Monopulse SAR Multi-Beam Imaging for Fast High Resolution
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Solution Overview
Problem
Existing radar systems face limitations in achieving fast, high-resolution imaging of ground and airborne objects due to long wavelength wide antenna patterns, which result in poor image resolution and increased signal processing time.
Innovation Solution
A monopulse synthetic aperture radar system utilizing non-scanning transmitting and receiving antennas with overlapping quadrature or multi-axis antenna patterns, coupled with separate receiver chains and multi-channel processors, enables simultaneous processing of signals to enhance imaging resolution and suppress clutter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If scanning radar with smaller wavelength and beamwidth is used, then image resolution is enhanced, but signal processing time increases and wave penetration decreases
Solution Approach 1:
The invention divides the imaging function into multiple simultaneous beams covering different spatial sectors. Each beam processes a portion of the scene in parallel, eliminating the sequential scanning process while maintaining high resolution through the monopulse method's precise amplitude and phase comparison capabilities.
Solution Approach 2:
The patent transitions from one-dimensional sequential scanning to two-dimensional simultaneous multi-beam processing by arranging antennas in quadrature or multi-axis directions. This spatial dimensionality change enables parallel processing of multiple spatial sectors, dramatically reducing processing time while preserving resolution.
2Productivity
If SAR with lower frequency and wide beam is used, then larger image footprint and faster processing are achieved, but image resolution deteriorates
Solution Approach 1:
The invention applies the monopulse method to create localized high-precision measurement zones within each beam sector. By using amplitude and phase comparison against reference beams, each spatial sector achieves high resolution comparable to narrow-beam scanning, while the overall system maintains wide coverage and fast processing through simultaneous multi-beam operation.
3Measurement precision
If multiple antennas with overlapping patterns are used, then direction-finding accuracy is improved, but device complexity increases
Solution Approach 1:
The patent employs asymmetric spatial tilting of antenna patterns in quadrature or multi-axis directions, where reference beams are deliberately positioned at specific angles relative to the main beam. This asymmetric arrangement enables the monopulse method to achieve high direction-finding accuracy through amplitude and phase comparison, while the fixed geometric configuration simplifies the overall system compared to fully adaptive antenna arrays.
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 system provides fast, high-resolution imaging by simultaneously processing signals from a wide space sector, achieving improved image resolution and reduced signal processing time, while also suppressing noise and clutter.
Implementation Method 1
Monopulse synthetic aperture radar for fast, high-resolution imaging of ground and/or airborne objects
Implementation Method 2
Image generation is based on analog and digital processing of reflected amplitudes, phases, and spectrum components
Implementation Method 3
The application of 360-degree staring radars instead of scanning radars for fast drone detection provides a wider area of observation and holographic technology with beamforming of receiving signals
Implementation Method 4
Armin W. Doerry showed that radar resolution can be increased by the application of a few (two-three) antennas with overlapping antenna patterns
Implementation Method 5
Lipsky S. E. in U.S. Pat. No. 4,257,047 (1981) proposed an antenna array of a plurality of fixed, narrow beamwidth antennas... Direction finding by way of amplitude comparison methods can provide a root mean square (RMS) accuracy smaller than 2° in 100 ns
Implementation Method 6
High-accuracy phase measurements provide high accuracy and fast direction finding
Data Source
AI summary
Monopulse synthetic aperture radar for fast, high-resolution imaging of ground and/or airborne objects consists set of non-scanning transmitting and receiving antennas with overlap antenna patterns positioned in quadrature or multi-axis directions and covering wide space sector, wherein each receiving antenna is coupled to monopulse processor and separate receiver chain coupled with digital multi-channel processor. Application of monopulse and digital multi-axis multi-channel processing of all signals in receiving chains provides simultaneous fast signal processing from all space sectors. The monopulse method combined with multi-channel digital processing, where amplitudes, phase, and frequency components shift of receiving signals processing relative to signals in overlap receiving antenna beams provides 3-5 times higher imaging resolution and allows to suppression influence of media and clutter. An array of directional antennas may be arranged for multi-frequency, multi-mode regimes.