Abstract: A method of navigation and serial guidance under utilization of elevational data correlation, wherein a correlator compares terrain specific elevational reference data, with actually acquired and processed altitude data, is improved by using a millimeter wave sensor operating in the atmospheric window of about 94 gigahertz; and being operated during cruising by back and forth scanning in a substantially vertical down direction across a prescribed flight path; occasionally the sensor is pivoted about a horizontal axis, for scanning in the forward direction in a forward search mode for purposes of target acquisition.

Abstract: A terrain-contour-matching guidance method is disclosed in which topographic reference data are made to include the same systematic errors which altitude measurement of an unmanned flight is expected to produce. Speed/course and general flight path tracking is operated on a higher resolution.