GPS could soon to be more power efficient thanks to Microsoft
Do you have the GPS feature of your phone activated at all times or only when you need it? Whenever I activate GPS it seems to use a lot of battery, which is why I make use of the feature rarely and then only when I really need it. The main problem with current technology is that communication takes a long time before the transfer of information to the phone is initiated and completed, and in that time, the power is draining from the phone because of the active chip. Once the data is downloaded, it has to be processed on the phone before it can be presented to the phone's user which takes additional power away.
There are two core reasons for the high energy consumption of GPS. The data rate at which information are sent from the satellite is 50bps (that is bytes per second) which requires the communication channels to be open for a long time before all data is received. The second issue is the amount of signal processing that is required to establish communication with a satellite due to signal strengths and Doppler frequency shifts.
Microsoft recently published the findings of a research project that aims to improve the energy efficiency of GPS by offloading work to the cloud.Â Instead of direct communication with the satellite to get the data for a long period of time, the new technology only has phones communicate with the satellite for a brief moment, while the remaining data is computed in the cloud and transferred to the phone via a network connection.
Location is a fundamental service for mobile computing. Typical GPS receivers, although widely available, consume too much energy to be useful for many applications. Observing that in many sensing scenarios, the location information can be post-processed when the data is uploaded to a server, we design a Cloud-Ofï¬‚oaded GPS (CO-GPS) solution that allows a sensing device to aggressively duty-cycle its GPS receiver and log just enough raw GPS signal for postprocessing. Leveraging publicly available information such as GNSS satellite ephemeris and an Earth elevation database, a cloud service can derive good quality GPS locations from a few milliseconds of raw data. Using our design of a portable sensing device platform called CLEO, we evaluate the accuracy and efï¬ciency of the solution. Compared to more than 30 seconds of heavy signal processing on standalone GPS receivers, we can achieve three orders of magnitude lower energy consumption per location tagging.
I suggest you read through the research paper if you are interested in the topic. Are you using GPS on your phone or tablet, and if you are, for what?