Radar Signal Processor Phase Correction for Spherical Wave Errors
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Solution Overview
Problem
Radar devices face challenges in accurately calculating the angle of an object due to phase rotation caused by spherical waves, especially when the object is at a different position from the reference reflection source used for error correction.
Innovation Solution
The radar device includes a signal processor that calculates the object's position by analyzing received signals from multiple receiving antennas. It corrects antenna errors using stored correction values and further corrects the phase based on the object's position to calculate an angle-calculation complex amplitude, thereby improving angle calculation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If error correction data is acquired using a reference reflection source at a short distance, then the calibration process is simple and quick, but the data includes phase rotation due to spherical wave which causes errors in angle calculation for objects at different positions
Solution Approach 1:
The patent applies preliminary action by acquiring error correction data at a short distance from the radar device, where the spherical wave phase rotation is minimal and can be easily captured. This preliminary calibration step is then used to create correction data that can be applied to objects at various distances, avoiding the need for complex multi-position calibration while still achieving accurate angle measurement.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the distance parameter during calibration. By performing calibration at a specific short distance where spherical wave effects are characterized, the system creates correction parameters that can be scaled or adjusted for use at different object distances, thereby resolving the contradiction between easy calibration and accurate measurement across various ranges.
2Device complexity
If antenna error correction is performed using error correction data including spherical wave phase rotation, then the calibration process is simplified, but angle calculation values contain errors for objects at positions different from the reference reflection source
Solution Approach 1:
The patent introduces an intermediary approach by using a reference reflection source at a controlled short distance as a mediator during calibration. This intermediary setup allows the system to capture spherical wave phase rotation characteristics without requiring the actual target objects to be at the same position. The correction data obtained from this intermediary calibration then serves as a reliable basis for accurate angle measurement of objects at various positions.
3Productivity
If the distance between radar device and reference reflection source is shortened for calibration, then data acquisition is faster and simpler, but phase rotation due to spherical wave becomes more significant and introduces errors
Solution Approach 1:
The patent applies the blessing in disguise principle by accepting that spherical wave phase rotation occurs at short distances during calibration, but converting this potentially harmful effect into a beneficial characteristic. By deliberately performing calibration at short distances where spherical wave effects are pronounced and easily measurable, the system captures accurate phase rotation data that can then be used to create correction parameters, turning the harmful spherical wave effect into a useful calibration feature.
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 enables the radar device to obtain more accurate angle calculation values by accounting for phase rotation due to spherical waves, thus enhancing the precision of object position detection.
Implementation Method 1
receives reflected waves obtained when a transmitted wave radiated from the transmitting antenna is reflected by an object
Implementation Method 2
the direction can be detected from a phase difference between the received waves received by a plurality of receiving antennas
Data Source
AI summary
This radar device includes a signal processor which calculates a position of an object by analyzing received signals received by a plurality of receiving antennas receiving reflected waves obtained when a transmitted wave radiated from a transmitting antenna is reflected by an object. The signal processor is configured to: calculate a distance of the object from an amplitude peak in a complex spectrum obtained by analyzing the received signals; acquire a complex amplitude at the amplitude peak; correct the complex amplitude by an antenna error correction value stored in advance, and further correct a phase of the corrected complex amplitude on the basis of the position of the object, to calculate an angle-calculation complex amplitude; and calculate an angle for the object, which is an arrival direction of the reflected wave, from the angle-calculation complex amplitude.