Multi-Polarized SAR With Bi-Static Satellite Coordination
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Solution Overview
Problem
Conventional quad-polarized SAR satellites are complex, expensive, and suffer from reduced signal-to-noise ratio due to power splitting between multiple polarizations, making them less economical and efficient for multi-polarized data acquisition.
Innovation Solution
Utilize two single-polarized SAR satellites in a bi-static configuration to record multi-polarized SAR data by transmitting and receiving signals with different polarizations from separate platforms, allowing for the measurement of the full quad-polarization scattering matrix without the need for complex, dual-polarization capable antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single SAR satellite transmits and receives signals in multiple polarizations simultaneously, then multi-polarized SAR data can be acquired, but the signal-to-noise ratio is reduced due to power splitting between multiple polarizations
Solution Approach 1:
The patent divides the multi-polarized SAR data acquisition task into separate single-polarization SAR satellites. Each satellite is dedicated to transmitting and receiving signals in a single polarization, avoiding power splitting. Multiple satellites work in coordination to provide comprehensive multi-polarized coverage, thereby maintaining high signal-to-noise ratio while achieving multi-polarized data acquisition capability.
2Adaptability or versatility
If a SAR satellite is equipped with dual-polarization capable antennas to transmit and receive multiple polarizations, then multi-polarized SAR data can be acquired, but the device complexity and cost increase significantly
Solution Approach 1:
The patent segments the complex dual-polarization antenna system into multiple simpler single-polarization antennas on separate satellites. Each satellite carries a simple single-polarization antenna, but the constellation as a whole provides multi-polarized capability through coordinated operation of multiple satellites with different polarization orientations.
Solution Approach 2:
The patent makes each single-polarization satellite multi-functional by enabling it to contribute to multiple polarization channels through coordinated operation with other satellites in the constellation. A single satellite can serve both as a transmitter for its designated polarization and as a receiver for multiple polarizations, thereby achieving universal multi-polarized data acquisition capability without requiring complex dual-polarization hardware on each platform.
3Adaptability or versatility
If a single SAR satellite alternately transmits radar pulses in two orthogonal polarizations, then multi-polarized SAR data can be acquired, but the data acquisition efficiency and productivity are reduced
Solution Approach 1:
The patent divides the data acquisition task across multiple satellites, with each satellite dedicated to transmitting in a specific polarization continuously. This eliminates the need for alternating transmission modes on a single satellite, allowing each transmitter to operate continuously at full power in its designated polarization, thereby significantly improving data acquisition efficiency and productivity.
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
This approach reduces costs and complexity while maintaining signal quality, enabling efficient acquisition of multi-polarized SAR data with improved swath width and potential phase coherence, suitable for various SAR applications.
Implementation Method 1
This is achieved by exploiting the Doppler effect created by the moving SAR platform
Implementation Method 2
SAR is a type of imaging technology that can be used for a variety of applications such as Earth observation, mapping, object tracking
Implementation Method 3
recording, by a first one of the SAR platforms, a first SAR return signal having the first polarization, wherein the first SAR return signal comprises backscattered energy from the first SAR signal
Data Source
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AI summary
Two or more synthetic aperture radar (SAR) platforms, including a first SAR platform and a second SAR platform, are used to record multi-polarized SAR data. One of the SAR platforms transmits a first SAR signal having a first polarization. A first one of the SAR platforms records a first SAR return signal having the first polarization, wherein the first SAR return signal comprises backscattered energy from the first SAR signal. A second one of the SAR platforms records a second SAR return signal having a second polarization, wherein the second SAR return signal comprises backscattered energy from the first SAR signal.