How Do Sat Actually Navs Work?

How Do Sat Navs Actually Navs Work

Have you ever wondered how satellite navigation systems can help you in searching for your route?

Around 14 million people, or approximately 52% of the driving population in the UK, regularly use the sat nav. Before the sat nav, people need to ask for directions or use a map to navigate the road. Now, the time is so much different as people are using modernised satellite navigation systems.

Have you ever used a sat nav? Were you able to see how it works and how you can use it in the future?

Page Contents

How does a sat nav work?

All of the available sat navs work in the same way as they detect signals from different satellites. Galileo has information that dominates the European system because it has 30 satellites planned for orbit last 2020 that can help triangulate your position.

The sat-nav works on calculating your position by having the speed-of-light signal triangulated from three or more satellites in just a blink of an eye. 

It continues to do this to adjust your real-time position as you become more accurate in simultaneously showing the direction of your travel. The speed could get to a higher degree of accuracy than possible even if NASA developed this technology several years ago. Because of this, the sat nav is a miracle made by modern science.

GPS Satellites

GPS or Global Positioning System is what sat navs use to determine the exact place where you are located on earth. The GPS uses a network of 30 satellites that they originally sent to space for military service.


Wherever you may be located in the world, you can see at least four GPS satellites. However, you only need three to generate an accurate location. Sat navs make use of this information that three different satellites send to calculate the exact destination of the sat nav. That is what they call trilateration.

Every time the vehicle is moving, three satellites would work on the recalculation of the location. Whenever it moves out of one sphere, the other satellite’s sphere will pick it up. Once everything gets in place with a decent signal, it will calculate further information like trip distance, speed, distance to your destination, and more.

If the sat nav, for some reason, is unable to lock onto three satellites, it will not generate a position. If you want to get a 3D position, you have to use four satellites instead of the standard three.

How accurate can my sat-nav be?

When it comes to your sat nav’s accuracy, it would depend on the number of satellites that it can see. Whenever it sees six satellites, it can be as accurate as 20 metres. However, if it could see 10-12, the accuracy can increase within 5 metres.

GPS Accuracy

So much has developed from GPS since the 1980s that it has become more and more accurate. The most authentic are receivers that have WAAS capability. These are the ones you will see on aeroplanes because they can keep the GPS throughout the flight.

How can a sat nav calculate a route?

The most impressive feature of sat navs is that they are capable of calculating the route. Imagine, there are so many different routes from Liverpool to Manchester! Now, how can the sat-nav figure out the best way from these two points?

Well, it begins by imagining how the car goes through this route and then having that route broken into stages using the nearest streets as a guide. After that, the road network is divided into a series of vectors or lines between different fixed points.

Generally, these fixed points are road junctions that often offer a binary right or left choice so that subsequent calculations will become relatively straightforward.

So, if you want to get to Manchester, the first part of your route, which is the initial vector, needs to be along your drive. That is a singularity. However, at the bottom of your drive, you can either turn right or left. This binary decision could get you to the main road, whatever you choose. However, when it comes to sat-navs, you can choose from two different vectors.

How a sat-nav chooses what to recommend is attributed to several factors in every vector: cost and length.

Multiple Routes

A direction may be longer than the other for fictional commutes, but the traffic could generally be free-flowing. Even if this vector has an extended length, it has a lower cost as the shorter road may be prone to congestion from schools or shopping malls, increasing expenses.

Because of that, it would depend on the parameters that you set. If you set for a direct or fast route, your sat nav will calculate both of the vectors’ values and choose the best one to balance the cost and the length.

That will continue to happen at each of the vectors of your journey until you get a suggested route created by linking numerous decisions in one coherent course on the road.

However, things won’t stop there as most sat-navs offer a choice from a couple or several different routes. Because of that, it may need to have the whole computation done several times. That is something you may have to reflect on whenever you feel impatient about waiting for it to have your route calculated.

Adjustment in Traffic

Almost every sat-nav system are now capable of adjusting your route so they can consider the existing traffic conditions and divert you whenever there is a traffic jam up ahead. How can it do this? The computer system of your sat nav gets data from different sources like the other speed cameras, sat navs, including the mobile phones that other drivers have. It is processed and sent to your vehicle’s sat nav. Because of that, it can detect if so many mobile phones and sat navs travel slowly on a particular road. It will deduce that something is slowing down the movement of drivers.

Again it will have a value assigned to calculate and delay if the optimum route will go a different way or if you can still be better at having things toughed out on the first road that you went through.

Yet, it may become quite clunky because with first-generation sat-navs, taking a detour may sometimes allow you to save several minutes. However, once they get better and the fuzzy logic helps calculate the genuine saving of ‘humanity’, unlike one that can be purely mathematical.

A great example of a system that uses crowd-sourced data to calculate the optimum route that would depend on traffic jams, user-reported obstructions, and other incidents is Waze. Even if it may not be effective in providing detours around heavy traffic, it can improve your sat-nav experience. It also reports where police vehicles and officers are located, including mobile and fixed speed traps.

Once sat-nav systems become linked together in the future, civil engineers would have other cars and vehicles directed along various routes that would depend on their assigned priority and size. One example of this is lorries. They may get directed to a course that avoids low bridges and city centres. If you have a more agile and smaller vehicle, it can go on a different and more direct route.

Have your sat nav linked to your car…

Evolution will happen when highly clever people think of various ways to use all of the great information that an in-car sat-nav provides. The engineers’ imagination may solely limit the possibilities as they work on these projects.

The cross-fertilisation of non-automotive engineers from Google and Apple can significantly help. Vehicle manufacturers have said that they have only started to scratch the surface of the available possibilities. As of the moment, we’ll illustrate what you can expect by informing you about two very different manufacturers. These are Rolls-Royce and Jeep.

The Rolls-Royce Wraith has a GPS signal that provides the automatic gearbox eight-speed warning if there is an impending corner or hill to pre-emptively change to a more responsive gear. Because of that, it gives anticipation similar to Jeeves with a seamless gear change that occurs in an unusually unobtrusive way that it can be genuinely clever and valuable.

Unlike Rolls-Royce, Jeep comes from a culture of risk-avoidance and consumer litigation, so it uses the same information in a highly different manner. It makes use of the sat-nav data so it can predict the upcoming corners’ severity and cross-conference it to the vehicle’s speed.

If the electronic brain of your Jeep thinks that you are driving too fast, it will hysterically shriek at you so that you will slow down. It may sound like a great idea, but this culture of risk avoidance and consumer litigation means that the threshold is set too low that it can lead to an overwhelming urge for you to turn it off and a lot of false positives.

In the extreme, the result can be so frustrating and annoying that it can ruin the vehicle for you. We hope that everything will get sorted before they have it linked into the braking system.

Limitations of the Sat-Nav System

Using your sat-nav system in a built-up area can make the signal bounce off walls and buildings, reducing its accuracy. In the worst possible scenario, it may mean that the signal may be ‘off’ by around hundreds of metres.

It can also be possible for the sat-nav system to throw an odd hissy fit and send you in a completely wrong direction. An extreme example of this is the Syrian lorry driver. He got diverted through to Skegness on his journey from Turkey to Gibraltar.

But, many people may be familiar with the stories of people who drive into lakes as they slavishly follow the directions of their sat navs. Remember that the sat-nav is just an aid and may never be a substitute for common sense!

Sat Navs in the Society

Because of the prevalence of sat navs, it is now incorporated into the UK driving test’s ‘independent driving’ sector. Here, candidates need to accurately follow the directions of the Sat Nav so they can pass.

Underway is a multi-million-pound project to create a database that has information on around 200 thousand miles of roadways. It aims to give accurate bridge heights, weight restrictions, and road widths so that cars and lorries won’t get stuck.

Keep your eyes on the road.

According to estimates, driver distraction is a factor in around a quarter of every road traffic accident. According to research in Sweden, the use of a sat-nav can be as distracting as your mobile device. Because of that, if you need to make adjustments or program your sat nav, it would be best to pull over where it would be safe for you to do so. By now, you have a lot of ideas on how sat navs work and how they can help you in your travel.

Add Comment