Radar Beam Steering Using Sidelobes for Off-Boresight Detection
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Solution Overview
Problem
Radar systems face challenges in accurately distinguishing between main beam and sidelobe detections due to high sidelobe levels, leading to ambiguity and clutter, especially in the presence of jamming signals, and existing methods to mitigate sidelobes are complex and costly.
Innovation Solution
A method involving progressive phase shifts between antenna elements to steer the main lobe away from boresight, utilizing a look-up table to differentiate between objects at boresight and sidelobes, and recording signal return levels to enhance sidelobe detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sidelobe levels are kept low through conventional methods (scaling/tapering/weighting), then clutter detections are minimized, but device complexity and cost increase
Solution Approach 1:
Instead of suppressing sidelobes to minimize clutter, the patent inverts the approach by intentionally enhancing sidelobe levels and using them as additional detection channels. The method applies progressive phase shifts to move the main lobe away from boresight, thereby increasing sidelobe signal return levels to detect objects that would otherwise be missed.
Solution Approach 2:
The patent adds a temporal dimension to the detection process by applying multiple progressive phase shifts sequentially and using a look-up table to correlate detections across different phase shift conditions. This transforms a single-dimensional spatial detection problem into a multi-dimensional detection scheme involving phase shift states.
2Measurement precision
If sidelobe levels are kept low, then target position ambiguity is reduced, but the field of regard is limited
Solution Approach 1:
The patent segments the detection space by creating multiple detection zones: the main lobe region for primary detections and enhanced sidelobe regions for secondary detections. By applying progressive phase shifts, the system creates distinct detection sectors that can be independently analyzed using the look-up table to determine object positions.
Solution Approach 2:
The patent extends the field of regard by utilizing the angular dimensions where sidelobes naturally occur. Through progressive phase shifting and look-up table correlation, objects detected in sidelobe regions are resolved into accurate positional information, effectively adding detectable coverage in previously ambiguous angular regions.
3Adaptability or versatility
If progressive phase shifts are applied to enhance sidelobe detection, then field of regard is improved, but signal return levels become more complex to interpret
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing the relationship between progressive phase shifts and expected signal return levels in a look-up table. This pre-computed reference data enables rapid comparison and interpretation of actual detections without requiring complex real-time calculations, significantly simplifying the interpretation process.
Solution Approach 2:
The system uses feedback by comparing detected signal return levels against the pre-stored look-up table values. The look-up table contains expected signal characteristics for objects at various positions under different phase shift conditions, allowing the system to feedback-determine object locations by matching actual detections to predicted patterns.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach simplifies radar antenna designs, reduces clutter, improves target discrimination, and enhances the field of regard by utilizing sidelobes for detailed environmental sensing.
Implementation Method 1
applying a progressive phase shift between a plurality of antenna elements of the radar system for moving the main lobe to a position other than the boresight for increasing a two-way signal return level of at least one sidelobe
Data Source
AI summary
A method of sensing an environment, using a radar system includes applying a progressive phase shift between a plurality of antenna elements of the radar system, recording signal return levels of the two-way radiation pattern upon application of the progressive phase shift, wherein the progressive phase shift moves the main lobe to a position other than boresight, and increases a signal return level of at least one sidelobe, and at least one object is detected at a position off-boresight based on the increased signal return level of the at least one sidelobe.