Limiting apparent target position in skin-return influenced cross-eye jamming

It is desirable to limit the apparent target to one side of a retrodirective cross-eye jammer despite the variation caused by platform skin return. The relationship between the jammer parameters and the jammer-to-signal ratio (JSR) to ensure that this occurs is investigated. When this relationship is not satisfied, the proportion of the apparent targets generated on the opposite side of the jammer is determined.This work was supported by the Armaments Corporation of South Africa (Armscor) under Contract KT521896.http://ieeexplore.ieee.org/arnumber=6558044hb201

Statistical skin-return results for retrodirective cross-eye jamming

The effect of the radar skin return from the platform on which a cross-eye jammer is mounted is significant in many practical cross-eye jamming scenarios. However, all published analyses of skin-return affected cross-eye jamming have significant limitations. These limitations are addressed by deriving equations for the distribution of the cross-eye gain in the presence of skin return. The values of these results are demonstrated by using them to gain insight into how skin return affects cross-eye jamming.The National Research Foundation of South Africa (Grant number 119151).http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?reload=true&punumber=7hj2019Electrical, Electronic and Computer Engineerin

Analysis of path-length effects in multiloop cross-eye jamming

The effect of path-length differences on multiloop retrodirective cross-eye jammers is evaluated. It is shown that such jammers may act as beacons, and the conditions under which this occurs are investigated for two-loop jammers. The sensitivity of the two-loop cross-eye gain to path-length differences is also studied and is found to be small for small path-length differences, but to increase rapidly. The effect of the two-loop cross-eye jammer parameters on path-length effects is also considered.The National Research Foundation of South Africa (NRF) [85845http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?reload=true&punumber=7hj2017Electrical, Electronic and Computer Engineerin

Cross-eye gain in multiloop retrodirective cross-eye jamming

The simultaneous use of multiple retrodirective cross-eye jammers is analysed for both the case where the jammer loops point in different directions and when they point in the same direction. In both cases, the use of multiple cross-eye jammer loops is shown to lead to significantly increased angular errors in the threat radar under certain conditions. Alternatively, the sum-channel return can be increased to reduce the jammer-to-signal ratio (JSR) requirements for each jammer loop.http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?reload=true&punumber=7hb2016Electrical, Electronic and Computer Engineerin

Phase‐conjugating retrodirective cross‐eye jamming

A cross‐eye jammer based on a phase‐conjugating (PC) retrodirective array is proposed. Such PC cross‐eye jammers eliminate the delay inherent in traditional Van‐Atta (VA) cross‐eye jammers and induce errors in radars that use the same antenna beam for transmission and reception, while VA cross‐eye jammers do not. Validated simulations are provided to confirm the effectiveness and retrodirective properties of the PC cross‐eye jammer.https://ietresearch.onlinelibrary.wiley.com/journal/1350911xhj2021Industrial and Systems Engineerin

Statistical skin-return results for retrodirective cross-eye jamming

The effect of the return from the platform on which a cross-eye jammer is mounted is significant in many practical cross-eye jamming scenarios. However, all published analyses of skin-return affected cross-eye jamming have significant limitations. These limitations are addressed by deriving equations for the distribution of the cross-eye gain in the presence of skin return. The value of these results is demonstrated by using them to gain insight into how skin return affects cross-eye jamming.http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?reload=true&punumber=7hb2017Electrical, Electronic and Computer Engineerin

Path-length compensation in multi-loop retrodirective cross-eye jamming

Multiloop retrodirective cross-eye jammers offer the possibility of both simplifying system implementation and improving system performance. However, the signals for each jammer loop propagate along different paths, leading to potentially detrimental effects on system performance. Static and dynamic compensation for path-length differences are introduced and analyzed. Of the two, static compensation is simpler but is only effective for limited engagement geometries. Dynamic compensation is more general but requires an accurate estimate of the engagement geometry.http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?reload=true&punumber=7hj2019Electrical, Electronic and Computer Engineerin

Efficient computation of array factor and sidelobe level of linear arrays

The implementation of code to efficiently compute the array factor and sidelobe level (SLL) of linear antenna arrays in MATLAB and GNU Octave is considered. The use of a fast Fourier transform (FFT) to compute the array factor is shown to be more efficient than other approaches. The automatic determination of the sidelobe region as a necessary step to computing the SLL is addressed. A number of codeoptimsation techniques in MATLAB and Octave are evaluated, including vectorisation, memory allocation and the use of built-in functions. Finally, an efficient function which can be used for the computation of the array factor and SLL of linear arrays in MATLAB and Octave is presented.This work is based on the research supported in part by the National Research Foundation (NRF) of South Africa (grant-specific unique reference number 85845).http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=74hb2017Electrical, Electronic and Computer Engineerin

A comprehensive investigation of retrodirective cross-eye jamming

Cross-eye jamming is an Electronic Attack (EA) technique that induces an angular error in the radar being jammed. The main benefit of cross-eye jamming is that it is effective against monopulse tracking radars, which are largely immune to other forms of jamming. The objective of this research is to gain a complete understanding of cross-eye jamming so that systems that might be developed in future can be properly specied. The main contribution of this work is a comprehensive mathematical and experimental study of retrodirective cross-eye jamming. The mathematical analysis considers all aspects of an isolated, single-loop, retrodirective cross-eye jamming engagement, thereby avoiding the approximations inherent in other cross-eye jamming analyses. Laboratory experiments that accurately represent reality by using the radar for both transmission and reception, and simulating a true retrodirective cross-eye jammer were performed to validate the theoretical analysis. Lastly, the relationship between the angular error induced in the radar being jammed and the matching required from a cross-eye jammer system is explored. The most important conclusion of this work is that the traditional analyses of cross- eye jamming are inaccurate for the conditions under which cross-eye jammers operate. These inaccuracies mean that the traditional analyses are overly conservative, particularly at short ranges and for high cross-eye gains, suggesting that practical cross-eye jammers can be realised more easily than is generally believed.Thesis (PhD)--University of Pretoria, 2010.Electrical, Electronic and Computer Engineeringunrestricte

Implementation and testing of a retrodirective cross-eye jammer

One of the few electronic attack techniques that can deceive radars in angle is cross-eye jamming, which mimics the naturally-occurring phenomenon glint. The extreme tolerance requirements of cross-eye jamming mean that a retrodirective implementation is required, but published measurements of cross-eye jamming either ignore the retrodirective implementation or only simulate it. The implementation of a retrodirective cross-eye jammer and its testing against a monopulse radar are described. A procedure for calibrating the jammer is outlined and is shown to be effective by achieving large angular errors. The measured results agree well with the extended analysis of cross-eye jamming and confirm that the implemented jammer is retrodirective. Specifically, the ability of a cross-eye jammer to generate an indicated angle that never becomes zero, thereby potentially breaking a tracking lock, is confirmed.http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?reload=true&punumber=7hj2023Electrical, Electronic and Computer Engineerin