Radar Sensor Angle Estimation via Distance-Dependent Frequency Selection
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Solution Overview
Problem
Radar sensors with large antenna arrays and high bandwidths face challenges in achieving simultaneous full range resolution and angle separation capability, as run length differences and phase shifts complicate signal mapping and calibration, leading to amplitude and phase errors.
Innovation Solution
The control and evaluation device adjusts the evaluation of signals by selecting specific frequency positions for each evaluation channel based on angle hypotheses, allowing for accurate angle estimation by accounting for distance and frequency position differences, thereby mitigating the effects of large bandwidth and aperture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If large antenna arrays and high bandwidths are used, then angle separation capability and range resolution are improved, but run length differences and phase shifts complicate signal mapping and calibration
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing run length differences and phase shifts for different antenna configurations and target distances in lookup tables during the calibration phase. This allows the evaluation device to quickly retrieve and apply correction values during actual operation without performing complex real-time calculations, thereby simplifying the operational complexity while maintaining high measurement precision.
Solution Approach 2:
The patent changes parameters by introducing distance-dependent frequency position adjustments for different evaluation channels. Instead of using a fixed frequency position for all channels, the system dynamically selects frequency positions based on the estimated target distance and antenna configuration, compensating for run length differences and phase shifts. This parameter adaptation resolves the contradiction by maintaining angle separation accuracy across varying operational conditions.
2Measurement precision
If large antenna arrays and high bandwidths are used, then range resolution is improved, but amplitude and phase errors increase
Solution Approach 1:
The patent implements feedback by using the estimated target distance from range resolution measurements to adjust the frequency positions and amplitude/phase values in subsequent angle estimation steps. The evaluation device continuously refines its measurements by feeding back distance information to correct amplitude and phase errors in different evaluation channels, thereby maintaining high signal accuracy while preserving the benefits of large antenna arrays and high bandwidths.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting frequency positions, amplitude weights, and phase corrections based on the estimated target distance and antenna configuration. This distance-dependent parameter adaptation compensates for amplitude and phase errors that arise from run length differences in large antenna arrays, ensuring reliable signal accuracy across the full operational range while maintaining high range resolution.
3Measurement precision
If different distances and frequency positions are selected for respective evaluation channels, then angle estimation accuracy is improved, but evaluation complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-computing and storing the relationships between antenna configurations, target distances, and optimal frequency positions in lookup tables during calibration. During operation, the evaluation device simply retrieves the appropriate frequency positions and amplitude/phase values based on the estimated distance and antenna setup, avoiding complex real-time calculations while maintaining high angle estimation accuracy.
Solution Approach 2:
The patent introduces an intermediary layer in the form of pre-computed lookup tables and distance-dependent correction factors that mediate between the raw signals from multiple evaluation channels and the final angle estimation. This intermediary structure simplifies the evaluation process by providing ready-to-use correction values and frequency position mappings, reducing computational complexity while preserving measurement precision.
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 simple and accurate angle estimation even with large antenna arrays and high bandwidths, improving the radar sensor's ability to resolve angles without compromising range resolution or separation capability.
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
Implementation Method 2
In an FMCW (frequency modulated continuous wave) measurement method with linear frequency ramps and an evaluation of the received signals using discrete Fourier transformation, in particular an FFT (Fast Fourier Transformation)
Data Source
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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 is designed for transmitting transmits a signal which is received by multiple antennas (10, 12) of the radar sensor that are designed for receiving, and the angle (θ) of a radar target is estimated based on amplitude and/or phase relationships between signals of respective evaluation channels (i), which correspond to different configurations of transmission-end and receiving-end antennas, wherein an evaluation of the signals of the evaluation channels for a respective distance (di) for a respective evaluation channel (i) occurs for an individual estimation of an angle (θ) of a radar target, wherein different distances (di) are selected for respective evaluation channels (i) depending on an angle hypothesis (Ohyp) or angle range hypothesis. The invention also relates to a method for this purpose.