There are around 31 active satellites used for GPS communication that rotate around the Earth's axis. Their orbit is inclined 55 degrees to the equator. The satellites are placed 20,000 kilometers from the Earth's surface and their orbits are designed in such a way that each satellite completes two orbits per day. Orbits are planned so that at least 6 satellites are visible, from most areas of the Earth [4]. C. TrilaterationTrilateration is a simple mathematical approach used to estimate vehicle location by calculating the distance to satellites in view. For 2D location estimation (latitude, longitude), the GPS receiver must lock on at least three satellite signals. However, estimating the location with three satellites can lead to inaccurate results if the vehicle is not at mean sea level. In this case, we need to derive the altitude information in addition to the latitude and longitude (3-D). This can only be established if the receiver receives signals from at least four