Radar Antenna Calibration Using Retro-Reflective Target
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Solution Overview
Problem
Existing radar system calibration techniques require external inspection or GPS data, making it difficult to accurately calibrate antennas enclosed in protective structures without removing the enclosure or using location determining equipment.
Innovation Solution
A method and system utilizing an arbitrarily positioned stationary target element, sensors for generating orientation data, radar system devices for measuring electromagnetic echo signals, a surveying device for generating reference location data, and a control unit to process these data and determine calibration bias values for the radar system, all without external inspection or GPS data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external inspection methods are used to calibrate the antenna, then measurement accuracy is improved, but the protective enclosure must be removed which reduces system reliability and increases complexity
Solution Approach 1:
A retro-reflective target is introduced as an intermediary object placed at a known position in the radar's field of view. This target enables optical measurement of the antenna beam direction without requiring removal of the protective enclosure, thus maintaining system reliability while achieving calibration accuracy through external optical inspection.
2Measurement precision
If GPS equipment is used for calibration, then position accuracy is improved, but device complexity increases and GPS availability is not guaranteed in all scenarios
Solution Approach 1:
The calibration method extracts the position measurement function from GPS equipment and implements it using a surveying device (total station) that measures the position of a retro-reflective target. This eliminates dependency on GPS satellites and reduces device complexity by using a standalone optical measurement system instead of satellite-based positioning.
3Reliability
If calibration is performed with the antenna enclosed, then system reliability is maintained, but measurement accuracy deteriorates due to inability to externally inspect antenna orientation
Solution Approach 1:
Direct mechanical/optical inspection of the antenna for orientation measurement is replaced by electromagnetic radar measurement of the beam direction. The radar system measures the actual beam direction by detecting signals from the retro-reflective target, substituting physical inspection with electromagnetic field-based measurement that works through the protective enclosure.
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
Enables accurate calibration of radar antennas over their entire range of orientations while operational, without removing protective enclosures or using GPS, thereby ensuring continuous reliable operation of the radar system.
Implementation Method 1
a radar antenna (12) mounted on a rotatable support (11) at a predetermined position relative to a reference point on the rotatable support... antenna measurement data indicative of electromagnetic echo signals received by the radar antenna (12) from the reference target element (1)
Data Source
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AI summary
Techniques for calibrating a radar antenna mounted at a predetermined position relative to a reference point on a rotatable support are disclosed. The calibration utilizes reference data indicative of a position of a target element relative to a reference location, of a position of the reference point on the rotatable support relative to the reference location, orientation data indicative of at least one angular position of the rotatable support, and antenna measurement data indicative of electromagnetic echo signals received by the radar antenna from the reference target element. A measured position of the target element relative to the radar antenna is determined based on at least a portion of the antenna measurement data. A reference position of the target element relative to the radar antenna is determined based on the reference data and on at least a portion of the orientation data. At least one bias value or function associated with at least one of the orientation data and the antenna measurement data is determined based on a deviation between the determined measured position and reference position of the target element.