A Study On Detection Techniques For Passive Radar Based On DVB-S Signal

The passive radar system using non-cooperative illuminator has lots of advantages in space target surveillance.It is therefore attracting great attention from researchers.In this paper,passive radar using a DVB-S(Digital Video Broadcasting Satellites)signal as source of illuminator is studied.To mitigate the impact of interference to detection performance,a weighted combining based multi-channel joint detection(MCJD)method is proposed,characterized by the novel setting of weights.Considering the fact that radar targets may appear with low probability,a two-stage cooperative detection method is proposed to improve energy efficiency while still guarantying the detection performance.Contents of each chapter are summarized as follows.After background introduction in Chapter 1.Chapter 2 describes the proposed passive radar system and demonstrates the field test results of channels for the Asia-Pacific six satellite,which broadcasts DVB-S signals over channels and may be used as opportunistic illuminator.In Chapter 3,simulations are conducted to demonstrate difficulties of detecting the weak DVB-S signals that are broadcasted by satellites and then reflected by targets.In Chapter 4,considering the fact that interference is usually i.i.d across frequency channels,a weighted combining based MCJD method is proposed to improve detection robustness to interference.Moreover,a conditional probability model is established to describe the characteristics that interference duration is often greater than a detection duration,and then a weight setting method that decides weights based on estimated existence probability of interference over each channel is proposed for the MCJD.Simulations are carried out to demonstrate performance of the proposed method,in comparison with the MCJD that decides weights based on estimated interference power.In Chapter 5,a two-stage cooperative detection scheme that combines correlation detection and cyclostationary detection is proposed to improve energy efficiency while maintaining sufficient detection performance.Correlation detection is superior on detection performance while cyclostationary detection is more energy efficient.Considering the fact that radar target appears with low probability,the radar system applies cyclostationary detection in general and switches to correlation detection when and only when detection results suggest presence of targets.