[SOLVED] MKR GPS Shield does not provide course/heading data

Projects Networking, Protocols, and Devices
1

Hello!
I recently got a MKR GPS shield and have been playing around with it. When I upload code, I get the correct output, (lat, long, speed, altitude, satellites,) but I cannot get heading/variation working.
The shield is connected via the I2C cable

Code:

/*
  GPS Location

  This sketch uses the GPS to determine the location of the board
  and prints it to the Serial monitor.

  Circuit:
   - MKR board
   - MKR GPS attached via I2C cable

  This example code is in the public domain.
*/

#include <Arduino_MKRGPS.h>

void setup() {
  // initialize serial communications and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

  // If you are using the MKR GPS as shield, change the next line to pass
  // the GPS_MODE_SHIELD parameter to the GPS.begin(...)
  if (!GPS.begin()) {
    Serial.println("Failed to initialize GPS!");
    while (1);
  }
  Serial.println("Aquiring satellites...");
}

void loop() {
  // check if there is new GPS data available
  if (GPS.available()) {
    // read GPS values
    float latitude          = GPS.latitude();
    float longitude         = GPS.longitude();
    float altitude          = GPS.altitude();
    float speed             = GPS.speed();
    int   satellites        = GPS.satellites();
    float crs  = GPS.course();
    float var  = GPS.variation();
    // print GPS values
    Serial.print("course: ");
    Serial.println(crs, 20);
    Serial.print("Variation: ");
    Serial.println(var, 20);

    
    Serial.print("Location: ");
    Serial.print(latitude, 20);
    Serial.print(", ");
    Serial.println(longitude, 20);

    Serial.print("Altitude: ");
    Serial.print(altitude);
    Serial.println("m");

    Serial.print("Ground speed: ");
    Serial.print(speed);
    Serial.println(" km/h");

    Serial.print("Number of satellites: ");
    Serial.println(satellites);

    Serial.println();
  }
}

Output:


course: nan
Variation: nan
Location: *my location*
Altitude: 124.90m
Ground speed: 0.08 km/h
Number of satellites: 9

course: nan
Variation: nan
Location: *my location*
Altitude: 124.60m
Ground speed: 0.14 km/h
Number of satellites: 9

Does anyone know why this is happening?
Thanks!

2

Is the GPS actually moving?

3

It is sitting on my desk, not moving.

4

Ground speed: 0.14 km/h

The lat and long from a GPS will normally vary a bit from fix to fix, so whilst physically its not moving, the GPS will think it is.

5

I believe that to get a course, the GPS must be moving so that it can calculate it from two consecutive fixes.

As srnet notes, the fix will vary naturally over time a bit, so I expect that there's some minimum distance that you need to move it before course calcs are enabled.

6

Makes sense. Thank you!