Multimodal radar -- concept, operation, bandwidth sharing and scheduling

Recent developments in radar have lead to them becoming multifunction, adaptive and cognitive. Radar waveform design has also been proposed for optimal detection and target information extraction. We propose an adaptive multimodal radar sensor that is capable of progressively varying its range resolution depending upon the target scattering features. Low range resolution profiles are formed using a low bandwidth waveform. High range resolution processing is then performed on selected range cells in which targets are declared. Thus the multimodal radar has the ability to provide target indication with a large range extent and can progressively switch to a narrow range extent mode for extracting recognizable target features. It consists of a test-bed that enables the generation of linear frequency modulated waveforms of various bandwidths for achieving the optimum resolution to image the target. This paper discusses the multimodal concept, explaining the advantages of a radar having different fields of view. Simulation results are presented to provide an initial demonstration of the proof-of-concept of multimodal radar. The architecture of the multimodal radar is explained, focusing on the important system parameters. The operation of the radar in staring and scanning mode is described. In staring mode, the radar is stationary and looks at the target scene. In scanning mode, an antenna positioner is used to enable surveillance of a wider field. Detailed experimental results are provided for both of these modes. A theoretical method to optimize the bandwidth used by the radar is also described. These theoretical results are compared with the results obtained in the field. Simulation results are provided which provide an insight into the performance of the radar. Receiver operating characteristic curves for the multimodal radar are presented.;In multi-functional radio frequency systems, bandwidth is a very scarce commodity which must be managed with diligence for optimal system performance. The multimodal radar uses variable bandwidth, making it possible to share the remaining bandwidth with some other application. In this work, we explore bandwidth sharing scenarios between radar surveillance, tracking and communications. We divide the surveillance space into sectors and use fuzzy logic to arrive at priorities for each sector. Priority for radar is based on separation between targets, signal to noise ratio, and existence of clutter. Multi-objective optimization is used to arrive at solutions making the best use of available bandwidth between radar and communications. We also consider the problem of scheduling between tracking and surveillance for the multimodal radar. Smart scheduling is employed to make the best use of available radar resources. The algorithms are applied to representative target scenarios for maximizing the track update rate while providing an adequate surveillance rate. Static radar scheduling algorithms are introduced for specific target scenarios. Dynamic radar scheduling is implemented to adapt to the changing target scenarios. Simulation results are provided to demonstrate the performance of these algorithms. The targets are tracked using the particle filter. Finally the conclusions are presented and a plan for future work is provided.