Closed-loop control for scanning application

Claim 1

A method of tracking a target with a sensor positioned without reference to the target and generating signals identifying target position at each of a plurality of measurement times, said method comprising the steps of: a) generating a sequence of error signals, each error signal representing an error between sensor and target position at measurement time by comparison of a predicted target position for the measurement time and one of said signals identifying target position at the measurement time, b) determining, from said sequence of error signals, products of sequential pairs of at least the polarity of said error signals, c) summing at least the polarity of the products to indicate any trend in a sequence of said error signals to produce a gain factor, d) sequentially storing that one of said error signals most recently generated, e) generating a trajectory correction by combining said gain factor and said stored error signal, f) developing from a current trajectory and said trajectory correction a corrected trajectory, and g) developing from a corrected trajectory a predicted target position for the next estimated measurement time.

Claim 2

A method of tracking a target with a sensor positioned without reference to the target and generating signals identifying target position at each of a plurality of measurement times, said method comprising the steps of: a) generating a sequence of error signals, each error signal representing an error between sensor and target position at measurement time by comparison of a predicted target position for the measurement time and one of said signals identifying target position at the measurement time, b) determining, from said sequence of error signals, products of sequential pairs of at least the polarity of said error signals, c) summing at least the polarity of the products to indicate any trend in a sequence of said error signals to produce a gain factor, d) sequentially storing that one of said error signals most recently generated, e) generating a trajectory correction by combining said gain factor and said stored error signal, f) developing from a current trajectory and said trajectory correction a corrected trajectory, and g) developing from a corrected trajectory a predicted target position for the next estimated measurement time.

Claim 5

A method of tracking a target with a sensor positioned without reference to the target, said method comprising the iteratively repeated steps of: a) based on a current trajectory, estimating target position at a future measurement time, b) measuring target position, subsequent to step a) and at said measurement time and obtaining a difference between said estimated target position and said target position measured at said measurement time, and c) updating said current trajectory prior to estimating target position for a next measurement time as follows: c1) obtaining a difference between said estimated position and said measured position as determined in steps a) and b) respectively, c2) determining and quantifying any trend in a sequence of differences of step c1) on sequential iterations, c3) adaptively weighting a trajectory gain coefficient in relation to the quantified trend of said difference of step c1), c4) using the difference of step c1) and the adapted gain coefficient of step c3) to obtain a corrected trajectory.

Claim 6

A method of tracking a target with a sensor positioned without reference to the target, said method comprising the iteratively repeated steps of: a) based on a current trajectory, estimating target position at a future measurement time, b) measuring target position, subsequent to step a) and at said measurement time and obtaining a difference between said estimated target position and said target position measured at said measurement time, and c) updating said current trajectory prior to estimating target position for a next measurement time as follows: c1) obtaining a difference between said estimated position and said measured position as determined in steps a) and b) respectively, c2) determining and quantifying any trend in a sequence of differences of step c1) on sequential iterations, c3) adaptively weighting a trajectory gain coefficient in relation to the quantified trend of said difference of step c1), c4) using the difference of step c1) and the adapted gain coefficient of step c3) to obtain a corrected trajectory.