VLBI Antenna Calibration via GPS

We propose to investigate and develop an inexpensive system to determine: 1)VLBI antenna properties such as axis-offset, non-intersection of axis and antenna reference point; 2) Gravitational and/or Thermal deformation; 3) The eccentricity vector from the VLBI antenna to nearby GPS receivers. The proposed system involves using several GPS receivers in close proximity driven by a common clock. Because of their proximity, atmosphere and ionosphere errors are common, and vanish when we take the difference of measurements from different receivers to a common a satellite. Satellite clock errors also vanish in this difference. Since the receivers use a common clock, receiver clock error also vanishes. The remaining error source is GPS multipath which can be mitigated.

Monitoring of large structures such as building, bridges and dams.

This technique is directly applicable to measuring the properties of the large radio antennas NASA uses. This includes the few VLBI antennas NASA supports, but also includes other antennas such as the DSN. The technique is also applicable to the monitoring of large NASA structures. In addition, it could be used to validate the structural models which predict the deformation of structures due to thermal changes and wind loading.

This is early/mid-stage (TRL 6) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.

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