Range measuring system

Claim 2

In a system for determining the range between two objects, one of the objects radiating electromagnetic wave energy having distinguishable characteristics which arrives at the other object by way of a direct path and a reflected path wherein it is reflected off of a surface, an apparatus comprising a direct channel and a reflected channel, both said direct and said reflected channels receiving direct and reflected waves by way of the two paths, variable means responsive to one of said direct and reflected channels for making the direct wave on said direct channel substantially equal in amplitude to the direct wave on said reflected channel, subtracting means responsive to said variable means and to the other of said channels which provides an output representative of the difference between the direct wave on said direct channel and the direct wave on said reflected channel, and correlator means responsive to said subtracting means and to said direct channel for providing a signal representative of the amplitude of said output, the signal from said correlator means being connected to actuate said variable means.

Claim 3

In a system for determining the range between two objects, one of the objects radiating electromagnetic wave energy having distinguishable characteristics which arrives at the other object by way of a direct path and a reflected path wherein it is reflected off of a surface, an apparatus comprising a direct channel and a reflected channel, both said direct and reflected channels receiving direct and reflected waves by way of the two paths, variable means responsive to one of said direct and reflected channels for making the direct wave on said direct channel substantially equal in amplitude to the direct wave on said reflected channel, subtracting means responsive to said variable means and to the other of said channels which provides an output representative of the difference between the direct wave on said direct channel and the direct wave on said reflected channel and also representative of the reflected wave on said reflected channel, and correlator means responsive to said subtracting means and said direct channel for providing a signal representative of the amplitude of said first output, the signal from said correlator means being connected to actuate said variable means and said second output being connected to means for determining the range between the two objects.

Claim 4

In a system for determining the range between two objects, one of the objects radiating electromagnetic wave energy having distinguishable characteristics which arrives at the other object by way of a direct path and a reflected path wherein it is reflected off of a surface, an apparatus comprising a direct channel and a reflected channel, both said direct and reflected channels receiving direct and reflected waves by way of the two paths, variable means responsive to one of said direct and reflected channels for making the direct wave on said direct channel substantially equal in amplitude to the direct wave on said reflected channel, subtracting means responsive to said variable means and to the other of said channels which provides an output representative of the difference between the direct wave on said direct channel and the direct wave on said reflected channel and also representative of the reflected wave on said reflected channel, and correlator means responsive to said subtracting means and said direct channel for providing a signal representative of the amplitude of said first output, the signal from said correlator means being connected to actuate said variable means and said second output being connected to means for determining the range between the two objects.

Claim 5

In a system for determining the range between two objects, one of the objects radiating electromagnetic wave energy having distinguishable characteristics which arrives at the other object by way of a direct path and a reflected path wherein it is reflected off of a surface, an apparatus comprising a direct channel And a reflected channel, both said direct and said reflected channels receiving direct and reflected waves by way of said two paths, variable means responsive to said direct channel for making the direct signal on said direct channel substantially equal in amplitude to the direct signal on said reflected channel, subtracting means responsive to said reflected channel and said variable means which provides an output representative of the difference in amplitude between its two inputs and correlator means responsive to said subtracting means and to said direct channel for providing an output representative of the amplitude of the difference between the direct signal on said direct channel and the direct signal on said reflected channel, said output from said correlator means being connected to actuate said variable means.

Claim 6

In a system for determining the range between two objects, one of the objects radiating electromagnetic wave energy having distinguishable characteristics which arrives at the other object by way of a direct path and a reflected path wherein it is reflected off of a surface, an apparatus comprising a direct channel And a reflected channel, both said direct and said reflected channels receiving direct and reflected waves by way of said two paths, variable means responsive to said direct channel for making the direct signal on said direct channel substantially equal in amplitude to the direct signal on said reflected channel, subtracting means responsive to said reflected channel and said variable means which provides an output representative of the difference in amplitude between its two inputs and correlator means responsive to said subtracting means and to said direct channel for providing an output representative of the amplitude of the difference between the direct signal on said direct channel and the direct signal on said reflected channel, said output from said correlator means being connected to actuate said variable means.

Claim 7

In a system for measuring the range between two objects having an apparatus of the type described in claim 3 wherein said variable means responsive to said direct channel comprises a variable attenuator.

Claim 8

A passive system for measuring the range between a first point and a second point at an unknown location from which detectable electromagnetic radiations having distinguishable characteristics are emanating, comprising first and second receiving means at the first point for receiving direct radiations and indirect radiations from the second point which have been reflected from a reflecting surface, a direct channel and a reflected channel responsive to said first and second receiving means, respectively, both the direct and reflected radiations appearing as signals on said direct and reflected channels, variable means responsive to said direct channel for making the direct signal on said direct channel substantially equal in amplitude to the direct signal on said reflected channel, subtracting means responsive to said variable means and said reflected channel for subtracting the direct signal on said direct channel at the output from said variable means from the signals on said reflected channel, correlator means responsive to said subtracting means and to said direct channel for providing an output representative of the difference in amplitude between the direct signal on said direct channel at the output from said variable means and the direct signal on said reflected channel, said output from said correlator means being connected to actuate said variable means, time delay measurement means responsive to the direct signal on said direct channel and to the reflected signal on said reflected channel taken from the output of said subtracting means for measuring the time interval between the arrival at the first point of the radiations from the second point by way of the direct and reflected paths, means for determining the angle of elevation of the second point relative to the first point, means for determining the altitude of the first point relative to the reflecting surface, and computer means for determining the range between the first and second points as a function of the time interval, the angle of elevation, the altitude of the first point, and the velocity of propagation of the radiations.

Claim 9

A passive system for measuring the range between a first point and a second point at an unknown location from which detectable electromagnetic radiations having distinguishable characteristics are emanating, comprising first and second receiving means at the first point for receiving direct radiations and indirect radiations from the second point which have been reflected from a reflecting surface, a direct channel and a reflected channel responsive to said first and second receiving means, respectively, both the direct and reflected radiations appearing as signals on said direct and reflected channels, variable means responsive to said direct channel for making the direct signal on said direct channel substantially equal in amplitude to the direct signal on said reflected channel, subtracting means responsive to said variable means and said reflected channel for subtracting the direct signal on said direct channel at the output from said variable means from the signals on said reflected channel, correlator means responsive to said subtracting means and to said direct channel for providing an output representative of the difference in amplitude between the direct signal on said direct channel at the output from said variable means and the direct signal on said reflected channel, said output from said correlator means being connected to actuate said variable means, time delay measurement means responsive to the direct signal on said direct channel and to the reflected signal on said reflected channel taken from the output of said subtracting means for measuring the time interval between the arrival at the first point of the radiations from the second point by way of the direct and reflected paths, means for determining the angle of elevation of the second point relative to the first point, means for determining the altitude of the first point relative to the reflecting surface, and computer means for determining the range between the first and second points as a function of the time interval, the angle of elevation, the altitude of the first point, and the velocity of propagation of the radiations.

Claim 10

A passive system of the type described in claim 5 wherein said variable means comprises a variable attenuator.

Claim 11

A passive system of the type described in claim 6 wherein said variable attenuator is electronic and comprises first and second electron tubes each having at least cathode, control grid, and plate elements, said direct channel being connected through a first impedance to said cathode element of said first electron tube, said cathode element of said first electron tube being connected through a second impedance to said cathode element of said second electron tube, third and fourth impedances connected to said cathodes of said first and second electron tubes, said control grids of said first and second electron tubes being responsive to said output from said correlator means, and the output from said variable attenuator being taken off of said cathode element of said second electron tube.