초록 ▼

A system which combines intensity area correlation is disclosed for use with terrain height radar and infrared emissivity systems to give a simultaneous three-mode map matching navigation system. The infrared system senses passive terrain emissions while the height finding radar measures the time be

A system which combines intensity area correlation is disclosed for use with terrain height radar and infrared emissivity systems to give a simultaneous three-mode map matching navigation system. The infrared system senses passive terrain emissions while the height finding radar measures the time between transmission of a radar signal to the ground and receipt of a radar return. The intensity correlator uses the radar returns to sense changes in the reflection coefficient of the terrain. Map matching all three modes simulanteously provides an accurate, highly jam resistant position determination for navigation update.

대표청구항 ▼

A map-matching aircraft navigation system which provides an identification of an aircraft\s position in latitude and longitude, said map-matching navigation system comprising: a first radar system which is housed in said aircraft and which transmits radio frequency signals in a point beam which sequ

A map-matching aircraft navigation system which provides an identification of an aircraft\s position in latitude and longitude, said map-matching navigation system comprising: a first radar system which is housed in said aircraft and which transmits radio frequency signals in a point beam which sequentially strikes terrain in a first rectangular matrix in a pattern of points in rows and columns on terrain beneath said aircraft, said radar system receiving terrain echo returns from said pattern of rows and columns to output a first sensed map of said terrain with varying reflectivity coefficients in each of the points in the rows and columns; a radiometer which is housed in said aircraft and which detects a radiometric temperature image of the terrain in a second rectangular matrix in a pattern of points to output a second sensed map of said terrain with varying measures of thermal emissions and reflected energy; and a means for comparing said first and second sensed maps respectively with first and second stored reference maps, said first stored reference map containing a third rectangular matrix of rows and columns indicative of expected terrain echo return signals from the terrain over which said aircraft is flying, said comparing means finding a maximum correlation between said first sensed map and said first stored reference map to position and first sensed map on said first stored reference map, said comparing means thereby locating said aircraft on said first stored reference map, said comparing means also identifying each point in said third rectangular matrix with a known corresponding latitude and longitude in order to extract and output said aircraft\s position in latitude and longitude from its location on said first stored reference map, said comparing means containing a fourth rectangular matrix of rows and columns indicative of expected radiometric temperature image signals from the terrain over which the aircraft is flying, said comparing means finding a maximum correlation between said second sensed map and said second stored reference map to position said second sensed map on said second stored reference map to position said aircraft on said second stored reference map, said comparing means also identifying each point on fourth rectangular matrix with a known corresponding latitude and longitude in order to extract and output said aircraft\s position in latitude and longitude from its location on said second stored reference map after said second sensed map has been positioned on said second stored reference map.