Microsoft develops a new GPS technology with very low consumption
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A very simple way to fry the battery of my old smartphone (an LG 900 Optimus) is to make intensive use of the capabilities geolocation, without being connected to an electricity source.
This is due to the calculation required to decode the signal received from the GPS satellites that orbit the earth, to find the positioning information that allows it to indicate where I am on the earth's surface with an error of about 10 meters.
What does a GPS have to do to know where it is?
There are 31 GNSS satellites in the sky (plus one for redundancy), each making two daily orbits around the globe. In addition to a set of ground stations that monitor the trajectories and status of the satellites, and that distribute this information among the rest of the constellation.
This communication includes two types of data on the trajectory of the satellites:The almanac, which contains the gross path of the orbit and the status of the satellite.The ephemeris, which contains the precise values of the trajectory.
All satellites are synchronized to the microsecond, with the ability to adjust timing to a few nanoseconds, thus ensuring that the constellation transmits signals of its exact position simultaneously and continuously.
The GPS receiver calculates its location by measuring the distance it is located in relation to various GNSS satellites that they cross the firmament; having to infer three essential data for its positioning:A precise period of time T. A set of satellites visible to the receiver and their location at time T.The distances from the receiver to each satellite at time T.
CO-GPS, improving by orders of magnitude
Typically, this data is obtained by processing the signals and data packets sent from the satellites, but this implies a high consumption of computing power and therefore battery.
To improve the consumption of receiving devices, there is assisted GPS technology (A-GPS) that allows receiving part of the positioning data through the network of telephony, instead of from satellite, in addition to being able to triangulate with broadcast towers or Wi-Fi access points to reduce the need for processing and consumption.
However, Microsoft Research is trying to improve this and, in a recently published article, it appears to have succeeded.
They have developed a technique called CO-GPS in which all the computing power is done in the Cloud. Unloading the receiver of the complex operations to infer the data required for its global positioning.
Microsoft researchers have made a prototype called CLEO that consumes the raw data from the satellite constellation that has been uploaded to the Cloud, and that allows high-precision geolocation but with a radical reduction in energy consumption, of about three orders of magnitude, since practically no computing power is necessary.
To make it easier to understand what this reduction means, with a couple of AA batteries you could update the geo positioning every second continuously for a year and a half.
Via | Neowin.net More information | Microsoft Research study
