Troubleshooting GPS

Normal behavior:

When Ruby is first powered up, the red light on the GPS module should blink to indicate that it's searching for satellites. Once it has acquired a fix, the light will stay off.

If powered up for the first time in a long time, or at a very different geographic location ( "cold start"), it may take 2-3 minutes for the search to end if outdoors, and longer if indoors. From some indoor locations, it may not be possible to acquire a fix.

Once it acquires satellites, the module will download and store "almanac" information from the satellites to its memory. This information enables the module to narrow its initial search for satellites so that for subsequent power ups, it should only take 20-30 seconds to acquire a fix. ( "warm start".)

Ideal location:

The GPS is ideally located near the top of the plane with little between it and the sky.

Be sure there are no wires, metallic , or graphite structures above or pressed against the side of the ceramic antenna..

Foam, plastic,and thin wood are not much of a concern. You can embed the GPS with foam, cover it with tape, or have it surrounded by a canopy.

If the GPS light does not stop blinking, even after several minutes
try the following to narrow down the problem:

• Move switching BEC away from GPS module
  For instance we've found that the ParkBEC will strongly interfere with the GPS module if located less than 2 inches away from it, but that there are no apparent problems at 3 or more inches separation.
• Take it outdoors where it has a clear view of the sky.
  Things like metal roofs or floors above your test area can make it impossible to get a lock indoors.
  
• Make sure it's pointed up at the sky.
  (Ceramic antenna pointing up, circuit board on the bottom.)
• Turn off video transmitter
• Try a different 5 volt power supply for Ruby.
  Some "switching BEC" power supplies might cause excessive radio interference

If the GPS light does not blink at least momentarily when power is first applied:

Check the cabling, connectors, and header pins.

 

What can damage the GPS?

Extreme physical shock

Moisture