| 摘要 |
A leading edge estimator for a vehicle terrain navigation system is described, the system having a radar terrain sensor which generates a position signal. The leading edge estimator includes a storage circuit for storing a time of arrival signal estimate. A delay circuit receives the position signal from the radar terrain sensor and produces a delayed version thereof. The position signal and the delayed version thereof are differenced and applied to a sample & hold circuit, which generates a sample of the differenced signal after a predetermined time period. The output of the sample & hold circuit is then applied to a one bit analog-to-digital convertor which determines the sign of the sampled difference signal. The output of the analog-to-digital convertor is then used as a control signal to effect the gating of one of two predetermined weighting factors. The estimator also includes an adder, connected to receive the selected weighting factor, for summing the weighting factor with the time of arrival signal estimate to generate an up-dated time of arrival signal estimate.
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