Geolocalization via Tracking of Wideband Radio Astronomical Sources in the Presence of Radio Frequency Interference
Muhammet Emin Yanik and Murat Torlak, Dept. of Electrical Engineering University of Texas at Dallas
Sky tracking of permanent radio astronomical sky sources have been shown to be a promising alternative method to global position system (GPS) especially when GPS signals are either unavailable or may have been compromised. On the other hand, in radio astronomy, observations are increasingly corrupted by man-made radio frequency interferences (RFI). In this paper, radio astronomical geolocalization is investigated from the viewpoint of wideband measurements while combating RFI. Specifically, an interferometer collects the visibility data from radio astronomical sources and phase of measured visibility from a known astronomical radio source can be used to determine the location of the interferometer. The proposed geolocalization algorithm is a joint iterative visibility phase reconstruction and localization algorithm based on unconstrained minimization. The effectiveness of the proposed localization algorithm is validated using simulated data. The results of the simulations demonstrate the proposed algorithm comparatively has a high localization precision in RFI corrupted environment. On the other hand, interferometer performance may degrade in the presence of an arbitrary signal steering vector mismatch that occurs because of imperfect array calibration. So, accurate and low-cost localization is a critical requirement for the calibration of radio interferometers. The method should be of interest in interferometer calibration for more robust wide-field imaging methods. This approach can also be extended to enable similar geolocating capability to other ground based objects such as rovers, etc. on other celestial bodies in the solar system where there are no orbiting satellites like GPS.