Accession Number : ADD012933

Title :   Gain Restoration After Doppler Filtering.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON DC

Personal Author(s) : Bryant,Stephen M ; Cole,Lanier G

Report Date : 09 Jun 1987

Pagination or Media Count : 8

Abstract : In a pulse doppler radar system which provides dynamic correction to variable radar echo return signals from clutter end targets using a block adaptive signal regulator (BASR) and a fast Fourier transform (FFT), a gain restoration circuit is used to optimize the gain corrected amplitudes over a plurality of time samples so that the tendancy of larger targets to obscure the return signals of smaller targets is minimized. The BASR conventionally evaluates the amplitude of echo returns in each time sample before it enters the FFT, by determining if they exceed the radar receiver's dynamic range, and dividing all samples by 2 to the Nth power when a sample exceeds the dynamic range (where N equals a shift number which signifies a shift by the BASR). The gain restoration circuit feeds information which indicates the number of BASR shifts to the output of the FFT as a function of range gate. This enables an evaluation to be made of all time samples in a range gate before they enter the FFT so that the largest sample is within the receiver's dynamic range, but the tendency to obscure smaller targets is reduced.

Descriptors :   *PATENTS, *ADAPTIVE SYSTEMS, *DOPPLER RADAR, *RADAR PULSES, *FAST FOURIER TRANSFORMS, *RADAR RECEIVERS, *RECEIVERS, FILTERS, SAMPLING, TIME, REGULATORS, SIGNALS, DOPPLER SYSTEMS, DYNAMIC RANGE, AMPLITUDE, CORRECTIONS, GAIN, ECHOES, CLUTTER, TARGETS, DYNAMICS, GATES(CIRCUITS), SHIFTING, RADAR REFLECTIONS, VARIABLES, OUTPUT

Subject Categories : Active & Passive Radar Detection & Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE