GlobalSat ET-332 User Manual

環天衛星科技股份有限公司

PRODUCT USER MANUAL

GPS ENGINE BOARD

ET-332

GlobalSat Technology Corporation

台北縣中和市建一路

16, No.186,Chien 1 Road, 235Chung Ho City,Taipei Hsien, Taiwan ,R.O.C.

186號16樓(

遠東世紀廣場

)

Tel: 886-2-8226-3799(Rep.) Fax: 886-2-8226-3899 Web: www.globalsat.com.tw E-mail: service@globalsat.com.tw

Features:

SiRF starⅢ high performance GPS Chip Set Very high sensitivity (Tracking Sensitivity: -159 dBm) Extremely fast TTFF (Time To First Fix) at low signal level Compact size (40.5mm * 35 mm * 10mm) suitable for space-sensitive application Support NMEA 0183 and SiRF binary protocol Build-in SuperCap to reserve system data for rapid satellite acquisition. Cold start under 40 seconds, average Hot start under 1 seconds, average

Specification:

General

Chipset SiRF StarⅢ Frequency L1, 1575.42 MHz C/A code 1.023 MHz chip rate Channels 20 channel all-in-view tracking Sensitivity -159 dBm

Accuracy

Position 10 meters, 2D RMS 5 meters, 2D RMS, WAAS enabled Velocity 0.1 m/s Time 1us synchronized to GPS time

Datum

Default WGS-84

Acquisition Time

Reacquisition 0.1 sec., average Hot start 1 sec., average Warm start 38 sec., average Cold start 42 sec., average

Dynamic Conditions

Altitude 18,000 meters (60,000 feet) max Velocity 515 meters /second (1000 knots) max

Acceleration Less than 4g Jerk 20m/sec **3

Power

Main power input 3.8V ~ 6.5V DC input Power consumption 75mA (Continuous mode) 30mA (Trickle power mode)

Interface

Baud rate 4,800 to 57,600 bps adjustable Output message SiRF binary or

NMEA 0183 GGA, GSA, GSV, RMC, VTG, GLL

Environmental

Operating Temp -40℃ to +85℃

Physical Characteristics

Interface Connection

* Pin-out of the 12-pin interface conne ctor

Pin Number Name

1

2

3

4

5

6

7

VBAT

GND

VDC

PBRES

GPIO1

TXA

RXA

Description

Ground

Backup Battery

3.8V~5.5V DC Power Input

Push Button Reset Input (Active Low) Input

(Reserved)

Serial Data Output A (GPS Data)

Serial Data Input A (Command)

Type

Input

Output

Input

8

9

10

11

12

TIMEMARK

GND

SELECT

GND

Ground

(Reserved)

1PPS Time Mark Output

Ground

Interface description

* VDC (DC power input):

This is the main DC supply for a 3.8V ~ 5.5V power module board.

* VBAT (Backup battery):

Output

This is the battery backup input that powers the SRAM and RTC when main power is removed .Typical current draw is 10uA. Without an external backup battery, the module/engine board will execute a cold star after every turn on. To achieve the

faster start-up offered by a hot or warm start, a battery backup must be connected. To maximize battery lifetime, the battery voltage should be between 2.5v and 3.6v.

* PBRES (Push button reset):

This pin provides an active-low reset input to the engine board. It causes the engine board to reset and start searching for satellites.

* SELECT :

Do not connect.

* TXA :

This is the main transmits channel for outputting navigation and measurement data to user’s navigation software or user written software. Output TTL level , 0V ~ 2.85V

* RXA :

This is the main receive channel for receiving software commands to the engine board from SiRFdemo software or from user written software. Normally this pin must be kept in high, and if you don’t use this pin please connect a resistor to pull high.

* Time mark :

This pin provides one pulse-per-second output from the engine board that is

synchronized to GPS time.

* GND :

GND provides the ground for the engine board. Connect all grounds.

SOFTWARE COMMAND

Message ID

$GPGGA

GGA protocol header

UTC Time

161229.487

hhmmss.sss

Latitude

3723.2475

ddmm.mmmm

N/S Indicator

N N=north or S=south

Longitude

12158.3416

dddmm.mmmm

E/W Indicator

W E=east or W=west

Position Fix Indicator

1 See Table B-3

Satellites Used

07 Range 0 to 12

HDOP

1.0 Horizontal Dilution of Precision

MSL Altitude1

9.0

meters

Units

M

meters

Geoid Separation1

meters

Units

M

meters

Age of Diff. Corr.

second

Null fields when DGPS is not used

Diff. Ref. Station ID

0000

Checksum

*18

End of message termination

Value

Description

0

Fix not available or invalid

1

GPS SPS Mode, fix valid

2

Differential GPS, SPS Mode , fix valid

3

GPS PPS Mode, fix valid

NMEA Output Command

GGA-Global Positioning System Fixed Data

Table B-2 contains the values for the following example:

$GPGGA,161229.487,3723.2475,N,12158.3416,W,1,07,1.0,9.0,M,,,,0000*18

Table B-2 GGA Data Format

SiRF Technology Inc. does not support geoid corrections. Values are WGS84 ellipsoid heights.

Table B-3 Position Fix Indicator

Name

Example

Units

Description

Message ID

$GPGLL

G LL protocol header

Latitude

3723.2475

ddmm.mmmm

N/S Indicator

n N=north or S=south

Longitude

12158.3416

dddmm.mmmm

E/W Indicator

W E=east or W=west

UTC Position

161229.487

hhmmss.sss

Status

A A=data valid or V=data not valid

Checksum

*2C

End of message termination

GLL-Geographic Position-Latitude/Longitude

Table B-4 contains the values for the following example:

$GPGLL,3723.2475,N,12158.3416,W,161229.487,A*2C

Table B-4 GLL Data Format

GSA-GNSS DOP and Active Satellites Table B-5 contains the values for the following example:

$GPGSA,A,3,07,02,26,27,09,04,15,,,,,,1.8,1.0,1.5*33

Table B-5 GSA Data Format

Name Example Units Description

Message ID $GPGSA GSA protocol header Mode1 A See Table B-6 Mode2 3 See Table B-7 Satellite Used1 07 Sv on Channel 1 Satellite Used1 02 Sv on Channel 2 ….. Satellite Used1 Sv on Channel 12 PDOP 1.8 Position dilution of Precision HDOP 1.0 Horizontal dilution of Precision VDOP 1.5 Vertical dilution of Precision Checksum *33 <CR><LF> End of message termination

1. Satellite used in sol ution.

Table B-6 Mode1

Value Description

M Manual-forced to operate in 2D or 3D mode A 2Dautomatic-allowed to automatically switch 2D/3D

Table B-7 Mode 2

Value Description

1 Fix Not Available 2 2D 3 3D

GSV-GNSS Satellites in View

Message ID

$GPGSV

GSV protocol header

Number of Messages1

2 Range 1 to 3

Message Number1

1 Range 1 to 3

Satellites in View

07

Satellite ID

07 Channel 1(Range 1 to 32)

Elevation

79

degrees

Channel 1(Maximum90)

Azimuth

048

degrees

Channel 1(True, Range 0 to 359)

SNR(C/No)

42

dBHz

Range 0 to 99,null when not tracking

…….

Satellite ID

27 Channel 4 (Range 1 to 32)

Elevation

27

Degrees

Channel 4(Maximum90)

Azimuth

138

Degrees

Channel 4(True, Range 0 to 359)

SNR(C/No)

42

dBHz

Range 0 to 99,null when not tracking

Checksum

*71

End of message termination

Message ID

$GPRMC

RMC protocol header

UTC Time

161229.487

hhmmss.sss

Status

A A=data valid or V=data not valid

Latitude

3723.2475

ddmm.mmmm

N/S Indicator

N N=north or S=south

Longitude

12158.3416

dddmm.mmmm

E/W Indicator

W E=east or W=west

Speed Over Ground

0.13

knots

Course Over Ground

309.62

degrees

True

Date

120598

ddmmyy

Magnetic Variation2

degrees

E=east or W=west

Checksum

*10

End of message termination

Table B-8 contains the values for the following example:

$GPGSV,2,1,07,07,79,048,42,02,51,062,43,26,36,256,42,27,27,138,42*71 $GPGSV,2,2,07,09,23,313,42,04,19,159,41,15,12,041,42*41 Table B-8 GSV Data Format

Depending on the number of satellites tracked multiple messages of GSV data may be required.

RMC-Recommended Minimum Specific GNSS Data

Table B-10 contains the values for the following example:

$GPRMC,161229.487,A,3723.2475,N,12158.3416,W,0.13,309.62,120598,,*10 Table B-10 RMC Data Format

SiRF Technology Inc. does not support magnetic declination. All “course over ground” data are geodetic WGS48 directions.

Message ID

$GPVTG

VTG protocol header

Course

309.62

degrees

Measured heading

Reference

T True

Course

degrees

Measured heading

Reference

M Magnetic

Speed

0.13

knots

Measured horizontal speed

Units

N Knots

Speed

0.2

Km/hr

Measured horizontal speed

Units

K Kilometers per hour

Checksum

*6E

End of message termination

VTG-Course Over Ground and Ground Speed

$GPVTG,309.62,T,,M,0.13,N,0.2,K*6E

NMEA Input Command

A). Set Serial Port ID:100 Set PORTA parameters and protocol

This command message is used to set the protocol(SiRF Binary, NMEA, or USER1) and/or the communication parameters(baud, data bits, stop bits, parity). Generally,this command would be used to switch the module back to SiRF Binary protocol mode where a more extensive command message set is available. For example,to change navigation parameters. When a valid message is received,the parameters will be stored in battery backed SRAM and then the receiver will restart using the saved parameters.

Format:

$PSRF100,<protocol>,<baud>,<DataBits>,<StopBits>,<Parity>*CKSUM <CR><LF>

<protocol> 0=SiRF Binary, 1=NMEA, 4=USER1 <baud> 1200, 2400, 4800, 9600, 19200, 38400 <DataBits> 8,7. Note that SiRF protocol is only valid f8

Data bits <StopBits> 0,1 <Parity> 0=None, 1=Odd, 2=Even

Example 1: Switch to SiRF Binary protocol at 9600,8,N,1

$PSRF100,0,9600,8,1,0*0C<CR><LF>

Example 2: Switch to User1 protocol at 38400,8,N,1

$PSRF100,4,38400,8,1,0*38<CR><LF>

**Checksum Field: The absolute value calculated by exclusive-OR the

8 data bits of each character in the Sentence,between, but excluding “$” and “*”. The hexadecimal value of the most significant and least significant 4 bits of the result are convertted to two ASCII characters (0-9,A-F) for transmission. The most

significant character is transmitted first.

**<CR><LF> : Hex 0D 0A

B). Navigation lnitialization ID：101 Parameters required for start

This command is used to initialize the module for a warm start, by providing current position （in X, Y, Z coordinates）,clock offset, and time. This enables the receiver to search for the correct satellite signals at the correct signal parameters. Correct initialization parameters will enable the receiver to acquire signals more quickly, and thus, produce a faster navigational solution.

When a valid Navigation Initialization command is received, the receiver will restart using the input parameters as a basis for satellite selection and acquisition.

Format：

$PSRF101,<X>,<Y>,<Z>,<ClkOffset>,<TimeOfWeek>,<WeekNo>,<chnlCount>,<R esetCfg> *CKSUM<CR><LF>

<X> X coordinate position

INT32

<Y> Y coordinate position

INT32

<Z> Z coordinate position

INT32

<ClkOffset> Clock offset of the receiver in Hz, Use 0 for

last saved value if available. If this is unavailable, a default value of 75000 for GSP1, 95000 for GSP 1/LX will be used.

INT32

<TimeOf Week> GPS Time Of Week

UINT32

<WeekNo> GPS Week Number

UINT16 （ Week No and Time Of Week calculation

from UTC time）

<chnlCount> Number of channels to use.1-12. If your

CPU throughput is not high enough, you

could decrease needed throughput by reducing the number of active channels

UBYTE

<ResetCfg> bit mask

0×01=Data Valid warm/hotstarts=1 0×02=clear ephemeris warm start=1 0×04=clear memory. Cold start=1 UBYTE

Example: Start using known position and time. ＄PSRF101,-2686700,-4304200,3851624,96000,497260,921,12,3*7F

C). Set DGPS Port ID:102 Set PORT B parameters for DGPS input

This command is used to control Serial Port B that is an input only serial port used to receive RTCM differential corrections. Differential receivers may output corrections using different communication parameters. The default communication parameters for PORT B are 9600 Baud, 8data bits, 0 stop bits, and no parity. If a DGPS receiver is used which has different communication parameters, use this command to allow the receiver to correctly decode the data. When a valid message is received, the parameters will be stored in battery backed SRAM and then the receiver will restart using the saved parameters. Format: ＄PSRF102,<Baud>,<DataBits>,<StopBits>,<Parity>*CKSUM<CR><LF>

<baud> 1200,2400,4800,9600,19200,38400 <DataBits> 8 <StopBits> 0,1 <Parity> 0=None,Odd=1,Even=2

Example: Set DGPS Port to be 9600,8,N,1

＄PSRF102,9600,8,1.0*12

D). Query/Rate Control ID:103 Query standard NMEA message and/or set output rate

This command is used to control the output of standard NMEA message GGA,

GLL, GSA, GSV

RMC, VTG. Using this command message, standard NMEA message may be

polled once, or setup for periodic output. Checksums may also be enabled or disabled depending on the needs of the receiving program. NMEA message settings are saved in battery backed memory for each entry when the message is accepted.

Format: ＄PSRF103,<msg>,<mode>,<rate>,<cksumEnable>*CKSUM<CR><LF>

<msg> 0=GGA,1=GLL,2=GSA,3=GSV,4=RMC,5=VTG <mode> 0=SetRate,1=Query <rate> Output every <rate>seconds, off=0,max=255 <cksumEnable> 0=disable Checksum,1=Enable checksum

for specified message

Example 1: Query the GGA message with checksum enabled

＄PSRF103,00,01,00,01*25

Example 2: Enable VTG message for a 1Hz constant output with checksum

enabled

＄PSRF103,05,00,01,01*20

Example 3: Disable VTG message

＄PSRF103,05,00,00,01*21

E). LLA Navigation lnitialization ID:104 Parameters required to start using Lat/Lon/Alt

This command is used to initialize the module for a warm start, by providing current position (in Latitude, Longitude, Altitude coordinates), clock offset, and time. This enables the receiver to search for the correct satellite signals at the correct signal parameters. Correct initialization parameters will enable the receiver to acquire signals more quickly, and thus, will produce a faster navigational soution. When a valid LLANavigationInitialization command is received,the receiver will restart using the input parameters as a basis for satellite selection and acquisition.

Format:

＄PSRF104,<Lat>,<Lon>,<Alt>,<ClkOffset>,<TimeOfWeek>,<WeekNo>, <ChannelCount>, <ResetCfg>*CKSUM<CR><LF>

<Lat> Latitude position, assumed positive north of equator and

negative south of equator float, possibly signed

<Lon> Longitude position, it is assumed positive east of Greenwich

and negative west of Greenwich

Float, possibly signed

<Alt> Altitude position

float, possibly signed

<ClkOffset> Clock Offset of the receiver in Hz, use 0 for last saved value if

available. If this is unavailable, a default value of 75000 for

GSP1, 95000 for GSP1/LX will be used. INT32 <TimeOfWeek> GPS Time Of Week UINT32 <WeekNo> GPS Week Number UINT16 <ChannelCount> Number of channels to use. 1-12

UBYTE

<ResetCfg> bit mask 0×01=Data Valid warm/hot starts=1 0×02=clear ephemeris warm start=1 0×04=clear memory. Cold start=1

UBYTE Example: Start using known position and time. ＄PSRF104,37.3875111,-121.97232,0,96000,237759,922,12,3*37

F). Development Data On/Off ID:105 Switch Development Data Messages On/Off

Use this command to enable development debug information if you are having trouble getting commands accepted. Invalid commands will generate debug information that should enable the user to determine the source of the command rejection. Common reasons for input command rejection are invalid checksum or parameter out of specified range. This setting is not preserved across a module reset.

Format: ＄PSRF105,<debug>*CKSUM<CR><LF>

<debug> 0=Off,1=On

Example: Debug On ＄PSRF105,1*3E Example: Debug Off ＄PSRF105,0*3F

G). Select Datum ID:106 Selection of datum to be used for coordinate Transformations

GPS receivers perform ini tial position and velocity calculations using an earth-centered earth-fixed (ECEF) coordinate system. Results may be converted to an earth model (geoid) defined by the selected datum. The default datum is WGS 84 (World Geodetic System 1984) which provides a worldwide common grid system that may be translated into local coordinate systems or map datums. (Local map datums are a best fit to the local shape of the earth and not valid worldwide.)

Examples: Datum select TOKYO_MEAN $PSRF106,178*32