GPS troubleshooting

For detailed GPS troubleshooting, GPS debug message can be enabled on OEM Server. When the debug level is set to Info, GPS debug messages will appear in the log. In addition to individual fix times, signal level diagnostics whenever a fix takes longer than 36 seconds, or the GPS decides to stay awake after a fix to collect more satellite information. Please note that while debug messages are enabled, uploads will use extra data.


The GPS debugging can be enabled on the OEM Admin Interface by selecting the device; going to Device Operations->Set Device Debug Flags; set GPS to Info; select an expiry date when the debugging should end; click OK.

The diagnostics will be available on the OEM Admin interface. Click device details and go to the logs tab. 


Uploaded debug messages will look like this:


Example

Description

Debug[GPS][Info]: TTFT=0s

Time taken for GPS to determine the time. Usually 0 or 1 seconds.

Debug[GPS][Info]: TTFF=3s PDOP(x10)=23 3Dfix=1

Time taken for a basic GPS fix. Usually between 1 and 36 seconds.

Debug[GPS][Info]: Valid=3s PDOP(x10)=23 3Dfix=1

Time taken before a GPS fix passes additional validity filters. Usually TTFF + 0 to 3 seconds.

Debug[GPS][Info]: ORB 54,4,10

Known orbitals. In this example, of 54 possible orbitals, 4 are known in detail, and the knowledge is useable for the next 10 x 15 minutes. Detailed orbital knowledge is not required for a fix, but can speed up the process.

Debug[GPS][Info]: SAT22 43402,43723,40663 …

Tracked satellites. In this example, 22 simultaneous channels are active (locked or searching). The best ten satellites are listed, with the first two digits of each number being the signal to noise ratio – 43, 43, and 40 dB Strengths above 25 are useable, above 35 are good, and above 45 are excellent.