MIMO GBSAR with Irregular Antennas and Compressive Sensing
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Solution Overview
Problem
Conventional Ground Based Synthetic Aperture Radar (GBSAR) systems face limitations in acquisition time due to mechanical scanning and suffer from strong side lobes due to regular antenna spacing, while MIMO GBSAR systems have not effectively reduced the number of antennas or addressed displacement measurement of targets in two different components.
Innovation Solution
A MIMO GBSAR system with an irregular distribution of multiple transmitting and receiving directional antennas, employing Compressive Sensing (CS) algorithms, reduces the number of antennas and eliminates side lobes, enabling faster image acquisition and measurement of two displacement components by simulating virtual antenna movement using switch systems and irregular antenna arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical scanning GBSAR systems are used, then angular resolution can be achieved, but acquisition time is excessive
Solution Approach 1:
The system divides the scanning function into multiple fixed antenna positions that simultaneously capture data, eliminating the need for sequential mechanical movement. Multiple antennas positioned at different locations segment the aperture synthesis process, allowing parallel data acquisition from multiple spatial points.
Solution Approach 2:
The patent replaces the mechanical scanning system with a static multi-antenna array combined with signal processing. Instead of physically moving antennas to synthesize aperture, the system uses multiple fixed antennas with irregular spacing and applies compressive sensing algorithms to reconstruct high-resolution images, substituting mechanical motion with computational methods.
2Device complexity
If regular antenna spacing is used in MIMO GBSAR, then system simplicity is maintained, but strong side lobes are generated
Solution Approach 1:
The patent employs asymmetric and irregular antenna spacing patterns instead of regular uniform grids. The transmitting and receiving antennas are positioned at non-uniform intervals, creating an irregular sparse array that disrupts the periodicity responsible for grating lobes, thereby suppressing side lobe levels while maintaining system feasibility.
Solution Approach 2:
The system applies different spacing characteristics to different regions of the antenna array. Rather than using a single uniform spacing rule throughout, the patent implements locally optimized positioning where antenna distances vary by position, with some regions having tighter spacing and others more sparse arrangements, tailored to minimize side lobe generation in specific angular sectors.
3Measurement precision
If conventional GBSAR systems are used, then single displacement component measurement is achieved, but capability to measure multiple displacement components is limited
Solution Approach 1:
The patent designs the MIMO antenna system to perform multiple measurement functions simultaneously. By configuring both transmitting and receiving antennas with irregular spacing and utilizing the full MIMO dataset, the system can extract multiple independent interferometric measurements from the same dataset, enabling measurement of displacement components in different directions without requiring separate radar systems.
Solution Approach 2:
The system transitions from measuring only line-of-sight displacement (single dimension) to capturing multi-component displacement vectors by exploiting the spatial diversity of the irregular antenna array. The additional spatial dimensions provided by the MIMO configuration with irregular geometry enable resolution of displacement in multiple orthogonal directions through appropriate signal processing.
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
The solution achieves reduced side lobes, faster image acquisition, and enhanced angular resolution, allowing for accurate measurement of millimetric displacements with larger directional antennas and the capability to capture two different displacement components in the radar field of view.
Implementation Method 1
ground based synthetic aperture radar (GBSAR) with an irregular distribution of multiple transmitting and receiving directional antennas (MIMO)
Implementation Method 2
interferometric Ground Based Synthetic Aperture Radar (SAR) (GBSAR)
Data Source
Figure 1~2
Figure 3~4
AI summary
Ground radar apparatus comprising: at least a main radar unit (U) provided with at least a transmitting unit (TX) and at least a receiving unit (RX); two parallel linear guides G1 and G2 with antenna securing systems; NTX antennas connected to the transmitting unit TX; NRX antennas connected to the RX transmitting unit. This radar is a MIMO (Multiple Input Multiple Output) that operates as an interferometric GBSAR (Ground Based Synthetic Aperture Radar) exploiting a particular implementation of the processing technique called Compressive Sensing (CS). In a further configuration of the same radar the parallel linear guides are three, in this way it is possible to acquire two different interferograms of the same scenario that allow to calculate two different components of the possible displacement of the targets.