Low angle radar processing means

DETAILED DESCRIPTION The present invention comprises improved means for processing a low elevation target signal received by a radar array by, in essence, subtracting from the received signal signals derived from estimated values of target elevation.
The estimated value of target elevation associated therewith is the best estimate of actual target elevation when the resultant signal has a minimum power content.
Specifically, the invention provides that the target signal input from each array element be quadrature demodulated to give in-phase and quadrature components, which together define a complex amplitude.
There are thus available N complex amplitudes, one for each element of an N array or channel radar.
A weight matrix based on a first estimate of the target elevation is applied to the set of N complex amplitudes to generate a new set of N amplitudes, one for each radar channel.
The power in each channel associated with the new complex amplitude is computed and the powers in all channels added together and the associated estimate of target elevation noted.
From the computed total power and target elevation values a new estimate of target elevation is formed and used to adjust the weight matrix.
The weight matrix is again applied to the set of N complex amplitudes and the total power again computed.
The whole process is iterated until the smallest power is computed.
The elevation angle associated with this power level is the best estimate of target elevation.