The effect of Travelling Ionospheric Disturbances upon the performance of an HF skywave MIMO radar

HF Skywave radars rely on the refractive properties of the ionosphere to reach distances beyond the horizon. The instability of this medium on wide temporal and spatial scales is one of the most important issue to be addressed in the design of such systems, especially when considering a MIMO (Multiple Input Multiple Output) configuration. In such a configuration, multiple transmitters emit orthogonal waveforms that are properly separated and processed at the receiver to extract the target parameters. The success of this process relies on the separability of the transmitted waveforms at the receiver. During the propagation through the ionosphere the transmitted radiowaves undergo different degrading phenomena that change their property so they might not be separated at the receiver with consequences on the radar performances. These degrading phenomena depend on the ionospheric state and cannot be avoided. The simulator described in this work has the aim to provide the evaluation of the effect of both disturbed and undisturbed ionospheres. In particular, the fading caused by TIDs (Travelling Ionospheric Disturbances) is considered. MIMO radar for different geometries are considered in order to show the advantages and the disadvantages of each configuration.