Array calibration for radar low-angle tracking based on electromagnetic matched field processing

The essence of the radar low-angle tracking is to estimate accurately the height of a specified target in the presence of complicated propagation conditions, including specular multipath propagation, diffuse reflection, diffraction propagation, range-dependent atmosphere refractivity stratification and other anomalous propagations conditions (e.g., ducting). An effective array data model for low-angle tracking is the prerequisite to many model-based low-angle tracking algorithm. The commonly-used planewave arrival data model usually can not take into account much aforementioned anomalous propagation in radar low-angle tracking, which results in serve performance deterioration in the practical low-angle tracking scenario. In light of the electromagnetic matched field processing (EM-MFP), an effective method of array calibration is proposed in this paper, in which the numerical solution of the parabolic wave equation (PWE) at sensor locations in 3D space is substituted for the traditional plane-wave arrival data model. The biggest advantage to using the PWE method is that it gives a full-wave solution for the field in the presence of range-dependent environments, and almost all aforementioned anomalous propagations conditions can be taken into account automatically. For demonstration, comparisons of the array data for a classic low-angle tracking scenario are presented between the traditional planewave arrival data model and the proposed PWE data model.