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APRS/GPS:

Garmin GPS-25

Sorry, Garmin has discontinued this product


Be sure to read the Garmin GPS-25 Frequently Asked Questions below.

Read about recommended power supply designs for the GPS-25.

  • Garmin GPS-25 (12 channel parallel sensor) engine (1.83" x 2.75" x .45")
  • Power/data cable with connector shell and pins
    (The connector is a mfg subminiature PCB edge connector with cable attached)
    A $12 value.
  • Documentation
    GPS-25 Technical Specification (pdf, 115K, 35 pages)

Please note: This is not an enclosed/sealed unit. It is assumed that the purchasers will be installing the unit in another enclosure for normal and experimental operations. These units will be useful with current APRS software and the TAC-2 (Totally Accurate Clock) kit designed by Tom Clark, W3IWI.

As well as the MIC-E kit for APRS tracking.


General Information

    All Garmin engines come complete with DGPS input capability (see note below), PPS timing output and lithium 3V battery on board

    The Garmin GPS-25 will simultaneously track up to twelve satellites providing fast time-to-first-fix, one second navigation updates and low power consumption.

    Footprint (1.83" x 2.75" x .45")

    Time to first fix
    reacquisition < 2 sec
    warm 15 sec
    cold 45 sec
    sky search 5 min
    update rate 1 sec continuous
    Dynamics
    velocity 999 knots
    acceleration 3 g
    jerk 20 m/s^3
    Datums
    102 predefined, 1 user defined
    Electrical
    input voltage 5.0V DC +- 5% regulated (a suitable regulator should be used)
    power consumption 220mA typical, 180mA reset, 350mA max.
    backup on board 3V lithium (10 year lifetime)
    sensitivity -165 dBW
    Connector
    antenna 50 ohm MCX female connector for active (5V DC @ 15ma) or passive antenna
    power/data single row, right angle 12 pin male
    Physical
    configuration 1 integrated board engine
    size 1.83"W X 2.75"L X 0.45"H
    weight 1.1 oz
    op temp -30 deg C - +85 deg C
    (remove Li battery for extended usage above 85 deg C)
    storage temp -40 deg C - +90 deg C
    Interface
    compatibility 2 RS-232 serial ports
    data rate User selectable baud rate 1200/2400/4800/9600
    format NMEA 0183 v.2.0, ASCII
    inputs Initial position, date and time (not required), 2D/3D & earth datum command, RTCM-104 v.2.0 differential
    outputs Position, velocity & time, receiver and satellite stautus, geometry and error estimates
    timing output Timing output with +- 1 microsecond accuracy


Ordering Information

Sorry, Garmin GPS25LVS is no longer available


Frequently Asked Questions

  • The GPS-25 can accept DGPS signals.

  • Antenna options (which can be purchased directly from Garmin if required) include:
    • mag mount
    • flange mount (bolt to a car)
    • trunk clip
    • suction cup mounted

  • The unit has true time clocks, PPS timing, and nonvolatile memory on board.

  • The interface is NMEA 0183 (TTL levels) and RS232 (+ and - 15 volts)

  • The unit can be powered by AA batteries. Batteries or external supplies will require a suitable power regulator.

  • The unit only gives NMEA sentences as output, no extraction of RTCM-104 data.

  • There's no problem with the antenna being close to the boards. All sensitive components are shielded.

  • The unit has a LNAs and you can use passive antennas. You need to keep the antenna runs short however.

  • The antenna is attached with a MCX (also know as OCX) connector, which is a friction lock connector.

  • There's a header for connecting the data cables. A connector and cable will be included in the kit. The connector is a subminiature PCB edge connector. This is not the same connector as used with many hand-held units.

  • You cannot adjust the intervals that the boards outputs data. However, you can adjust their baud rate.

  • The boards do adjust for leap seconds (via the satellites).

  • For DGPS, since these are just the boards, you can't use the Garmin DGPS receivers. The Garmin units get tuning instructions from the GPS keyboard (which are not on the boards). To receive DGPS signals, you'll need a tunable beacon receiver. Correction signals are sent in through the data in cable (just like the handhelds).

  • Will the documentation include full description of the proprietary protocol?
    The data on their "proprietary" command protocol is included. Here "proprietary" means a "non-standard" NMEA command. They start with $PG instead of $GP...

  • Will there be a 1 Hz output?
    Yes, there is a 1pps signal at no extra charge!

  • Does Garmin have a web page?
    www.garmin.com.

  • It appears the GPS-25 does NOT have a built-in display but one has to use an external computer with unspecified software. Also the external computer is required to provide tuning instructions. Is this correct?
    This is just the GPS engine that produces NMEA outputs. No display, no user functions...

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