With global positioning capabilities baked into most modern smartphones, it’s easy to take GPS for granted. Yet, pinpointing a location to a detailed spot on the planet is actually a lot more complicated than it looks.
While GPS works great in most situations, it can be less than optimal in dense urban environments, such as the crowded downtown areas of major cities where billions of people live and work.
These so-called “urban canyons” can reflect and even block GPS signals, causing significant errors. In these kinds of environments, with very few direct satellite views, unaided GPS can be off anywhere from tens of meters to even kilometers in some cases.
“User expectations for accuracy are very high, and we are dealing with signals that are reflected or blocked,” said Steven Malkos, senior program manager in the Mobile & Wireless Group at Broadcom. “No matter how many satellites we put in the sky, GPS alone will not solve the downtown dense deep urban problem.”
That’s where an innovative Broadcom-built technology comes in. The Hybrid Universal Location Application (HULA) takes the GPS and GNSS (Global Navigation Satellite System) data and combines it with the location information collected from the sensors on various other sources so it can better triangulate a specific location.
These sensors, which engineers call Micro-Electro-Mechanical Systems (MEMS), have been a hot topic of late. Last week, Malkos spoke at a conference devoted to exploring MEMS-based innovations and a blog post in the EETimes quoted him as saying, “Broadcom has been working on HULA since 2006. Now it provides superior accuracy even in the canyons of cities where buildings are often in the way of GPS signals.”
Although the conference discussion gets pretty techie, Malkos described how MEMS sensors on the smartphone – including accelerometers, gyroscopes, magnetometers and altimeters – can help compensate for blocked GPS signals or stray magnetic fields, resulting in more accurate location information.
All of the inputs from these sensors are synthesized using Broadcom’s Positioning Engine (HULA). This engine cuts the positioning errors back to a more acceptable two-to-five meters and greatly reduces “position jumps” in the GPS as users move around a city.
HULA is a host-based solution that runs partially on the GNSS chip and partially on the application processor chip. Today, all of Broadcom’s product offerings for smartphones, tablets, laptops and portable navigation devices ship with it.
Since 2007, HULA has been shipping as the industry standard, Malkos said, who also noted that Broadcom continues to improve and define the next generation of geolocation services to make them even more accurate.
“GPS works well in calibrating out sensor errors, but sensors also help calibrate out GPS errors,” Malkos said. “You need both.”
Improved GPS chips and better smartphone sensors — along with more refined algorithms — will lead to even greater accuracy in challenging urban environments.