GNSS Vertical Dilution of Precision Reduction using Terrestrial Signals of Opportunity

Reducing the vertical dilution of precision (VDOP) of a global navigation satellite system (GNSS) position solution by exploiting terrestrial signals of opportunity (SOPs) is considered. A receiver is assumed to make pseudorange observations on multiple GNSS satellite vehicles (SVs) and multiple terrestrial SOPs and to fuse these observations through an estimator. This paper studies GNSS VDOP reduction by adding a varying number of cellular SOPs, which are inherently at low elevation angles. It is demonstrated numerically and experimentally that adding SOP observables is more effective to reduce VDOP over adding GNSS SV observables.