Global Sat ET-333 User manual

環天衛星科技股份有限公司
PRODUCT USER MANUAL
GPS ENGINE BOARD
ET-333
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: [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 (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 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 3.8V ~ 6.5V DC input
Power consumption 70mA (Continuous mode)
60mA (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 connector
Pin
Number Name Description Type
1 GND Ground
2 VBAT Backup Battery Input
3 VDC 3.8V~5.5V DC Power Input Input
4 PBRES Push Button Reset Input (Active Low) Input
5 GPIO1 (Reserved)
6 TXA Serial Data Output A (GPS Data) Output
7 RXA Serial Data Input A (Command) Input
8
GND Ground
9 GND Ground
10 SELECT (Reserved)
11 TIMEMARK 1PPS Time Mark Output Output
12 GND 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):
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.
* RF_IN(MMCX connector) :
This pin receives signal of GPS analog via active antenna .

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 Exam
p
le Units Descri
p
tio
n
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 Descri
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 Exam
p
le Descri
p
tio
n
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
(
T
r
ue
,
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 Exam
p
le Units Descri
p
tio
n
Messa
g
e ID $GPRMC RMC
p
rotocol heade
r
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
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 Exam
p
le Units Descri
p
tio
n
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