Abstract:

To estimate the angle of arrivals (AOA) of wideband chirp sources, a new time-frequency algorithm is proposed. In this method, virtual sensors are constructed based on the fact that the steering vectors of wideband chirp signals are linear and vary with time. And the randon Wignersville distribution (RWVD) of real sensors and virtual sensors are calculated to yield the new time-invariable steering vectors, furthermore, the noise and cross terms are suppressed. In addition, the multiple chirp signals are selected by their time-frequency points. The cost of computation is lower than the common AOA estimation methods of wideband sources due to nonrequirement of frequency focusing, interpolating and matrix decomposition, including subspace decomposition. Under the lower signal noise ratio (SNR) condition, the proposed method exhibits better precision than the method of frequency focusing (FF). The proposed method can be further applied to nonuniform linear array (NLA) since it is not confined to the array geometry. Simulation results illustrate the efficacy of the proposed method.