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Introduction
GE-1722 is powered by latest SiRF Star III low power single chip. It uses the proprietary navigation technology to provide you with stable and accurate navigation data. The high sensitivity, ultra low power consumption and miniature design is the best choice to be embedded in a device such as portable navigation device, personal locator, Speed Camera detector and vehicle locator.

Product Features

  • 20 parallel channels
  • SMT type with stamp holes
  • Ultra low power consumption
  • TCXO design
  • 0.1 second reacquisition time
  • Small form factor with embedded SiRF Star III single chip technology.
  • NMEA-0183 compliant protocol/ customize protocol
  • Enhanced algorithm for navigation stability
  • Excellent sensitivity for urban canyon and foliage environments.
  • DGPS (WAAS, EGNOS) support
  • Build-in LNA and saw filter

Product Applications

  • Automotive navigation
  • Personal positioning and navigation
  • Marine navigation
  • Timing application

Product Pictures

GE-1722 Series Block Diagram
System block diagram description:

    a. External antenna.
    b. 4 Mega bits flash memory.
    c. 28 pin I/O pin.

GE-1722 Technical Specification
Impedance: 50Ω

No Function Specification
GPS receiver
1 Chipset SiRF Star III, GSC3f/LPx
(Digital, RF in a single package)
2 Frequency L1 1575.42MHz.
3 Code C.A. Code.
4 Channels 20 parallel
5 Chip Sensitivity Tracking: 159dBm.
6 Chip Cold start 35 sec @ open sky (Typical)
7 Chip Warm start 35 sec @ open sky (Typical)
8 Chip Hot start 1 sec @ open sky (Typical)
9 Reacquisition 0.1sec typical
10 Position accuracy 10meters at 2D RMS.
11 Maximum altitude 18000 m
12 Maximum velocity 515 m/s
13 Update rate Continuous operation: 1Hz
14 Protocol setup It shall store the protocol setup in the SRAM memory.
15 DGPS 1.WAAS, EGNOS
2.RTCM protocol
Interface
16 LNA 18dB Gain. (Typical)
17 I/O Pin 28pins
Mechanical requirements
18 Weight ≤3.5g
Power consumption
19 VCC DC +3.0~3.6V
20 V_BCKP DC +1.4~3.6V
21 Current Avg. ≤ 28mA@3.3V(without ext. antenna)
Environment
22 Temperature - Operating: -40 ~ 85°C
- Storage: -40 ~ 85°C
23 Humidity ≤95%

Application Circuit
Reference schematic:
For example:

Note:

  • Ground Planes:
    These pins (7, 13, 14, 15, 17) should be connected to ground.
  • Serial Interface:
    (i) The TxD1 pin is the serial output data (Default NMEA).
    (ii) The RxD1 pin is the serial input data (Default NMEA).
  • Backup Battery:
    When module is working, must to supply VCC (P6) and V_BCKP (P11) power at the same time.
    It's recommended to connect a backup battery to V_BCKP pin and to enable the warm start and hot start features of the GPS receiver.
    If you use backup battery, should be adding a bypassing capacitor (0.01~10uF) at V_BCKP pin. It can reduce noise and increase the stability.
  • RF_IN:
    Connecting to the antenna has to be routed on the PCB. The transmission line must to controlled impedance to connect RF_IN to the antenna or antenna connector of your choice. (Impedance 50Ω)
  • Power:
    Connect VCC pin to DC+3.0~3.6V. The power supply must add bypassing capacitor (10uF and 0.1uF).It can reduce the Noise from power supply and increase power stability.
  • Active antenna bias voltage:
    The VCC_RF pin (pin 18) is provided voltage 2.85V. If you use active antenna, you can connect this pin to V_ANT pin (pin 19) to provide bias voltage of active antenna. The bias voltage will be through GPS_RF_IN pin to provide active antenna bias voltage from VCC_RF pin.
    If your bias voltage of active antenna isn't 2.85V, you can input bias voltage to V_ANT pin (pin 19) and input bias voltage of you need. The input bias voltage will through GPS_RF_IN pin to provide active antenna bias voltage from V_ANT pin.
    PS:
  • The maximum power consumption of active antenna is about 85mW.
    The input gain ranges are 19~ 27dB.

Recommend Layout PAD:



Footprint and paste mask

Mechanical Layout

Hardware interface
Interface Pin Number

Pin define:

Pin # Signal Name I/O Description Characteristics
1 SDA2 I/O General purpose I/O 3.15V ≥ Vih ≥ 2.0V
-0.3V ≤ Vil ≤ 0.86V

2.85V ≥ V0h ≥ 2.14V
Vol ≤ 0.71V
2 SCL2 I/O General purpose I/O 3.15V ≥ Vih ≥ 2.0V
-0.3V ≤ Vil ≤ 0.86V

2.85V ≥ V0h ≥ 2.14V
Vol ≤ 0.71V
3 TxD1 O Serial port A 2.85V ≥ V0h ≥ 2.14V
Vol ≤ 0.71V
4 RxD1 I Serial port B 3.15V ≥ Vih ≥ 2.0V
-0.3V ≤ Vil ≤ 0.86V
5 N.C. ~ N.C. None connector
6 VCC I DC Supply Voltage input DC +3.0~3.6V
7 GND ~ Ground Reference Ground
8 VCC_OUT O   Connected to VCC, can open
9 CFG_COM1 I Config.Pin 3.15V ≥ Vih ≥ 2.0V
-0.3V ≤ Vil ≤ 0.86V
10 RESET_N I Reset (Active low) Vih > 2.3V
Vil < 0.8V
11 V_BCKP I Backup voltage supply DC + 1.4 ~ +3.6
Current ≤ 10uA
12 BOOT I Boot mode 3.15V ≥ Vih ≥ 2.0V
-0.3V ≤ Vil ≤ 0.86V
13 GND ~ Ground Reference Ground
14 GND ~ Ground Reference Ground
15 GND ~ Ground Reference Ground
16 RF_IN I GPS Signal input 50 Ω @1.57542GHz
17 GND ~ Ground Reference Ground
18 VCC_RF O Supply Antenna Bias voltage DC +2.85V ±2%
Current < 20mA
19 V_ANT I Active Antenna Bias voltage Receiving DC power supply for active antenna bias.
20 AADET0_N I Active Ant. Detect Detect Active Antenna=> "low"
3.15V ≥ Vih ≥ 2.0V
-0.3V ≤ Vil ≤ 0.86V
21~26 N.C. ~ N.C. None connector
27 EXTINT0 I Ext. Interrupt Internal pull-up resistor to 2.85V
3.15V ≥ Vih ≥ 2.0V
-0.3V ≤ Vil ≤ 0.86V
28 TIMEMARK O One pulse per second 3.15V ≥ Vih ≥ 2.0V
-0.3V ≤ Vil ≤ 0.86V
  • VCC_3V3 (DC 3.0~3.6V Power Input)
    This is the DC power supply input pin for GPS system. It provides voltage to module.
  • GND
    GND provides the ground.
  • Boot
    Set this pin to high for programming flash.
  • RXD1
    This is the main receiver channel and is used to receive software commands to the board from SIRFdemo software or from user written software.
  • TXD1
    This is the main transmitting channel and is used to output navigation and measurement data to SiRFdemo or user written software.
  • GPS_RF_IN
    This pin receives GPS analog signal. The line on the PCB between the antenna(or antenna connector) has to be a controlled impedance line (Microstrip at 50Ω).
  • V_ANT_IN
    This pin is reserved as external DC power supply input for active antenna.
    1. If using external supply DC+3.3V~5V to Active antenna
    2. If using connects to VCC_RF pin supply to Active antenna, pin 18 has to be connected to pin 19
    PS: The current must be ≤100mA and voltage ≤5.5V, if using external power supply.
  • VCC_RF_OUT
    This pin can provide power 20mA@DC+2.85V for active antenna.
  • Reset_N
    This pin provides an active-low reset input to the board. It causes the board to reset and start searching for satellites. If not utilized, it may be left open.
  • TIMEMARK
    This pin provides one pulse-per-second output from the board, which is synchronized to GPS time.
  • V_RTC_3V3 (Backup battery)
    This is the battery backup input that powers the SRAM and RTC when main power is removed. Typical current draw is 10uA.
    The supply voltage should be between 1.4V and 3.6V.
  • GPIO Functions (SCL2, SDA2, CFG_COM1, AADET0_N, EXTINT0)
    Several I/Os are connected to the digital interface connector for custom applications.
  • AADET0_N
    AADET0_N is an input pin and it is used to report whether an external circuit has detected an external antenna or not. Low means antenna has been detected. High means no external antenna has been detected.

Software Interface
NMEA Protocol
NMEA Output Messages: the Engine board outputs the following messages as shown in
Table 1:

Table 1 NMEA-0183 Output Messages
NMEA Record Description
GGA Global positioning system fixed data
GSA GNSS DOP and active satellites
GSV GNSS satellites in view
RMC Recommended minimum specific GNSS data
GLL Geographic position - latitude/longitude
VTG Course over ground and ground speed

GGA-Global Positioning System Fixed Data
Table 2 contains the values of the following example:
$GPGGA, 161229.487, 3723.2475, N, 12158.3416, W, 1, 07, 1.0, 9.0, M, , , ,0000*18

Table 2 GGA Data Format
Name Example Units Description
Message ID $GPGGA   GGA protocol header
UTC Position 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 2-1
Satellites Used 07   Range 0 to 12
HDOP 1.0   Horizontal Dilution of Precision
MSL Altitude 9.0 meters  
Units M meters  
Geoid Separation   meters  
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


Table 3 Position Fix Indicators
Value Description
0 Fix not available or invalid
1 GPS SPS Mode, fix valid
2 Differential GPS, SPS Mode, fix valid
3-5 Not Supported
6 Dead Reckoning Mode, fix valid

GSA-GNSS DOP and Active Satellites
Table 4 contains the values of the following example:
$GPGSA, A, 3, 07, 02, 26, 27, 09, 04, 15, , , , , , 1.8,1.0,1.5*33

Table 4 GSA Data Format

Name Example Units Description
Message ID $GPGSA   GSA protocol header
Mode 1 A   See Table 5
Mode 2 3   See Table 6
ID of Satellite Used 07   Sv on Channel 1
ID of Satellite Used 02   Sv on Channel 2
....     ....
ID of Satellite Used     Sv 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

Table 5 Mode 1

Value Description
M Manual-forced to operate in 2D or 3D mode
A Automatic-allowed to automatically switch 2D/3D

Table 6 Mode 2

Value Description
1 Fix not available
2 2D
3 3D

GSV-GNSS Satellites in View
Table 7 contains the values of 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

Table 7 GSV Data Format

Name Example Units Description
Message ID $GPGSV   GSV protocol header
Total Number of Messages1 2   Range 1 to 3
Messages Number1 1   Range 1 to 3
Satellites in View 07    
Satellite ID 07   Channel 1(Range 1 to 32)
Elevation 79 degrees Channel 1(Range 00 to 90)
Azimuth 048 degrees Channel 1(True, Range 000 to 359)
SNR (C/No) 42 dBHz Channel 1(Range 0 to 99, null when not tracking)
Satellite ID 27   Channel 4(Range 01 to 32)
Elevation 27 degrees Channel 4(Range 00 to 90)
Azimuth 138 degrees Channel 4(True, Range 000 to 359)
SNR (C/No) 42 dB-Hz Channel 4(Range 00 to 99, null when not tracking)
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 8 contains the values of the following example:
$GPRMC, 161229.487, A, 3723.2475, N, 12158.3416, W, 0.13, 309.62, 120598, ,*10

Table 8 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 True
Course Over Ground 309.62 degrees  
Date 120598   ddmmyy
Magnetic Variation   degrees  
Variation sense     E=east or W=west (Not shown)
Mode A   A=Autonomous, D=DGPS, E=DR
Checksum *10    
<CR><LF>     End of message termination

VTG-Course Over Ground and Ground Speed
Table 9 contains the values of the following example:
$GPVTG,79.65,T,,M,2.69,N,5.0,K,A*38

Table 9 VTG Data Format

Name Example Units Description
Message ID $GPVTG   VTG protocol header
Course over rgound 79.65 degrees Measured heading
Reference T   True
Course over ground   degrees Measured heading
Reference M   Magnetic
Speed over ground 2.69 Knots Measured speed
Units N   Knots
Speed over ground 5.0 Km/hr Measured speed
Units K   Kilometer per hour
Mode A   A-autonomous, D=DGPS, E=DR
Checksum *38    
<CR> <LF>     End of message termination

GLL-Geographic Position - Latitude/Longitude
Table 10 contains the values of the following example:
$GPGLL,2503.6319,N,12136.0099,E,053740.000,A,A*52

Table 10 GLL Data Format

Name Example Units Description
Message ID $GPGLL   GLL protocol header
Latitude 2503.6319   ddmm.mmmm
N/S indicator N   N=north or S=south
Longitude 12136.0099   Dddmm.mmmm
E/W indicator E   E=east or W=west
UTC Time 053740.000   hhmmss.sss
Status A   A=data valid or V=data not valid
Mode A   A=autonomous, D=DGPS, E=DR
Checksum *52    
<CR> <LF>     End of message termination

GPS Receiver User's Tip

  • GPS signal will be affected by weather and environment conditions, so it is recommended to use the GPS receiver under less shielding environments to ensure GPS receiver has better receiving performance.
  • When GPS receiver is moving, it will prolong the time to fix the position, so it is recommended to wait for the satellite signals locked at a fixed point when first power-on the GPS receiver to ensure to lock the GPS signal at the shortest time.
  • The following situation will affect the GPS receiving performance:
      • i. Solar control filmed windows.
      ii. Metal shielded, such as umbrella, or in vehicle.
      iii. Among high buildings.
      iv. Under bridges or tunnels.
      v. Under high voltage cables or near by radio wave sources, such as mobile phone base stations.
      vi. Bad or heavy cloudy weather.
  • If the satellite signals can not be locked or encounter receiving problem (while in the urban area), the following steps are suggested:
      • i. Please plug the external active antenna into GPS receiver and put the antenna on outdoor or the roof of the vehicle for better receiving performance.
      ii. Move to another open space or reposition GPS receiver toward the direction with less blockage.
      iii. Move the GPS receiver away from the interferences resources.
      iv. Wait until the weather condition is improved.
  • While a GPS with a backup battery, the GPS receiver can fix a position immediately at next power-on if the build-in backup battery is full-recharged.

Package Specification and Order Information

Shipment Method: Tape and reel

SMT type with stamp holes (28 holes)