Multi-Static SAR Beamforming Across LEO Collection Orbits
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Solution Overview
Problem
Existing synthetic aperture radar systems face limitations in achieving high spatial resolution and efficient data collection using low earth orbit configurations, particularly in multi-static scenarios.
Innovation Solution
A satellite system employing a geostationary illumination satellite and multiple low earth orbit collection satellites, utilizing beamforming techniques to transmit and receive beamformed illumination signals, which are processed to form multi-static synthetic aperture radar images, enabling improved geospatial information acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single orbit configuration is used for SAR satellites, then system complexity is reduced, but spatial resolution and imaging flexibility are limited
Solution Approach 1:
The system divides the SAR functionality into two separate satellite groups: illumination satellites in a first orbit that transmit signals, and collection satellites in a second orbit that receive reflections. This segmentation allows each satellite type to be optimized for its specific function while achieving high spatial resolution through the multi-static configuration, without requiring every satellite to carry both complex transmit and receive systems.
Solution Approach 2:
The system transitions from a single-orbit (one-dimensional orbital configuration) to a multi-orbit system where illumination satellites and collection satellites operate in different orbital planes and altitudes. This dimensional change in orbital configuration enables the collection of signals from multiple geometric perspectives, significantly improving spatial resolution and imaging flexibility while distributing system complexity across separate satellite groups.
2Productivity
If multiple satellites are deployed in different orbits, then spatial resolution and data collection efficiency are improved, but system complexity and coordination requirements increase
Solution Approach 1:
The illumination satellites transmit radar signals that serve dual purposes: primary communication signals for their intended coverage areas and illumination signals for SAR imaging. The collection satellites receive both communication signals and SAR reflection signals, processing them separately. This multi-functionality increases data collection efficiency without proportionally increasing system complexity, as the same infrastructure supports multiple functions.
Solution Approach 2:
The system introduces a ground-based processing system that acts as an intermediary, receiving data from multiple satellites in different orbits and synthesizing the multi-static SAR images. This centralized processing approach coordinates the complex multi-satellite data collection efficiently, managing the integration of signals from various orbital configurations without requiring complex on-satellite coordination.
3Use of energy by moving object
If beamforming is used to transmit illumination signals to multiple coverage areas, then signal efficiency is improved, but processing complexity increases
Solution Approach 1:
The illumination satellites pre-form beams toward multiple coverage areas using beamforming technology before signal transmission. This preliminary beam formation concentrates signal energy efficiently toward intended targets, improving signal efficiency. The beamforming parameters and coverage area information are pre-calculated and stored, reducing real-time processing complexity while maintaining efficient signal delivery to multiple regions.
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 achieves enhanced spatial resolution and accuracy in imaging by combining multi-static data from multiple collection satellites, leveraging beamforming and orbital dynamics to synthesize apertures, providing detailed geospatial information.
Implementation Method 1
The illumination satellite may transmit beamformed illumination signals such as beamformed communication signals to different beam coverage areas
Implementation Method 2
Each of the collection satellites may receive reflections of the beamformed illumination signals
Implementation Method 3
The reflected signals received at the collection satellites may be processed taking into account the beamforming matrix used to transmit the beamformed illumination signals to obtain an image of a geographical area
Data Source
AI summary
A multi-static synthetic aperture radar using beamformed illumination beams and multiple collection satellites is described. An illumination satellite may be in first orbit and multiple collection satellites may be in a second orbit. The illumination satellite may transmit beam signals (e.g., communication signals carrying modulated data to user terminals) from an antenna array to different beam coverage areas according to a beamforming matrix. Each of the collection satellites may receive reflections of the beam signals. The reflected signals received at the collection satellites may be processed according to the beam signals and beamforming matrix used to transmit the beam signals to obtain an image of a geographical area. In some cases, the collection satellites may relay the received signals for processing via the illumination satellite.