How a Sat Nav Works


Satellite Navigation, commonly known as sat nav, GPS navigation system or GPS nav, is generally used as a route finder on all forms of transport. It is used in vehicles to provide directions, and route analysis to the drivers. Most of the vehicles use sat navs, and are highly available to the general public. Sat Nav does its job with the help of a complex software, maps, a GPS receiver and more. Here is a simple explanation on how a sat nav works.

The basic method on which a sat nav works is on Triangulation Method. It is a method of determining the location of a map by using three or more points, through which the lines are drawn. The intersection of these lines will be the desired location. This could be also said as triangulating a place. Ideally, three or four satellites are required to pin down an exact position. That is, three satellites will concentrate on determining the position, and the fourth one will check for errors in the other sat navs.

To elaborate, the GPS receiver installed in a sat nav device will receive the radio signals from the satellites. By measuring the time taken for the signals to reach the sat nav, the GPS receiver will calculate the distance. For an accurate calculation of distance, a comparison between the time signal is sent, and the time signal is received is done, and is multiplied by the speed of light. The satellites are fitted with atomic clocks, which are permanently accurate and hence, the timings will be sent correctly. The key factor that ensures that the timing of GPS and satellites get synchronized is this accuracy. But, even if it goes wrong, the GPS receiver is capable to calculate and correct the errors themselves.

Along with the distance, the exact position of satellite in space is required. This is for range measurements. The satellites are positioned on high orbits, between 10,600 miles to 12,625 miles. Hence, the chance of getting satellites off the orbit is quite rare. The signals have to pass through different layers of atmosphere, and these can cause delays in GPS. But it is factored out using mathematics.

Using the distance and the time taken for the signals to reach receiver, the GPS receiver will lock down the precise position on to the built-in map of the device. Besides, the speed and direction to which the user is travelling is calculated. In an aircraft, the altitude is also calculated by the device. Once the position is overlaid on to the maps, the built-in software allows you to set destination and will guide you through the routes.

Depending on the features installed in various satellite navigation devices, it will be capable to alert the user on traffic information or speed camera warning and so on.