Indoor GPS Signal Replication Using a Hardware Simulator

Tao Hu, Gérard Lachapelle and Richard Klukas

Abstract:	Laboratory testing is becoming a cost-efficient method for GPS receiver manufacturers due to its representative, repeatable and controllable features. Recent studies and results have demonstrated the success of replicating lineof- sight (LOS) GPS signals with a hardware simulator. However, the same is not true for degraded GPS signal environment simulation, such as indoors and in urban canyons. Indoor GPS signals suffer from power attenuation and severe multipath, which are highly correlated to the specific surroundings. Multipath, one GPS error source, introduces error in the carrier to noise density ratio (C/N0), pseudorange and carrier phase of GPS signals. The C/N0 and pseudorange errors display different characteristics according to specific multipath signals. In order to study the indoor characteristics of GPS signals, a high sensitivity GPS (HSGPS) receiver has been used to collect degraded, indoor signal data. The observable characteristics of signal power fading and estimated pseudorange error (EPE) are used to determine the simulated signal parameters. Empirical and theoretical analysis of the fading and EPE help to estimate the LOS signal power and multipath signal parameters for the simulation. The simulation is based on the assumption that the simulation result should have statistical characteristics similar to those of the field result. Probability density functions (PDF) are used to describe the stochastic characteristic of the environment. The correlation coefficient between the PDF of simulation data and that of field data is employed to quantify how much the simulated data matches the field data. GPS signals in three environments are analyzed and simulated. Highly compatible statistics between field and simulated data demonstrate the validity of the simulation.
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:	2728 - 2742
Cite this article:	Hu, Tao, Lachapelle, Gérard, Klukas, Richard, "Indoor GPS Signal Replication Using a Hardware Simulator," 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. 2728-2742.
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