Radar Azimuth Detection Using Composite Wave Phase Shifting
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Solution Overview
Problem
Existing radar devices face challenges in accurately determining the azimuth angle of targets due to phase wrapping, leading to erroneous detections and safety hazards, especially when the reflection cross-sectional area of the target varies.
Innovation Solution
The radar device employs a composite wave generation unit to combine received waves and uses a phase shifter to create composite waves with steep antenna patterns, allowing for true/false judgments based on wave levels, thereby preventing erroneous detections by ensuring the composite wave level does not exceed the threshold value even for large reflection cross-sectional areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the radar device uses phase difference between received waves to detect azimuth angle, then the azimuth angle can be determined within the phase wrapping interval, but phase wrapping occurs when the phase difference exceeds ±π leading to non-unique determination of azimuth angle
Solution Approach 1:
The patent introduces a composite wave as an intermediary to resolve the phase wrapping problem. The composite wave is generated by combining received waves with different phase relationships, creating a new signal whose properties (antenna pattern) provide additional information to disambiguate azimuth angles that would otherwise be indistinguishable due to phase wrapping.
Solution Approach 2:
The patent transitions from using only phase difference information (one-dimensional measurement) to incorporating both phase difference and composite wave level information (two-dimensional measurement space). This additional dimension allows the system to distinguish between multiple possible azimuth angles that map to the same phase difference.
2Reliability
If the radar device makes true/false judgments based on received wave levels, then erroneous detections can be prevented, but the judgment becomes inaccurate when the reflection cross-sectional area of the target varies
Solution Approach 1:
The patent performs preliminary generation of composite waves with known antenna pattern characteristics before making true/false judgments. By pre-establishing the expected composite wave levels for different azimuth angles within the phase wrapping interval, the system creates a reference framework that is independent of target reflection cross-sectional area, enabling accurate judgments across varying target sizes.
Solution Approach 2:
The patent changes the parameter used for judgment from received wave level alone to composite wave level. The composite wave level exhibits different characteristics that are less sensitive to variations in reflection cross-sectional area, thereby improving the adaptability of the judgment mechanism to different target sizes while maintaining reliability.
3Device complexity
If the radar device uses a single antenna to receive waves, then the device complexity is low, but the antenna pattern is not steep enough for accurate true/false judgments
Solution Approach 1:
The patent merges multiple received waves (from the same or different antennas) to generate a composite wave. This combining process creates an enhanced antenna pattern with steeper characteristics, achieving the desired measurement precision without requiring additional physical antennas, thus maintaining low device complexity while improving performance.
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 accurate true/false judgments of detected azimuth angles, preventing safety hazards by correctly identifying the presence or absence of targets within the phase wrapping interval, even when the reflection cross-sectional area is large.
Implementation Method 1
the azimuth angle is detected based on the phase difference of received wave pairs received by antenna pairs separated by a prescribed distance
Implementation Method 2
radar waves are transmitted in a reference direction, the radar waves reflected by a target are received as received waves
Data Source
AI summary
An electronic scanning radar device that detects an azimuth angle of a target based on a phase difference between a first pair of received waves received by a first pair of antennas separated by a prescribed distance, and combines the first pair of received waves and generates a first composite wave. The composite wave has a steep antenna pattern, for which the amount of level change is large for the amount of change in azimuth angle, and an azimuth angle judgment unit performs true/false judgment in which a detected azimuth angle is judged to be true when the level of the above first composite wave is equal to or above a reference value, and the azimuth angle is judged to be false when the level is below the reference value.