Motion Extended Array Synthesis for Large Virtual Aperture Imaging
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Solution Overview
Problem
Current aperture synthesis systems are limited in constructing arbitrarily large, multi-dimensional apertures without a reference waveform, especially for spatially coherent and incoherent scenes, arbitrary bandwidth scenarios, and various collector configurations.
Innovation Solution
The Motion Extended Array Synthesis (MXAS) system uses the differential motion of two or more collectors to create a temporally-distributed virtual imaging array, allowing for the construction of arbitrarily large apertures suitable for both spatially coherent and incoherent scenes, arbitrary bandwidth, and various collector configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional aperture synthesis systems are used, then imaging is achieved with physical collection elements, but the synthetic aperture size is limited by the maximum dimensions spanned by the physical elements
Solution Approach 1:
The patent creates a virtual copy of the aperture through signal processing. By recording signals at multiple positions and times, and then computationally synthesizing the aperture, the system achieves a virtual aperture larger than any physical structure without building corresponding physical infrastructure.
Solution Approach 2:
The patent transitions from a two-dimensional physical array to a three-dimensional temporal-spatial distribution of measurements. By exploiting the time dimension and multiple position measurements, the system synthesizes a one-dimensional extended aperture that would be impossible to achieve physically.
2Adaptability or versatility
If the Extended Towed Array Measurements (ETAM) algorithm is used for narrowband signals, then an aperture eight times longer than the physical array is synthesized, but the approach is not applicable to non-narrowband signals
Solution Approach 1:
The patent changes the fundamental parameter of how aperture synthesis is performed by using cross-correlation of signals recorded at different positions and times. This parameter change enables the method to work with any signal bandwidth by exploiting temporal-spatial correlations rather than frequency-domain properties.
3Measurement precision
If a larger physical aperture is used to increase resolution and sensitivity, then imaging performance improves, but the infrastructure becomes unfeasibly large and expensive
Solution Approach 1:
The patent replaces the mechanical/physical aperture system with a computational system. Instead of building a large physical array to achieve high resolution, the system uses a small physical array combined with computational algorithms to synthesize the aperture functionally, substituting mechanical scale with computational processing.
Data Source
AI summary
A process and systems for constructing arbitrarily large virtual arrays using two or more collection platforms (e.g. AUX and MOV systems) having differing velocity vectors. Referred to as Motion Extended Array Synthesis (MXAS), the resultant imaging system is comprised of the collection of baselines that are created between the two collection systems as a function of time. Because of the unequal velocity vectors, the process yields a continuum of baselines over some range, which constitutes an offset imaging system (OIS) in that the baselines engendered are similar to those for a real aperture of the same size as that swept out by the relative motion, but which are offset by some (potentially very large) distance.