Global Sat ET-112 User manual

ET-112
Specifications are subject to be changed without notice.
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Version 1.3
GPS Engine Board
ET-112/ER-112
Globalsat Technology Corporation
16F., No. 186, Jian-Yi Road, Chung-Ho City, Taipei Hsien 235, Taiwan
Tel: [phone]/ Fax: [phone]
[e-mail]
www.globalsat.com.tw
USGlobalSat, Inc.
14740 Yorba Court, Chino, CA 91710
Tel: [phone] / Fax: [phone]
[e-mail]
www.usglobalsat.com

ET-112
Specifications are subject to be changed without notice.
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Version 1.3
1. Product Information
Product Part I.D. ET-112
Product Description
The ET-112 GPS engine board is low cost but maintains high reliability and accuracy making it an ideal
choice for integration with OEM/ODM systems.
Product Features
SiRF GSC2x high performance GPS Chip Set
Very high sensitivity (Tracking Sensitivity: -159dBm)
Extremely fast TTFF (Time To First Fix) at low signal levels
Supports the NMEA 0183 data protocol
Connector for active antenna
Enhanced algorithm for navigation stability
Foliage Lock for weak signal tracking
All-in-view 20-channel parallel processing
Snap Lock 100ms re-acquisition time
Superior urban canyon performance
Full-duplex RS-232 for navigation and control messages
Differential GPS capability through second RS232 port
RoHS compliant
Product Specifications
GPS Receiver
Chipset SiRF GSC2X Single
Frequency L1, 1575.42 MHz
Code 1.023 MHz chip rate
Protocol Electrical Level: TTL level,
Output Voltage Level: 0V~2.85V
Baud Rate: 4800 bps
Output Message: NMEA 0183 GGA, GSA,
GSV, RMC (VTG, GLL optional)
Serial I/O Port 1-port for GPS
1-port for DGPS

ET-112
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Version 1.3
Channels 20
Sensitivity -155dBw
Cold Start 48 seconds average
Warm Start 38 seconds average
Hot Start 8 second average
Reacquisition 0.1 second average
Accuracy Position: 15 meters, 2D RMS 10 meters,
2D RMS, WAAS enable 1~5 meters DGPS
corrected
Velocity: 0.1 ms (95% SA Off)
Time: 1µs synchronized to GPS time
Maximum Altitude 18,000 meters (60,000 feet) max
Maximum Velocity 515 meter/second (1000 knots) max
Maximum Acceleration 4G
Datum WGS-84
Jerk Limit Jerk: 20m/sec **3
Electrical Level ET-112: TTL output voltage: 0~3.5V
ER-112: RS232 Level
Communication Full-Duplex asynchronous
Code Type ASCII
Protocol NMEA 0183 (default) / SiRF Binary
(available)
GPS Message Output NMEA 0183 >> GGA, GSA, GSV, RMC,
(VTG & GLL optional)
DGPS Protocol RTCM SC-104, v2.00, type 1, 2 and 9
Time Mark (1 PPS) Level: TTL
Pulse Duration: 100ms
Time Reference: At the pulse positive edge
Measurement: Aligned to GPS sec, +/- 1us
Interface
External Antenna Port MMCX
Physical Characteristic
Dimensions 2.8” x 1.6” x 0.4” (71 x 40.5 x10mm)
DC Characteristics
Power Supply 3.8V~6.5V DC

ET-112
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Version 1.3
Backup Voltage +2.5V to +3.6V
Power Consumption 42mA (Continuous Mode)
29mA (Trickle Power Mode)
Backup Current 10uA typical
Environmental Range
Humidity Range
Operation Temperature -40F to +176F (-40C to 85C)
2. Technical Information
Physical Characteristics

ET-112
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Version 1.3
OPTIONAL MCX CONNECTOR
Φ4.5
1. Needs external Active-antenna & its power Vant.6.4 mm
2. Needs external Vdc = 3.8 --- 6.5 Vcc 10.0 mm
3. Current supply I = 150 mA
4. PCB SIZE: 40.64mm x 71.12mm Φ0.95 pin x 5
5. Connector (pitch=2.0 mm) pin-assignment
Pin Assignment
ET-112 equipped with MMCX female
connector

ET-112
Specifications are subject to be changed without notice.
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Version 1.3
1 VANT Antenna DC Voltage (Input)
2 VDC 3.3~5.5 DC power input (Input)
3 VBAT Backup Battery (Input)
4 VDC (shorted with pin #2)
5 PBRES Push Button Reset Input (Active Low) (Input)
6 ---- (RESERVED)
7 SELECT Download data from RS232 to flash ROM (RESERVED)
8 ---- (RESERVED)
9 ---- (RESERVED)
10 GND Ground
11 TXA Serial Data Output A (GPS Data)
12 RXA Serial Data Input A(Commands)
13 GND Ground
14 TXB Serial Data Output B (Not Used)
15 RXB Serial Data Input B (Not Used)
16 GND Ground
17 ---- (RESERVED)
18 GND Ground
19 TIMEMARK 1PPS Time Mark Output
20 ---- (RESERVED)
Pin Explanation
VANT: DC Voltage is for an active antenna.
VDC: (DC power input) This is the main DC supply for a 3.3V~5.5V power module board.
VBAT: (Backup Battery) This is the battery backup that powers the SRAM and RTC when main power is
removed. Typical current draw is 10uA. Without an external backup battery or Gold-capacitor, the
module/engine board will execute a cold start after every turn on. To achieve the faster start, a battery or
capacitor should be installed. To maximize battery lifetime, the battery voltage should not exceed the
supply voltage and 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 transmit channel for outputting navigation and measurement data to user’s

ET-112
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Version 1.3
navigation software or user-written software.
RXA: This is the main receive channel for receiving software commands to the engine board from SiRF
Demo software or from user-written software. (NOTE:When not in use this pin must be kept “HIGH” for
operation. From Vcc connect a 470 Ohm ¼ Watt resistor in series with a 3.2v Zener diode to Ground. Then,
connect the Rx input to Zener’s cathode to pull the input “HIGH”.)
TXB: No function. Do not connect.
RXB: This is the auxiliary receive channel for inputting differential corrections to the engine board to
enable DGPS navigation.
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 boards. Be sure to connect all grounds
Mounting
Recommended mounting methods:
a. Use industrial grade double-sided foam tape. Place it on the bottom side of the engine board.
b. A recessed cavity in your housing design with a foam pad to eliminate shifting or movement.
c. Use provided mounting holes on the GPS engine board PCB.
3. Software Commands
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
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

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Version 1.3
Satellites Used 07 Range 0 to 12
HDOP 1.0 Horizontal Dilution of Precision
MSL Altitude19.0 meters
Units M meters
Geoid Separation1meters
Units M meters
Age of Diff. Corr. second Null 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 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
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 Example Units Description
Message ID $GPGLL GLL 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
<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
TableB-5GSADataFormat

ET-112
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Version 1.3
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 2D automatic-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 Units Description
Message ID $GPGSV GSV protocol header
Number of Messages12 Range 1 to 3
Message Number11 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 3
5

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Version 1.3
SNR(C/No) 42 dBHz Range 0 to 99,null when not tr
a
……. …….
Satellite ID 27 Channel 4 (Range 1 to 32)
Elevation 27 Degrees Channel 4(Maximum90)
Azimuth 138 Degrees Channel 4(True, Range 0 to 3
5
SNR(C/No) 42 dBHz Range 0 to 99,null when not tr
a
Checksum *71
<CR><LF> End of message termination
Depending on the number of satellites tracked multiple messages of GSV data may be required.
RMC-Recommended Minimum Specific GNSS Data
Table B-9 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-9 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.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 Variation2degrees E=east or W=west
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.
VTG-Course Over Ground and Ground Speed
$GPVTG,309.62,T,,M,0.13,N,0.2,K*6E
Table B-9 VTG Data Format
Name Example Units Description
Message ID $GPVTG VTG protocol header
Course 309.62 degrees Measured heading
Reference T True
Course degrees Measured heading
Reference M Magnetic