gps GPS example

This example can be used to interact with GPS devices in NuttX. It uses the MINMEA library to parse standard NMEA messages and print out GPS data to the console.

To use the program, provide the character device path for the GPS serial connection as the only argument. If no path is provided, the program will default to /dev/ttyS1.

If you want to be able to see the floating point output of this program, make sure you remember to enable CONFIG_LIBC_FLOATINGPOINT.

The program loops forever parsing NMEA values from the serial device.

Waiting for GPS Fix

nsh> gps /dev/ttyS3
Fixed-point Latitude...........: 0
Fixed-point Longitude..........: 0
Fixed-point Speed..............: 0
Floating point degree latitude.: nan
Floating point degree longitude: nan
Floating point speed...........: nan
Fix quality....................: 0
Altitude.......................: 0
Tracked satellites.............: 0

The output will show nan and 0 for values while waiting to obtain a fix, at which point real values will begin to appear.

With GPS Fix

nsh> gps /dev/ttyS3
Altitude.......................: 73172
Tracked satellites.............: 5
Fixed-point Latitude...........: 4628356
Fixed-point Longitude..........: -8058408
Fixed-point Speed..............: 110
Floating point degree latitude.: 46.476547
Floating point degree longitude: -80.977995
Floating point speed...........: 0.001833
Fix quality....................: 1

You can now see the information is filled in with the data from the GPS.

Note

Fixed-point readings may have a different scale than the floating-point readings. For instance, the altitude above is fixed-point, but is actually 73.172 meters in floating point.