UK based satellite programme to launch

It's anticipated funding for the UK to set up its own satellite navigation system is going to be announced soon and this is going to be a rival for the European Union's Galileo project that the UK looks like it's going to be excluded from after Brexit. But how does GPS work. Could technology actually improve it. Chris Smith is joined by tech correspondent Peter Cowley, who explained whether we need our own GPS system in the first place, when the EU and America have one.

Peter -  It all comes down to how much we trust each other. In all these satellite systems that are two times when things can be reduced in accuracy or switched off. So the switching off would generally be used as it was used in the Gulf war just by the system having some recryption putting in place and then nobody can use it at all. Now you can imagine how many people use it particularly millennials who don’t know how to walk in the central London or the central region just got completely lost without GPS. We’d be completely stuck there so that’s why the Russians set up their own system. That’s why the Chinese have set up their own systems thats why Galileo was set up so that we are independent of each other should something horrible go wrong

Chris - It’s not just navigation though is it. We use the time signatures for even I learned the other day ATM machines at banks knowing when they’re doing transactions the time signatures arrive by GPs.

Peter -  Im not surprised at all because its a constellation of atomic clocks floating around and several of them. So there are 30 or so in each system and each of them is incredibly accurate

Chris -  and the anticipated price if we have to go down this route will be what to set our own system up?

Peter -   The European system was set up in about 0 5. It start and the first satellites launched in 2011 and are just about ready now. Quite a few satellites up there. The total cost of course was overrun it was about 10 billion euros of which the UK has paid one point two billion euros already and may want that back and that’s part of the big negotiating mix that’s going on with Brexit. It’s a complex project that brings a number of satellites transmitting signal down throughout the whole globe.

Chris - Do you not think it’s fairly daring on the part of the EU to chuck us out because the UK has been pretty instrumental in doing a lot of the coding and the security that’s associated with the Galileo system, it’s a bit like Microsoft sort of chucking out half the coders who wrote windows and saying thank you very much we’ll do fine. No thank you.

Peter -  That’s correct that the encryption was done in the UK and also the UK is pretty well known for quite good satellites. There’s a cluster of skills in Surrey and one in Glasgow. So yes that would have to be rewritten so they would cost money but at the same time there are a whole stack of things that Brexit is discussing that may be one of them.

Chris - Now you say that there’s an opportunity for us to go one better and improve on the system, in what way?

Peter - So think about it you’ve got a satellite that’s floating around about eleven or twelve thousand miles up there, 500 watts being sent out. It works out were getting the most amazingly small amount of power down on the earth on the antenna

Chris - in your detector you mean, the thing that’s picking it up?

Peter -  Yes exactly. which is very small antenna anyway, one with about 17 or 18 noughts afterwards. I did a rough calculation which I might be miles out but I think if you were to shine it down and tried to boil a kettle, with that power it would take the lifetime of the universe to actually boil that kettle, I might be out by lots of zeros.

Chris - So what your saying is that the satellites are sending a minuscule amount of energy which we detect with our devices so what's the problem that?

Peter -  The problem is that it doesn’t get inside buildings very easily. And more importantly as its going down in a city where there are skyscrapers there or even smaller buildings, it's bouncing off them and it works on the basis of time of flight from the satellite to the receiver. So if it's bouncing around obviously the time of flight is longer and therefore it becomes less accurate.

Chris - These are urban canyons these effects

Peter -  Yes or canyon cities.

Chris - So how can we get around that?

Peter -   Well there's a company which I'm invested here in Cambridge called focal point positioning and I'm sure there's plenty of other companies around the world which is doing it by detecting the differences within line of sight a non-line of sight and then calculating base the different so ignore the non light of sight if it can do and it's using what's called sensor fusion so it's collecting together all the sensors in the phone to effectively produce a larger antenna.

Chris - Presumably if the UK does commission its own GPS system then there'll be a tender. So it's not a guarantee that the company that youre talking about would get a slice of the action

Peter - They wouldn't want to do the satellite system itself, its to do with what's embedded in the device in our phones for instance or our wearables. The thing about if Britain was going to do it, of course our technology has moved on a lot in the last 15 years and the thought is that it would be a low orbit set of satellites which obviously spin around earth quickly but the amount of power generated from the sun could mean that you get more power down on the earth and therefore you could get better signals anywhere indoors.