An Indoor Positioning Using GPS Repeater

S-C. Bu, J-H. Choi, G-I. Jee, H.S. Kim

Abstract:	In this paper we propose a new method to deal with GPS indoor positioning by means of GPS signal re-radiator or repeater. Usually, the signal repeater consists of a reference GPS receiver installed at a certain location with good signal reception condition, and a amplifier that amplifies the satellite signal to guarantee enough signal power for signal transmission through long cable and an antenna that will re-transmit satellite signal inside. After traveling for different propagation time, the signals from all visible satellites reached at the reference antenna. From that point, the signals feed through cable connecting the reference antenna and re-transmit antenna. The satellite signals from the re-transmit antenna travel the same distance until they reach at the indoor user antenna. This means that the corresponding incremental pseudoranges from the reference antenna to the user are equal for the all visible satellites. Therefore the resulting user position is the same as that of the reference antenna. But for the each position determination at the reference and the user, the common error terms that correspond to the receiver clock bias will have different values. The receiver clock bias estimation at the indoor user includes incremental pseudorange from the reference antenna to the user. We call this clock bias as a pseudo-clock bias. This fact enables us to measure the pseudorange from the indoor antenna to the indoor user. That is a pseudo-clock bias estimation value at the indoor user is actually a pseudorange between the indoor antenna and the indoor user. From this observation, we can formulate the new measurement equations as follows. Zi=Li+Cb, i=1,2,?,n. Here Zi is a pseudo-clock bias for the i-th repeater and Cb is the real receiver clock bias. Thus, if we have at least 4 repeaters at known locations then we can calculate the indoor user position
Published in:	Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003) September 9 - 12, 2003 Oregon Convention Center Portland, OR
Pages:	1129 - 1134
Cite this article:	Bu, S-C., Choi, J-H., Jee, G-I., Kim, H.S., "An Indoor Positioning Using GPS Repeater," Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003), Portland, OR, September 2003, pp. 1129-1134.
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