Global Sat ET-312 User manual

ET-312
Page1of21
Version 1.4
GPS Engine Board ET-312
Version 1.4
01/20/2010
Globalsat Technology Corporation Headquarters (Far East Century Park)
16F., No. 186, Jian-Yi Road, Chung-Ho City, Taipei Hsien 235, Taiwan
Tel: [phone]/ Fax: [phone]
E-mail : [e-mail]
Website: www.globalsat.com.tw

ET-312
The Specifications are subject to be changed without notice. Copyright ©2007, GlobalSat Technology.
Page 2 of 21
Version 1.4
1. Product Information
Product Name: ET-312
Product Description:
ET-312 is a compact, high performance, and low power consumption GPS engine board. It uses SiRF
Star III chipset which can track up to 20 satellites at a time and perform fast TTFF in weak signal
environments. ET-312 is suitable for the following applications:
‧ Automotive navigation
‧ Personal positioning
‧ Fleet management
‧ Mobile phone navigation
‧ Marine navigation
Product Features:
SiRF star III high performance GPS Chipset
Very high sensitivity (Tracking Sensitivity: -159 dBm)
Extremely fast TTFF (Time To First Fix) at low signal level
One serial ports
4Mb flash
Built-in LNA
Compact size (28mm * 20 mm * 2.9mm) suitable for space-sensitive application
One size component, easy to mount on another PCB board
Support NMEA 0183 and SiRF binary protocol
Product Specifications
GPS Receiver
Chipset SiRF GSC3f/LP
Frequency L1, 1575.42 MHz
Code C/A Code
Protocol NMEA 0183 v2.2
Default:GGA,GSA,GSV,RMC
Support:VTG,GLL,ZDA)
SiRF binary and NMEA Command
Available Baud Rate 4,800 to 57,600 bps adjustable

ET-312
The Specifications are subject to be changed without notice. Copyright ©2007, GlobalSat Technology.
Page 3 of 21
Version 1.4
Channels 20
Flash 4Mbit
Sensitivity Tracking:-159dBm
Cold Start 42 seconds, average
Warm Start 38 seconds, average
Hot Start 1 second, average
Reacquisition 0.1 second, average
Accuracy Position: 10 meters, 2D RMS
5 meters, 2D RMS, WAAS enabled
Velocity: 0.1 m/s
Time: 1us synchronized to GPS time
Maximum Altitude ＜18,000 meter
Maximum Velocity ＜515 meter/second
Maximum Acceleration ＜4G
Update Rate 1 Hz
DGPS WAAS, EGNOS, MSAS
Datum WGS-84
Interface
I/O Pins 1 serial ports
Physical Characteristic
Type 13-pin stamp holes
Dimensions 28 mm * 20 mm * 2.9 mm
DC Characteristics
Power Supply 3.3Vdc ± 5%
Backup Voltage 2.0 ~ 3.6Vdc ± 10%
Power Consumption Acquisition: 60mA
Tracking: 42mA
Environmental Range
Humidity Range 5% to 95% non-condensing
Operation Temperature -30℃ to 85℃
Storage Temperature -40℃ to 85℃

ET-312
The Specifications are subject to be changed without notice. Copyright ©2007, GlobalSat Technology.
Page 4 of 21
Version 1.4
2. Technical Information
Block Diagram
Module Pin Assignment:
M1
GPS Engine Board
5
6
7
11
12
13
1
2
3
4
8
9
10
GND
GND
VIN
RX
GND
GND
GND
RF
GND
GND
BATTERY
GPIO1
TX
Pin NO. Pin Name Remark
1. GND Ground.
2. RF Connect to External Active Antenna. While external antenna is used, the
optional power is needed.
3. GND Ground.
4. GND Ground.
5. GND Ground.
6. GND Ground.
7. VIN This is the main DC supply for a 3.3V +- 5% DC input power module board.
8. BATTERY This is the battery backup input that powers the SRAM and RTC when main
power is removed. Typical current draw is 15uA. 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. The battery voltage should be between 2.0v and

ET-312
The Specifications are subject to be changed without notice. Copyright ©2007, GlobalSat Technology.
Page 5 of 21
Version 1.4
5.0v.
9. GPIO1 User can use this I/O pin for special function.For example, on/off LED
10. 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
11. RX This is the main receive channel for receiving software commands to the
engine board from SiRFdemo software or from user written software.
12. GND Ground.
13. GND Ground.

ET-312
The Specifications are subject to be changed without notice. Copyright ©2007, GlobalSat Technology.
Page 6 of 21
Version 1.4
Application Circuit
GPS Active Antenna Specification(Recommendation)
Frequency: 1575.42+2 MHz
Axial Ratio: 3 dB Typical
output Impedance: 50Ω
Polarization: RHCP
Amplifier Gain :18~22dB Typical
Output VSWR: 2.0 Max.
Noise Figure: 2.0 dB Max

ET-312
The Specifications are subject to be changed without notice. Copyright ©2007, GlobalSat Technology.
Page 7 of 21
Version 1.4
Dimensions

ET-312
The Specifications are subject to be changed without notice. Copyright ©2007, GlobalSat Technology.
Page 8 of 21
Version 1.4
Recommend Layout PAD

ET-312
The Specifications are subject to be changed without notice. Copyright ©2007, GlobalSat Technology.
Page 9 of 21
Version 1.4
Recommended Reflow Profile:
Pre heating temperature: 150±10[ ]℃Pre heating time: 90±30[sec.]
Heating temperature: 235±5[ ]℃Heating time: 10±1[sec.]
Peak temperature must not exceed 240 and the duration of ove℃r 200 should be 30±10℃
Seconds.
10±1s
240℃Max.
30±10s
200℃
150±10℃
90±30s
235±5℃.
Temperature [℃]
Time [sec.]

ET-312
The Specifications are subject to be changed without notice. Copyright ©2007, GlobalSat Technology.
Page 10 of 21
Version 1.4
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
MSL Altitude19.0 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
Va l u e D e s c r i
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