Monopulse receiver circuit for an anti-radar missile tracking system

• US 3,949,955 A
• Filed: 04/04/1963
• Issued: 04/13/1976
• Est. Priority Date: 04/04/1963
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Atkinson, Robert E., Russell, Duane J., Sykes, Langthorne
• Primary Examiner(s): Hubler, Malcolm F.
• Application Number:
  US04/270,773
• Time in Patent Office: 4,758 Days
• Field of Search: 244/14, 244/14.3, 244/3.19, 343/16 M
• US Class Current: 244/3.19
• CPC Class Codes: F41G 7/22 Homing guidance systems
• CPC Class Codes: G01S 13/44 Monopulse radar, i.e. simultaneous lobing

Abstract

1. In a monopulse radar receiver system for determining the angular co-orates of a pulsed RF radiation source, the combination comprising:

An RF signal processing circuit adapted to convert a directional antenna input signals to inversely related pairs of computer input pulses;

A pair of automatic gain control pre-amplifiers connected to said processing circuit adapted to simultaneously receive and amplify the pairs of input signals;

A difference circuit connected between the outputs of each pair of pre-amplifiers for providing a difference signal pulse;

Amplifying means connected with said difference circuit for amplifying said difference signal pulse;

A leading-edge gate circuit connected with said amplifying means, adapted to be operatively triggered at the pulse-repetition rate of the pulses propagated by the RF radiation source for accepting only the leading edge of each amplified difference signal pulse;

Means for triggering the gate circuit;

A pulse integrator circuit connected with the output of said gate circuit adapted to provide an output signal which is a function of the position of the source of radiation;

Direct connecting means joining the output of said integrator with one pre-amplifier of said pair for directing the integrator output signal to the one pre-amplifier for dirving the gain thereof in a first direction;

An inverter circuit connecting the output of said integrator with the other pre-amplifier of said pair, adapted to invert and combine a reference voltage with the output of said integrator circuit to provide an inverted gain control signal having a reference imposed thereon for driving the gain of the other pre-amplifier in a second direction opposed to said first direction; and

A second difference circuit connected with the output of said integrator and the output of said inverter circuit for deriving a difference signal indicative of the angular co-ordinate of the source of pulsed RF radiation, relative to said system, when the difference signal is driven to a zero valve.

Claims

1. In a monopulse radar receiver system for determining the angular co-ordinates of a pulsed RF radiation source, the combination comprising:

an RF signal processing circuit adapted to convert a directional antenna input signals to inversely related pairs of computer input pulses;

a pair of automatic gain control pre-amplifiers connected to said processing circuit adapted to simultaneously receive and amplify the pairs of input signals;

a difference circuit connected between the outputs of each pair of pre-amplifiers for providing a difference signal pulse;

amplifying means connected with said difference circuit for amplifying said difference signal pulse;

a leading-edge gate circuit connected with said amplifying means, adapted to be operatively triggered at the pulse-repetition rate of the pulses propagated by the RF radiation source for accepting only the leading edge of each amplified difference signal pulse;

means for triggering the gate circuit;

a pulse integrator circuit connected with the output of said gate circuit adapted to provide an output signal which is a function of the position of the source of radiation;

direct connecting means joining the output of said integrator with one pre-amplifier of said pair for directing the integrator output signal to the one pre-amplifier for driving the gain thereof in a first direction;

an inverter circuit connecting the output of said integrator with the other pre-amplifier of said pair, adapted to invert and combine a reference voltage with the output of said integrator circuit to provide an inverted gain control signal having a reference imposed thereon for driving the gain of the other pre-amplifier in a second direction opposed to said first direction; and

a second difference circuit connected with the output of said integrator and the output of said inverter circuit for deriving a difference signal indicative of the angular co-ordinate of the source of pulsed RF radiation, relative to said system, when the difference signal is driven to a zero valve.

2. In a monopulse receiver circuit adapted to solve relative angular RF target-source position relative to the boresight axis of an anti-radar missile guidance system, means comprising in combination:

an RF receiving directional antenna having four output terminals;

two pairs of automatic gain control pre-amplifiers;

a crystal detector connected between each of said output terminals and an automatic gain control pre-amplifier for converting antenna output signals to video pulsed pre-amplifier input signals having an amplitude and polarity dictated by the intensity of the RF signals and the attitude of the target source relative to the antenna;

a difference circuit connected between the pre-amplifiers of each pair of said pairs of pre-amplifiers for simultaneously obtaining a pair of pre-amplifier output signals indicative of the attitude of the target-source relative to a pair of normally disposed planes intersecting along the boresight axis of a given missile for thereby obtaining intelligence signals indicative of boresight error with respect to said target source;

a pair of automatic gain control difference video amplifiers connected at the output of each difference circuit;

a leading-edge track gate circuit adapted to be triggered at a determinable rate for discarding received signals having a pulse repetition rate in variance with said target-source connected at the output of each video difference amplifier;

a pair of signal integrator circuits coupling the output of each track gate with the gain control means of the automatic gain control pre-amplifiers through which the connected track gate circuit receives a signal;

an integrator output signal inverter and reference voltage applying circuit connected between each integrator circuit and one of the pre-amplifiers connected thereto for providing an inverter output signal proportional to the detected boresight error for driving the output signals of the pre-amplifier-connected difference circuit to a zero valve;

3. circuit means for detecting and converting the inverter output signals to missile guidance control input signals;

a sum circuit connected with each crystal detector for adding the output signals from the detectors to provide an RF intensity signal;

an automatic gain control sum video amplifier connected with the output of said sum circuit for amplifying said intensity signal;

a reference voltage comparator circuit connected with the output of the sum video amplifier for combining the amplified intensity signal with a reference voltage and providing a difference output signal;

an integrator circuit connected between the output of the reference voltage comparator circuit and the gain control of each video amplfier adapted to control the gain thereof in accordance with the output signal from the comparator circuit for effectively canceling the effect of the intensity factor of the output signals from the video amplifier for thus negating the effects of the intensity factor of the input signals thereof; and

means connecting the output of the sum video amplifier to the leading edge track gate for supplying gate triggering signals thereto, whereby said receiver may be locked onto the target-source of RF signals and maintin guidance thereon.

4. In a passive radar guidance receiver system adapted to utilize closed loop monopulse tecniques for homing on a target-source of pulsed RF radiation operating in a field of radiation propagated for means including a plurality of radiation sources and a plurality of surfaces reflecting RF signals, the combination comprising:

a forward-looking, four-way directional antenna system adapted to receive RF signals propagated within said field;

an RF signal processing circuit including two pairs of crystal detectors connected with said antenna system for converting said RF signals to pulsed radiation source and reflecting surface direction information signal pulses;

a first signal pulse processing, closed loop circuit connected with said processing system for rejecting received reflecting surface direction information signal pulses and processing said source direction information signal pulses to provide source position intelligence with respect to a first plane;

a second signal pulse processing, closed loop circuit connected with said processing system for rejecting received reflecting surface direction information signal pulses and processing said source direction information signal pulses to provide source position intelligence with respect to a second plane disposed at right angles to said first plane;

each signal processing closed loop circuit including a pair of RF signal processing circuit-connected automatic gain control pre-amplifiers, the input of each being connected to a given crystal of said pair for providing a pair of inversely related pulsed signals of varying amplitudes;

a difference circuit connected between the outputs of said pair of pre-amplifiers adapted to combine the output signals of said pair of pre-amplifiers to provide an output difference signal pulse;

an automatic gain control amplifier connected with the output of said difference circuit for amplifying the difference signal pulse;

a leading-edge track gate circuit connected with the output of said automatic gain control amplifier adapted to be triggered in response to the pulse repetition frequency of the target-source for accepting only the leading edge portion of each amplified difference signal pulse directed thereto to provide an integrator input pulse;

a gate circuit-connected pulse integrator circuit adapted to receive the integrator input pulse and provide an integrator output signal which is a function of the position of the target-source of pulsed RF radiation when the difference signal is of a zero value;

means connecting the output of said integrator directly to one pre-amplifier of said pair, whereby the integrator output signal serves as a first gain control signal for controlling the gain of said one pre-amplifier;

a signal inverting and reference signal voltage combining inverter circuit connected between the output of said integrator circuit and the other pre-amplifier of said pair of pre-amplifiers adapted to invert and impose a reference voltage on said integrator output signal for providing a second gain control signal for controlling the gain of said other pre-amplifier of said pair of pre-amplifiers, whereby the gain of said pre-amplifiers are caused to vary inversely with respect to each other for causing the difference signal to approach a zero value;

a second difference circuit connected between the output of the integrator and the output of said inverter circuit adapted to combine the first and second gain control signals for providing a servo control input signal; and

a sum loop circuit connected with said first and second signal processing closed loop circuits and said RF signal processing circuit for eliminating the effects of source position intelligence for all sources having intensity factors differing from the intensity factors above a predetermined level, whereby the source position intelligence is reduced to position intelligence indicative of the target source position with respect to the first and second planes.