High resolution ionospheric technique for regional area high-accuracy global positioning system applications

Abstract

A Global Positioning System includes a ground monitoring network having a plurality of dual frequency receivers that obtain ionospheric delay measurements to provide double difference ionospheric delay residuals. These double difference delay residuals are converted to zero differences based upon a new mathematical technique. The zero differences are fit to measurement epoch specific and transmitter specific mathematical surfaces (i.e. planes). These planes represent precise ionospheric delay corrections in the area of the ground monitoring network for a specific transmitter at the measurement epoch. The planes are then provided as correction information for use by inexpensive single frequency receivers to obtain highly accurate corrections for single frequency receivers by interpolating the correction planes to the location of the single frequency receiver. With this technique higher accuracy surveying results can be achieved with low cost single frequency receivers in real-time or in post-processing than what is currently achievable even with more expensive dual frequency receivers.