Radar Signal Phase Error Compensation via Digital Substitution
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Solution Overview
Problem
Existing radar systems with monolithic microwave circuits (MMIC) face challenges in accurately determining azimuth and elevation angles due to the lack of exact separation of transmitted signals, leading to phase distortion and measurement errors, especially in digital beamforming applications.
Innovation Solution
An error-compensated method is implemented using a priori knowledge, such as lookup tables or equations, to iteratively correct phase differences and calculate compensated azimuth and elevation angles, minimizing systematic errors caused by signal coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signal separation is performed in MMIC circuits, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical/electrical signal separation approach with a mathematical substitution method. By substituting the coupled signal equations and solving the system of equations digitally, the patent eliminates the need for complex hardware signal separation circuits while maintaining measurement accuracy. This is achieved through algebraic manipulation of the signal model and digital computation of the separation results.
2Productivity
If transmitting antennas operate simultaneously, then productivity improves, but measurement precision deteriorates due to phase distortion
Solution Approach 1:
The patent implements a feedback mechanism where the known antenna positions and signal models are used to calculate expected phase relationships. The actual received signals are compared against these expectations, and the phase distortion information is fed back into the signal processing algorithm to compensate for the coupling effects, enabling accurate angle determination despite simultaneous transmission.
Solution Approach 2:
The patent performs preliminary characterization of the antenna coupling effects during system setup or calibration. The coupling coefficients and phase distortion characteristics are pre-determined and stored, then used during operation to correct the measured signals. This preliminary action eliminates the need for real-time separation and allows simultaneous antenna operation without precision loss.
3Measurement precision
If error compensation methods are implemented, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent replaces complex hardware-based error compensation with mathematical substitution and digital processing. By formulating the error compensation as a system of equations that can be solved algebraically, the patent achieves high measurement precision using standard digital signal processing techniques rather than complex additional hardware circuits.
Data Source
AI summary
A method for measuring an elevation angle and/or azimuth angle with an antenna array. Identical transmitted signals that are formed of successive linear-frequency-modulated ramps are transmitted through the transmitting antennas of the antenna array using time division multiplexing, wherein the time division multiplexing is achieved through alternating attenuation of the signals transmitted by the transmitting antennas. Echoes of the transmitted signals are received by the receiving antennas and are down-converted to a baseband and sampled. The down-converted and sampled echoes are transformed by an FFT into a 2D image domain. Phase differences are determined from the image data, and, in order to compensate for a systematic error present because of the lack of separation of the two transmitted signals, an error-compensated elevation angle and/or an error-compensated azimuth angle is determined by means of a compensation.