Vehicle Radar Antenna Vertical Spacing for Height Detection
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Solution Overview
Problem
Current vehicle radar systems face challenges in accurately distinguishing between important and unimportant obstacles, such as bridges and gantries, due to limitations in vertical spacing between transmitter antennas, which affects the system's ability to detect height with increased accuracy.
Innovation Solution
A vehicle radar sensor unit with an antenna arrangement featuring at least two transmitter antennas and two receiver antennas, where the transmitter antennas have a first horizontal spacing and a vertical spacing exceeding half the free-space wavelength, allowing for time division multiplexed signal transmission and processing to determine radial velocities and heights with minimal change across radar cycles, thereby resolving geometrical ambiguities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the vertical spacing between transmitter antennas is increased to improve height detection accuracy, then measurement precision is improved, but geometrical ambiguity occurs
Solution Approach 1:
The patent segments the height detection process into multiple measurement cycles with different antenna configurations. By dividing the detection into phases (first cycle with first antenna pair, second cycle with second antenna pair), the system resolves geometrical ambiguity through temporal separation while maintaining large vertical spacing for accuracy.
Solution Approach 2:
The patent employs periodic switching between different transmitter antenna pairs across multiple measurement cycles. This periodic action allows the system to collect data from different spatial configurations and resolve ambiguities by comparing measurements taken at different times, thereby maintaining both large vertical spacing and reliability.
2Measurement precision
If the vertical spacing between transmitter antennas is increased to improve height detection accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the functionality of multiple transmitter antenna pairs into a single integrated antenna arrangement. By combining the antennas and sharing common receiver antennas and processing units, the system achieves large vertical spacing for accuracy while reducing overall device complexity through resource sharing and integration.
Solution Approach 2:
The receiver antennas and processing units serve multiple functions by working with different transmitter antenna pairs across different measurement cycles. This multi-functionality reduces the need for separate dedicated components for each measurement configuration, thereby reducing device complexity while maintaining measurement precision.
3Reliability
If time division multiplexed signals are transmitted to resolve geometrical ambiguity, then reliability is improved, but loss of time occurs
Solution Approach 1:
The patent performs measurements in multiple cycles with different antenna configurations, using partial redundancy in the measurement process. By collecting data from multiple perspectives and processing it through ambiguity resolution algorithms, the system achieves high reliability while minimizing time loss through efficient use of the collected data.
Solution Approach 2:
The system uses feedback from measurements taken in one cycle to inform and adjust measurements in subsequent cycles. By comparing results from different antenna configurations and using this feedback to resolve ambiguities, the system improves reliability while reducing the total time needed compared to single-cycle measurements.
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 configuration enhances the accuracy of height detection in vehicle radar systems, providing improved reliability for obstacle differentiation and collision prevention functions.
Implementation Method 1
Determine a first radial velocity of each radar detection by tracking the change of radial distance to each radar detection for each radar cycle during a plurality of radar cycles
Data Source
AI summary
A vehicle radar sensor unit (2) arranged to acquire a plurality of radar detections, and including an antenna arrangement (3), a transmitter unit (4), a receiver unit (5) and a processing unit (6). The antenna arrangement (3) has at least two transmitter antennas (7, 8) and at least two receiver antennas (9, 10, 11, 12), where two transmitter antennas (7, 8) have a vertical spacing (h) between their respective phase centers (17, 18) that exceeds half the free-space wavelength of the transmitted signal. The processing unit (5) is arranged to determine a first radial velocity of each radar detection by tracking the change of radial distance (r) to each radar detection for a plurality of radar cycles; determine a second radial velocity that best matches the first radial velocity; track a plurality of measured heights (z) as a function of radial distance (r); and to choose a measured height (zGT) among the tracked measured heights (z) that has a minimal change from radar cycle to radar cycle.