On the Resolution of the Interferometric Measurement of the Angular Velocity of Moving Objects

An analysis of the resolution of a new method of measuring the angular velocity of moving objects using an interferometric sensor is presented in this paper. The frequency of the sensor response is proportional to the angular velocity of the object, which can thus be calculated with a simple frequency analysis of the sensor output. The resolution of the frequency measurement is therefore representative of the resolution of the angular velocity. The derivation of the interferometer response to a single source is presented, and the resolution of the angular velocity measurement is derived for an ideal interferometer beam pattern and a more realistic Gaussian shaped beam pattern. The normalized frequency resolution is shown to be inversely proportional to the beamwidth of the interferometer pattern and inversely proportional to the antenna baseline. Measurements of a walking human taken with a narrow-beamwidth 27.4 GHz passive radiometric interferometer with multiple antenna baselines are presented, verifying the inverse dependence of the resolution on the baseline. Comparison of theoretical results to the measured frequency shift and measured frequency resolution show good agreement.