Surface-Database Radar Altimeter Beam Control for Reflection Avoidance
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Solution Overview
Problem
Radar altimeter measurements are prone to errors and reduced reliability due to radio reflections from surfaces like buildings and trees, leading to altitude measurement inaccuracies and reduced repeatability, especially in complex environments.
Innovation Solution
A system utilizing a radar sensor unit with a processor and a surface database to steer radar beams and process data, avoiding or filtering out areas with obstacles like buildings and trees, ensuring stable and accurate altitude measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radar beams are transmitted to measure altitude, then altitude measurement capability is provided, but measurement precision deteriorates due to reflections from buildings and trees
Solution Approach 1:
The system performs preliminary identification of ground surface areas to be avoided using a database of natural and manmade features before conducting radar measurements. This allows the radar to pre-calculate modified scan patterns that exclude areas with buildings, trees, and other reflective surfaces, thereby preventing measurement errors before they occur.
Solution Approach 2:
The radar scan pattern is made dynamic and adaptive rather than fixed. The system continuously modifies the scan pattern based on real-time calculation of vehicle position, attitude, and the database of ground features, allowing the radar to dynamically avoid areas with reflective surfaces while maintaining measurement capability over safe areas.
2Reliability
If radar scans all areas including those with obstacles, then complete coverage is achieved, but reliability of measurements deteriorates due to errors from complex structures
Solution Approach 1:
The system performs preliminary identification of ground surface areas to be avoided using a database of natural and manmade features before conducting radar measurements. This allows the radar to pre-calculate modified scan patterns that exclude areas with buildings, trees, and other reflective surfaces, thereby preventing measurement errors before they occur.
Solution Approach 2:
The radar system applies different scanning strategies to different areas of the field of view. Areas identified as containing reflective surfaces (buildings, trees) are excluded or scanned with modified parameters, while areas identified as safe (open terrain, water) are scanned with standard parameters, creating a spatially differentiated scanning approach.
3Measurement precision
If conventional radar altimeter is used, then simple operation is maintained, but measurement precision deteriorates in complex environments with buildings and forests
Solution Approach 1:
A database of natural and manmade ground surface features serves as an intermediary between the radar system and the complex environment. This database, combined with vehicle position and attitude data, allows the system to identify and avoid areas with reflective surfaces without requiring complex real-time analysis of radar returns from each surface type.
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
Provides reliable and accurate radar altimeter measurements by minimizing errors from obstacles, enhancing navigation reliability and integrity, particularly during approach and landing applications.
Implementation Method 1
a transmitter operatively coupled to the at least one antenna, the transmitter configured to transmit one or more radar beams toward a surface through the at least one antenna
Implementation Method 2
a receiver operatively coupled to the at least one antenna, the receiver configured to receive a reflected return signal of the transmitted one or more radar beams through the at least one antenna
Implementation Method 3
A radar altimeter measures the altitude above the terrain presently beneath a vehicle such as an aircraft by timing how long it takes a beam of radio waves to travel to the ground, reflect, and return to the vehicle
Data Source
AI summary
A system comprises a vehicle radar sensor including an antenna, transmitter, receiver, and processor. The processor hosts a scanning control module that sends a control signal to the transmitter, receiver, or both, to generate radar beams; and a signal processing module that receives a reflected signal from the receiver to generate radar data. The system also includes an onboard application module and ground surface database. The application module is operative to access information from the surface database, access position and attitude data, access position and attitude uncertainty data, access radar installation data, and access radar data from the signal processing module; identify ground surface areas to be avoided based on the information from the surface database, the position and attitude, the position and attitude uncertainty, and the radar installation data; and perform modified radar operations and/or processing when the ground surface areas to be avoided are within a radar FOV.