A GNSS-reflections simulator and its application to widelane observations

This paper discusses an effort to create a fast, yet accurate GNSS-R simulator capable of spacecraft-altitude studies. A number of new techniques will be presented which were developed to significantly increase the simulation speed. The end goal of this work is to assess measurement fundamentals such as ocean altimetry accuracy as a function of altitude and antenna size. The first application of this new simulator was to evaluate the GPS L2-L5 widelane signal for altimetric applications. It has been suggested that this widelane signal could result in an accurate, coherent phase-delay height observable. Simulation results, along with a simple physical model, indicate this widelane combination does not produce a coherent phase observable under typical conditions. The incoherence appears to be due to the surface area corresponding to the signal´s autocorrelation function being much larger than the widelane Fresnel zone.