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

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 PAD¡BBlue Block(Gray region is paste mask pad recommend)

Mechanical Layout

Hardware interface
Interface Pin Number:

Pin define:

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

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

Table 3 Position Fix Indicators

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

Table 5 Mode 1

Table 6 Mode 2

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

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

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

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

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.

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)