Title: GPS Watch - An Analogue Watch Including a Very Low Power GPS Receiver
Author(s): P.-A. Farine, J.-J. Born, J.-D. Etienne, Y. Ferri, K. Imfeld, S. Kunzi, T. K. Nguyen, A. Monthéard, Y. Oesch, F. Piccini, P. Vez, J.-P. Wattenhofer, F. Wiget, E. Zellweger and R. Dinger
Published in: Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000)
September 19 - 22, 2000
Salt Palace Convention Center
Salt Lake City, UT
Pages: 311 - 316
Cite this article: Farine, P.-A., Born, J.-J., Etienne, J.-D., Ferri, Y., Imfeld, K., Kunzi, S., Nguyen, T. K., Monthéard, A., Oesch, Y., Piccini, F., Vez, P., Wattenhofer, J.-P., Wiget, F., Zellweger, E., Dinger, R., "GPS Watch - An Analogue Watch Including a Very Low Power GPS Receiver," Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000), Salt Lake City, UT, September 2000, pp. 311-316.
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Abstract: An analogue wristwatch has been equipped with a GPS receiver. The very low power consumption (in the range of 100 mW) obtained and the very low dimensions of the electronics for the GPS part are compatible with the re- quirements of a normal size watch. A 12-channel GPS re- ceiver processing the coarse acquisition C/A signals of the L1 band has been implemented. The electronics contains two microcontrollers: the first is working at 8.8 MHz for the GPS device, and is controlled by the second micro- controller working at 32,768 Hz, which is the master of the system. The watch case has a size slightly smaller than the Swatch .beat (47x57x20 mm3) and can be metal- lic (except the bezel part) or plastic. The watch includes a patch antenna, the electronics of the GPS sensor, an origi- nal user interface placed in the watch microcontroller, two bi-directional step motors, a dot matrix LCD and a re- chargeable Li-ion battery having a capacity around 300 mAh. The watch is equipped with a data port for a personal computer also serving to recharge the battery. The user interface contains as display means two hands and a dot matrix LCD display to indicate the velocity or the directions of the goal and of the North Pole in the navigation mode.