Single-pass Barankin Estimator for SAR Target Height
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Solution Overview
Problem
Traditional multi-pass radar techniques are not suitable for missions where the aerial platform both identifies and prosecutes a target in a single pass, as they require multiple radar passes to derive 3D target height information, which is not feasible for nonlinear flight paths.
Innovation Solution
A single-pass method using a Barankin Estimator to provide 3D target height information by collecting coherent radar data while flying in a nonlinear path, forming a 2D SAR image, and applying the Barankin Estimator to derive pixel heights, allowing for 3D target imaging and prosecution during a single radar pass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional multi-pass radar techniques are used to derive 3D target height information, then measurement precision of target height is improved, but loss of time increases and the method becomes unsuitable for single-pass missions
Solution Approach 1:
The patent applies preliminary action by incorporating nonlinear flight path maneuvers with known acceleration characteristics before and during the imaging pass. The Barankin estimator uses these pre-planned motion characteristics to extract height information from phase variations in the SAR data, enabling single-pass 3D target imaging without requiring multiple passes as in traditional interferometric methods
Solution Approach 2:
The patent changes the operational parameters by using nonlinear flight paths with nonzero acceleration out of the slant plane, rather than the linear or stationary platform trajectories used in traditional SAR. This parameter change enables the Barankin estimator to derive quadratic phase terms that contain height information, resolving the contradiction between single-pass operation and height measurement precision
2Measurement precision
If traditional multi-pass techniques are used, then target height information is obtained, but adaptability to nonlinear flight paths deteriorates
Solution Approach 1:
The patent applies dynamics by designing the system to work with time-varying flight paths and accelerations. The Barankin estimator explicitly accounts for nonlinear motion dynamics by using the known acceleration profile to model the phase evolution of scatterers, enabling the system to adapt to various nonlinear flight paths while maintaining height measurement precision
Solution Approach 2:
The patent changes the flight path parameters from linear or stationary trajectories to nonlinear paths with controlled acceleration. This enables the system to adapt to different mission profiles (reconnaissance, prosecution, intercept) while the Barankin estimator extracts height information from the resulting phase variations, improving both adaptability and measurement precision
3Productivity
If 2D SAR imaging is used, then imaging speed is improved, but loss of information occurs due to projection of 3D targets into 2D plane
Solution Approach 1:
The patent applies dimensionality change by using the nonlinear flight path to introduce a time-varying geometric relationship between the platform and targets. The Barankin estimator exploits the quadratic phase terms that arise from this dimensional change to recover height information, effectively adding the third dimension back into the imaging process without sacrificing imaging speed
Solution Approach 2:
The patent changes the imaging approach by incorporating acceleration-induced phase modulations into the SAR processing. The Barankin estimator uses these parameter changes to separate height information from the 2D SAR image data, maintaining fast single-pass imaging while recovering the lost third dimension through sophisticated parameter estimation
Data Source
AI summary
Traditional multi-pass radar techniques are not suitable for missions in which the aerial platform both identifies and prosecutes the target at termination of a single pass. A single pass method running a Barankin Estimator provides target height and variance for 3D target imaging that is suitable for war fighters, missiles, UAV, and other aerial platforms capable of nonlinear flight paths.