Global Sat EM-408 User manual

環天衛星科技股份有限公司
PRODUCT USER MANUAL
GPS ENGINE BOARD
EM-408
GlobalSat Technology Corporation
台北縣中和市建一路 186 號16 樓(遠東世紀廣場)
16F ,No.186,Chien 1 Road, 235Chung Ho City,Taipei Hsien, Taiwan ,R.O.C.

Tel: [phone](Rep.) Fax: [phone]
Web: www.globalsat.com.tw E-mail:[email protected]
Features:
SiRF starⅢhigh performance GPS Chip Set
Very high sensitivity (Tracking Sensitivity: -159 dBm)
Extremely fast TTFF (Time To First Fix) at low signal level
Compact size (36.4mm * 35.4 mm * 8.3mm) suitable for space-sensitive application
Support NMEA 0183 and SiRF binary protocol
Specification:
General
Chipset SiRFStarⅢ
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 3.3V DC input
Power consumption 75mA (Continuous mode)
Interface
Dimension 36.4mm * 35.4mm * 8.3mm
Baud rate 4,800 to 57,600 bps adjustable
Electrical level TTL level, Output voltage level: 0V ~ 2.85V
Output message SiRF binary or
NMEA 0183 GGA, GSA, GSV, RMC, VTG, GLL
Environmental
Operating Temp -40℃to +85℃

Dimensions

Pin Assignment
Pin description
* VIN (DC power input):
This is the main DC supply for a 3.3V DC input power module board.
* GPS-TX:
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
* GPS-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.
* Enable/Disable:
On/Off

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
Table B-2 GGA Data Format
Name
Example
Units
Description
Messa
g
e ID
$
GPGGA GGA
p
rotocol heade
r
UTC Time 161229.487 hhmmss.sss
Latitude 3723.2475 ddmm.mmmm
N
/S Indicato
r
N
N
=north or S=south
Lon
g
itude 12158.3416 dddmm.mmm
m
E/W Indicato
r
W E=east or W=wes
t
Position Fix Indicato
r
1 See Table B-3
Satellites Use
d
07 Ran
g
e 0 to 12
HDOP 1.0 Horizontal Dilution of Precision
MSLAltitude19.0 meters
Units M meters
Geoid Se
p
aration1meters
Units M meters
A
g
e of Diff. Corr. second
N
ull fields when DGPS is not used
Diff. Ref. Station ID 0000
Checksu
m
*18
<CR><LF> End of messa
g
e 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

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
TableB-4GLLDataFormat
Name Exam
p
le Units Desc
r
i
p
tion
Messa
g
e ID
$
GPGLL GLL
p
rotocol heade
r
Latitude 3723.2475 ddmm.mmmm
N
/S Indicato
r
n
N
=north or S=south
Lon
g
itude 12158.3416 dddmm.mmm
m
E/W Indicato
r
W E=east or W=wes
t
UTC Position 161229.487 hhmmss.sss
Status A A=data valid or V=data not valid
Checksu
m
*2C
<CR><LF> End of messa
g
e 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
TableB-5GSADataFormat
Name Example Units Description
Message ID $GPGSA GSA protocol header
Mode1 A See Table B-6
Mode2 3 See Table B-7
Satellite Used107 Sv on Channel 1
Satellite Used102 Sv on Channel 2
…..
Satellite Used1Sv 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.
TableB-6Mode1
Value Description
M Manual-forced to operate in 2D or 3D mode
A 2Dautomatic-allowed to automatically switch 2D/3D
TableB-7Mode2
Value Description
1 Fix Not Available
2 2D
3 3D

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
TableB-8GSVDataFormat
Name
Example
Description
Messa
g
e ID
$
GPGSV GSV
p
rotocol heade
r
N
umber of Messa
g
es12 Ran
g
e 1 to 3
Messa
g
e Numbe
r
11 Ran
g
e 1 to 3
Satellites in View 07
Satellite ID 07 Channel 1
(
Ran
g
e 1 to 32
)
Elevation 79 de
g
rees Channel 1
(
Maximum90
)
Azimuth 048 de
g
rees Channel 1
(
True
,
Ran
g
e 0 to 359
)
SNR
(
C/No
)
42 dBHz Ran
g
e 0 to 99
,
null when not trackin
g
……. …….
Satellite ID 27 Channel 4
(
Ran
g
e 1 to 32
)
Elevation 27 De
g
rees Channel 4
(
Maximum90
)
Azimuth 138 De
g
rees Channel 4
(
True
,
Ran
g
e 0 to 359
)
SNR
(
C/No
)
42 dBHz Ran
g
e 0 to 99
,
null when not trackin
g
Checksu
m
*71
<CR><LF> End of messa
g
e termination
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
TableB-10RMCDataFormat
Name
Example
Units
Description
Messa
g
e ID
$
GPRMC RMC
p
rotocol heade
r
UTC Time 161229.487 hh
m
mss.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
Lon
g
itude 12158.3416 dddmm.mmm
m
E/W Indicato
r
W E=east or W=wes
t
S
p
eed Over Ground 0.13 knots
Course Over Ground 309.62 de
g
rees True
Date 120598 ddmm
yy
Ma
g
netic Variation2de
g
rees E=east or W=wes
t
Checksu
m
*10
<CR><LF> End of messa
g
e termination
SiRF Technology Inc. does not support magnetic declination. All “course over ground” data are
geodetic WGS48 directions.

VTG-Course Over Ground and Ground Speed
$GPVTG,309.62,T,,M,0.13,N,0.2,K*6E
Name
Example
Units
Description
Messa
g
e ID
$
GPVTG VTG
p
rotocol heade
r
Course 309.62 de
g
rees Measured headin
g
Reference T True
Course de
g
rees Measured headin
g
Reference M Ma
g
netic
S
p
eed 0.13 knots Measured horizontal s
p
eed
Units
N
Knots
S
p
eed 0.2 Km/h
r
Measured horizontal s
p
eed
Units K Kilometers
p
er hou
r
Checksu
m
*6E
<CR><LF> End of messa
g
e termination

2.2 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