CO-GPS from Microsoft Research: better GPS with incredible battery life

We’ve all been there: using our favorite apps to track our jogging, or navigating around a new city when we notice that our phones only have 5% charge left. It’s frustrating, depressing and potentially dangerous if you rely too much on your phones locations services. The reason this happens is that GPS destroys batteries due to the amount of information it needs to receive and then compute in order to show our location.

Most standalone GPS receivers get their data directly from the satellites that are orbiting the Earth, and this data can come down as slowly as 50 bits per second, not to mention the receiver has to do a lot of processing to correctly interpret this data. That’s why it can take up to 30 seconds, and a lot of battery usage, until you get your first tracked position.

We do a little better than this on mobile phones due to a technology called Assisted GPS (A-GPS) in which phones receive part of the GPS data through the phone’s network rather than decoding it from a satellite. Apps on our smartphones can also use cell tower triangulation and Wi-Fi access points to speed up getting a precise fix on our location. However there’s still a lot of processing involved and that uses up our battery.

But Microsoft Research is trying to improve this and in a paper published last month they seem to have done it. Microsoft has developed a technique called Cloud Offloaded GPS (CO-GPS) in which all the computation is done in the cloud. The prototype they developed called CLEO pushed raw GPS data to the cloud for processing which resulted in high precision location information with a dramatic reduction in power consumption – three orders of magnitude less power used compared to today’s mobile phones. Or put differently “with a pair of AA batteries, CLEO can theoretically sustain continuous GPS sensing ( at 1s/sample granularity) for 1.5 years”.

Now before you go out to celebrate this amazing feat remember this is still a trial, and Microsoft is looking at standalone receivers rather than mobile phones. However, such dramatic improvements will no doubt one day come to our smartphones and other devices. The sooner the better.

Via: Ars Technica  Source: Microsoft Research | Satellite Navigation Image via Shutterstock

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That's really brilliant. Microsoft is really turning a lot of industries on their head. It's great to hear and I can't wait until a feature like this is broadly available...

This is actually quite cool idea. If you read the paper, you will see that this is not really about 'complex calculations' (the calculations are actually quire simple), the power drain is caused by the fact that device has to stay powered on for 30 or more seconds to obtain first fix (CPU can't sleep).

It takes so long because device has to obtain all the required data (current time, satellites position, etc) and transmission is done only at 50 bps. If it is interrupted, by some obstacle for instance, the whole process has to be done again.

The idea here is to take just a few ms sample of RAW GPS data and send it to 'cloud' processing server that already has got all the required information (time, satellite details) so it can instantly calculate position from this tiny bit of RAW data provided by device.

That requires data transfer, however. If you are in a location where there is no carrier then what ?
Also sending data to the cloud and receiving it may result in lower response time - so precision may be affected.
That may work only together with classical soplutions.

Most GPS applications update the position only once every second so they have plenty of time to communicate with the servers and if for any reason the connection drops (if you're in a car it certainly won't be stable) the calculations can resume on the phone/PNA CPU without problems. The battery life won't likely have a very noticeable improvement for end users though because the display and CPU/GPU rendering for the navigation software does certainly use far more power than the GPS chip alone.

mog0 said,
As long as they don't rely on this and it can still get a fix when there is no network signal!

My thoughts exactly.
But I'm sure it would work like this, otherwise it'd be completely idiotic and unreliable.


> Now before you go out to celebrate this amazing feat remember this is still a trial, and Microsoft is looking at standalone receivers rather than mobile phones.

Just another day at Microsoft, publish a paper, don't work on general availability and 10 years later when Apple invents it say: we had it 10 years ago, yay

It is very likely this will never be a Microsoft product but rather a technique incorporated into different services. Most likely the next version of AGPS will use this technique

The battery hit isn't shocking at all. Doing all the math to convert the raw GPS strings from multiple satellites into a location is pretty power intensive. The interesting part will be how they offload the data to the cloud. As the most expensive thing in mobile is usually the cellphone data connection.

The research paper explains that using this technique you only need 2 milliseconds of RAW data which only amounts to a few bytes. So data isn't an issue here.