Characteristic research of ionospheric clutter in over the horizon HFSWR

The presence of ionospheric clutter in high-frequency over the horizon surface wave radar may extremely affect the performance of radar system and degrade the capability of detecting target, so it should be suppressed. The characteristic analysis of ionospheric clutter is the foundation of studying method to suppress ionospheric clutter, so it is necessary to research characteristic of ionospheric clutter. Aim at ionospheric clutter which specifically appears at some altitude range, the conception of spread Es-layer clutter is advanced to classify this kind of ionospheric clutter, which is helpful to expound directivity characteristic of ionospheric clutter. By using the MUSIC algorithm to analyze plentiful radar echoes data, directivity characteristic of several major kinds of ionospheric clutter has been summarized and the superposition situation that two kinds of ionospheric clutter exist at the same altitude has been discussed, thereby it is more convenient to advance and realize ionospheric clutter suppression methods based on directivity characteristic of ionospheric clutter.