Radar littoral environment predictions and measurements

The littoral scenario is a difficult environment for radar operation. The presence of the complex sea/land interface at variable ranges provides many problems for naval radar, especially as coherent seaborne radar operating Doppler or MTI waveforms have often been optimised for open ocean operation. One of the primary concerns is the highly heterogeneous clutter environment. In standard RF propagation conditions the returns are complex enough. In non-standard atmospheric conditions the problems are even worse, particularly in the presence of range ambiguous clutter returns from land. Several papers have considered sea clutter backscatter in ducting conditions via the use of the parabolic equation and standard clutter algorithms. Theoretical consideration of land clutter backscatter has also received some attention. A programme of work is underway to enhance our understanding of the effects of littoral environments on radar performance. Emphasis has been placed on propagation factors giving clutter returns in excess of those obtained in standard atmospheric conditions. The work combines the gathering of raw data (both clutter returns and atmospheric measurements), with the results of theoretical algorithms modelling radar propagation and clutter backscatter. This paper describes, the clutter data gathering system, corresponding atmospheric profile measurement, models simulating radar propagation and clutter backscatter, and a comparison of measured and calculated returns.