Sat Nav and The Science Behind It

The thought of travelling to a far-off village with a road map in tow has become antiquated in recent years, and that’s primarily due to satellite navigation. This remarkable tech is now so common that most of us carry a global navigation system in our pockets every day.

Sat nav was originally invented for the US military, and was based on primitive navigation systems that had been prototyped in the 1960s. Mapping as we know it was opened up to consumers after the US government decrypted its navigation systems and improved accuracy, which took place around 20 years ago.

In the mid-2000s, the first commercially available sat nav systems were fitted to cars, and there’s now very little practical difference between the system on your phone and the system used by the military.

How Sat Nav Works - the Basics

The GPS chip in your phone or sat nav system scans the sky looking for positioning satellites.

There are 24 of these satellites currently in orbit, although your sat nav only needs to be able to see three of them to get a location. In practice, most of our devices can see several at any time.

If your device can see four satellites, rather than three, it gets a little bit more information: it can also calculate your altitude.

The phone in your pocket, or sat nav in your car, still requires the resources of the US military on the ground, too. Two ground stations in the United States ensure that the satellites are functional by tracking data from a global network of monitoring stations. There’s more information on the US government website.

Calculating location in this way is fraught with complicated problems. For example, although these satellites carry atomic clocks, the time stamps they generate can be slowed down by the earth’s atmosphere. Also, time ticks by at a slightly different speed in space, because the pull of gravity is different. So sat nav satellites have to be able to compensate for all of these small differences to give an accurate location.

Evolving Tech

Sat nav has evolved in the last few years, fuelled in part by the rise in 4G connectivity. Now, maps can be automatically updated when roads are closed, or when roadworks are in place, giving people more useful directions. Additionally, 4G is used in combination with self-driving technology to create driverless vehicle systems.

In theory, this will mean that self-driving cars will soon be able to avoid collision by constantly knowing the location of all the other cars around them.

This combination of GPS and two-way connectivity has also turned sat nav into a way to track and locate people. There’s still controversy over the use of location data by companies that track us to sell us things and serve us ads.

The one downside of all this clever tech is that it could be switched off or disrupted, and there are signs that sat nav signals are already being jammed by rogue states as a form of cyber attack. In fact, the humble sat nav is perhaps one of the most important advances of the modern world because most of us are so dependent on it being functional.

With the above in mind, there would be nothing worse than something happening to your trusty road partner. If it's a cracked screen or it's been stolen, we've got you covered.

*The information in this blog is designed to provide helpful information on the subjects discussed. Please seek a professional for expert advice as we can not be held responsible for any damages or negative consequences upon following this information.

4K Ultra HD, 4K UHD, or just plain old 4K. These have all become stock phrases you have probably seen or heard shouted loud and proud from ads and promotions for the latest TV sets. But what exactly do they mean, and why should you get excited about them?

Technical jargon has a way of worming itself into our collective vocabulary without much thought about whether everyone really understands what the terms mean or not. 4K Ultra HD is a classic example. Over the last few years, it has become marketing shorthand for “this TV provides amazing picture quality - don’t settle for any less when you are bingeing on your favourite series or cheering on your favourite sports team!”

And that’s as much as the average person in the street would be able to tell you - 4K UHD means brilliant picture quality. But what is the difference to, say, plain old HD? And is 4K really the best of the best if you are on the hunt for the perfect picture?

Screen resolution explained

Let’s start by going back to basics. HD, of course, is shorthand for high definition, which is a term used to describe the resolution, or picture quality, of a screen. Resolution is a technical feature defined by the number of pixels on the screen. The basics of it are, the more pixels you have on a screen, the more detail you are able to render and so the better the picture quality.

Prior to the arrival of HD in the late 1990s, the standard definition for TV sets (SDTV) had been 720x480 pixels - or close to 350,000 pixels in total. When HDTV arrived, it improved on this in two phases, first of all with ‘HD ready’ sets with roughly one million pixels (1366×768 was a typical resolution of early HD ready LCD screens), then ‘full HD’ - 1920×1080, or approximately two million pixels.

This is where the naming conventions of screen resolutions starts to get a little confusing. Full HD is often known as ‘1080p’ - describing the number of pixels you get in a single vertical column on the screen. At the same time, you may see it referred to as ‘2K’ - because full HD screens usually have around 2000 pixels in every horizontal row.

It is this latter (though probably less common) convention that the ‘4K’ part of 4K Ultra HD has followed - UHD screens have roughly 4000 pixels in every row. A typical Ultra HD resolution, for example, is 3,840x2,160. The mathematically minded amongst you will have spotted that that works out as more than eight million pixels in total - so four times the resolution of a full HD screen.

So if you’re looking for the best picture quality available, surely it’s a no-brainer - you have to go for 4K UHD, right?

Well, yes and no. There’s no doubting 4K looks great, it’s a marked improvement even on full HD, and 4K screens are no longer even that expensive. But whether you need 4K UHD is another question. To get the best picture quality on the biggest screens, for example - certainly anything upwards of 40 inches - you want as many pixels as possible, so 4K should be your starting point. But if you are content with a much smaller screen - for secondary TV screens in bedrooms, for example - you might not notice much of a difference between full HD and UHD.

Another consideration is that to get the true Ultra HD experience, TV programmes and movies have to be shot in UHD as well as broadcast/played in UHD. Although production companies are now responding to increased demand for 4K, there is still a lot of TV and video content out there that is made for lower resolution playback. Put simply, video filmed below 4K doesn’t have the detail to fill all those pixels on a UHD screen. Your Ultra HD set therefore has to adjust to fill in those blanks, and some people complain they don’t like how that looks.

Finally, while 4K Ultra HD has become the de facto standard for new TVs and film making, it is no longer the hottest prospect in town in terms of picture quality. If you really want to crank up the picture quality - and have the deep pockets to match - 8K UHD next generation screens are available, packing a massive 32 million-plus pixels, or four times the resolution of 4K.

Whether you decide to play it safe with a budget full HD TV or splash out on a next generation 8K set, make sure you insure your TVs with Row.co.uk’s fabulous value TV insurance, starting at just £1.49 a month.

ultra 4k tv with man watching Netflix in his modern living room

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