Realisable GPS Antennas for Integrated Hand Held products

T. Haddrell, J. P. Bickerstaff and M. Phocas

Abstract:	With the ever increasing use of high sensitivity GPS devices integrated into hand held devices, Ceva and iNS have undertaken a study and practical testing of a range of candidate antennas in relation to their use in such products. The study is in support of integration activities at customers of both companies. It quickly became apparent that such problems would be expected across a large range of products and environments, and so a wide experience base, backed up by measurements, would be a useful asset. The decision to take a practical approach was made because of the high number of variables. A standard platform (the iNS ‘Sapphire’ black box) encompassing the Ceva GPS3000 receiver technology was used, to allow comparative trials to be made. The areas of investigation began with the identification of suitable candidates for mass-market products, of which 8 types were selected according to cost, expected performance, size. The types covered dielectric loaded patches, dielectric non-patch types, and printed antennas. For each antenna measurements were made in three separate environments, outdoor, in-car, and indoor. Additional tests were added to provide some indication of the effects of integration, and of sensitivity to a communications transmission (i.e. unintentional jamming). The measurements were taken from the debug facility of the receiver, and logged on a PC. The relevant parameters were then parsed and manipulated into meaningful tables, graphs, and plots. The paper presents abbreviated results for each of the candidate antennas. Because of the number of variables a scoring system, which allows some weighting of each antenna feature has been developed, since different designers will face different compromise criteria according to the end product and its market. Practical use of the study results are currently being made to assist OEMs and system integrators for rapid integration and improved performance of the final product. Whilst highly integrated and embedded high sensitivity GPS receivers are in their infancy, the mass market destination of new product designs mean that system integrators need all the help they can get from their technology suppliers in order to produce competitive products. As we all know, the antenna performance can make or break the entire GPS system performance. The paper includes some conclusions and recommendations which may aid such designers going forward.
Published in:	Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005) September 13 - 16, 2005 Long Beach Convention Center Long Beach, CA
Pages:	679 - 689
Cite this article:	Haddrell, T., Bickerstaff, J. P., Phocas, M., "Realisable GPS Antennas for Integrated Hand Held products," Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005), Long Beach, CA, September 2005, pp. 679-689.
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