GPS Reviews & Technology

Assisted GPS (A-GPS) Powering the Real World Web

According to Qualcomm location awareness technology will be the next must-have on mobile phones. Qualcomm recently announced that is has shipped worldwide 200 million mobile handsets using its gpsOne assisted-GPS technology. Gartner believe that location aware technologies including A-GPS will mature in less than two years and contribute to the emergence of a Real World Web where mobile devices will interact with their surroundings which have local processing capabilities. The Internet will become embedded in our reality. According to Gartner, “An increasing number of organizations have deployed location-aware mobile business applications, mostly based on GPS-enabled devices, to support queue business processes and activities, such as field force management, fleet management, logistics and good transportation.

Location aware mobile devices will fuel location services beyond the current services available such as mapping, tracking, navigation and the most important location-based emergency phone service. Many more services will become available through mobile device web interfaces and likely take the form of mash-ups which integrate the location information with other relevant databases. As an example, a mash-up may combine a mobile devices GPS position with a mapping application and a directory of restaurants to find the closest Chinese restaurant. Once selected, a navigation application might provide spoken instructions to guide the user to the restaurant using the mobile device’s GPS positioning feedback to track progress towards the target location.

Assisted GPS (A-GPS) Technology
A-GPS vastly improves the performance of a mobile GPS device by utilizing a mobile phone network to access resources for assistance with acquiring GPS reference information, processing requirements and low signal levels due to signal masking by ground clutter (eg. buildings) . A-GPS systems will often operate in locations where conventional standalone GPS receivers would not be able to establish a position fix.

After being turned on, a stand-alone GPS device could take ten minutes or more to lock (Time To First Fix – TTFF) which is unacceptable timeframe. Part of the problem is the time to download data from the GPS satellites which includes data for precise satellite position calculation and almanac data on satellite positioning within the constellation.. Data acquisition time can be reduced to seconds if the same data is provided by a A-GPS server at the local cell tower which gains its information from its own reference GPS receiver. The computational overhead for calculating an accurate position is considerable and the task time can be significantly decreased by accessing the mobile network for remote processing. With the outlined mode of operation, the mobile GPS receiver need only a partial GPS receiver mainly responsible for obtaining and forwarding GPS satellite signals. Providing an infrastructure for Assisted GPS allows much less expensive GPS devices to access GPS based applications/services.

Categories: GPS Technology

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