I'm using Unity3D and I created simple distance, speed and acceleration calculator using latitude and longitude of last position. I'm calculating last distance, speed and acceleration in each GPS update (approximately once per second). But sometimes (2-3 second interval) latitude and longitude values changes rapidly (in clear weather and no obstacles). That's why speed and acceleration values gets unreal results. For example, at stable 40 km/h speed, speed value becomes 60 km/h and returns to 40 km/h within 2-3 second. I'm here to ask how can I avoid this inaccurate and rapid GPS data changes?
I'm using Nexus 5 device
Thanks for any help and tip
PS. Please edit my question if I made any grammar and logical mistake.
What I have tried:
There is my code:
using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using UnityEngine.SceneManagement;
public class Manager : MonoBehaviour
{
public Text longitude, latitude, lonAText, latAText, lonBText, latBText;
public Text result, overallResult, speedText, lastTimeText, timerText, accelerationText, speed0Text;
float lonA, lonB, latA, latB, overallDistance, lastDistance, timer, lastTime, speed, speed0, acceleration;
bool firstTime, allowTimer;
public AudioSource audio;
void Awake()
{
overallDistance = 0;
lastDistance = 0;
timer = 0;
lastTime = 0;
speed = 0;
speed0 = 0;
firstTime = true;
allowTimer = true;
}
IEnumerator Start()
{
if (!Input.location.isEnabledByUser)
yield break;
Input.location.Start(1, 1);
int maxWait = 20;
while (Input.location.status == LocationServiceStatus.Initializing && maxWait > 0)
{
yield return new WaitForSeconds(1);
maxWait--;
}
if (maxWait < 1)
{
print("Timed out");
yield break;
}
if (Input.location.status == LocationServiceStatus.Failed)
{
print("Unable to determine device location");
yield break;
}
else
{
print("Location: " + Input.location.lastData.latitude + " " + Input.location.lastData.longitude + " " + Input.location.lastData.altitude + " " + Input.location.lastData.horizontalAccuracy + " " + Input.location.lastData.timestamp);
longitude.text = Input.location.lastData.longitude.ToString();
latitude.text = Input.location.lastData.latitude.ToString();
lonA = Input.location.lastData.longitude;
latA = Input.location.lastData.latitude;
}
}
void Update()
{
longitude.text = Input.location.lastData.longitude.ToString();
latitude.text = Input.location.lastData.latitude.ToString();
timer += Time.deltaTime;
timerText.text = timer.ToString();
if (lonA != Input.location.lastData.longitude || latA != Input.location.lastData.latitude)
{
audio.Play();
CalculateDistances(lonA, latA, Input.location.lastData.longitude, Input.location.lastData.latitude);
lonA = Input.location.lastData.longitude;
latA = Input.location.lastData.latitude;
lastTime = timer;
lastTimeText.text = lastTime.ToString();
timer = 0;
speed0 = speed;
speed0Text.text = speed0.ToString();
CalculateSpeed();
CalculateAcceleration();
}
}
public static float Radians(float x)
{
return x * Mathf.PI / 180;
}
public void CalculateDistances(float firstLon, float firstLat, float secondLon, float secondLat)
{
lonAText.text = firstLon.ToString();
latAText.text = firstLat.ToString();
lonBText.text = secondLon.ToString();
latBText.text = secondLat.ToString();
float dlon = Radians(secondLon - firstLon);
float dlat = Radians(secondLat - firstLat);
float distance = Mathf.Pow(Mathf.Sin(dlat / 2), 2) + Mathf.Cos(Radians(firstLat)) * Mathf.Cos(Radians(secondLat)) * Mathf.Pow(Mathf.Sin(dlon / 2), 2);
float c = 2 * Mathf.Atan2(Mathf.Sqrt(distance), Mathf.Sqrt(1 - distance));
lastDistance = 6371 * c * 1000;
result.text = lastDistance.ToString() + " meters";
overallDistance += lastDistance;
StartCoroutine(Overall());
}
IEnumerator Overall()
{
if (firstTime)
{
firstTime = false;
yield return new WaitForSeconds(2);
if (overallDistance > 6000000)
{
overallDistance = 0;
lastDistance = 0;
}
}
overallDistance += lastDistance;
overallResult.text = overallDistance.ToString() + " meters";
}
void CalculateSpeed()
{
speed = lastDistance / lastTime * 3.6f;
speedText.text = speed.ToString();
}
void CalculateAcceleration()
{
acceleration = (speed - speed0) / lastTime;
accelerationText.text = acceleration.ToString();
}
}