Abstract: A timing and control method and apparatus (111) for performing precise range rate aiding includes a range gate delay means (114) for generating an estimate of the range gate delay (135) each pulse repetition interval as a function of the initial range (134) and velocity (133) provided by a processor (104). The range gate delay (135) is converted into a coarse delay (138) defining the integral number of clock cycles preceding the range gate, and a fine delay (139) for positioning a range gate to within a fraction of a clock cycle. Fine temporal control is achieved using programmable delay lines (117) and (118), which retard various control signals, including the system clock signal (131), in accordance with the fine delay (139). A modified signal (126) then drives a counter means (119) which outputs a signal (128) that defines an analog-to-digital sampling window beginning at the elapse of the range gate delay (135).

Abstract: A method and apparatus that uses iteration to achieve a better prediction of the values of the commands needed to balance the gains of .SIGMA.+.DELTA. and .SIGMA.-.DELTA. channels of a radar guidance system, when an imbalance occurs due to a change caused by the AGC circuitry. An improved method of measuring channel-to-channel gain imbalance versus AGC measurements is provided, which produces modified input values that are used as commands that correct the mismatch during missile flight so that residual error is minimized and more accurate guidance is achieved. The present method is implemented by measuring the gain imbalance at predetermined AGC points during system calibration, and iterating these measurements to produce a relatively small channel-to-channel gain imbalance at the .DELTA.AGC amplifiers. The measured imbalance is then converted to .DELTA.AGC commands and applied to the .DELTA.AGC amplifiers. The resulting gain imbalance is measured and this value is added to the originally measured value.

Abstract: A phase dependent radar guidance system, the receiver (18) of which separates returns into a channel (22) where returns are summed (S) and a further channel (24) where the returns are differenced (jD). The S and jD signals are combined (26) and formed into two further channels as S+jD and s-jD, both of which are passed through AGC controlled amplifiers (28, 30) into a phase angle detector (32) which provides the target (14) angle .beta. to boresight (20). A test signal is applied to the receiver (18) with jD=O, the output value of the phase angle detector (32) for various values of AGC attenuation are stored by a digital processor (34), and the processor (34) modifies measured target phase value with the stored values to correct for AGC amplifier-induced errors.