The use of the DPT in passive acoustic aircraft flight parameter estimation

Passive acoustic techniques may be used to estimate flight parameters such as the ground speed, altitude and range of a propeller driven aircraft as it passes over an observer. Most techniques used to date are based on estimating the Doppler shifted tone of the propeller blades during the aircraft´s transition. Less used is the amplitude of the signal, which also changes due to the variation in distance between the aircraft and observer. Here the discrete polynomial phase transform (DPT) is used to estimate the Doppler shifted instantaneous phase of the signal. Following instantaneous phase estimation, the amplitude may be estimated. Nonlinear least squares methods are then used to obtain flight parameter estimates from the instantaneous phase and amplitude estimates. This paper investigates the accuracy of these methods