Moving object depending on player's GPS movement: null reference exception with accessing speed variable = if (speedGPS.speedInKmPerHour >=5f)

Hello,

I'm trying to move an object depending on the speed that the player is travelling at in real life (using GPS): I have the two scripts separately, but I'm having trouble accessing the speed variable in the speedometer script using this line: if (speedGPS.speedInKmPerHour >=5f)

As it's throwing the Null Reference Exception: object reference not set to an instance of an object.

This is the movement script (which moves two terrains to give the appearance of the object moving):

 public class MoveTerrain : MonoBehaviour {
 
     public float moveForwards = 20f;
     public GameObject terrain;
     public Vector3 targetPos;
     public GameObject otherTerrain;
     private Speedometer speedGPS;
 
     static public float speed = 10.0f;
 
     void Update () {
 
         if (speedGPS.speedInKmPerHour >=5f)
         //    if (Input.GetKey("w"))
         terrain.transform.Translate(Vector3.forward * Time.deltaTime * moveForwards * speed);
 
     }
 
     void LateUpdate()
     {
         if (targetPos.z - terrain.transform.position.z < 10f)
             terrain.transform.position = otherTerrain.transform.position + new Vector3(0.0f, 0.0f, -250);
     }
 }

And this is the speedometer script that accesses the speed the player is moving at:

     public float speedInKmPerHour = 0f;
     public float timeframe = 0f;
     public int recordSize = 2;
 
     private List<LocationInfo> record = new List<LocationInfo> ();
     private LocationServiceController service;
 
     // -------------------------------------------------------------------
 
     /* Request location services to start */
     void Start(){
 
         service = gameObject.AddComponent<LocationServiceController> ();
 
     }
 
     /* Wait until services are ready */
     void Update(){
 
         if (!service.ready)return;
         AddValidSample ();
         if (record.Count >= 2) {
             UpdateSpeed (forelast, last);
         }
             
     }
     
     void AddValidSample(){
 
         LocationInfo sample = current;
         // discard duplicates
         if (record.Count > 0 && sample.timestamp == last.timestamp) {
             return;
         }
         record.Add (sample);
         while (record.Count > recordSize) record.RemoveAt (0);
 
     }
 
     void UpdateSpeed(LocationInfo a, LocationInfo b){
         
         float D = Speedometer.distInKm (a, b); 
         timeframe = (float)(b.timestamp - a.timestamp);
         float speedInKmPerSecond = D / timeframe;
         speedInKmPerHour = speedInKmPerSecond * 3600;
 
     }
 
     LocationInfo last        { get { return record [record.Count-1]; } }
     LocationInfo forelast    { get { return record [record.Count-2]; } }
     LocationInfo current    { get { return Input.location.lastData; } }
 
     public static float distInKm(LocationInfo A, LocationInfo B){
 
         float lat1 = A.latitude;
         float lon1 = A.longitude;
         float lat2 = B.latitude;
         float lon2 = B.longitude;
         float R = 6371e3f; // ~ earth radius in metres
         float φ1 = lat1*Mathf.Deg2Rad;
         float φ2 = lat2*Mathf.Deg2Rad;
         float Δφ = (lat2-lat1)*Mathf.Deg2Rad;
         float Δλ = (lon2-lon1)*Mathf.Deg2Rad;
         float a = Mathf.Sin(Δφ/2) * Mathf.Sin(Δφ/2) 
             + Mathf.Cos(φ1) * Mathf.Cos(φ2) * Mathf.Sin(Δλ/2) * Mathf.Sin(Δλ/2);
         float c = 2f * Mathf.Atan2(Mathf.Sqrt(a), Mathf.Sqrt(1f-a));
         float d = R * c;
         return (float)d * 0.001f;  
 
     }
 
 }

Does anyone know what I'm doing wrong?

All the best,

Laurien