Time-Dependent Phase Error Correction in Radar Waveform Synthesis
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Solution Overview
Problem
Current radar systems face challenges in mitigating time-dependent phase errors, which can be introduced by power droop in amplifiers, leading to distortions in the radar waveform and affecting the range resolution and detectability of targets.
Innovation Solution
A system that includes a time-dependent phase error correction component, which uses a look-up table to apply a time domain correction based on monitored phase errors during the radar signal generation process, ensuring that the phase errors are compensated before the waveform is transmitted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pre-distortion using frequency-dependent phase correction is applied to LFM chirp signals, then frequency-dependent phase errors are mitigated, but time-dependent phase errors (e.g., from power droop) remain uncorrected
Solution Approach 1:
The patent applies preliminary action by pre-distorting the waveform with time-dependent phase correction before transmission. A look-up table stores pre-calculated phase correction values that are applied in advance to compensate for expected power droop effects during the pulse duration, ensuring the waveform remains accurate despite amplifier characteristics.
Solution Approach 2:
The patent implements feedback by measuring the actual phase error introduced by power droop during waveform generation and using this measured error to update the look-up table for future corrections. This closed-loop approach continuously improves the accuracy of time-dependent phase correction based on actual system behavior.
2Speed
If a look-up table is used for phase correction, then correction speed is improved, but the system cannot adapt to changing amplifier characteristics over time
Solution Approach 1:
The patent applies dynamics by making the look-up table updateable and adaptive. Instead of using a static correction table, the system periodically measures actual phase errors and updates the look-up table contents to reflect changing amplifier characteristics, allowing the correction mechanism to adapt dynamically to system drift while maintaining fast correction speeds.
Solution Approach 2:
The patent implements parameter changes by modifying the look-up table parameters (phase correction values) based on measured system performance. The system adjusts the correction parameters in the look-up table to match actual amplifier behavior, enabling adaptation to changing conditions while preserving the speed advantages of table-based correction.
3Measurement precision
If continuous phase variation is used in pulse compression, then range resolution is improved, but the system becomes more sensitive to phase perturbations
Solution Approach 1:
The patent applies preliminary anti-action by pre-distorting the transmitted waveform with the opposite phase error that is expected to be introduced by the amplifier. This anticipatory correction ensures that when power droop occurs during transmission, the waveform already contains the compensating phase adjustment, effectively canceling out the harmful phase perturbations before they degrade range resolution.
Data Source
AI summary
The various technologies presented herein relate to correcting a time-dependent phase error generated as part of the formation of a radar waveform. A waveform can be pre-distorted to facilitate correction of an error induced into the waveform by a downstream operation/component in a radar system. For example, amplifier power droop effect can engender a time-dependent phase error in a waveform as part of a radar signal generating operation. The error can be quantified and an according complimentary distortion can be applied to the waveform to facilitate negation of the error during the subsequent processing of the waveform. A time domain correction can be applied by a phase error correction look up table incorporated into a waveform phase generator.