Extracting Geodetic Data from GNSS-VLBI Co-Observation

TL;DR

This paper introduces a novel interferometric technique combining VLBI and GNSS data to improve geodetic measurements and directly estimate local tie vectors between reference points.

Contribution

It presents a new interferometer setup using high-rate GNSS receivers and VLBI, enabling direct comparison and integration of geodetic data from both systems.

Findings

Preliminary VLBI analysis with differential positioning using phase delays.

Potential for cross-verification of GNSS and VLBI position and clock estimates.

Development of methods to estimate local tie vectors from experimental data.

Abstract

We have been developing a novel interferometer formed directly between a Very Long Baseline Interferometry (VLBI) radio telescope and a Global Navigation Satellite Systems (GNSS) antenna/receiver. This interferometer is enabled by the High Rate Tracking Receiver (HRTR), a high-performance GNSS software-defined receiver that records baseband data similar to a VLBI receiving system. Of particular interest is the potential of the technique to produce precise local tie vectors directly between the geodetic reference points of VLBI and GNSS antennas for use in the determination of combination terrestrial reference frames. In this paper, we will describe the unique setup of this interferometer before discussing current developmental work in estimating local tie vectors from experimental data collected using this technique. In particular, much recent work has been in exploring the possibility of direct comparison of the GNSS and VLBI processing techniques. A significant advantage of GNSS-VLBI co-observation of GNSS satellites comes from the ability to cross-check position and clock estimates derived from differential measurements in VLBI-style processing with differential GNSS processing and absolute GNSS positioning with Precise Point Positioning (PPP). We show a preliminary VLBI analysis of interferometric data including a differential positioning solution using phase delays.