Towed Drogue Radar Jamming System
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Solution Overview
Problem
Existing radar jamming techniques are insufficient in masking the angular position of aircraft, as some radar systems can home in on the noise jamming signal, allowing for accurate targeting despite the denial of range information.
Innovation Solution
A ventriloqual-like jamming system that includes a single wire transmission line towed behind the aircraft, with a broadband noise signal launched as a surface wave and radiated from a drogue radiator at a safe distance, combined with an anti-integration network to create time domain 'holes' in the noise signal, hiding the radar return signal energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a broadband noise jamming signal is transmitted from the aircraft, then range information is denied to radar systems, but the angular position of the aircraft can still be accurately determined by radar systems homing in on the jamming signal source
Solution Approach 1:
A single wire transmission line is introduced as an intermediary between the aircraft and the drogue radiator. The transmission line carries the jamming signal from the aircraft to the drogue, which then radiates the signal at a location far behind the aircraft. This spatial separation masks the true source of the jamming signal, preventing radar systems from accurately determining the aircraft's angular position while still denying range information.
Solution Approach 2:
The jamming system is segmented into distinct functional components: the aircraft carries the signal generator, the transmission line carries the signal, and the drogue radiator transmits the signal. This segmentation allows the jamming function to be separated from the aircraft platform, creating a deceptive spatial distribution of the jamming signal source that confuses radar angle measurement.
2Reliability
If radar return signal energy is present on top of the jamming noise signal, then signal integration techniques can resolve the return signal as an energy bump, revealing the aircraft position
Solution Approach 1:
The anti-integration network generates periodic dips or gaps in the noise jamming signal at regular intervals. These periodic interruptions create a pattern that prevents radar systems from using signal integration techniques to resolve the radar return signal, as the integration process assumes a continuous noise background. The periodic action disrupts the statistical accumulation of signal energy that would otherwise reveal the aircraft position.
Solution Approach 2:
The anti-integration network uses feedback from the radar return signal to dynamically adjust the timing and depth of the dips in the noise jamming signal. By detecting the presence of radar return signals and responding with targeted interruptions, the system adaptively prevents the integration of return signal energy, maintaining the masking effect even when radar attempts to overcome the jamming through integration techniques.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively denies both range and angle information to tracking radar systems, preventing accurate targeting by masking the aircraft's position and resolving the issue of signal integration techniques that enhance tracking capabilities.
Implementation Method 1
a broadband electromagnetic wave launcher for launching the noise signal produced by the signal generator onto a leading end of the single wire transmission line such that the electromagnetic noise energy is transmitted as a surface wave along the line
Implementation Method 2
A drogue radiator is attached to the trailing end of the single wire transmission line for both aerodynamically stabilizing the line and for radiating the noise signal away from the axis of the line and toward the tracking radar
Implementation Method 3
tracking radar using signal integration techniques cannot resolve the radar return signal which would otherwise be superposed as a signal energy 'bump' on a constant level background of the jamming noise signal
Data Source
AI summary
A radar jamming signal generated by equipment carried by a target aircraft, is launched onto the leading end of a towed single wire transmission line so as to travel the length of the line as a nonradiating surface wave. A drogue radiator is attached to the trailing end of the line for radiating the jamming signal transversely of the towed line so as to be received by and cause jamming of tracking and/or fire control radar. The length of the single wire transmission line is selected so that the trailing radiator causes the jamming signal to emanate from a position sufficiently behind the aircraft so as to be outside the destructive radius of weapon fire directed at the apparent source of the jamming signal by fire control radar. A ventriloqual-like deception of the radar is thus achieved. A wave launcher couples the jamming signal to the leading end of the transmission line and for this purpose includes an electrically conducted horn-shaped structure, a tunable coaxial feed end at the constricted end of the horn structure, an inner transition conductor connecting the inner conductor of the coaxial feed to a leading end of the single wire transmission line, and a plurality of annular dielectric lenses and dielectric guides cooperatively shaped and fitted to the horn structure in a manner that effectively matches the bounded electromagnetic transmission wave characteristics of the coaxial feed cable with the surface wave transmission characteristics of the single wire transmission line. Coacting with the ventriloqual-like radiation of the jamming signal from the trailing end of the transmission line is an anti-integration network that hides the return radar signal reflected off the target aircraft in a signal energy “hole” created for such purpose in a secondary low level noise signal transmitted directly from the aircraft.