longitude = 0° (Grenwich Meridian) Height = 0 m (GPS Height)
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Input Command POSITION-HOLD POSITION
Motorola Binary Format
• Poll current Position-Hold Position:
@@AsxxxxxxxxxxxxxC<CR><LF>
xxxxxxxxxxxx 13 out of range bytes $7fffffff7fffffff7fffffffff C checksum Message length: 20 bytes
• Change current Position-Hold Position:
@@AslllloooohhhhtC<CR><LF>
llll latitude in mas -324,000,000 .. 324,000,000 (-90° .. 90°) oooo longitude in mas -648,000,000 .. 648,000,000 (-180° .. 180°) hhhh height in cm -100000 .. 1,800,000 (-1,000.00 .. 18,000.00 m) t height type 0 = GPS height C checksum Message length: 20 bytes
• To either command:
@@AslllloooohhhhtC<CR><LF>
llll latitude in mas -324,000,000 .. 324,000,000 (-90° .. 90°) oooo longitude in mas -648,000,000 .. 648,000,000 (-180° ..180°) hhhh height in cm -100,000 .. 1,800,000 (-1,000.00 .. 18,000.00 m) t height type 0 = GPS height C checksum Message length: 20 bytes
NOTE: Position-Hold Position is enabled and disabled using the Position Control command
(@@Gd).
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Response Message
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ALTITUDE-HOLD HEIGHT
The user can specify the receiver height for manual altitude-hold applications. Use the Position Control (@@Gd) command to enable or disable the altitude-hold feature. The Altitude-Hold Height is specified in units of meters to a resolution of
0.01 meters. The height is referenced to the GPS reference ellipsoid. The datum for the height is the one selected using the Select Datum command.
Default value: 0 m
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ALTITUDE-HOLD HEIGHT
Motorola Binary Format
• Poll current Altitude-Hold Height:
@@AuxxxxxC<CR><LF>
xxxx 5 out of range bytes $7ffffffff C checksum Message length: 12 bytes
• Change current Altitude-Hold Height:
@@AuhhhhtC<CR><LF>
hhhh height in cm -100,000 .. 1,800,000 (-1000.00 to + 18,000.00 m) t height type 0 = GPS height C checksum Message length: 12 bytes
• To either command:
@@AuhhhhtC<CR><LF>
hhhh height in cm -100,000 .. 1,800,000 (-1000.00 to + 18,000.00 m) t height type 0 = GPS height C checksum Message length: 12 bytes
Note: Altitude-Hold Height is enable and disabled using the Position Control command
(@@Gd).
Input Command
Response Message
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TIME MODE
This command selects the type of time (either GPS or UTC) to be output in the Position/Status/Data and Short Position Messages. The Time Mode command will be used to determine the synchronization point for the 1PPS timing pulse.
Note that if the receiver does not have the UTC parameters portion of the almanac, UTC will be output as being equal to GPS time and a flag denoting the lack of UTC parameters will be set in the Position/Status/Data message (@@Ha).
The receiver will have the UTC parameters once an almanac has been downloaded from the satellites.
Default mode: UTC
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TIME MODE
Motorola Binary Format
• Poll current Time Mode:
@@AwxC<CR><LF>
x 1 out of range byte $ff C checksum Message length: 8 bytes
• Change current Time Mode:
@@AwmC<CR><LF>
m mode 0 = GPS
1 = UTC C checksum Message length: 8 bytes
• To either command:
@@AwmC<CR><LF>
m mode 0 = GPS
1 = UTC C checksum Message length: 8 bytes
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Input Command
Response Message
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1PPS CABLE DELAY
The GPS receiver outputs a 1PPS signal, the rising edge of which is placed at the top of the GPS or UTC one second time mark epoch as specified by the Time Mode. The 1PPS Cable Delay command allows the user to offset the 1PPS time mark in one nanosecond increments relative to the measurement epoch.
This parameter instructs the GPS receiver to output the 1PPS output pulse earlier in time to compensate for antenna cable delay. Up to one millisecond of equivalent cable delay can be removed. Zero cable delay is set for a zero-length antenna cable. The user should consult a cable data book for the delay per foot for the particular antenna cable used in order to compute the total cable delay needed for a particular installation.
This parameter also allows the user to adjust the position of the 1PPS to compensate for other system delays.
Range: 0.000 to 0.000999999 s Default value: 0.000 s Resolution: 1 ns
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1PPS CABLE DELAY
Motorola Binary Format
• Poll current 1PPS Cable Delay:
@@AzxxxxC<CR><LF>
xxxx 4 out of range bytes $ffffffff C checksum Message length: 11 bytes
• Change current 1PPS Cable Delay:
@@AzttttC<CR><LF>
tttt time offset in ns 0 .. 999,999 ns
(0.0 to 0.000999999 s) C checksum Message length: 11 bytes
• To either command:
@@AzttttC<CR><LF>
tttt time offset in ns 0 .. 999,999 ns
(0.0 to 0.000999999 s) C checksum Message length: 11 bytes
Input Command
Response Message
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POSITION LOCK PARAMETERS
This message allows the user to enter a threshold speed (default 0.5 m/sec) and a threshold distance (default 100 meters). The position will be locked if the current speed and distance traveled are both less than their respective thresholds. The parameters will be remembered through power cycles if battery back-up is provided.
Default values: Speed threshold = 0.5 m/s
Distance threshold = 100 m
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POSITION LOCK PARAMETERS
Motorola Binary Format
• Poll Current Position Lock Paramater:
@@AMxxxxC<CR><LF>
xxxx 4 ou t of ran ge byt es $ffffffff C checksum Message Length: 11 bytes
• Change Current Position Lock Paramaters:
@@AMifddC<CR><LF>
i integer part of
Speed threshold 0…255 m/s
f fractional part of speed
threshold 0…99 cm/s d distance threshold 0…65535 m C checksum Message Length: 11 bytes
• To either command:
@@AMifddC<CR><LF>
i integer part of speed
threshold 0…255 m/s f fractional part of speed
threshold 0…99 cm/s d distance threshold 0…65535 m C checksum
Message Length: 11 bytes
Input Command
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Response Message
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VELOCITY FILTER
The Velocity Filter command controls the velocity filtering feature. The velocity filter is useful in marine applications to filter out some of the wave motion in the reported velocity.
The filter is a single order alpha filter, where alpha is the value entered by the user ranging from 10 to 100 in increments of one. Alpha is then used in the filtered velocity solution representing 10% to 100% of the last calculated velocity, the remainder of which uses the previously reported velocity. If a value of 10 is entered for alpha, the maximum filtering will be done. An alpha value this low must be used with caution; the reported velocity will have extreme latency. An alpha value of 100 will result in no filtering, which is the default alpha value.
Default value: 100
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VELOCITY FILTER
Motorola Binary Format
• Poll current Velocity Filter parameter:
@@ANxC<CR><LF>
x 1 out of range byte $ff C checksum Message length: 8 bytes
• Change current Velocity Filter parameter:
@@ANfC<CR><LF>
f filter parameter 10 .. 100 (max. filtering to no filtering) C checksum Message length: 8 bytes
• To either command:
@@ANfC<CR><LF>
f filter parameter 10 .. 100 (max. filtering to no filtering) C checksum Message length: 8 bytes
Input Command
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Response Message
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RTCM PORT MODE
This command allows the user to select the baud rate of the RTCM serial input port (pin 8). The allowable baud rates are 2400, 4800 and 9600. The baud rate of this secondary port is independent of the status of the primary serial port.
Default mode: 9600 baud
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RTCM PORT MODE
Motorola Binary Format
• Poll current RTCM Port Mode:
@@AObC<CR><LF>
x 1 out of range byte $ff C checksum Message length: 8 bytes
• Change current RTCM Port Mode:
@@AObC<CR><LF>
b RTCM port baud rate 0 = 9600
1 = 4800
2 = 2400 C checksum Message length: 8 bytes
• To either command:
@@AObC<CR><LF>
b RTCM port baud rate 0 = 9600
1 = 4800
2 = 2400 C checksum Message length: 8 bytes
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Input Command
Response Message
Page 38
POSITION FILTER SELECT
This message enables or disables the position filter. The default value will be filter enabled. The selection will be remembered through power cycles if battery back-up is provided.
Default mode: Enabled
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POSITION FILTER SELECT
Motorola Binary Format
• Poll current Position Filter Selection:
@@AQxC<CR><LF>
x 1 out of range byte $ff C checksum Message Length: 8 bytes
• Change current Position Filter Selection:
@@AQsC<CR><LF>
s selection 0 = Disabled
1 = Enabled C checksum Message Length: 8 bytes
• To either command:
@@AQsC<CR><LF>
s selection 0 = Disabled
1 = Enabled C checksum Message Length: 8 bytes
Input Command
Response Message
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POSITION LOCK SELECT
This message enables or disables the position lock feature. The default value will be disabled. The selection will be remembered through power cycles if battery back-up is provided.
Default mode: Disabled
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POSITION LOCK SELECT
Motorola Binary Format
• Poll Current Position Lock Selec:
@@ASxC<CR><LF>
x 1 out of range byte $ff C checksum Message Length: 8 bytes
• Change Current Position Lock Select:
@@ASeC<CR><LF>
e selection 0 = Disabled
1 = Enabled C checksum Message Length: 8 bytes
• To either command:
@@ASeC<CR><LF>
e selection 0 = Disabled
1 = Enabled C checksum Message Length: 8 bytes
Response Message
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Input Command
Page 42
VISIBLE SATELLITE STATUS
This command requests the results of the most current satellite alert computation. The response message gives a summary of the satellite visibility status showing the number of visible satellites, the Doppler frequency and the location of the currently visible satellites (up to 12 satellites). The reference position for the most recent satellite alert is the current position coordinates. Note that these coordinates may not compare to the GPS receiver’s actual position when initially turned on, since the GPS receiver may have moved a great distance since it was last used.
Default mode: Polled
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VISIBLE SATELLITE STATUS
Motorola Binary Format
• Poll Visible Satellite Status:
@@BbmC<CR><LF>
m mode 0 = output response message once (polled)
1 = output response message when visibility data changes
C checksum Message length: 8 bytes
• To above command:
@@Bbniddeaasiddeaasiddeaasiddeaasiddeaasiddeaasid
deaasiddeaasiddeaasiddeaasiddeaasiddeaasC<CR><LF>
n number of visible sats 0 .. 12
For each visible satellite, up to n fields contain the following valid data i satellite ID 1 .. 32
dd Doppler in Hz -5000 .. 5000 e elevation in degrees 0 .. 90 aa azimuth in degrees 0 .. 359 s satellite health 0 = healthy and not removed
1 = healthy and removed 2 = unhealthy and not removed
3 = unhealthy and removed C checksum Message length: 92 bytes
Response Message
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Input Command
Page 44
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ALMANAC STATUS
This command requests almanac status information corresponding to the currently used satellite almanac data stored in RAM. The GPS receiver continually captures a complete new almanac to internal RAM while tracking satellites. If an existing almanac is stored in RAM on power-up, satellite visibility information will be available immediately. If no almanac data is stored in RAM on power-up, the receiver will download a new almanac and then compute satellite visibility information.
Almanac data is stored in memory only while main or battery back-up power is applied.
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ALMANAC STATUS
Motorola Binary Format
• Request Almanac Status Command:
@@BdmC<CR><LF>
m mode 0 = Output status once (polled)
1 = Output status when RAM almanac data
changes (continuous) C checksum Message Length: 8 bytes
• To above command:
@@BdvwtassssrrrrrrrrC<CR><LF>
RAM Almanac Status
v almanac valid flag 0 = no almanac in receiver
1 = valid almanac in receiver
w almanac week number (raw) 0 .. 255 (ICD-GPS-200)
t time of almanac (raw) 0 .. 147 (ICD-GPS-200)
a number of available SVs 0 .. 32
ssss SVs in almanac 0 = SV not available
32 bit binary field, 1 = SV included each bit represents one SVID (msb = SVID 32; lsb = SVID 1)
rrrrrrrr reserved
C checksum Message Length: 23 bytes
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Input Command
Response Message
Page 46
ALMANAC DATA OUTPUT
This command is used to output the almanac data. The user has the option of requesting the almanac data output one time (polled), or each time the almanac data changes (continuously).
The state of the mode parameter is stored in RAM. If the GPS receiver was continuously outputting the almanac data when turned off, and backup power is applied, then it will begin to output this message continuously again when the main power is reapplied. If backup power is not applied during power down, then the GPS receiver will start up in polled only mode.
Almanac data for the GPS satellites is transmitted in words 3 through 10 of subframe 5 (pages 1 through 25), and words 3 through 10 of subframe 4 (pages 2 through 5, 7 through 10, and 25) of the satellite broadcast data message. Refer to the ICD-GPS-200 for a detailed almanac data description.
The GPS receiver outputs the almanac data through a series of output messages, each of which is identified by the particular subframe and page numbers. The data fields of each individual message correspond to words 3 through 10 of the broadcast data. Each word contains 24 data bits.
The entire almanac data output consists of 34 output response messages corresponding to the 25 pages of subframe 5 and the 9 pages in subframe 4 that contain almanac data (pages 2 through 5, 7 through 10, and 25). The total message output for one output request is 1122 bytes including the @@Be prefix and the checksum, carriage return, and line feed for each output. The output message begins with subframe 5 page 1.
The GPS receiver will output about 750 bytes of message data for each one second output opportunity. If selected, the almanac response message is output until the total number of bytes sent in a one-second epoch exceeds 750. The remainder of the almanac message is sent in the next one-second epoch (up to the 750 byte limit per second) until all of the almanac data is output.
If the user issues this command and the GPS receiver does not contain an almanac, then the GPS receiver returns one response message with the subframe and page bytes equal to zero.
Default mode: Polled
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ALMANAC DATA OUTPUT
Motorola Binary Format
• Request Almanac Data:
@@BemC<CR><LF>
m mode 0 = output response message once (polled)
1 = output response message when almanac
data changes (continuous) C checksum Message length: 8 bytes
• To above command:
@@Cbspxxx...xxxC<CR><LF>
sp subframe/page subframe 5 / pages 1 – 25, or
subframe 4 / pages 2 – 5, 7 – 10, 25
xxx....xxx data words words 3 - 10, each word is 3 bytes long
(format per ICD-GPS-200) C checksum Message length: 33 bytes
NOTE: If an almanac is present in the GPS receiver, then the receiver outputs all of the
almanac pages. Otherwise, it returns one output message with all of the message bytes set to zero.
Input Command
Response Message
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EPHEMERIS DATA INPUT
This command will cause the receiver to accept satellite ephemeris data input via communications port 1 (pin 2). The receiver keeps the ephemerides decoded from all satellites in RAM, as long as the 3v BATT voltage is applied to the receiver and the ephemerides are still valid (t-toe < 4 hours).
The input format is identical to the format output by the previous Oncore Receivers using the output ephemeris command. This allows the same ephemeris output file to be used by the receiver for an ephemeris input file. The receiver echoes the input ephemeris data format message so the user can validate the ephemeris data with the new user supplied ephemeris upon completion of the receipt of a valid ephemeris.
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EPHEMERIS DATA INPUT
Motorola Binary Format
Input one ephemeris data page:
@@Bfixxx...xxxC<CR><LF>
i SVID 1 .. 37 xxx ... xxx ephemeris sf 1 – 3/words 3 – 10 (72 bytes per sat;
format per ICD-GPS-200)
C checksum
Message length: 80 bytes
• To above command:
@@Ccixxx...xxxC<CR><LF>
i SVID 1 .. 37 xxx ... xxx ephemeris sf 1 – 3/words 3 – 10 (72 bytes per sat;
format per ICD-GPS-200)
C checksum
Message length: 80 bytes
Response Message
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Input Command
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ALMANAC DATA INPUT
This input data command loads an almanac into the receiver’s random access memory (RAM) via the serial port. The entire almanac data message consists of 34 unique formatted messages that correspond to the subframe and page number of the almanac data (see GPS-ICD-200 for format description).
It is not necessary to input an almanac at power up. If backup power has been applied, the almanac will be retained in RAM. If the almanac is not available, it will be downloaded from the satellites. This can take anywhere from 15 to 30 minutes if satellites are tracked continuously. Manually loading an almanac will reduce the TTFF.
The GPS receiver echoes the input almanac data subframe and page numbers of messages received so the user can validate that each almanac slice has been accepted. It is not necessary nor is it recommended to wait for an echo before sending the next data page. The Oncore GPS receiver will collect an entire almanac in local storage, then check the almanac for validity. The receiver will update the internal almanac data with the new user-supplied almanac upon completion of the receipt of a valid almanac.
Any single input message that has an invalid subframe (i.e., not 4 or 5) will reset the almanac collection software so that the local collection of almanac data can begin fresh. Subframe 5 page 1 marks the beginning message and resets the collection process. The data for subframe 5 page 1 must appear first in the string of 34 commands that make up the total almanac input data. The order for the remaining data is not important.
At 9600 baud, the user can insert up to about 1K of data per second into the serial port. Consequently, the user should be aware that the 34 total messages (of 33 bytes each) that make up the almanac data will take longer than one second to input into the receiver.
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ALMANAC DATA INPUT
Motorola Binary Format
• Input one almanac data page:
@@Cbspxxx...xxxC<CR><LF>
sp subframe/page subframe 5 / pages 1 – 25, or
subframe 4 / pages 2 – 5, 7 – 10, 25
xxx....xxx data words words 3 – 10, each word is 3 bytes long
(format per ICD-GPS-200) C checksum Message length: 33 bytes
• To above command:
@@ChspC<CR><LF>
sp subframe/page subframe 5 / pages 1 – 25, or
subframe 4 / pages 2 – 5, 7 – 10, 25 C checksum Message length: 9 bytes
Input Command
Response Message
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UTC OFFSET STATUS
This message allows the user to request the UTC offset that is currently being used in the time solution. The value reported is the integer number of seconds between UTC and GPS time. If the offset is zero, the receiver does not currently have the portion of the almanac that contains the UTC parameters. The UTC parameters are broadcast by the satellites as part of the almanac, which is repeated every 12.5 minutes.
The message can be set to output either once (polled), or any time the UTC offset has been updated or changed from its previous value.
Default mode: Polled
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UTC OFFSET STATUS
Motorola Binary Format
• Request UTC Offset Status Message:
@@BomC<CR><LF>
m mode 0 = output UTC offset once (polled)
1 = output UTC offset every time it is updated C checksum Message length: 8 bytes
• To above command:
@@BouC<CR><LF>
u UTC offset in seconds -128 ..+127 C checksum Message length: 8 bytes
Input Command
Response Message
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UTC/IONOSPHERIC DATA OUTPUT
This message allows the user to request UTC and ionospheric data decoded from the Navigation Data Message.
Default mode: Polled
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UTC/IONOSPHERIC DATA OUTPUT
Motorola Binary Format
• Poll Current UTC/Ionosheric Data:
@@BpmC<CR><LF>
m mode 0 = output response once (polled)
1 = output response when either
UTC or ionospheric data changes
C checksum
• To above command:
@@CoabcdefghAAAAaaaadtwWnDC<CR><LF>
lonospheric Data (see ICD-GPS-200, Table 20-X for scale factors) a α
0
-128…+127 seconds
b α
1
-128…+127 seconds/semi-circle
c α
2
-128…+127 seconds/(semi-circle)
2
d α
3
-128…+127 seconds/(semi-circle)
3
e β
0
-128…+127 seconds
f β
1
-128…+127 seconds/semi-circle
g β
2
-128…+127 seconds/(semi-circle)
2
h β
3
-128…+127 seconds/(semi-circle)
3
UTC Data (see ICD-GPS-200, Table 20-IX for scale factors) AAAA A
0
-2,147,483,648…+2,147,483,647 seconds
aaaa A
1
-8,388,608…+8,388,607 seconds/second
d
t
LS
-128…+127 seconds
tt
ot
0…602,112 seconds
wWN
t
0…255 weeks
WWN
LSF
0…255 weeks
n DN 1…7 days D
t
LSF
-128…+127 seconds
C checksum Message Length: 29 bytes
Input Command
Response Message
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PSEUDORANGE CORRECTION INPUT
Enabling this option allows the GPS receiver to accept pseudorange correction messages from a differential master site receiver. The input message is structured to accept pseudorange and pseudorange-rate corrections for up to six satellites. The slave receiver uses the corrections in the input message by associating the satellite ID with the corresponding satellite (channel) that the slave is tracking. The user can specify up to 12 satellite corrections through the use of two back-to-back input commands. Back-to-back commands must be input with no time delay in between.
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PSEUDORANGE CORRECTION INPUT
Motorola Binary Format
Input pseudorange corrections (for up to six satellites):
@@Cetttippprrdippprrdippprrdippprrdippprrdi
ppprrdC<CR><LF>
ttt GPS time ref 0 .. 6047999 (0.0 .. 604799.9) i SVID 0..37
0 = not used 1-37 = SVID
ppp pseudorange corr -1,048,576 ..+1,048,576
0.01 meter resolution (-10485.76 ..+10485.76)
rr pseudorange-rate corr -4096 .. 4096
0.001 m/s resolution (-4.096 .. 4.096) d issue of data ephemeris 0 .. 255 C checksum Message length: 52 bytes
• To above command:
@@CkC<CR><LF>
C checksum Message length: 7 bytes
Input Command
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Response Message
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SET-TO-DEFAULTS
This command sets all of the GPS receiver parameters to their default values. Execution of this command results in all continuous messages being reset to polled only output and clears the almanac and ephemeris data. The time and date stored in the internal real-time clock will be reset to their default values.
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SET-TO-DEFAULTS
Motorola Binary Format
• Set the Oncore GPS receiver to default values:
@@CfC<CR><LF>
C checksum Message length: 7 bytes
• To above command:
@@CfC<CR><LF>
C checksum Message length: 7 bytes
Input Command
Response Message
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SWITCH TO NMEA
This command switches the serial data format on the primary port from Motorola binary to NMEA 0183. The baud rate of the port is switched from 9600 to 4800 and input commands are recognized in NMEA format only. Note that the default mode of all of the NMEA output messages is off. To initiate NMEA output, the input commands must be utilized.
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SWITCH TO NMEA
Motorola Binary Format
• Switch to NMEA format:
@@CimC<CR><LF>
m format 1 = NMEA C checksum Message length: 8 bytes
• There is no response message to this input command.
NOTE: The Motorola DOS controller software does not support NMEA messages.
Input Command
Response Message
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RECEIVER ID
The GPS receiver outputs an ID message upon request. The information contained in the ID string is self-explanatory. The model number can be used to determine the type of receiver installed.
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RECEIVER ID
Motorola Binary Format
• Poll Receiver ID string:
@@CjC<CR><LF>
C checksum Message length: 7 bytes
To above command:
Input Command
Response Message
@
# R T S X X X X T S
@ M
E W O
X X X E T
C O X
A F
X X X
j T X V R T M X X X X
O X E E W O
X X X
R X R
A D
X X X
C O X
R R E H X X X X
O L X # E E L D
X X X
P A X
V
W
X X X
Y
X X
D # R S X X X
R I X X # A
E
X X
I N X X
T
P R
X X
G C X X X E
/ I M X X
H . X X X
N A A
X
T
X X X
X
L N
X
X X X X X #
U O X
1 S X X X X X
# F P C
9 F
X X X X X
A T
9 T
X X X X X
C I
1 W S X X X X X
T O
O
X X X X X U N
1 P F
X X X X X R S
9 / T S X X X X X
9 N W O
X X X X D L
x
A F
X X X X A I
1
2
3
4
5
6
7
8
9
10
11
12
(cr) (lf)
(cr) (lf)
12345678910111213141516171819202122232425
(cr) (lf)
(cr) (lf)
(cr) (lf)
(cr) (lf)
(cr) (lf)
(cr) (lf)
(cr) (lf)
(cr) (lf)
(cr) (lf)
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UTC/IONOSPHERIC DATA INPUT
As well as being the response to the @@Bp message, this message allows the user to input UTC and ionospheric data into the receiver which is then echoed in the response.
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UTC/IONOSPHERIC DATA INPUT
Motorola Binary Format
• Change UTC/Ionospheric Data:
@@CoabcdefghAAAAaaaadtwWnDC<CR><LF>
Ionospheric Data (see ICD-GPS-200, Table 20-X for scale factors)
a α
0
-128…+127 seconds
b α
1
-128…+127 seconds/semi-circle
c α
2
-128…+127 seconds/(semi-circle)
2
d α
3
-128…+127 seconds/(semi-circle)
3
e β
0
-128…+127 seconds
f β
1
-128…+127 seconds/semi-circle
g β
2
-128…+127 seconds/(semi-circle)
2
h β
3
-128…+127 seconds/(semi-circle)
3
UTC Data (see ICD-GPS-200, Table 20-IX for scale factors)
AAAA A
0
-2,147,483,648…+2,147,483,647 seconds
aaaa A
1
-8,388,608…+8,388,607 seconds/second
d
t
LS
-128…+127 seconds
tt
ot
0…602,112 seconds
wWN
t
0…255 weeks
WWN
LSF
0…255 weeks n DN 1…7 days D
t
LSF
-128…+127 seconds
C checksum Message Length: 29 bytes
• To above command:
@@CoabcdefghAAAAaaaadtwWnDC<CR><LF>
Ionospheric Data (see ICD-GPS-200, Table 20-X for scale factors)
a α
0
-128…+127 seconds
b α
1
-128…+127 seconds/semi-circle
c α
2
-128…+127 seconds/(semi-circle)
2
d α
3
-128…+127 seconds/(semi-circle)
3
e β
0
-128…+127 seconds
f β
1
-128…+127 seconds/semi-circle
g β
2
-128…+127 seconds/(semi-circle)
2
h β
3
-128…+127 seconds/(semi-circle)
3
UTC Data (see ICD-GPS-200, Table 20-IX for scale factors)
AAAA A
0
-2,147,483,648…+2,147,483,647 seconds
aaaa A
1
-8,388,608…+8,388,607 seconds/second
d
t
LS
-128…+127 seconds
tt
ot
0…602,112 seconds wWN
t
0…255 weeks WWN
LSF
0…255 weeks n DN 1…7 days D
t
LSF
-128…+127 seconds
C checksum Message Length: 29 bytes
Input Command
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Response Message
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ASCII POSITION MESSAGE
The ASCII position output message contains position, time and receiver status information. The ASCII message may be a more convenient interface for certain applications. The units and style of the data is similar to NMEA output.
Default mode: Polled
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ASCII POSITION MESSAGE
Motorola Binary Format
• Request ASCII Position Message:
@@EqmC<CR><LF>
m mode 0 = output response message once (polled)
1..255 = response message output at indicated rate (continuous) 1 = once per second 2 = once every two seconds 255 = once every 255 seconds
C checksum
Message length: 8 bytes
• To above command:
@@Eq,mm,dd,yy,hh,mm,ss,dd,mm.mmmm,n,ddd,mm.mmmm,w, shhhhh.h,sss.s,hhh.h,m,t,dd.d,nn,rrrr,aa,CCC<CR><LF>
Date
mm month 01 .. 12 dd day 01 .. 31 yy year 99 .. 19
UTC Time
hh hours 00 .. 23 mm minutes 00 .. 59 ss seconds 00 .. 60
Latitude
dd degrees 00 .. 90 mm.mmmm minutes 00 .. 59.9999 n direction N = North, S = South
Longitude
ddd degrees 000 .. 180 mm.mmmm minutes 00 .. 59.9999 w direction W = West, E = East
Height
s sign of height +/­hhhhh.h height in meters -1000.0 .. 18,000.0
Velocity
sss.s speed in knots 000.0 .. 999.9 hhh.h heading in degrees 000.0 .. 359.9
Receiver status
m fix mode 0 = autonomous
1 = differential
t fix type 0 = no fix
1 = 2D fix 2 = 3D fix 3 = propagate mode
dd.d dilution of precision (DOP) 00.0...99.9
HDOP if 2D, PDOP if 3D nn number of satellites in use 00...37 rrrr reference station ID 0000..1023 aa age of differential data in s 00..60 CCC checksum 000...255
Message length: 96 bytes
Input Command
Response Message
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COMBINED POSITION
This message allows the user to enter an initial position estimate. The parameters will be remembered through power cycles if battery back-up is provided.
Default Values: Latitude = 0
0
Longitude = 0
0
Height = 0m (GPS Height)
Default mode: Polled
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COMBINED POSITION
Motorola Binary Format
Poll Combined Position Message:
@@GaxxxxxxxxxxxxxC<CR><LF>
xxxxxxxxxxxxx 13 out of range bytes $ffffffffffffffffffffffffffffffffffff C checksum Message Length: 20 bytes
Change current Position values:
@@GaaaaaoooohhhhtC<CR><LF>
aaaa latitude in mas -324,000,000 ..+324,000,000
(-90
0
to + 900)
oooo longitude in mas -648,000,000 ..+648,000,000
(-180
0
to + 1800) hhhh height -100,000 .. 1,800,000 cm (-1000 to 18000 m) t height type 0 = GPS, 1 = MSL C checksum Message Length: 20 bytes
• To either input command:
@@GaaaaaoooohhhhtC<CR><LF>
aaaa latitude in mas 324,000,000 .. +324,000,000
milliarcseconds (-90
0
to + 900)
oooo longitude in mas -648,000,000 ..+648,000,000
milliarcseconds (-180
0
to + 1800) hhhh GPS height in cm -100,000 .. 1,800,000 cm (-1000 to 18000 m) t height type 0 = GPS, 1 = MSL C checksum Message Length: 20 bytes
Input Command
Response Message
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COMBINED TIME
This message allows the user to enter an initial time estimate. The parameters will be remembered through power cycles if battery back-up is provided.
Default Values: 12:00:00 1/1/99
GMT offset = 0:00
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COMBINED TIME
Motorola Binary Format
• Poll Current Time Parameters:
@@GbxxxxxxxxxxC<CR><LF>
xxxxxxxxxx 10 out of range bytes $ffffffffffffffffffff Message Length: 17 bytes
• Change current Time Parameters:
@@GbmdyyhmsshmC<CR><LF>
Date
m month 1…12 d day 1…31 yy year 1982…2100
Time
h hours 0…23 m minutes 0…59 s seconds 0…59 s signed byte of GMT offset 00 = positive, ff = negative h hour of GMT offset 0…+23 m minutes of GMT offset 0…59 C checksum Message Length: 17 bytes
• To above command:
@@GbmdyyhmsshmC<CR><LF>
Date
m month 1…12 d day 1…31 yy year 1982…2100
Time
h hours 0…23 m minutes 0…59 s seconds 0…59 s signed byte of GMT offset 00 = positive, ff = negative h hour of GMT offset 0…+23 m minutes of GMT offset 0…59 C checksum Message Length: 17 bytes
Input Command
Response Message
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1PPS CONTROL
This message allows the user to choose how the 1PPS output in the receiver will behave. The selection will be remembered through power cycles if battery back-up is provided.
Default mode: Continuous
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1PPS CONTROL
Motorola Binary Format
• Poll Current 1PPS Setting:
@@GcxC<CR><LF>
x 1 out of range byte $ff C checksum Message Length: 8 bytes
• Change Current 1PPS Setting:
@@GcpC<CR><LF>
p 1PPS control 0 = 1PPS disabled
1 = 1PPS on continuously 2 = pulse active only when tracking
at least one satellite C checksum Message Length: 8 bytes
• To either input command:
@@GcpC<CR><LF>
p 1PPS control 0 = 1PPS disabled
1 = 1PPS on continuously 2 = pulse active only when tracking
at least one satellite C checksum Message Length: 8 bytes
Input Command
Response Message
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POSITION CONTROL
This message allows the user to choose in which positioning mode the receiver will operate. The selection will be remembered through power cycles if battery back-up is provided.
Default mode: Disabled
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POSITION CONTROL
Motorola Binary Format
• Poll Current Position Control Setting:
@@GdxC<CR><LF>
x 1 out of range byte $ff C checksum Message Length: 8 bytes
• Change Current Position Control Setting:
@@GdcC<CR><LF>
c control type 0 = no hold or normal positioning
1 = enable position hold
2 = enable altitude hold C checksum Message Length: 8 bytes
• To either input command:
@@GdcC<CR><LF>
c control type 0 = no hold or normal positioning
1 = enable position hold
2 = enable altitude hold C checksum Message Length: 8 bytes
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Response Message
Input Command
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LEAP SECOND STATUS
This command polls the receiver for leap second status infomation decoded from the Navigation Data message. The output response provides specific date and time information pertaining to any future leap second addition or subtraction. Present and future leap second values are also output rounded to the nearest integer value. This command has only a polled response, thus it must be requested each time leap second information is desired.
Leap seconds are occasionally inserted in UTC and generally occur on midnight UTC June 30 or midnight UTC December 31. The GPS control segment typically notifies GPS users of pending leap second insertions to UTC several weeks before the event.
When a leap second is inserted, the time of day will show a value of 60 in the seconds field. When a leap second is removed, the date will roll over at 58 seconds.
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LEAP SECOND STATUS
Motorola Binary Format
• Poll Current Leap Second Pending States:
@@GjC<CR><LF>
C checksum Message Length: 7 bytes
• To above comand:
@@GjpfyymdiffffhmsC<CR><LF>
p present leap second value f future leap second value yy year of the future leap second application m month of the future leap second application d day of the future leap second application i integer part of current UTC offset (seconds) ffff fraction part of current UTC offset (nanoseconds) h hour of the leap second application 0...23 m minute of the leap second application 0...59 s second of the leap second application 0...60 C checksum Message Length: 21 bytes
Response Message
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Input Command
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ID TAG
This message sets or defaults the ID tag. The ID tag shall be remembered through power cycles if battery back-up is provided.
If all six ASCII characters or ID tag are pluses (+), the ID tag will be the receiver serial number read out of the manufacturing data block. If all six are spaces, the ID tag will remain unchanged. Any other combination of ASCII characters (from 0x20 to 0x7e) will be construed as a new ID tag. Any out of range character will also cause the ID tag to remain unchanged.
The ID tag is also output in the 12-channel Position/Status/Data Message (@@Ha). status message.
Default value: Receiver Serial Number
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ID TAG
Motorola Binary Format
• Poll current ID tag:
@@GkvvvvvvC<CR><LF>
vvvvvv ASCII ID tag 6 ASCII space characters (0x20) C checksum Message Length: 13 bytes
Change current ID Tag:
@@GkvvvvvvC<CR><LF>
vvvvvv ASCII ID tag ++++++ (0x2B) = receiver serial number
6 characters 0x20 to 0x7e
C checksum Message Length: 13 bytes
• To above Command:
GkvvvvvvC<CR><LF>
vvvvvv ASCII ID tag 6 characters 0x20 to 0x7e
C checksum Message Length: 13 bytes
Response Message
Input Command
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POSITION/STATUS/DATA MESSAGE (12 CHANNEL)
This message provides position and channel related data to the user at a specified update rate. The output rate will be remembered through a power cycle if battery back-up is provided.
Default mode: Polled
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POSITION/STATUS/DATA MESSAGE (12 CHANNEL)
Motorola Binary Format
• Request Position/Status/Data 12 Channel Output:
@@HarC<CR<LF>
r Output Rate 0 = output response msg once (polled)
1...255 = response msg output at indicated rate (continuous) 1 = Once per second 2 = Once every 2 seconds 255 = Once every 255 seconds
C checksum Message Length: 8 bytes
• To above command:
@@Hamdyyhmsffffaaaaoooohhhhmmmmaaaaoooohhhhmmmm
VVvvhhddntimsidd (repeat imsidd for remaining 11 channels)ssrrccooooTTushmvvvvvvC<CR><LF>
Date
m month 1…12 d day 1…31 yy year 1980…2079
Time
h hours 0…23 m minutes 0…59 s seconds 0…60 ffff fractional seconds 0…999999999 nanoseconds
Position (Filtered or Unfiltered Following Filter Select)
aaaa latitude in mas -324000000…324000000 (-90
0
to + 900)
oooo longitude in mas -648000000…648000000 (-180
0
to + 1800) hhhh GPS height in cm -100000…+1800000 (-1000 to +18000m) mmmm MSL height in cm -100000…+1800000 (-1000 to +18000m)
Position (Always Unfiltered)
aaaa latitude in mas -324000000…324000000 (-90
0
to + 900)
oooo longitude in mas -648000000…648000000 (-180
0
to + 1800) hhhh GPS height in cm -100000…+1800000 (-1000 to +18000m) mmmm MSL height in cm -100000…+1800000 (-1000 to +18000m)
Speed/Heading
VV 3D speed in cm/s 0…51400 (0.0 to 514 m/s) vv 2D speed in cm/s 0…51400 (0.0 to 514 m/s) hh 2D heading 0…3599 tenths of degrees (0.0 to 359.9
0
)
Input Command
Response Message
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POSITION/STATUS/DATA MESSAGE (12 CHANNEL)
Motorola Binary Format
Geometry
dd current DOP(0.1 res) 0…999 (0.0 to 99.9 DOP)
(PDOP for 3D fix, HDOP for 2D fix, 0 No Fix)
Satellite Data
n number of visible satellites 0…12 t number of tracked satellites 0…12
Channel Data
i SVID 0…37 m mode 0…8 s signal strength 0…255 i IODE 0…255 dd channel status (16 bits) (msb) Bit 15: Reserved
Bit 14: Reserved Bit 13: Reserved Bit 12: Reserved Bit 11: Used For Time Bit 10: Differential Corrections Available Bit 9: Invalid Data Bit 8: Parity Error Bit 7: Used For Position Fix Bit 6: Satellite Momentum Alert Flag Bit 5: Satellite Anti-Spoof Flag Set Bit 4: Satellite Reported Unhealthy Bits 3-0: Satellite Accuracy as follows
(per para 20.3.3.3.1.3 ICD-GPS-200) 0000 (0) 0.00 <URA<=2.40 0001 (1) 2.40 <URA<=3.40 0010 (2) 3.40 <URA<=4.85 0011 (3) 4.85 <URA<=6.85 0100 (4) 6.85 <URA<=9.65 0101 (5) 9.65 <URA<=13.65 0110 (6) 13.65 <URA<=24.00 0111 (7) 24.00 <URA<=48.00 1000 (8) 48.00 <URA<=96.00 1001 (9) 96.00 <URA<=192.00 1010 (10) 192.00 <URA<= 384.00 1011 (11) 384.00 <URA<=768.00 1100 (12) 768.00 <URA<=1536.00 1101 (13) 1536.00 <URA<=3072.00 1110 (14) 3072.00 <URA<=6144.00
1111 (15) 6144.00 <URA* *No accuracy prediction is available – unauthorized users are advised to use the SV at their own risk)
Response Message
(Continued)
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POSITION/STATUS/DATA MESSAGE (12 CHANNEL)
Motorola Binary Format
ss receiver status (msb) Bit 15-13: 111 = 3D Fix
110 = 2D Fix 101 = Propagate Mode 100 = Position Hold 011 = Acquiring Satellites 010 = Bad Geometry 001 = Reserved
000 = Reserved Bit 12-10: Reser ved Bit 9: Fast Acquisition Position Bit 8: Filter Reset To Raw GPS Solution Bit 7: Cold Start (no almanac, almanac out of date or
have almanac but time or position unknown) Bit 6: Differential Fix Bit 5: Position Lock Bit 4: Autosurvey Mode Bit 3: Insufficient Visible Satellites Bit 2-1: Antenna Sense 00 = OK
01 = OC 10 = UC 11 = NV
Bit 0: Code Location 0 = EXTERNAL
1 = INTERNAL
rr Reserved
Oscillator and Clock Parameters
cc clock bias -32768…32767 ns oooo oscillator offset 0…250000 Hz TT temperature -110…250 half-degrees C
(-55.0…+125.0
0
C)
Response Message
(Continued)
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POSITION/STATUS/DATA (12 CHANNEL)
Motorola Binary Format
UTC Parameters u Bit 7: UTC mode 1 = enabled
0 = disabled
Bit 6: UTC offset 1 = decoded
0 = NOT decoded
Bits 5 – 0: Present UTC offset value, range –32…+31;
from GPS time* (ignore if Bit 6 = 0).
GMT Offset s signed byte of GMT offset 00 = positive, ff = negative h hour of GMT offset 0…+23 m minute of GMT offset 0…59 vvvvvv ID tag 6 characters (0x20 to 0x7e) C checksum Message Length: 154 bytes
* Represents UTC time offset from GPS time. Offset is rounded to the nearest integer value
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Response Message
(Continued)
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SHORT POSITION MESSAGE (12 CHANNEL)
This is a shortened position message provided to the user at a specified update rate. The selected rate will be remembered through a power cycle if battery back-up is provided.
Default mode: Polled
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SHORT POSITION/ MESSAGE (12 CHANNEL)
Motorola Binary Format
• Request Short Position Data Message:
@@HbrC<CR<LF>
r Output Rate 0 = output response msg once (polled)
1...255 = response msg output at indicated rate (continuous) 1 = Once per second 2 = Once every 2 seconds
255 = Once every 255 seconds C checksum Message Length: 8 bytes
• To above command:
@@HbmdyyhmsffffaaaaoooohhhhmmmmVVvvhhddntssrrvvv
vvvC<CR><LF>
Date
m month 1…12 d day 1…31 yy year 1980…2079
Time
h hours 0…23 m minutes 0…59 s seconds 0…60 ffff fractional seconds 0…999999999 ns
Position (Filtered or Unfiltered Following the Filter Select)
aaaa latitude in mas -324000000…324000000 (-90° to + 90°) oooo longitude in mas -648000000…648000000 (-180° to + 180°) hhhh GPS height in cm -100000…+1800000 (-1000 to +18000m) mmmm MLS height in cm -100000…+1800000 (-1000 to +18000m)
Speed/Heading VV 3D speed in cm/s 0…51400 (0.0 to 514 m/s) vv 2D speed in cm/s 0…51400 (0.0 to 514 m/s) hh 2D heading 0…3599 tenths of degrees (0.0 to 359.9
0
)
Response Message
Input Command
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SHORT POSITION/ MESSAGE (12 CHANNEL)
Motorola Binary Format
Geometry
dd current DOP 0…999 (0.0 to 99.9 DOP)
(0.1 res) (PDOP for 3D fix, HDOP for 2D fix,
0 otherwise)
Satellite Data
n number of visible satellite 0…12 t number of tracked satellite 0…12 ss receiver status (msb) Bit 15-13: 111 = 3D Fix
110 = 2D Fix 101 = Propagate Mode 100 = Position Hold 011 = Acquiring Satellites 010 = Bad Geometry 001 = Reserved
000 = Reserved Bit 12-10: Reserved Bit 9: Fast Acquisition Position Bit 8: Filter Reset To Raw GPS Solution Bit 7: Cold Start (no almanac, almanac out
of date or have almanac but time or
position unknown) Bit 6: Differential Fix Bit 5: Position Lock Bit 4: Autosurvey Mode Bit 3: Insufficient Visible Satellites Bit 2-1: Antenna Sense 00 = OK
01 = OC 10 = UC 11 = NV
Bit 0: Code Location 0 = EXTERNAL
1 = INTERNAL rr Reserved vvvvvv ID tag 6 characters (0x20 to 0x7e) C checksum Message Length: 54 bytes
Response Message
(Continued)
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SELF-TEST MESSAGE (12 CHANNEL)
The GPS receiver user has the ability to perform an extensive self-test. The tests that are accomplished during the commanded self-test are as follows:
• Antenna connection
• RTC communication and time
• Temperature sensor
• RAM
• FLASH ROM
• Correlator IC
The output of the self-test command is a 24-bit field, where each bit of the field represents Pass/Fail condition for each parameter tested. When the self-test is initiated, the next output message may not be the response. The self-test may take up to ten seconds to execute. Once the self-test is complete, the acquisition process starts all over as if the receiver were first powered on. The date, time, position, almanac and ephemeris information is all retained.
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SELF-TEST MESSAGE (12 CHANNEL)
Motorola Binary Format
• Request Self-Test:
@@IaC<CR><LF>
C checksum Message Length: 7bytes
• To above command:
@@IasssC<CR><LF>
sss self test results
(msb) Bit 23-22 antenna sense
00 = OK 01 = OC 10 = UC
11 = NV Bit 21: RTC comm & time Bit 20: temperature sensor Bit 19: spare Bit 18: RAM Bit 17: ROM Bit 16: 1 KHz presence Bit 15: spare Bit 14: Temperature Sensor Data Checksum Bit 13: Oscillator Data Checksum Bit 12: Manufacturing Data Checksum Bit 11: channel 12 correlation test Bit 10: channel 11 correlation test Bit 9: channel 10 correlation test Bit 8: channel 9 correlation test Bit 7: channel 8 correlation test Bit 6: channel 7 correlation test Bit 5: channel 6 correlation test Bit 4: channel 5 correlation test Bit 3: channel 4 correlation test Bit 2: channel 3 correlation test Bit 1: channel 2 correlation test Bit 0: channel 1 correlation test
C checksum Message Length: 10 bytes
Response Message
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Input Command
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SYSTEM POWER-ON FAILURE
Immediately after power-up, the Oncore’s ROM is tested. If this test does not pass, the Oncore firmware will not execute its positioning algorithms. Rather, it will continuously output this message at a 10 second rate. Receipt of this message indicates that the receiver will need to be repaired and/or reprogrammed. This feature keeps the receiver from being utilized when the ROM is, for some reason, compromised and therefore, unreliable. This feature helps to protect the integrity of the application.
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SYSTEM POWER-ON FAILURE
Motorola Binary Format
@@SzcC<CR><LF>
c constant equal to 0 C checksum Message length: 8 bytes
Output Command
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GPGGA (GPS FIX DATA)
This command enables the GPGGA GPS Fix Data message and determines the rate at which the information is transmitted. The periodic rate field (yyyy) instructs the receiver either to output this message once (polled), or to output this message at the indicated update rate (continuously). Once the receiver is set to continuous output, the continuous flow can be stopped by sending a one-time (polled) output request. The receiver will output the response one final time, and then terminate any further message outputs. The value of the periodic rate is retained through a power cycle only if battery backup power is applied.
If the receiver has just powered up and has yet to compute a position fix (GPS quality indicator field (q) is zero), then the time (hhmmss.ss) and HDOP (y.y) fields will be nulled. If the receiver is not currently computing a position fix sometime after the first fix, (GPS quality indicator field (q) is zero), the time field (hhmmss.ss) will be frozen and the HDOP field (y.y) will be nulled. If the receiver is not using differential GPS (GPS quality indicator field (q) is not two), then the age of differential data (t.t) and differential reference station ID (iiii) fields will be nulled.
NOTE: Height reported in the GPGGA message is GPS height, and the geoidal
separation field (g.g) will always be null since the M12 Oncore does not contain this information.
Default mode: Disabled
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GPGGA (GPS FIX DATA)
NMEA-0183 Format
• Set response message rate:
$PMOTG,GGA,yyyyCC<CR><LF>
yyyy update rate 0 .. 9999 seconds CC optional checksum
• To above command:
$GPGGA,hhmmss.ss,ddmm.mmmm,n,dddmm.mmmm,e,q,ss, y.y,a.a,z,g.g,z,t.t,iiii*CC<CR><LF>
hhmmss.ss UTC of position fix
hh hours 00 .. 24 mm minutes 00 .. 59 ss.ss seconds 00.000 .. 59.99
ddmm.mmmm,n latitude
dd degrees 00 .. 90 mm.mmm minutes 00.000 .. 59.999 n direction N = North
S = South
dddmm.mmmm,e longitude
ddd degrees 000 .. 180 mm.mmm minutes 00.00 .. 59.9999 e direction E = East
W = West
q GPS status indicator 0 = GPS not available
1 = GPS available
2 = GPS differential fix ss number of sats being used 0 .. 12 y.y HDOP a.a,z antenna height
a.a height z units M = meters
g.g,z geoidal separation
g.g height
z units M = meters t.t age of differential data iiii differential reference 0000 . . 1023
station ID
CC checksum
Response Message
Input Command
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GPGLL (GEOGRAPHIC POSITION-LATITUDE/LONGITUDE)
This command enables the GPGLL Geographic Position-Latitude/Longitude message and determines the rate at which the information is transmitted. The periodic rate field (yyyy) instructs the receiver either to output this message once (polled), or to output this message at the indicated update rate (continuously). Once the receiver is set to continuous output, the continuous flow can be stopped by sending a one-time (polled) output request. The receiver will output the response one final time, and then terminate any further message outputs. The value of the periodic rate is retained through a power cycle only if battery backup power is applied.
If the receiver has just powered up and has yet to compute a position fix (GPS quality indicator (q) is zero), then the time field (hhmmss.ss) will be nulled. If the receiver is not computing a position fix sometime after the first fix (GPS quality indicator (q) is zero), then the time field (hhmmss.ss) will be frozen.
Default mode: Disabled
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Response Message
Input Command GPGLL (GEOGRAPHIC POSITION-LATITUDE/LONGITUDE)
NMEA-0183 Format
• Set response message rate:
$PMOTG,GLL,yyyyCC<CR><LF>
yyyy update rate 0 .. 9999 seconds CC optional checksum
• To above command:
$GPGLL,ddmm.mmmm,n,dddmm.mmmm,e,hhmmss.ss,a*CC<CR><LF>
ddmm.mmmm,n latitude
dd degrees 00 .. 90 mm.mmmm minutes 00.000 .. 59.9999 n direction N = North
S = South
dddmm.mmmm,e longitude
ddd degrees 00 ..180 mm.mmmm minutes 00.000 .. 59.9999 e direction E = East
W = West
hhmmss.ss UTC of position fix
hh hours 00 ..24 mm minutes 00 .. 59 ss.ss seconds 00.00 .. 59.99 a status A = valid
V = invalid
CC checksum
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GPGSA (GPS DOP AND ACTIVE SATELLITES)
This command enables the GPGSA GPS DOP and Active Satellites message and determines the rate at which the information is transmitted. The periodic rate field (yyyy) instructs the receiver either to output this message once (polled), or to output this message at the indicated update rate (continuously). Once the receiver is set to continuous output, the continuous flow can be stopped by sending a one-time (polled) output request. The receiver will output the response one final time, and then terminate any further message outputs. The value of the periodic rate is retained through a power cycle only if battery backup power is applied.
If the receiver is not computing a position fix (mode field (b) is one), then the xDOP fields (p.p, q.q, r.r) will be nulled. If the receiver is computing a 2-D position fix (mode field (b) is two), then the PDOP field (p.p) and the VDOP field (r.r) will be nulled. Only satellite IDs used in the solution are output; the remaining satellite ID fields will be nulled.
Default mode: Disabled
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GPGSA (GPS DOP AND ACTIVE SATELLITES)
NMEA-0183 Format
• Set response message rate:
$PMOTG,GSA,yyyyCC<CR><LF>
yyyy update rate 0 .. 9999 seconds CC optional checksum
• To above command:
$GPGSA,a,b,cc,dd,ee,ff,gg,hh,ii,jj,kk,mm,nn,oo, p.p,q.q,r.r*CC<CR><LF>
a sat acquisition mode M = manual (forced to operate in 2D or 3D mode)
A = automatic (auto switch 2D/3D)
b positioning mode 1 = fix not available
2 = 2D
3 = 3D cc, dd, ee, SVIDs used in solution (null for unused fields) ff, gg, hh, ii, jj, kk, mm, nn, oo
p.p PDOP 1.0 .. 9.9 q.q HDOP 1.0 .. 9.9 r.r VDOP 1.0 .. 9.9 CC checksum
Input Command
Response Message
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GPGSV (GPS SATELLITES IN VIEW)
This command enables the GPGSV GPS Satellites in View message and determines the rate at which the information is transmitted. The periodic rate field (yyyy) instructs the receiver either to output this message once (polled), or to output this message at the indicated update rate (continuously). Once the receiver is set to continuous output, the continuous flow can be stopped by sending a one-time (polled) output request. The receiver will output the response one final time, and then terminate any further message outputs.
If the receiver is not tracking the satellite, the SNR field (ss) will be nulled. Further, an entire group — satellite ID field (ii), elevation field (ee), azimuth field (aaa), and SNR field (ss) — will be nulled if not needed.
NOTE: The SNR field (ss) is the same as the C/No value in the
Position/Status/Data Message and the Short Position Message.
Default mode: Disabled
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