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Technical Article • November/December 2007
![]() Measuring Up: Certification Processes and Testing of A-GPS Equipped Cellular PhonesAssisted-GPS designs have gotten a lot of attention in recent years as manufacturers try to build high-sensitivity receivers that work indoors or in other challenging environments. Interest has surged as wireless carriers and mobile handset manufacturers have adopted GPS technology. But how do carriers and end users know that their A-GPS products will work? This article describes the standards, processes, and test procedures that lead to certification of devices incorporating A-GPS. More and more GPS-enabled devices are entering the consumer marketplace, many incorporating assisted-GPS (A-GPS) technology. These include not only cellular phones, but laptop datacards, PDAs, and other mobile equipment. Increasingly, GPS devices that were previously standalone now incorporate a cellular modem for such applications as mapping download or live traffic alerts. The proliferation of GPS in the consumer space can also be seen in the availability of GPS automotive navigation systems in local supermarkets or large grocery stores. Those who purchase these products expect the technology to function everywhere, continuously, be simple to use and to always have the most obscure address in its database. To help ensure the successful deployment of this concept in cellular devices, the telecommunications industry’s standards and certification bodies have been working diligently on a standardized approach to A-GPS certification. In recent years, the subject of A-GPS, its purpose, and operation, has gotten a lot of attention in the technical and trade media. The authors of these various sources have focused on either the technical details or on the performance of the technology in the areas for which it was or was not primarily designed. For example, performance in urban canyons and indoor environments or development and testing by manufacturers, cellular network operators or research organizations of products using this technology. In contrast, this paper focuses on how a mobile device that incorporates A-GPS technology gains certification for use on a 2G or 3G (GSM or UMTS) cellular network. (For the rest of this story, please download the complete article using the link above.) ManufacturersThe test equipment used in preparing this article was a Spirent ULTS, A-GPS Test platform from Spirent Communications Inc., Eatontown New Jersey, USA. Author ProfilesAndy Proctor served in the British Royal Navy for 12 years, leaving as a communications and electronic warfare engineer. He joined Spirent Communications and worked with customers in a number of roles with the Satellite Navigation testing group (GPS/GLONASS/Galileo testing). At SGS Wireless Europe, Proctor has responsibility for business development activities for the company’s wireless test facility at Cambridge, United Kingdom (GSM/UMTS/A-GPS/WiMAX testing and validation). He received a British Excellence in Sales and Marketing Award in 2007 Richard Catmur is a 31-year veteran of the wireless industry who joined Spirent from Racal Instruments, where he was a product marketing and business development manager for its test and measurement division. Catmur now has global responsibility for Spirent’s location test products. He has also made major contributions to development of location-based services standards in both the 3GPP and OMA.
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