Passive monopulse ranging to a non-cooperative emitter and non-emitting object

Claim 2

A passive monopulse radar ranging system for determining the range of a scanning, emitting source and a reflecting object illuminated by said emitting source and angularly separated therefrom comprising, in combination: an antenna array having a first plurality of ports providing a distribution or received energy phases as a function of an angle of arrival of a plurality of emitting source signals and a plurality of echo signals from said reflecting object; a beam forming matrix responsive to said first plurality of ports and having a second plurality of ports, ports of said second plurality providing said emitting source signals and said echo signals to discrete ports of said second plurality of ports as a function of said angle of arrival at said antenna array; emitter receiver means of said passive monopulse radar ranging system for receiving said emitting source signals from said beam forming matrix and for providing a time early output signal T E representing the arrival time of said emitting source signals, an output bearing angle β of said emitting source signals with respect to an angular reference, and a signal A E representative of the scan rate of said emitting source, said emitting source scanning at a constant rate through 360°; target receiver means of said passive monopulse radar ranging system for separately receiving said echo signals from said beam forming matrix and for providing a plurality of signals T t representing the arrival time of said echo signals, and for providing an angle α representative of the bearing angle of said reflecting object with respect to said angular reference; first resolver means responsive to said α and β angles for computing their difference φ representative of an angle between said emitting source and said reflecting object; second resolver means responsive to said time early output signal T E and said echo signal arrival time T t for driving their difference Δt; third resolver means responsive to said signal A E and said time early output signal T E for deriving a pointing angle θ of said emitting source toward said reflecting object with respect to a range line between said passive monopulse radar ranging system and said emitting source; range resolver means responsive to said φ, α, β, Δt and θ signals for generating a plurality of range signals R E , R t and R E/t , said range signal R E being between said passive monopulse radar ranging system and said emitting source, said range signal R t being between said passive monopulse radar ranging system and said reflecting object, and said range signal R E/t being between said emitting source and said reflecting object, said range resolver means solving the equations. ##EQU10## said passive radar ranging system capable of accurately determining the location of said emitting source and said reflecting object in a monopulse scan of said emitting source, said antenna array arranged to provide dual, angularly overlapping beam patterns while said emitter receiver means and said target receiver means being arranged to provide monopulse operation employing said dual beam patterns.

Claim 3

A passive monopulse radar ranging system for determining the range of a scanning, emitter source and a reflecting object illuminated by said emitting source and angularly separated therefrom comprising, in combination; an antenna array having a first plurality of ports providing a distribution of received energy phases as a function of an angle of arrival of a plurality of emitting source signals and a plurality of echo signals from said reflecting object; a beam forming matrix responsive to said first plurality of ports and having a second plurality of ports, ports of said second plurality of providing said emitting source signals and said echo signals to discrete ports of said second plurality of ports as a function of said angle of arrival at said antenna array; emitter receiver means of said passive monopulse radar ranging system for receiving said emitting source signals from said beam forming matrix and for providing a time early output signal T E representing the arrival time of said emitting source signals, an output bearing angle β of said emitting source signals with respect to an angular reference, and a signal A E representative of the scan rate of said emitting source, said emitting source scanning at a non-constant rate through sectors of 360°; target receiver means of said passive monopulse radar ranging system for separately receiving said echo signals from said beam forming matrix and for providing a plurality of signals T t representing the arrival time of said echo signals, and for providing an angle α representative of the bearing angle of said reflecting object with respect to said angular reference; first resolver means responsive to said α and β angles for computing their difference φ representative of an angle between said emitting source and said reflecting object; second resolver means responsive to said time early output signal T E and said echo signal arrival time T t for deriving their difference Δt; third resolver means responsive to said signal A E and said time early output signal T E for deriving a pointing angle θ of said emitting source toward said reflecting object with respect to a range line between said passive monopulse radar ranging system and said emitting source; and range resolver means responsive to said φ, α, β, Δt and θ signals for generating a plurality of range signals R E , R t and R E/t , said range signal R E being between said passive monopulse radar ranging system and said emitting source, said range signal R t being between said passive monopulse radar ranging system and said reflecting object, and said range signal R E/t being between said emitting source and said reflecting object, said range resolver means solving the equations. ##EQU11## said passive radar ranging system capable of accurately determining the location of said emitting source and said reflecting object in a monopulse scan of said emitting source, said antenna array arranged to provide dual, angularly overlapping beam patterns while said emitter receiver means and said target receiver means being arranged to provide monopulse operation employing said dual beam patterns.

Claim 4

A passive monopulse radar ranging system for determining the range of a scanning, emitter source and a reflecting object illuminated by said emitting source and angularly separated therefrom comprising, in combination; an antenna array having a first plurality of ports providing a distribution of received energy phases as a function of an angle of arrival of a plurality of emitting source signals and a plurality of echo signals from said reflecting object; a beam forming matrix responsive to said first plurality of ports and having a second plurality of ports, ports of said second plurality of providing said emitting source signals and said echo signals to discrete ports of said second plurality of ports as a function of said angle of arrival at said antenna array; emitter receiver means of said passive monopulse radar ranging system for receiving said emitting source signals from said beam forming matrix and for providing a time early output signal T E representing the arrival time of said emitting source signals, an output bearing angle β of said emitting source signals with respect to an angular reference, and a signal A E representative of the scan rate of said emitting source, said emitting source scanning at a non-constant rate through sectors of 360°; target receiver means of said passive monopulse radar ranging system for separately receiving said echo signals from said beam forming matrix and for providing a plurality of signals T t representing the arrival time of said echo signals, and for providing an angle α representative of the bearing angle of said reflecting object with respect to said angular reference; first resolver means responsive to said α and β angles for computing their difference φ representative of an angle between said emitting source and said reflecting object; second resolver means responsive to said time early output signal T E and said echo signal arrival time T t for deriving their difference Δt; third resolver means responsive to said signal A E and said time early output signal T E for deriving a pointing angle θ of said emitting source toward said reflecting object with respect to a range line between said passive monopulse radar ranging system and said emitting source; and range resolver means responsive to said φ, α, β, Δt and θ signals for generating a plurality of range signals R E , R t and R E/t , said range signal R E being between said passive monopulse radar ranging system and said emitting source, said range signal R t being between said passive monopulse radar ranging system and said reflecting object, and said range signal R E/t being between said emitting source and said reflecting object, said range resolver means solving the equations. ##EQU11## said passive radar ranging system capable of accurately determining the location of said emitting source and said reflecting object in a monopulse scan of said emitting source, said antenna array arranged to provide dual, angularly overlapping beam patterns while said emitter receiver means and said target receiver means being arranged to provide monopulse operation employing said dual beam patterns.

Claim 5

A passive monopulse radar ranging system for determining the range of a scanning, emitting source and a reflecting object illuminated by said emitting source and angularly separated thereform comprising, in combination: antenna means having a first plurality of ports providing a distribution of received energy phases as a function of an angle of arrival of a plurality of emitting source signals and a plurality of echo signals from said reflecting object; a beam forming matrix responsive to said first plurality of ports and having a second plurality of ports, ports of said second plurality providing said emitting source signals and said echo signals to discrete ports of said second plurality of ports as a function of said angle of arrival at said antenna means; emitter receiver means of said passive monopulse radar ranging system for receiving said emitting source signals from said beam forming matrix and for providing a time early output signal T E representing the arrival time of said emitting source signals, an output bearing angle β of said emitting source signals with respect to an angular reference, and a signal A E representative of the scan rate of said emitting source, said emitting source scanning at a constant rate through 360°; target receiver means of said passive monopulse radar ranging system for separately receiving said echo signals from said beam forming matrix and for providing a plurality of signals T t representing the arrival time of said echo signals, and for providing an angle α representative of the bearing angle of said reflecting object with respect to said angular reference; first resolver means responsive to said α and β angles for computing their difference φ representative of an angle between said emitting source and said reflecting object; second resolver means responsive to said time early output signal T E and said echo signal arrival time T t for deriving their difference Δt; third resolver means responsive to said signal A E and said time early output signal T E for deriving a pointing angle θ of said emitting source toward said reflecting object with respect to a range line between said passive monopulse radar ranging system and said emitting source; and range resolver means responsive to said φ, α, β, Δt and θ signals for generating a plurality of range signals R E , R t and R E/t , said range signal R E being between said passive monopulse radar ranging system and said emitting source, said range signal R t being between said passive monopulse radar ranging system and said reflecting object, and said range signal R E/t being between said emitting source and said reflecting object, said range resolver means solving the equations ##EQU12## said passive radar ranging system capable of accurately determining the location of said emitting source and said reflecting object in a monopulse scan of said emitting source, said antenna means having at least a pair of driven antennas arranged to provide angularly independent beam patterns while said emitter receiver means and said target receiver means being arranged to provide monopulse operation employing said independent beam patterns.

Claim 6

A passive monopulse radar ranging system for determining the range of a scanning, emitting source and a reflecting object illuminated by said emitting source and angularly separated thereform comprising, in combination: antenna means having a first plurality of ports providing a distribution of received energy phases as a function of an angle of arrival of a plurality of emitting source signals and a plurality of echo signals from said reflecting object; a beam forming matrix responsive to said first plurality of ports and having a second plurality of ports, ports of said second plurality providing said emitting source signals and said echo signals to discrete ports of said second plurality of ports as a function of said angle of arrival at said antenna means; emitter receiver means of said passive monopulse radar ranging system for receiving said emitting source signals from said beam forming matrix and for providing a time early output signal T E representing the arrival time of said emitting source signals, an output bearing angle β of said emitting source signals with respect to an angular reference, and a signal A E representative of the scan rate of said emitting source, said emitting source scanning at a constant rate through 360°; target receiver means of said passive monopulse radar ranging system for separately receiving said echo signals from said beam forming matrix and for providing a plurality of signals T t representing the arrival time of said echo signals, and for providing an angle α representative of the bearing angle of said reflecting object with respect to said angular reference; first resolver means responsive to said α and β angles for computing their difference φ representative of an angle between said emitting source and said reflecting object; second resolver means responsive to said time early output signal T E and said echo signal arrival time T t for deriving their difference Δt; third resolver means responsive to said signal A E and said time early output signal T E for deriving a pointing angle θ of said emitting source toward said reflecting object with respect to a range line between said passive monopulse radar ranging system and said emitting source; and range resolver means responsive to said φ, α, β, Δt and θ signals for generating a plurality of range signals R E , R t and R E/t , said range signal R E being between said passive monopulse radar ranging system and said emitting source, said range signal R t being between said passive monopulse radar ranging system and said reflecting object, and said range signal R E/t being between said emitting source and said reflecting object, said range resolver means solving the equations ##EQU12## said passive radar ranging system capable of accurately determining the location of said emitting source and said reflecting object in a monopulse scan of said emitting source, said antenna means having at least a pair of driven antennas arranged to provide angularly independent beam patterns while said emitter receiver means and said target receiver means being arranged to provide monopulse operation employing said independent beam patterns.

Claim 7

A passive monopulse radar ranging system for determining the range of a scanning, emitting source and a reflecting object illuminated by said emitting source and angularly separated thereform comprising, in combination: antenna means having a first plurality of ports providing a distribution of received energy phases as a function of an angle of arrival of a plurality of emitting source signals and a plurality of echo signals from said reflecting object; a beam forming matrix responsive to said first plurality of ports and having a second plurality of ports, ports of said second plurality providing said emitting source signals and said echo signals to discrete ports of said second plurality of ports as a function of said angle of arrival at said antenna means; emitting receiver means of said passive monopulse radar ranging system for receiving said emitting source signals from said beam forming matrix and for providing a time early output signal T E representing the arrival time of said emitting source signals, an output bearing angle β of said emitting source signals with respect to an angular reference, and a signal A E representative of the scan rate of said emitting source, said emitting source scanning at a non-constant rate through sectors of 360°; target receiver means of said passive monopulse radar ranging system for separately receiving said echo signals from said beam forming matrix and for providing a plurality of signals T t representing the arrival time of said echo signals, and for providing an angle α representative of the bearing angle of said reflecting object with respect to said angular reference; first resolver means responsive to said α and β angles for computing their difference φ representative of an angle between said emitting source and said reflecting object; second resolver means responsive to said time early output signal T E and said echo signal arrival time T t for deriving their difference Δt; third resolver means responsive to said signal A E and said time early output signal T E for deriving a pointing angle θ of said emitting source toward said reflecting object with respect to a range line between said passive monopulse radar ranging system and said emitting source; and range resolver means responsive to said φ, α, β, Δt and θ signals for generating a plurality of range signals R E , R t and R E/t , said range signal R E being between said passive monopulse radar ranging system and said emitting source, said range signal R t being between said passive monopulse radar ranging system and said reflecting object, and said range signal R E/t being between said emitting source and said reflecting object, said range resolver means solving the equations. ##EQU13## said passive radar ranging system capable of accurately determining the location of said emitting source and said reflecting object in a monopulse scan of said emitting source, said antenna means having at least a pair of driven antennas arranged to provide angularly independent beam patterns while said emitter receiver means and said target receiver means being arranged to provide monopulse operation employing said independent beam patterns.

Claim 8

A passive monopulse radar ranging system for determining the range of a scanning, emitting source and a reflecting object illuminated by said emitting source and angularly separated thereform comprising, in combination: antenna means having a first plurality of ports providing a distribution of received energy phases as a function of an angle of arrival of a plurality of emitting source signals and a plurality of echo signals from said reflecting object; a beam forming matrix responsive to said first plurality of ports and having a second plurality of ports, ports of said second plurality providing said emitting source signals and said echo signals to discrete ports of said second plurality of ports as a function of said angle of arrival at said antenna means; emitting receiver means of said passive monopulse radar ranging system for receiving said emitting source signals from said beam forming matrix and for providing a time early output signal T E representing the arrival time of said emitting source signals, an output bearing angle β of said emitting source signals with respect to an angular reference, and a signal A E representative of the scan rate of said emitting source, said emitting source scanning at a non-constant rate through sectors of 360°; target receiver means of said passive monopulse radar ranging system for separately receiving said echo signals from said beam forming matrix and for providing a plurality of signals T t representing the arrival time of said echo signals, and for providing an angle α representative of the bearing angle of said reflecting object with respect to said angular reference; first resolver means responsive to said α and β angles for computing their difference φ representative of an angle between said emitting source and said reflecting object; second resolver means responsive to said time early output signal T E and said echo signal arrival time T t for deriving their difference Δt; third resolver means responsive to said signal A E and said time early output signal T E for deriving a pointing angle θ of said emitting source toward said reflecting object with respect to a range line between said passive monopulse radar ranging system and said emitting source; and range resolver means responsive to said φ, α, β, Δt and θ signals for generating a plurality of range signals R E , R t and R E/t , said range signal R E being between said passive monopulse radar ranging system and said emitting source, said range signal R t being between said passive monopulse radar ranging system and said reflecting object, and said range signal R E/t being between said emitting source and said reflecting object, said range resolver means solving the equations. ##EQU13## said passive radar ranging system capable of accurately determining the location of said emitting source and said reflecting object in a monopulse scan of said emitting source, said antenna means having at least a pair of driven antennas arranged to provide angularly independent beam patterns while said emitter receiver means and said target receiver means being arranged to provide monopulse operation employing said independent beam patterns.

Claim 11

The method of claim 3 wherein the step of determining an angle θ subtended by path R 2 comprises calculating the difference between said angle of arrival B 1 of said first energy signal and said angle of arrival B 2 of said energy signal echo.

Claim 12

The method of claim 3 wherein the step of determining an angle φ subtended by path R 1 comprises solving for φ according to θ=[(T.sub.2 -T.sub.1)A]/P.

Claim 13

The method of claim 3 wherein the step of utilizing said angles θ and φ and said difference t in time to determine distances along paths R 3 , R 1 and R 2 , comprises determining CT=(R.sub.1 +R.sub.2)-R.sub.3 where C=velocity of light t being in microseconds ##EQU14##