Dynamic Azimuth Scanning for Rotating AESA Radar
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Solution Overview
Problem
Rotating three-dimensional surveillance radars face reduced probability of detection and target range in azimuth angles affected by non-uniform weather conditions, such as heavy rain, due to limited energy distribution and beamshape losses, which existing designs fail to adequately compensate for.
Innovation Solution
A rotating active electronically scanned array radar system with dynamic electronic azimuth beam steering, adjusting scan rates and energy distribution based on azimuth offset profiles derived from gain profiles to maintain constant target detection range across all azimuths, even in non-uniform weather conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a higher energy template is used to counter extra loss in heavy rain azimuth regions, then the probability of detection improves at those angles, but the template duration increases and azimuth spacing increases, resulting in increased beamshape loss and decreased target detection range
Solution Approach 1:
The patent implements dynamic azimuth scanning that adjusts the radar beam's azimuth angle continuously during rotation, allowing the system to spend more time (increased dwell time) on azimuth sectors experiencing heavy rain attenuation. This dynamic adjustment enables the radar to adaptively allocate energy resources to compensate for weather-related losses without requiring a static increase in template energy that would degrade azimuth spacing and detection range elsewhere
Solution Approach 2:
The system changes the scanning parameters (azimuth angle, dwell time, scan rate) based on detected weather conditions. By monitoring attenuation patterns and adjusting scanning parameters in real-time, the radar maintains optimal probability of detection in heavy rain regions while preserving adequate azimuth spacing and detection range in clear weather regions, thus resolving the contradiction between reliability and productivity
2Use of energy by moving object
If the radar rotation rate is reduced to spend more time per azimuth degree, then more energy can be allocated to each azimuth sector, but the overall surveillance coverage rate decreases
Solution Approach 1:
The patent employs dynamic scanning that varies the azimuth scan rate continuously during rotation rather than using a fixed slow rotation. The system accelerates through clear weather azimuths and decelerates (spending more dwell time) in heavy rain azimuths, thereby allocating more energy to problematic sectors without reducing the overall rotation speed and surveillance coverage rate
Solution Approach 2:
The system applies different scanning strategies to different azimuth sectors based on local weather conditions. Clear weather sectors receive standard scanning parameters for efficient coverage, while heavy rain sectors receive enhanced dwell time and energy allocation. This localized adaptation resolves the contradiction by optimizing energy distribution spatially without compromising overall productivity
3Use of energy by moving object
If the maximum elevation angle is limited in heavy rain to allocate more energy to low elevations, then energy distribution improves, but the search volume is reduced
Solution Approach 1:
The patent implements dynamic elevation scanning that adjusts the elevation angle range and dwell time based on azimuth-specific weather conditions. In heavy rain azimuths, the system can allocate more energy to low elevations by adjusting the elevation scan parameters dynamically, while in clear weather azimuths, the full elevation range is scanned. This temporal and spatial variability resolves the contradiction between energy distribution and search volume
Solution Approach 2:
The system uses periodic weather surveys to identify heavy rain azimuth regions and adjusts elevation scanning parameters accordingly during subsequent surveillance scans. This periodic adaptation allows the radar to optimize energy distribution in affected sectors while maintaining full search volume coverage in clear weather sectors, resolving the contradiction through cyclical optimization
Data Source
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AI summary
Embodiments for providing dynamic azimuth scanning are generally described herein. In some embodiments, weather survey measurements are performed to estimate environmental losses as a function of azimuth angles. Gain improvements are determined based on the amount of energy increase used at different azimuth angles derived from the azimuth loss survey measurements. A gain profile is generated based on the determined gain improvements. An azimuth offset profile is derived using the gain profile to define azimuth angles where progressive scan back is used in the area of environmental losses to provide additional power and to define azimuth angles where progressive scan forward is used in regions of low loss. Dynamic electronic azimuth beam steering provides a near-constant average target detection range as a function of azimuth in the presence of non-uniform loss.