Retrieving tropospheric delays from GPS networks densified with single frequency receivers

In order to improve the spatial resolution of GPS (Global Positioning System) derived zenith total delays (ZTD), existing GPS networks must be considerably densified. Due to economic reasons, this densification is recommended with single frequency receivers. We prove the epoch‐differenced ionospheric delay is sufficient for estimating ZTD from single frequency GPS data. Based on this result, the Satellite‐specific Epoch‐differenced Ionospheric Delay model (SEID) is developed which uses the observations from surrounding dual frequency stations. With the derived ionospheric corrections, single frequency data is converted to dual frequency data which can be processed using any existing GPS processing software package. The approach is validated with regional GPS networks by comparing ZTDs from the converted and the observed dual frequency data. Their differences in RMS is about 3 mm which is negligible compared to the differences among various state‐of‐the‐art software packages. The easy implementation and the accuracy of the new approach may speed up the densification of existing networks with single frequency receivers.