Multiple source tracking system

A detector for adapting a monopulse tracking receiver system to detect the presence of multiple radiating sources within the effective antenna beamwidth of the system comprising:

• amplitude measurement means connected to a difference channel output of the receiving system for generating an amplitude signal proportional to the amplitude of the signal at said output;
• absolute magnitude measurement means connected to the receiver system for generating a magnitude signal proportional to the absolute magnitude of the error signal derived from the difference channel output signal by the receiver system;
• and
• decision means connected to said amplitude measurement means and to said absolute magnitude measurement means for providing an indication when the amplitude signal from said amplitude measurement means is greater than the magnitude signal from said absolute magnitude measurement means thereby indicating the presence of multiple radiating sources within the effective antenna beamwidth of the receiver system.

A monopulse tracking system for tracking one of multiple radiating sources comprising:

• a monopulse radio receiver connected to a steerable monopulse antenna, said receiver having a difference channel output, a first angular error signal output, and a servo for steering said antenna;
• signal processing means connected to said receiver, said signal processing means generating an amplitude signal proportional to the amplitude of the signal at said difference channel output and a magnitude signal proportional to the absolute magnitude of the signal at said error signal output, said signal processing means also having decision circuit means for comparing the amplitude signal and the magnitude signal, said decision means generating a second angular error signal when the amplitude signal is greater than the magnitude signal;
• and
• steering control means connected to said signal processing means and said receiver, said steering control means arranged to connect said first error signal output to said servo only when a single radiating source is within the effective beamwidth of said antenna and to connect the second error signal from said decision circuit to said servo only when multiple radiating sources are within the effective beamwidth of said antenna.

A monopulse radio tracking system capable of discriminating among multiple radiating sources comprising:

• a monopulse tracking radio receiver having a steerable directional monopulse antenna, said antenna steerable in response to antenna control signals;
• signal processing means connected to said receiver for determining the presence of multiple radiating sources within the beamwidth of said antenna, said signal processing means comparing the relative amplitudes of output signals from said receiver system;
• decision means connected to said signal processing means for providing an indication when the relative amplitudes of such signals are characteristic of the presence of multiple radiating sources;
• and
• control signal generation means connected to said receiver, said signal processing means, and said decision means, for generating antenna control signals, such control signals utilized to steer said antenna toward only one of such multiple radiating sources.

A monopulse tracking system for tracking one of multiple radiating sources comprising;

• a monopulse radio receiver connected to a steerable monopulse antenna, said receiver having a sum channel signal output, an azimuth difference channel output, an elevation difference channel output, a first azimuth angular error signal output, a first elevation angular error signal output, an azimuth servo for steering said antenna in the azimuthal plane, and an elevation servo for steering said antenna in the elevation plane;
• azimuth signal processing means connected to said azimuth difference channel output and to said first azimuth angular error signal output, said azimuth signal processing means for generating an azimuthal amplitude signal proportional to the amplitude of the signal at said azimuth difference channel output and an azimuthal magnitude signal proportional to the absolute magnitude of the signal at said first azimuth angular error signal output, said azimuth signal processing means also having azimuth decision circuit means for comparing the azimuthal amplitude signal and the azimuthal magnitude signal, said azimuth decision means generating a second azimuth angular error signal when the azimuthal amplitude signal is greater than the azimuthal magnitude signal;
• elevation signal processing means connected to said elevation difference channel output and to said first elevation angular error signal output, said elevation signal processing means for generating an elevation amplitude signal proportional to the amplitude of the signal at said elevation difference channel output and an elevation magnitude signal proportional to the absolute magnitude of the signal at said first elevation angular error signal output, said elevation signal processing means also having elevation decision circuit means for comparing the elevation amplitude signal and the elevation magnitude signal, said elevation decision means generating a second elevation angular error signal;
• diagonal plane detection means connected to said sum channel output, said elevation difference channel output, and said azimuth difference channel output, said diagonal plane detection means arranged to produce a clockwise control signal when multiple radiating sources lie in a diagonal plane rotated in a clockwise direction with respect to the elevation and azimuth planes, and to produce a counterclockwise control signal when multiple radiating sources lie in a diagonal plane rotated in a counterclockwise direction with respect to the elevation and azimuth planes;
• steering control means connected to said azimuth signal processing means, said elevation signal processing means, and said diagonal plane detection means, said steering control means responsive to said second azimuth angular error signal and said second elevation angular error signal to cause said azimuth servo to steer said antenna so as to move the boresight azimuthal plane toward one of the multiple radiating sources, and to cause said elevation servo to steer said antenna so as to move the boresight elevation plane toward one of the multiple radiating sources, and said control signal from said diagonal plane detection means operative to cause azimuth servo and said elevation servo to each steer said antenna toward the same one of such multiple radiating sources whereby the boresight of said antenna becomes aligned with said one source.