Global Sat ET-333 User manual

ET-333
Specifications are subject to be changed without notice.
Page 1 of 15
Version 1.3.1
GPS Engine Board
ET-333
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.
1308 John Reed Court, City of Industry, CA 91745
Tel: [phone] / Fax: [phone]
[e-mail]
www.usglobalsat.com

ET-333
Specifications are subject to be changed without notice.
Page 2 of 15
Version 1.3.1
1. Product Information
Product Part I.D. ET-333
Product Description:
The ET-333 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:
9SiRF StarIII
9Very high sensitivity (Tracking Sensitivity: -159dBm)
9Extremely fast TTFF (Time To First Fix) at low signal levels
9Supports the NMEA 0183 data protocol
9Connector for active antenna
9Compact size
9Foliage Lock for weak signal tracking
9All-in-view 20-channel parallel processing
9Enhanced algorithm for navigation stability
9Enhanced algorithm for navigation stability
9Superior urban canyon performance
9SuperCap Pad to maintain system data for rapid satellite acquisition (Optional)
9RoHS compliant
Product Specifications
GPS Receiver
Chipset SiRF StarIII
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 ~ 57600 bps adjustable
Output Message: NMEA 0183 GGA, GSA,
GSV, RMC, SiRF binary (VTG, GLL optional)
Channels 20
Sensitivity -159dBm

ET-333
Specifications are subject to be changed without notice.
Page 3 of 15
Version 1.3.1
Cold Start 42 seconds average
Warm Start 38 seconds average
Hot Start 1 second average
Reacquisition 0.1 second average
Accuracy Position: 15 meters, 2D RMS
10 meters, 2D RMS, WAAS enabled
Velocity: 0.1 ms (95% SA Off)
Time: 1µs synchronized to GPS time
Maximum Altitude 18,000 meter (60,000 feet) max
Maximum Velocity 515 meter/second (1000 knots) max
Maximum Acceleration 4G
Jerk 20m/sec **3
Interface
I/O Connector Type
External Antenna Port
Physical Characteristic
Dimensions 1.3” x 1.3” x 0.2” (31.8 x 31.8 x 6mm)
DC Characteristics
Power Supply 3.8V ~ 6.5V DC Input
Backup Voltage 2.5 ~ 3.6V 10uA backup current
Power Consumption 42mA (Continuous Mode)
25mA (Trickle Power Mode)
Environmental Range
Humidity Range 5% to 95% non-condensing
Operation Temperature -40F to +176F (-40C to +85C)

ET-333
Specifications are subject to be changed without notice.
Page 4 of 15
Version 1.3.1
2. Technical Information
Physical Characteristics

ET-333
Specifications are subject to be changed without notice.
Page 5 of 15
Version 1.3.1
Pin Assignment
1 GND Ground 3.8~6.5 DC power input (Input)
2 VBAT Backup Battery (Input)
3 VDC 3.3~5.5 DC power input (Input)
4 PBRES Push Button Reset Input (Active Low) (Input)
5 GP101 Special function
6 TX Serial Data Output (GPS Data)(Output)
7 RX Serial Data Input (Command)
8 GND Ground
9 GND Ground
10 SELECT (Reserved)
11 TIMEMARK 1PPS Time Mark Output
12 GND Ground

ET-333
Specifications are subject to be changed without notice.
Page 6 of 15
Version 1.3.1
Pin Explanation
GND: GND provides the ground for the engine boards. Be sure to connect all grounds
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. (NOTE:This pin must be kept “HIGH” for operation.
From Vcc connect a 470 Ohm resistor in series with a 3.2v Zener diode to Ground. Then, connect the
VBAT input to Zener’s cathode to pull the input “HIGH”.)
GPI01: User can use this I/O pin for special functions (for example, an on/off indicator LED).
VDC (DC power input) This is the main DC supply for a 3.3V~5.5V power module board.
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.
GP101: User can use this I/O pin for special functions (for example, an on/off indicator LED).
SELECT: Do not connect (do not use)
TX: This is the main transmit 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.
SELECT: Do not connect (Reserved)
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.

ET-333
Specifications are subject to be changed without notice.
Page 7 of 15
Version 1.3.1
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
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

ET-333
Specifications are subject to be changed without notice.
Page 8 of 15
Version 1.3.1
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
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.

ET-333
Specifications are subject to be changed without notice.
Page 9 of 15
Version 1.3.1
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
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.

ET-333
Specifications are subject to be changed without notice.
Page 10 of 15
Version 1.3.1
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
Speed 0.13 knots Measured horizontal speed
Units N Knots
Speed 0.2 Km/hr Measured horizontal speed
Units K Kilometers per hour
Checksum *6E
<CR><LF> End of message termination