Ever find yourself without battery at the worst time possible? Don’t want to throw down money on portable chargers? Think that bringing chargers for your phone is just too bulky and inconvenient? Microsoft has found a way to drastically reduce power consumption on your smartphone by targeting the biggest power hog inside the device—the GPS chip.
This component can take 30 seconds just to acquire the satellite data necessary to get the information it needs for an initial location fix, and then it has to churn through the downloaded codes to calculate its location precisely, which is a huge drain on power and resources. Jie Liu, a principal researcher at Microsoft Research, and his team developed a GPS system that collects only a few milliseconds of the most crucial information from satellites. This data is then combined with other important information from public, online databases, such as satellite trajectories and Earth elevation values, to calculate the device’s past locations. But the data fusion and location calculations happen on a remote server.
The researchers call the approach cloud-offloaded GPS, and they call the system they built CLEO (Cultivating the Long tail in Environmental Observations). In a paper presented last month at Toronto’s SenSys 2012 conference, the researchers claim that CLEO can perform continuous GPS sensing for a year and a half efficiently enough to be sustained by just two AA batteries. “Continuous GPS sensing would burn through the device’s battery in roughly six hours,” Liu said. “[CLEO] could be integrated into an Internet capable device, saving power and time when GPS is in use.”
Microsoft isn’t the only one trying to bring the juice back into smartphones that the GPS chip is taking away—Swiss company U-blox has developed GPS chips based on similar principles, with the company’s commercial GPS systems connecting with networks in real time. “The processing could be done either on a server or an Internet-connected PC or tablet, depending on the desired product concept,” said product manager Chris Marshall. Researchers at MIT, Duke, and the University of Southern California (USC) have also developed signal processing and other engineering tricks to make location services that use GPS faster and ultimately more energy efficient.
“Low-power GPS systems on mobile phones could make continuous location logging feasible, which could make the device smarter,” Liu said. “Those continuous location-sensing applications have a lot of value, and today we’re not doing that.”