Phased Array Calibration Using OFDM-BPSK for Accurate Phase Estimation
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Solution Overview
Problem
Phased arrays in satellite communications face challenges in achieving accurate phase calibration due to temperature fluctuations in low-Earth orbit satellites, which require frequent recalibration simultaneous with digital beam-forming processing.
Innovation Solution
The use of OFDM-BPSK symbol sequences for mutual-coupling based phase array calibration instead of CDMA sequences, allowing for more accurate phase estimation within a given duration without compromising amplitude and group delay estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CDMA sequences are used for calibration, then calibration can be performed simultaneously with service, but phase estimation accuracy is compromised
Solution Approach 1:
The patent changes the calibration sequence type from CDMA to OFDM-BPSK, fundamentally altering the signal parameters. OFDM sequences provide superior phase estimation accuracy due to their orthogonal structure and spectral properties, while still enabling simultaneous calibration and service operation through proper resource allocation
2Loss of time
If calibration sequence duration is reduced, then operational degradations are minimized, but estimation accuracy may be compromised
Solution Approach 1:
OFDM sequences have inherent properties that provide robust estimation performance in shorter durations. The orthogonal structure and frequency-domain representation of OFDM signals enable accurate parameter extraction with fewer samples, thus reducing calibration time while maintaining accuracy
3Measurement precision
If frequent recalibration is performed to compensate for temperature changes, then accuracy is maintained, but service degradation increases
Solution Approach 1:
The patent enables continuous operation by performing calibration simultaneously with service rather than interrupting service for calibration. The OFDM-based calibration sequence allows both calibration and data transmission to occur in parallel, eliminating service interruptions while maintaining calibration accuracy despite temperature variations
Data Source
AI summary
OFDM-BPSK symbol sequences are used for mutual-coupling based phase array calibration. Such substitution allows phase to be estimated more accurately using a given estimation duration without compromising other estimates (amplitude and group delay) accuracies.