Vehicle Radar Phase Shift Correction via Local Check Signal
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Solution Overview
Problem
Radar appliances in driver assistance devices face challenges in achieving maximum precision in determining target angles and other measured variables due to phase shift discrepancies between reception paths, which are influenced by operating temperature and production parameters, making it difficult to correct errors and check the functional status of individual paths.
Innovation Solution
Incorporating test means to produce a local check signal that is coupled into both reception paths, allowing the control device to detect phase shifts and correct measured variables, ensuring precise determination of target angles by recognizing phase properties independently of temperature and production parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase shift correction is implemented using a shared local oscillator, then measurement precision is improved, but device complexity increases due to additional test means and signal coupling paths
Solution Approach 1:
The local oscillator serves dual purposes: it provides the oscillation signal for normal reception path operation and simultaneously serves as the source for test signals during calibration. The test means and coupling paths enable the same hardware components to perform both measurement and self-calibration functions, eliminating the need for separate calibration equipment.
Solution Approach 2:
The radar appliance performs its own calibration using internally generated test signals from the local oscillator. The control device automatically routes test signals through reception paths, measures phase shifts, and corrects measured variables without external intervention, enabling autonomous error compensation.
2Reliability
If test signals are coupled into reception paths using directional couplers, then operational status checking is enabled, but manufacturing precision requirements increase
Solution Approach 1:
Directional couplers act as intermediary components that selectively tap test signals into reception paths without disrupting normal signal flow. These couplers enable independent testing of reception path components while maintaining the integrity of the primary measurement function.
3Measurement precision
If phase shifts in reception paths are corrected using local oscillator signals, then measurement precision is improved, but loss of information increases due to temperature and production parameter variations
Solution Approach 1:
The system continuously monitors phase shifts in reception paths by comparing test signal phases and uses this feedback information to correct measured variables. The control device automatically adjusts for phase discrepancies caused by temperature variations and production tolerances, maintaining measurement accuracy under varying conditions.
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 appliance to determine measured variables with utmost precision, including target angles, by correcting for phase discrepancies and identifying operational errors, thereby enhancing the reliability of the driver assistance device.
Implementation Method 1
a radar appliance for determining at least one measured variable referenced to an object that is external to the vehicle
Implementation Method 2
The down-converters are used to down-convert the received signals into respective baseband signals
Data Source
AI summary
The invention relates to a driver assistance device (2) for a vehicle (1), which driver assistance device has a radar appliance (3, 4) for determining at least one measured variable (α1, α2, R1, R2) referenced to an object (10) that is external to the vehicle, wherein the radar appliance (3, 4) comprises:at least a first and a second reception antenna (14, 15), each for receiving signals (SE1, SE2),a first down-converter (17), which is coupled to the first reception antenna (14) via a first reception path (16), and a second down-converter (23), which is coupled to the second reception antenna (15) via a second reception path (21), each for down-converting the received signals (SE1, SE2) into respective baseband signals (SB1, SB2), anda control device (5) for receiving the baseband signals (SB1, SB2) and for determining the at least one measured variable (α1, α2, R1, R2) using the baseband signals (SB1, SB2),wherein the radar appliance (3, 4) has test means (32) for producing a local check signal (SP) and for coupling same check signal (SP) into the first reception path (16) and/or into the second reception path (21), as a result of which the control device (5) receives firstly the check signal (SP) that has been down-converted by the first down-converter (17) as a first test signal (ST1) and/or secondly the check signal (SP) that has been down-converted by the second down-converter (23) as a second test signal (ST2). The invention also relates to an appropriate method.