Radar Antenna Calibration Through Radome Without GPS
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Radar antenna calibration techniques are inadequate for accurately determining calibration bias values for non-externally viewable antennas, especially when GPS data is limited or unavailable, as existing methods require direct sight or global positioning systems for calibration.
Innovation Solution
A method and system using an arbitrarily positioned stationary target element, sensors for orientation data, a surveying device for measuring target and pedestal positions, and a control unit to process data and determine calibration biases without external location determination, employing optical surveying equipment like gyro theodolites and EDM meters to calibrate rotatable radar antennas within opaque structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radar antenna is enclosed in protective enclosure (Radome) to prevent environmental wear/damages and conceal the antenna, then reliability and protection are improved, but external inspection and calibration become difficult or impossible
Solution Approach 1:
The patent introduces an intermediary optical measurement system (theodolite, laser distance measurer, CCD camera) that measures the position and orientation of the radar antenna through the protective Radome without requiring direct access to the antenna. This intermediary system bridges the gap between the need for protection and the need for calibration access.
Solution Approach 2:
The patent replaces traditional mechanical calibration methods (which require physical access to the antenna) with an optical measurement system using theodolites, laser distance measurers, and CCD cameras. This substitution allows calibration to be performed through the protective enclosure without mechanical intervention.
2Adaptability or versatility
If calibration flight approach is used to calibrate radar antenna, then calibration can be performed without stationary target, but accurate trajectory knowledge and GPS reception are required
Solution Approach 1:
The patent introduces a stationary optical measurement system (theodolite and laser distance measurer) as an intermediary to accurately determine the position of the radar antenna and calibration target. This intermediary system provides precise position data without relying on GPS or complex trajectory calculations, resolving the measurement precision issue while maintaining calibration versatility.
3Ease of operation
If calibration tower approach with stationary RFT is used, then calibration can be performed with fixed target, but accurate positions of both antennas are difficult to obtain without GPS
Solution Approach 1:
The patent introduces an optical measurement system (theodolite and laser distance measurer) as an intermediary to accurately determine the positions of both the radar antenna and the stationary RFT. This intermediary provides precise position data through optical triangulation and distance measurement, eliminating the need for GPS while maintaining ease of operation with a stationary target.
4Adaptability or versatility
If sensors and devices have non-linear operational regions and varying accuracy ranges, then they can adapt to different conditions, but calibration becomes necessary to filter out bias values
Solution Approach 1:
The patent implements a feedback-based calibration process where the optical measurement system provides reference measurements of the radar antenna position and orientation. These reference measurements are used to calculate bias values and correction factors that are fed back to the radar system's sensors and devices, improving their measurement precision while maintaining adaptability to different operational 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
Enables accurate calibration of radar antennas over their entire range of orientations without removing protective enclosures or using GPS, ensuring continuous reliable operation by determining and applying bias values for orientation and position measurements.
Implementation Method 1
employing optical surveying equipment like gyro theodolites and EDM meters to calibrate rotatable radar antennas
Implementation Method 2
EDM meters to calibrate rotatable radar antennas within opaque structures
Implementation Method 3
radar systems calibration is usually carried out by measuring radar signals received from a known reference target
Data Source
AI summary
A calibration utilizes reference data indicative of a position of a target element relative to a reference location, of a position of a reference point on a 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 a radar antenna from the 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 the orientation data and/or the antenna measurement data is determined based on a deviation between the determined measured position and reference position.