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 Engineering / unrestricted

Cross-Eye (CE) jamming is a technique aimed at inducing false target angles in radar measurements. The potential to deceive monopulse radar, a radar type commonly used due to its angular accuracy and resilience against jamming, has captured the interest of Electronic Warfare (EW) system manufacturers. CE jamming may increase the capability of self-defense against radar guided missiles. In this thesis, a CE jammer, based on the retrodirective channel design, for use in an EW systems is modeled and analyzed. The focus of the analysis is on the non-reciprocal Active Electronically Scanned Arrays (AESA). An electrical model of the jammer system and the AESA, including variations in the electrical properties, together with three different system correction methods are used. A simulation procedure, using single frequency (CW) signals, is defined and used for estimating total level of reciprocity, which is a primary contributor to jammer performance. Reciprocity error sensitivity for variations in model parameters is simulated to indicate which AESA aspects are essential for performance. Further, the influence of characterization and calibration noise is investigated. The usability of the model is demonstrated in different types of simulations, which highlights the differences between the system correction methods. Simulations show that a relatively high level of reciprocity can be achieved when using system correction, if measurement noise and model limitations are disregarded. The expected degradation in reciprocity from differences in electrical properties between the reception and transmission branch of the AESA has been confirmed. The effect of characterization and calibration noise, for realistic levels of noise, seems to be a dominating factor in the total reciprocity error. A significant increase in reciprocity error can likely be expected when non-CW signals are used and when realistic levels of noise and non-linear effects are added. / Cross-eye (CE) är en störprincip som har potential att inducera vinkelmätfel i radar. Dess möjlighet att störa monopulsradar, en vanligt förekommande typ av radar som är motståndskraftig mot många störformer, har skapat ett intresse för metoden hos tillverkare av system för elektronisk krigföring (EW-system). Användning av CE störning i ett EW-system skulle kunna öka möjligheten till självskydd vid attack från en monopulsradarstyrd robot. Avhandlingen analyserar en modell av en retrodirektiv CE störare som är avsedd för integration i ett multifunktionellt EW-system. Fokus i analysen är på de aktiva gruppantennerna (AESA) som används i systemet. En elektrisk modell av systemet används, vilken inkluderar variationer i parametrar hos AESA samt tre olika systemkorrektionsmetoder. En simuleringsprocedur som ger möjlighet att uppskatta reciprocitetsfel och känslighet för parametervariationer i AESA är definierad. Vidare undersöks inverkan av karaktäriserings och kalibreringsbrus. Modellens användningsområden visas i olika typer av prestandasimulering där effekter av de olika systemkorrektionsmetoderna tydliggörs. Simuleringsresultat för enkelfrekvens (CW) signaler visar en relativt hög nivå av reciprocitet om brus och olinjäriteter ignoreras. Det förväntade resultatet, att elektriska skillnader mellan mottagar- och sändargrenarna orsakar en försämring i reciprocitet, bekräftas. Inverkan av karaktäriserings och kalibreringsbrus verkar vara en dominerande faktor i det totala reciprocitetsfelet då rimliga brusnivåer används. En signifikant höjning av reciprocitetsfelet kan sannolikt förväntas då signaler med en viss bandbredd används och då rimliga nivåer av brus samt olinjäriteter inkluderas. / <p>QC 20171102</p>