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Introduction
GE-1315LPX small form factor board is the newest generation of GPS module. The module is powered by latest SiRF Star III single chip and proprietary navigation technology that provides you with stable and accurate navigation data. The smallest form factor 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
  • 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
  • Auto recovery while RTC crashes
  • Build-in LNA and saw filter

Product Applications
Automotive navigation
Personal positioning and navigation
Marine navigation
Timing application

Product Pictures

GE-1315LPX Series Block Diagram
System block diagram description:
a. External antenna.
b. 4 Mega bits flash memory.
c. 22 pin I/O pin.

GE-1315LPX Technical Specificatio
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 -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 514 m/s
13 Trickle power mode Duty cycle ≤ 34%. (Variable)
14 Update rate Continuous operation: 1Hz
15 Protocol setup It shall store the protocol setup in the SRAM memory.
16 DGPS 1.WAAS, EGNOS
2.RTCM protocol
Interface
17 LNA 17dB Gain. (Typical)
18 I/O Pin 22pins
Mechanical requirements
19 Weight ≤3.5g
Power consumption
20 VCC DC 3.3 ±5%
21 Current 33mA@3.3V (Acquisition w/o ext. Antenna) Typical
32mA@3.3V (tracking w/o ext. Antenna) Typical
11mA@3.3V (Standby mode w/o ext. Antenna) Typical
Environment
22 Temperature - Operating : -40 ~ 85°C
- Storage :  -40 ~ 85°C
23 Humidity ≤95%

Application Circuit
Reference schematic:
For example:

Notes:

  1. Ground Planes:
    These pins (18, 20, 21, 22) should be connected to ground.
  2. Serial Interface:
    (1) The TXA pin is the serial output data. Default output GPS protocol. (NMEA sentence) .
    (2) The RXA pin is the serial input data. Default output GPS protocol. (NMEA sentence)
    (3) The TXB pin is the serial output data (Default Null)
    (4) The RXB pin is the serial input data (Default Null).
  3. Backup Battery:
    It's recommended to connect a backup battery to V_RTC_3V3 pin.
    In order to enable the warm start and hot start features of the GPS receiver.
    If you use backup battery, should be adding a bypassing capacitor (10uF) at
    V_RTC_3V3 pin. It can reduce noise and increase the stability.
  4. RF_IN:
    Connecting to the antenna has to be routed on the PCB. The transmission
    line must to be control impedance from RF_IN pin to the antenna or antenna
    connector of your choice. (Impedance 50Ω)
  5. Power:
    Connect V_GPS_3V3 pin to DC 3.3V. The power supply must add bypass
    capacitor (10uF and 1uF). It can reduce the Noise from power supply and
    increase power stability.
  6. Active antenna bias voltage:
    The RF_OUT pin (pin 17) is provide voltage 2.85V. If you use active antenna,
    you can use this pin to provide bias voltage for active antenna, but you must
    design the RF chock circuit to avoid the RF signal jamming.
    P.S. :
    (1) This pin can provide maximum current is 30mA @ 2.85V.
    (2) The active antenna input gain ranges are recommend 19~22dB.
  7. GPIO :
    The GPIOs functions are for customer used.
    If no use GPIO functions, it doesn’t connect anything.

Recommend Layout PAD:

Recommend paste mask pad
Recommend paste mask pad is shift outside the layout pad 0.2mm(See under figure)
Black Block is layout PADĦBBlue Block(Gray region is paste mask pad recommend)

Mechanical Layout

Hardware interface
Interface Pin Number:

Pin define:

Pin # Signal Name I/O Description Characteristics
1 RXB I Serial port B 3.15V≥VIH ≥ 1.995V -0.3V≥VIL ≥ 0.855V
2 TXB O Serial port B 2.85V≥VOH ≥ 2.375V VOL ≤ 0.715V
3 PPS O One pulse
per second
2.85V≥VOH ≥ 2.375V VOL ≤ 0.715V
4 TXA O Serial port A 2.85V≥VOH ≥ 2.375V VOL ≤ 0.715V
5 RXA I Serial port A 3.15V≥VIH ≥ 1.995V -0.3V≥VIL ≥ 0.855V
6 GPIO [10] I/O General
purpose I/O
3.15V≥VIH ≥ 1.995V -0.3V≥VIL ≥ 0.855V
2.85V≥VOH ≥ 2.375V VOL ≤ 0.715V
7 GPIO [0] I/O General
purpose I/O
3.15V≥VIH ≥ 1.995V -0.3V≥VIL ≥ 0.855V
2.85V≥VOH ≥ 2.375V VOL ≤ 0.715V
8 GPIO [1] I/O General
purpose I/O
3.15V≥VIH ≥ 1.995V -0.3V≥VIL ≥ 0.855V
2.85V≥VOH ≥ 2.375V VOL ≤ 0.715V
9 RF_PWR O Indicates
power state
of RF part
VOH = 2.85V VOL = 0V
10 ON_OFF I Edge
triggered
soft on/off
request.
3.15V≥VIH ≥ 1.995V
11 V_RTC_3V3 I Backup voltage supply DC + 2.5 ~ +3.6 V
Current ≤10 uA
12 VIN_3V3 I DC supply voltage input DC + 3.3V ±5%
13 GPIO [14] I/O General
purpose I/O
3.15V≥VIH ≥ 1.995V -0.3V≥VIL ≥ 0.855V
2.85V≥VOH ≥ 2.375V VOL ≤ 0.715V
14 GPIO [15] I/O General
purpose I/O
3.15V≥VIH ≥ 1.995V -0.3V≥VIL ≥ 0.855V
2.85V≥VOH ≥ 2.375V VOL ≤ 0.715V
15 GPIO [13] I/O General
purpose I/O
3.15V≥VIH ≥ 1.995V -0.3V≥VIL ≥ 0.855V
2.85V≥VOH ≥ 2.375V VOL ≤ 0.715V
16 Boot I Boot mode 3.15V≥VIH ≥ 1.995V  -0.3V≥VIL ≥ 0.855V
17 RF_VOUT O Supply
Antenna
Bias voltage
VO = 2.85V±5%
Current 30mA
18 GND G Ground Reference Ground
19 RF_IN I GPS Signal input 50 Ω@1.57542GHz
20 GND G Ground Reference Ground
21 GND G Ground Reference Ground
22 GND G Ground Reference Ground

VIN_3V3(+3.3V DC power Input)
This is the DC power supply input pin for GPS system. It provides voltage to module.
GND
GND provides the reference ground .
Boot
Set this pin to high for programming flash.
RXA
This is the main receiver channel and is used to receive software commands to the board from
SIRFdemo software or from user written software.
RXB
This is the auxiliary receiving channel and is used to input differential corrections to the board to enable
DGPS navigation. (Default Null).
TXA
This is the main transmitting channel and is used to output navigation and measurement data to
SiRFdemo or user written software.
TXB
For user’s application (not currently used). (Default Null).
RF_PWR
This pin indicates state of RF voltage.

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).
RF_VOUT
This pin can provide maximum power 30mA @2.85V for active antenna.
PPS
This pin provides one pulse-per-second output from the board, which is synchronized to GPS time. This
is not available in Trickle Power mode.

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 2.5V and 3.6V.
ON_OFF
Edge triggered soft on/off request. Should only be used to wake up chip.
GPIO Functions

Several I/Os are connected to the digital interface connector for custom applications.

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

A. 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.

B. 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.

C. he 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.
D. 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.

E. 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 (22 holes)