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

Abstract

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.

Low sidelobe waveform design with constant modulus constraint for high‐frequency radar

“…range processing). Characterising the second order statistics of environmental disturbance by a covariance matrix , which can be obtained by the cognitive paradigm given in [10], the response of WF is jointly determined by the covariance matrix and the transmitted waveform : Next, with the receiver fixed as , we investigate the waveform design problem for transmitter. The formulas of the SINR metric and IRSL metric are given first, followed with the MSMI design and MSMI‐CMC design.…”

“…To this end, the framework in [3] is extended so as to account for a similarity constraint to ensure the designed waveform sharing some desired auto‐correlation features with the reference waveform, such as linear frequency modulation (LFM) waveform [4]. Controlling sidelobe level by similarity constraint has been discussed in many published works [10–13]. However, this kind of method, in essence, shaping the auto‐correlation function of probing waveform, effectively suppress the sidelobes only when the receiver is a matched filter.…”

“…In this paper, we consider the waveform design problem for high‐frequency radar in fast‐time domain. WF is the optimal processor for fast‐time processing, due to the second order statistics of radar's operating environment is considered as invariable during one pulse repetition interval and can be available based on a cognitive paradigm [10]. Waveform is designed aiming to mitigate the co‐channel interference and coloured noise, with the range sidelobes level controlled effectively.…”

Radio frequency interference suppression filters design for HF radar based on SOCP

“…We denote the designed filter as , then, the output SINR of the filter is expressed as [12]: where is the covariance matrix of the interference and noise. In general cases, for high‐frequency radar, the second‐order statistics of its working environment is considered to be invariable within a period of time, which means can be approximated as through a cognitive paradigm [13].…”