Cramer-Rao bounds for HF source geolocation with a vector sensor array

Passive geolocation of a skywave HF source requires accurate estimation of azimuth and elevation angles together with correct ionospheric modeling. Arrays of polarimetric vector sensors have been proposed to reduce the array aperture required for this purpose. However, several factors complicate their application including magneto-ionic raymode splitting resulting in closely-spaced arrivals in both elevation and azimuth, partially correlated multipath, and array calibration errors. In this work, these issues are studied via Cramer-Rao lower bound (CRLB) analysis for a vector sensor array. A realistic, but known, ionospheric model is considered and the bound is evaluated for geolocation of a source at ~500 km. range using a 3 node vector sensor array.