Improving Meteor Radar’s Precision and Uncertainties through a Novel GNSS-like Position Solution

Specular meteor radar (SMR) remains one of the few tools able to provide temporally and spatially dense observations of the mesosphere/lower thermosphere (MLT, 70-120 km). SMR systems take advantage of the radar reflective plasma trails left by ablating meteors; a radar signal is sent out, scatters off a meteor trail, and recorded by a receiver on the ground. By investigating the distortions the reflected signal, environmental characteristics like wind, pressure, and temperature can be inferred. The measurements are representative of the environment at the point of reflection, which is fully specified by the signal’s total path length and the angle of arrival to the receiver. While the path length is easily measured using traditional radar time-of-flight techniques, the angle of arrival is typically estimated through interferometry. This requires a precisely placed array of at least five antennas, which involves difficult set-up and tedious empirical calibration. Interferometry performs poorly for targets at low elevations or low SNR, and phase ambiguities make it difficult to quantify the uncertainty of each observation’s position. This absence of reliable uncertainties can be an impediment when analyzing the measured winds.
This work outlines a new method to estimate the position of observations made by meteor radar. Four or more receivers placed a few kilometers from each other can be used in conjunction with one or more transmitters, and the range information alone is used to form a bistatic GNSS-type position solution. Compared to interferometry, this method promises a more precise position estimate with more easily derived uncertainties, all while requiring potentially less infrastructure and eliminating the need for calibration entirely. The technique’s viability is shown both through simulations and worst-case analysis.