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Note: The GPS-NAV is not currently in production but a few units are available directly from Cambridge.  I can sell accessories.

Repairs and Calibrations
I (Paul Remde of Cumulus Soaring, Inc.) can replace logger backup batteries, re-seal the electronic security seal, and calibrate the logger altimeters for all Cambridge GPS-NAV and 302 products. You can see details here: Services.

Garmin GPS Failures in Cambridge Products
Cambridge soaring instruments (and most other brands) used Garmin GPS engines which seem to have a bug such that they are failing. The issue has occurred to a very high percentage of Cambridge products. If yours hasn't failed, it probably will. The great news is that Gary Kammerer (formerly of Cambridge and ClearNav) can repair or replace the built-in Garmin GPS - making the instrument fully functional again. If your Cambridge flight recorder won't record a flight log, or records flights with a date from several years ago, your logger probably needs repair. Please see the PDF file below for details on the services Gary offers.

Cambridge Repair Services by Gary Kammerer

Click on the images below to view larger versions.

GPS-NAV Model 20 GPS-NAV Model 25

LCD Navigation Display

The Model 20's small package features a built in antenna, allowing easy installation and removal. Using the same 1/4"-20 mounting screw as a camera allows simple attachment to a standard camera mount. The small size also permits installation on or just under the instrument panel cover. For more difficult installations the Model 25 features an external antenna, rather than a built-in antenna. This allows the GPS antenna to be located remotely and connected to the flight recorder via a coaxial cable. The optional LCD Navigation Display offers a very simple user interface and can be used to edit tasks and make electronic flight declarations.

Cambridge pioneered Secure GPS Flight Recording and Navigation with the introduction of the Model 10. This was the first GPS based Flight Recorder to score a World Championship. It was first to receive FAI approval. The Model 10 set the standard for all to follow.  The Model 20 and 25 used the latest technology and eliminate the Model 10's internal battery. This reduces both size and cost. All GPS-NAV models have the same functionality and are approved for validation of FAI Badge and Record flights (but not World Record flights).

Better by Design
Cambridge systems are designed by glider pilots for glider pilots. The FAI approved GPS-NAV replaces both cameras and barographs. Ease of use and attention to detail make Cambridge the best GPS system for soaring.


  • The optional LCD display is very easy-to-use in flight - perfect for use in gliders owned by clubs or syndicates.
  • Small size
  • Wind speed and direction calculated while circling. Helps you locates wind shear and blue streets.
  • IGC approved GPS position recorder, pressure altitude recorder (barogram), and motorglider engine run sensor, approved for badge and record flights (but not World Record flights)
  • Automatice motion based recording - It notices when you start flying and uses a buffer to record the two minutes preceding the flight.
  • 9900 GPS/Altitude fixes are logged - 11 hours of logging at 4 second intervals.
  • Works great with an L-NAV.  The GPS-NAV sends destination elevation data to the L-NAV so that the L-NAV can display differential final glide data.  No other logger offers that feature with the L-NAV. 
  • Works great with Glide Navigator II software for Pocket PC.  Glide Navigator can download flight logs from the GPS-NAV and send flight declarations to the GPS-NAV.  The GPS-NAV also relays data from the L-NAV to Glide Navigator.  No other logger can do that.
  • The GPS-NAV can provide 5V power for a Compaq Aero 1550 Pocket PC.  It may, or may not have enough current to power an iPAQ.  It may work as long as the iPAQ is fully charged, but most pilots invest in a 12V to 5V converter like the Goddard PS-5a to be on the safe side.

Need to Know Items
I am very up-front about the limitations of the products I sell.  I want to be sure that you feel I have helped you select the best system for your needs.  This section points out some items that may not be obvious when comparing products.

  • The GPS-NAV is somewhat expensive when compared with similar competitive products.  The 302A is also a much lower cost solution.  However, the optional LCD display offer the best user interface by far.  Also, the GPS-NAV works better with the L-NAV than competitive products.
  • Memory for only 250 waypoints.  The 302 and CFR hold 2000 waypoints.
  • Memory for only 11 hours of flight recording at 4 second intervals.  The 302 and CFR hold up to 100 hours at 4 second intervals.
  • Flight logs files downloaded from the GPS-NAV are stored in ".cai" files and must be converted to ".igc" files using PC software.  Most flight analysis software programs prefer ".igc" files.  It is very easy to convert the files, but a little bit of a pain.
GPS-NAV Model 20 and Model 25 Dimensions
Size: 4.7" x 2.7" x 2.0"
120mm x 68mm x 51mm
Weight:         13 oz. (.36 kg)
Supply Voltage: 12-14 VDC
Current:         50 mA @ 12V

LCD Navigation Display

  • Fast and simple navigation point selection.
  • Instant bearing and distance display for up to 250 points.
  • Instant toggle between a turnpoint and a landing field.
  • Navigation points listed by full 12 character names.
LCD Navigation Display Dimensions
Size: 2.6" (66 mm) height and width,
0.47" (12mm) in front of instrument panel
0.80" (20 mm) behind instrument panel
fits standard 57 mm panel opening,
Weight:         0.35 lbs (0.15 Kg)

Example System

  • Cambridge Aero Instruments GPS-NAV Model 20, IGC Approved Flight Logger - $1220
  • Glide Navigator II Soaring Software with Moving Map, Final Glide, Flight Logging, etc. - $149
  • Compaq iPAQ 3950 Pocket PC - $459.95  (any iPAQ (other than the 1900 series) will work, see the iPAQ comparison on the Pocket PC page)
  • :: Goddard :: PS-5a and PGNAV-1 - PS-5a 12 V to 5 V high efficiency power converter and PGNAV-1 cable to connect the GPS-NAV to the PS-5a.  Supplies 12V power to the GPS-NAV. $88 + $65 = $153
  • TEKK-iPAQ-3900-Gn15cm-DB - $195, Gooseneck mount for iPAQ 3800, 3900, or 5400 Pocket PC.  Includes cable to connect to PS-5a.

Total Price of all the components: $2176.95
If you already own an iPAQ, it is only $1717
If you already own a GPS-NAV, it is only $956.95
If you already own a GPS-NAV and an iPAQ, it is only $497

There are lower cost mount options.  See the Mount Comparison page.

GPS-NAVs can be purchased as part of a System, or as individual components.  Below is a summary of what's included with each kit.
GPS-NAV Model 20 or Model 25 System - Special Package Price
These systems include everything you need in a complete system - including the LCD Navigation Display.  You save $77 when you purchase the packaged Model 20 system and $86 on the packaged Model 25 system.  If you don't need the display you should order the GPS-NAV unit only at right.

Models (select one when ordering)

  • CAF 016S, GPS-NAV Model 20 Logger with built-in antenna, $1560
  • CAF 017S, GPS-NAV Model 25 Logger, with CAA-074 GPS antenna, $1625

The GPS-NAV System comes complete with the following accessories:

  • CAF 013, LCD Navigation Display (English, French, Deutsch or Italian)
  • Charger
    • HA 333, Input: 120 V, 60 Hz, Output: 12 V, 500 mA
    • HA 334, 220 V
  • CAA 074, GPS Antenna (Model 25)
  • HA 349, Serial Data Cable
  • MA 008, GPS-NAV Manual and Software
  • Kit of modular cables, RFI filters, and mounting hardware

Optional (select when placing order):

  • CAA 064, GPS-NAV External Power Pack, battery and cable, 12V, 2 AH, $80
  • CAA 065, Canopy Quick Mount for GPS-NAV Model 20/25, suction cup mount, $80


GPS-NAV Model 20 or Model 25 - GPS Only - No Display
Order these parts if you don't need the LCD Navigation Display.  If you need the display, order the packaged systems above.

Models (select one when ordering)

  • CAF 016, GPS-NAV Model 20 Logger with built-in antenna, $1220
  • CAF 017, GPS-NAV Model 25 Logger, with CAA-074 GPS antenna, $1294

The GPS-NAV System comes complete with the following accessories:

  • CAA 074, GPS Antenna (Model 25)
  • MA 008, GPS-NAV Manual and DOS Software on Floppy Disks
  • Kit of modular cables, RFI filters, and mounting hardware

Optional (select when placing order):

  • Charger (Highly Recommended Option)
    • HA 333, Input: 120 V, 60 Hz, Output: 12 V, 500 mA, $11
    • HA 334, 220 V, $32
  • HA 349, Serial Data Cable, $11 (Highly Recommended Option)
  • CAA 064, GPS-NAV External Power Pack, battery and cable, 12V, 2 AH, $80
  • CAA 065, Canopy Quick Mount for GPS-NAV Model 20/25, suction cup mount, $80

There are several PC software programs which may be used to edit waypoint databases, transfer waypoint files to the GPS-NAV, and download flight logs from the GPS-NAV. 

Demo/Training Files for Cambridge GPS-NAV Flight Recorder and LCD Display
This is an html (web page) demo/training system for the Cambridge GPS-NAV flight recorder and LCD Navigation Display.  It is a great way to learn more about the GPS-NAV, or to learn how to use it if you already own one.  It was created by Paul Remde for Cambridge in 1998. 


  • Download and open the zip file: demogpsn.zip
  • Extract the files to a directory somewhere on your PC - I recommend the "My Documents/GPS-NAV Demo" folder
  • Open the folder and double-click on the file "demogpsn.htm"
  • Follow the directions on the screen

Cumulus Soaring, Inc.
Paul E. Remde

8661 Connelly Place
Savage, Minnesota 55378

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Phone: 1-952-445-9033
FAX: 1-952-445-8954