Abstract: A system includes an angular rate sensor disposed in a vehicle for providing angular rates of the vehicle, and an instrument disposed in the vehicle for providing line-of-sight control with respect to a line-of-sight reference. The instrument includes an integrator which is configured to integrate the angular rates of the vehicle to form non-compensated attitudes. Also included is a compensator coupled across the integrator, in a feed-forward loop, for receiving the angular rates of the vehicle and outputting compensated angular rates of the vehicle. A summer combines the non-compensated attitudes and the compensated angular rates of the to vehicle to form estimated vehicle attitudes for controlling the instrument with respect to the line-of-sight reference. The compensator is configured to provide error compensation to the instrument free-of any feedback loop that uses an error signal. The compensator may include a transfer function providing a fixed gain to the received angular rates of the vehicle.

Abstract: A method of determining a phase between a first signal and a second signal is provided. The first signal and the second signal correspond to signal transmissions between a first device and a second device. The second device periodically moves along a translational axis with respect to the first device in a first direction or a second direction. The method includes assigning a positive or negative value to each of a plurality of positive and negative zero crossings of the first signal. The method also includes counting a numerator and a denominator counter for a predetermined interval. The method also includes calculating a raw phase between the first signal and the second signal by dividing a value of the numerator by a corresponding value of the denominator after the predetermined interval.

Abstract: A simultaneous rapid open and closed loop bode measurement plot is described in which testing of the servo controlled instrument occurs under closed loop conditions using a binary pseudo-random sequence. The binary pseudo-random sequence is injected into the servo while the system under test is operating closed loop in order to generate bode plots for open loop and closed loop conditions. The present invention provides measurement results approximately 1,000 times faster than a swept sinusoid approach and provides superior dynamic range as compared to random white noise test input sources.

Abstract: A servo control calibration apparatus and method for correcting repeatable errors in position transducers is described. Unlike prior static direct measurement techniques or prior repetitive control techniques that correct error signals only within a low bandwidth, the present servo control calibration apparatus and method is done in-situ with the position transducer using a dynamic, closed loop servo operation. The present servo control calibration apparatus and method combine an in-situ error measurement and calibration device with a normal operation servo control closed-loop mechanism. In the calibration mode, the present servo control calibration apparatus and method measure the repeatable errors in a position transducer. Correction characteristics are stored and used in the normal operation of the servo control calibration apparatus and method to eliminate error from the control of the associated servo.

Abstract: A simultaneous rapid open and closed loop bode measurement plot is described in which testing of the servo controlled instrument occurs under closed loop conditions using a binary pseudo-random sequence. The binary pseudo-random sequence is injected into the servo while the system under test is operating closed loop in order to generate bode plots for open loop and closed loop conditions. The present invention provides measurement results approximately 1,000 times faster than a swept sinusoid approach and provides superior dynamic range as compared to random white noise test input sources.

Abstract: A servo control calibration apparatus and method for correcting repeatable errors in position transducers is described. Unlike prior static direct measurement techniques or prior repetitive control techniques that correct error signals only within a low bandwidth, the present servo control calibration apparatus and method is done in-situ with the position transducer using a dynamic, closed loop servo operation.