Get the speed differential from 2 Longitude and Latitude points.

speed_gps.js

/**
 * Created by ramor11 on 3/3/2017.
 */

function distance_on_geoid(lat1, lon1, lat2, lon2) {

	// Convert degrees to radians
	lat1 = lat1 * Math.PI / 180.0;
	lon1 = lon1 * Math.PI / 180.0;

	lat2 = lat2 * Math.PI / 180.0;
	lon2 = lon2 * Math.PI / 180.0;

	// radius of earth in metres
	var r = 6378100;

	// P
	var rho1 = r * Math.cos(lat1);
	var z1 = r * Math.sin(lat1);
	var x1 = rho1 * Math.cos(lon1);
	var y1 = rho1 * Math.sin(lon1);

	// Q
	var rho2 = r * Math.cos(lat2);
	var z2 = r * Math.sin(lat2);
	var x2 = rho2 * Math.cos(lon2);
	var y2 = rho2 * Math.sin(lon2);

	// Dot product
	var dot = (x1 * x2 + y1 * y2 + z1 * z2);
	var cos_theta = dot / (r * r);

	var theta = Math.acos(cos_theta);

	// Distance in Metres
	return r * theta;
}


var p1 = {
	latitude: '36.082329',
	longitude: '-79.483449',
	timestamp: '0'
}

var p2 = {
	latitude: '36.079751',
	longitude: '-79.493433',
	timestamp: '300000' //5 minutes
}

var dist = distance_on_geoid(p1.latitude, p1.longitude, p2.latitude, p2.longitude);
var time_s = (p2.timestamp - p1.timestamp) / 1000.0;
var speed_mps = dist / time_s;
var speed_kph = (speed_mps * 3600.0) / 1000.0;
var speed_mph = speed_kph / 1.609344;

console.log('meters per second', speed_mps);
console.log('kilometer per hr', speed_kph);
console.log('miles per second', speed_mph);