Radar Sensor Angle Estimation Using Distance Constraints
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Solution Overview
Problem
Radar sensors face ambiguities in angle estimation due to large antenna apertures and noisy radar echoes, leading to unclear angle measurements and increased hardware costs with MIMO configurations.
Innovation Solution
The control and evaluation device determines individual distances for each evaluation channel corresponding to different antenna configurations, using these distances to resolve ambiguities in angle estimation by calculating differences and selecting the most accurate angle value from possible estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the aperture of the antenna is increased to achieve high angular resolution, then the angular resolution is improved, but ambiguities in angle measurement occur due to large distances between antennas
Solution Approach 1:
The patent transitions from 2D angle estimation to 3D position estimation by incorporating distance information from multiple evaluation channels. By using individual distances determined from different transmitting-receiving antenna configurations, the system resolves angle ambiguities through spatial trilateration, effectively adding a dimensional constraint that eliminates ambiguous solutions.
2Measurement precision
If MIMO configuration with multiple transmitting antennas is used to improve angular resolution, then the aperture is virtually enlarged, but the number of evaluation channels and hardware costs increase
Solution Approach 1:
The patent creates virtual receiving antennas through the combination of multiple transmitting antennas and receiving antennas in MIMO configuration. These virtual antennas replicate the effect of a physically larger aperture without requiring proportional increases in hardware, as the virtual array is synthesized through signal processing of existing antenna elements.
Solution Approach 2:
The patent makes each transmitting-receiving antenna pair serve multiple functions: they simultaneously contribute to angle estimation, distance measurement, and ambiguity resolution. The same hardware infrastructure supports multiple evaluation channels that perform different measurement functions, reducing the need for dedicated hardware for each function.
3Reliability
If tracking is used to resolve ambiguities by selecting angle values from previous estimates, then ambiguities are resolved, but the assignment takes time and can be subject to errors in noisy conditions
Solution Approach 1:
The patent performs preliminary distance measurements for multiple evaluation channels simultaneously with the angle estimation process. By determining individual distances from different transmitting-receiving antenna configurations in parallel, the system prepares multiple constraint equations upfront, enabling immediate ambiguity resolution without sequential processing or time-consuming tracking delays.
4Reliability
If a ULA structure with antenna intervals of λ/2 is used to achieve clear angle measurement, then ambiguities are avoided, but the number of antennas and hardware costs increase
Solution Approach 1:
The patent changes the evaluation parameters by incorporating distance measurements from multiple evaluation channels into the angle estimation process. By using individual distances determined from different transmitting-receiving antenna configurations, the system resolves angle ambiguities through spatial constraints without requiring increased antenna density or uniform spacing.
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 enhances the accuracy of angle estimation by resolving ambiguities and reducing hardware requirements, improving the radar sensor's angular resolution and accuracy while maintaining clarity in noisy conditions.
Implementation Method 1
Radar sensors are used in motor vehicles, for example, to measure the distances, relative speeds and azimuth angles of vehicles or other radar targets located in front of the vehicle
Implementation Method 2
Radar sensors are used in motor vehicles, for example, to measure the distances, relative speeds and azimuth angles of vehicles or other radar targets
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to an angle-resolving radar sensor for motor vehicles, comprising an antenna assembly having multiple antennas (10, 12) designed for receiving, which are arranged in different positions (yi) in a direction (y) in which the radar sensor is angle resolving, and comprising a control and evaluation device (30), which is designed for an operating mode in which at least one antenna (22) of the radar sensor that designed for transmitting transmits a signal which is received by multiple antennas (10, 12) of the radar sensor that are designed for receiving, wherein, in said operating mode for an individual estimation of an angle (θ) of a radar target for respective evaluation channels (i), which correspond to different configurations of transmission-end and receiving-end antennas (22, 10, 12), the control and evaluation device (30) is designed to determine respective individual distances (di) of the radar target and to use the individual distances (di) in the estimation of the angle (θ) of the radar target. The invention also relates to a method for this purpose.