USE OF ITERATION TO IMPROVE THE CORRECTION OF AGC DEPENDENT CHANNEL- TO-CHANNEL GAIN IMBALANCE

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. This iterated value is again converted to DELTA AGC commands and applied to the DELTA AGC amplifiers, and again the imbalance is measured, and is added to the first measurement. This procedure is repeated until a satisfactory level of error is measured which produces the proper correction factor that balances the channel-to-channel gains for each value of AGC. These correction factors are stored in a lookup table and are subsequently applied to the missile during flight. The improved apparatus of the present invention comprises a DELTA AGC controller containing a lookup table that contains the correction factors determined using the above method and an amplifier control circuit that responds to the correction factors to apply modified gain factors to the DELTA AGC amplifiers. These correction factors are applied to the DELTA AGC amplifiers during operation of the guidance system to achieve more accurate missile guidance.

Source: Google Patents

35 USC §181 Secrecy Order

Inventor

• 1RICHARD C. PRINGLE

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