Design of a High Fidelity Signal Simulator Aided with Precise Point Positioning

GNSS signal simulator, which can provide controllable and repeatable GNSS signals in different scenarios, has been playing a very important role in the user receiver design and testing. The existing simulators have high fidelity electronic signal models but the fidelity of their satellite constellation simulations is relatively low because the constellation and transmission delay errors are very difficult to model and predict. To have a high fidelity signal simulator, a software IF GPS signal simulator aided with the precise point positioning (PPP) is introduced in this paper. The proposed simulator design includes two modules: a constellation generator and an electronic signal generator. The constellation generator simulates the signal delays based on the satellite constellation and propagation delay errors, and the electronic signal generator simulates the signal waveforms based on the delays generated by the constellation generator, and it also combines with the use of wireless channel models. The prototype of the simulator is implemented and tested by a proprietary software receiver and a commercial software receiver (NordNav R&D software receiver). The simulated IF signals are verified with respect to the power spectrum, correlation performance, pseudo-range Doppler measurements and positioning solutions.