Waveform design based on environmental sensing for sky-wave over-the-horizon radar

Sky-wave over-the-horizon (OTH) radar operates in the high-frequency (HF) band congested by external interferences. Owing to the serious occupancy, sometimes OTH radar cannot find suitable clear channel with sufficient bandwidth, especially when broad band is needed. This paper proposes a cognitive scheme of transmit waveform design in the presence of cochannel interference and colored noise. In the scheme, OTH radar monitors the environment in real time and designs transmit waveform adaptively. Environmental sensing based waveform (ESBW) is optimized under the criteria of maximizing the output signal-to-interference-plus-noise ratio (SINR) of matched filtering, and similarity constraint for reasonable range resolution and sidelobes level. The analytic solution to this constrained optimization problem is developed. A simulated scenario with strong interference and colored noise has been introduced. Simulation results demonstrate that ESBW suppresses the interference and colored noise effectively, and detects the target successfully.