Weighted phase difference short-time Doppler estimation and fixed-gain tracking for industrial sensor applications

The issue of estimating sub-kilohertz frequencies of single complex exponentials in white Gaussian noise for the purpose of Doppler tracking is investigated. Many industrial sensor applications, especially in safety appliances, require short response times. Our key aspect is Doppler estimation under the constraint of short measurement periods. A weighted phase-averaging frequency estimator is combined with an α-β-γ tracker to achieve fast responses with high computational efficiency. Fundamentals of the used frequency estimator, the tracking algorithm, and parameter determination are described against the background of the system´s specification. Based on a simulated non-canonical three-dimensional scenario, the flexibility and the tracking capability of the proposed algorithm are demonstrated. Also, real measured data from a low-cost homodyne Doppler radar module was applied to validate the algorithm. It is found that also strongly varying target velocities can be tracked with sufficient steadiness.