Implementation and Verification of a Software-Based IF GPS Signal Simulator

Lei Dong, Changlin Ma, and Gérard Lachapelle

Abstract:	The development and verification of a software-based intermediate frequency (IF) GPS signal simulator for the L1 C/A code signal is described in this paper. A mathematical signal model is developed that expresses the digitized IF GPS signal as a function of various errors during propagation, such as satellite clock error, ionosphere error, troposphere error, and user defined parameters, such as date and GPS time, user trajectory, expected C/N0, noise density, intermediate frequency, sampling rate, front-end bandwidth, and quantization bit. The correctness of the simulator is verified by comparing the simulated signal with the hardware front-end collected IF GPS signal in the time, frequency, correlation, measurement, and position domains. A software GPS receiver, developed partially for signal verification, is also described in the paper. It consists of several modules: signal acquisition, signal tracking, bit synchronization, sub-frame synchronization and navigation solution. It is verified by using a set of real world GPS signal data collected by a commercial hardware front-end and comparing the tracking result and navigation solution with the corresponding results of a hardware GPS receiver.
Published in:	Proceedings of the 2004 National Technical Meeting of The Institute of Navigation January 26 - 28, 2004 The Catamaran Resort Hotel San Diego, CA
Pages:	378 - 389
Cite this article:	Dong, Lei, Ma, Changlin, Lachapelle, Gérard, "Implementation and Verification of a Software-Based IF GPS Signal Simulator," Proceedings of the 2004 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 2004, pp. 378-389.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In