The Performance and Simulation of a C-CDMA Pseudolite Indoor Geolocation System

l.F. Progri, J. Maynard, W.R. Michalson, J. Wang

Abstract:	In an indoor environment, geolocation signals are subject to much more interference, multi-path fading, and nearfar effect than in outdoors. In this paper a C-CDMA pseudolite indoor geolocation system that operates in an indoor environment is simulated via MATLAB Simulink. The geolocation and communication information is represented via geolocation signals. First, in the transmitter the geolocation information consists of the transmitter position and time assuming that each transmitter is stationary. For each transmitter this information is 4-ary encoded data at a rate of 1 KHz. The encoded geolocation signal is spread using a Kasami sequence which runs at a rate of 1.024 MHz and then the signal is modulated on [10 15 20 25] MHz carrier signals each one of which corresponds to each of the transmitters via a QPSK modulator to resist interference encountered in an indoor environment. A total of 4 transmitters are simulated to enable a geolocation solution for the receiver. Second, the channel consists of the following models: (1) free-space path loss, (2) Rayleigh, Rician, and Lognormal fading channels, (3) receiver thermal noise, (4) phase frequency offset and (5) additive white Gaussian noise. Third, the receiver consists of four channels each one of which is designated to one transmitter. On each receiving channel the received signal is down-converted in the baseband. Then the signal is de-spread using the Kasami sequence and then is demodulated and decoded. Future result will show an estimate of the distance between the transmitter and the receiver. Four distance estimates will be used in the Least Squares filter to provide an estimate of the receiver location and time.
Published in:	Proceedings of the 19th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2006) September 26 - 29, 2006 Fort Worth Convention Center Fort Worth, TX
Pages:	2465 - 2477
Cite this article:	Progri, l.F., Maynard, J., Michalson, W.R., Wang, J., "The Performance and Simulation of a C-CDMA Pseudolite Indoor Geolocation System," Proceedings of the 19th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2006), Fort Worth, TX, September 2006, pp. 2465-2477.
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