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Retrodirective Beacon
The analysis presented in Section 4.2.1 is performed with the objective of analysing cross-eye jamming, but the result is general enough to be applied to other scenarios. A retrodirective beacon (Van Atta array) consisting of two antenna elements with signals that can propagate in both directions is one of the cases that is also covered by the analysis in Section 4.2.1. A retrodirective beacon appears as a point target between the its two antenna elements in its far-eld region.
Phase-Front Analysis
The analyses of glint have been shown to be accurate through extensive measurements over many years [31].3 The results derived in Section 4.2.1 should thus give the same results as the analyses of glint described in Section 2.4.1 under the conditions for which those analyses are valid.
Results and Discussion
In this section, the extended analysis of cross-eye jamming derived in Section 4.2 is examined and compared to the linear-t analysis for a typical cross-eye jamming scenario. A number of cases that highlight dierences between the results are considered, and the implications of the results derived in Section 4.2 are highlighted. A far wider range of parameters is considered in Chapter 5, where both the extended and linear-t analyses are compared to laboratory measurements.
The following parameters typical of a missile threat against an aircraft or ship will be used in this section:
10 radar antenna beamwidth (dr = 2.54 wavelengths, and each radar antenna element is a uniformly-excited aperture 2.54 wavelengths long),
the jammer antenna elements are uniformly-excited apertures 2.54 wavelengths long,
1 km jammer range (r = 1 km),
10 m jammer antenna element separation (dc = 10 m),
30 jammer rotation (c = 30), and
0.5 dB jammer amplitude mismatch (a = 0.9441).
The total angular separation of the cross-eye jammer antenna elements as seen by the radar for the parameters above is 0.4962 (e = 0.2481), which is 5.0% of the radar antenna’s 3-dB beamwidth. The value of the jammer phase match () and the resulting cross-eye gain (GC) will be specied on the gures below. Results for a number of phase-match (and consequently cross-eye gain) cases are shown in Figures 4.2 to 4.4 when the radar antenna is rotated. The case with the best phase match (highest cross-eye gain) in Figure 4.4 is also considered at a range of 10 km in Figure 4.5 to show the eect of varying the jammer antenna element spacing. Results for the case where the jammer system is rotated are in given Figure 4.6 again for the case in Figure 4.4 to show the eect of rotating the jammer system. Results are given for both the extended analysis outlined in Section 4.2.1 and Sher- man’s linear-t analysis [30, 40] described in Section 2.4.1. The linear-t analysis is used here because the other analyses do not explicitly consider the sum- and diference- .
1 Introduction
1.1 Introductory Remarks
1.2 Background and Motivation
1.3 Scope and Objectives
1.4 Original Contributions
1.5 Overview of the Thesis
2 Background
2.1 Introductory Remarks
2.2 Electronic Warfare
2.3 Tracking Radar
2.4 Glint Analysis
2.5 Cross-Eye Jammer Implementation
2.6 Concluding Remarks
3 Monopulse Model
3.1 Introductory Remarks
3.2 Mathematical Analysis
3.3 Results and Discussion
3.4 Concluding Remarks
4 Mathematical Analysis
4.1 Introductory Remarks
4.2 Mathematical Analysis
4.3 Results and Discussion
4.4 Concluding Remarks
5 Experiments
5.1 Introductory Remarks
5.2 Experimental Setup
5.3 Data Processing
5.4 Results and Discussion
5.5 Concluding Remarks
6 Tolerance Analysis
6.1 Introductory Remarks
6.2 Mathematical Analysis
6.3 Results and Comparison
6.4 Concluding Remarks
7 Conclusions and Future Research
7.1 General Conclusions
7.2 Future Research
References
