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環天衛星科技股份有限公司
PRODUCT USER MANUAL
RS232 GPS RECEIVER
BR-355
GlobalSat Technology Corporation
台北縣中和市建一路 186 號 16 樓(遠東世紀廣場)
16, No.186,Chien 1 Road, 235Chung Ho City,Taipei Hsien, Taiwan ,R.O.C.
Tel: 886-2-8226-3799(Rep.) Fax: 886-2-8226-3899
Web: www.globalsat.com.tw E-mail:service@globalsat.com.tw
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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
Support NMEA 0183 data protocol
Built-in SuperCap to reserve system data for rapid satellite acquisition
Built-in patch antenna
Super-cohesive magnetic for mounting on the car
Water resisted and non-slip on the bottom
RS232 interface connection port
LED indicator for GPS fix or not fix
LED OFF: Receiver switch off
LED ON: No fixed, Signal searching
LED Flashing: Position Fixed
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
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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 4.5V ~ 6.5V DC input
Power consumption 42mA
Protocol
Electrical level Output voltage level: 0V ~ 2.85V
Baud rate 4,800 bps
Output message NMEA 0183 GGA, GSA, GSV, RMC, VTG, GLL
Physical Characteristics
Dimension 53mm diameter, 19.2mm height
Cable Length 65＂
Operating temperature -30℃ to +85℃
Pin Assignment
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Pin description
* VIN (DC power input):
This is the main DC supply for a 4.5V ~6.5 DC input power.
* TX:
This is the main transmits channel for outputting navigation and measurement
data to user’s navigation software or user written software.
* RX:
This is the main receive channel for receiving software commands to the engine
board from SiRFdemo software or from user written software.
* GND:
GND provides the ground for the engine board. Connect all grounds.
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SOFTWARE COMMAND
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
T a bl e B-2 GGA Data Format
Name Example Units Description
Message ID $GPGGA GGA protocol heade
r
UTC Time 161229.487 hhmmss.sss
Latitude 3723.2475 ddmm.mmmm
N
/S Indicator
N N
=north or S=south
Longitude 12158.3416 dddmm.mmm
m
E/W Indicator W E=east or W=wes
t
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 Separation
1
meters
Units M meters
Age of Diff. Corr. second
N
ull fields when DGPS is not used
Diff. Ref. Station ID 0000
Checksum *18
<CR><LF> End of message termination
SiRF Technology Inc. does not support geoid corrections. Values are WGS84 ellipsoid heights.
Table B-3 Position Fix Indicator
Value Descri
p
tion
0 Fix not available or invali
d
1 GPS SPS Mode, fix vali
d
2 Differential GPS, SPS Mode , fix vali
d
3 GPS PPS Mode, fix vali
d
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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
Name Exam
p
le Units Description
Message ID $GPGLL GLL protocol heade
r
Latitude 3723.2475 ddmm.mmmm
N
/S Indicator n
N
=north or S=south
Longitude 12158.3416 dddmm.mmm
m
E/W Indicator W E=east or W=wes
t
UTC Position 161229.487 hhmmss.sss
Status A A=data valid or V=data not valid
Checksum *2C
<CR><LF> End of message termination
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 solution.
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
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GSV-GNSS Satellites in View
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
Name Example Descriptio
n
Message ID $GPGSV GSV protocol heade
r
N
umber of Messages1 2 Range 1 to 3
Message Numbe
r
1
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
<CR><LF> End of message termination
Depending on the number of satellites tracked multiple messages of GSV data may be required.
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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
Name Example Units Description
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.mmm
m
E/W Indicator W E=east or W=wes
t
Speed Over Ground 0.13 knots
Course Over Ground 309.62 degrees True
Date 120598 ddmm
yy
Magnetic Variation2 degrees E=east or W=wes
t
Checksum *10
<CR><LF> End of message termination
SiRF Technology Inc. does not support magnetic declination. All “course over ground” data are
geodetic WGS48 directions.
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VTG-Course Over Ground and Ground Speed
$GPVTG,309.62,T,,M,0.13,N,0.2,K*6E
Name Example Units Description
Message ID $GPVTG VTG protocol header
Course 309.62 degrees Measured headin
g
Reference T True
Course degrees Measured headin
g
Reference M Magnetic
Speed 0.13 knots Measured horizontal speed
Units
N
Knots
Speed 0.2 Km/h
r
Measured horizontal speed
Units K Kilometers
p
er hour
Checksum *6E
<CR><LF> End of message termination
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