Adaptive Radar Beamforming for Ionospheric Clutter Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In high frequency surface wave radars, the peak power of the Doppler spectrum of the target signal can be buried within the power of the ionospheric clutter, leading to suppression of the target signal along with the ionospheric clutter, especially when the peak power of the target signal is smaller than that of the ionospheric clutter.
Innovation Solution
A beam formation device comprising a Doppler analysis unit, correlation matrix calculation unit, Doppler bin detection unit, target signal removal unit, weighting calculation unit, and beam formation unit, which calculates and removes the target signal from the correlation matrix to form an adaptive beam, avoiding suppression of the target signal by ionospheric clutter even when its peak power is smaller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If adaptive weighting is obtained for each range bin to suppress ionospheric clutter, then ionospheric clutter suppression is improved, but the target signal may be suppressed together with the ionospheric clutter
Solution Approach 1:
The patent segments the Doppler spectrum into multiple Doppler bins and processes each bin independently to identify target signal peaks. By dividing the clutter suppression process into discrete Doppler bin segments, the system can apply adaptive weighting selectively to bins containing clutter while preserving bins containing target signals, thus resolving the contradiction between clutter suppression and target signal preservation
Solution Approach 2:
The patent introduces an intermediary detection mechanism that identifies target signal peaks in the Doppler spectrum before applying adaptive weighting. This intermediary step acts as a mediator between the target signal and the clutter suppression process, allowing the system to recognize and protect target signals while still suppressing ionospheric clutter in other Doppler bins
2Measurement precision
If the peak power of the Doppler spectrum of the target signal is smaller than the power of the ionospheric clutter, then the target signal detection becomes more difficult, but the target signal may be buried and suppressed
Solution Approach 1:
The patent applies local quality by treating each Doppler bin independently with different processing characteristics.Bins containing target signals receive different adaptive weighting treatment compared to bins containing only clutter. This localized processing allows weak target signals to be preserved while strong ionospheric clutter in other bins is suppressed, resolving the power imbalance issue
3Quantity of substance
If the ionospheric clutter has a wider bandwidth than the target signal, then the clutter occupies more Doppler spectrum, but the target signal peak may be buried in the clutter power
Solution Approach 1:
The patent segments the wide bandwidth Doppler spectrum into multiple discrete bins, allowing independent analysis of each segment. This segmentation enables the system to identify narrowband target signal peaks within the broader clutter spectrum by examining individual bins, thus resolving the issue of target signals being buried in wideband clutter
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
This beam formation device includes: a Doppler bin detection unit (5) that detects a target Doppler bin which is a Doppler bin in which a target signal is present, from a correlation matrix calculated by a correlation matrix calculation unit (4) and a reception signal vector calculated by a Doppler analysis unit (3); a target signal removal unit (6) that removes, from the correlation matrix calculated by the correlation matrix calculation unit (4), the target signal in the target Doppler bin detected by the Doppler bin detection unit (5) and thereby calculates a target-signal-removed correlation matrix from which the target signal has been removed; and a weighting calculation unit (7) that calculates an adaptive weighting of the reception signal vector from the target-signal-removed correlation matrix calculated by the target signal removal unit (6). A beam formation unit (8) forms an adaptive beam from the reception signal vector calculated by the Doppler analysis unit (3) and the adaptive weighting calculated by the weighting calculation unit (7).