FMCW Radar Altimeter Sling Load Interference Segmentation
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Solution Overview
Problem
Current RADAR altimeter systems face interference and accuracy issues when measuring height above terrain in the presence of a sling load, leading to costly solutions that compromise sensitivity and detection accuracy.
Innovation Solution
A method utilizing a frequency modulated continuous wave (FMCW) RADAR altimeter with discrete Fourier transform processing and threshold detection to differentiate between the vehicle's altitude and sling load range, enabling accurate altitude determination by analyzing altitude history images and ignoring intermediate results from weather or obstructions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex techniques are used to avoid false indication from sling load, then accuracy of altitude measurement is improved, but device complexity and cost increase
Solution Approach 1:
The patent segments the RADAR signal processing into distinct time windows: a first time window captures reflections from the sling load, while a second time window captures reflections from the terrain. This temporal segmentation allows the system to process different targets separately, eliminating interference from the sling load while maintaining measurement accuracy without adding complex hardware modifications.
Solution Approach 2:
The system performs preliminary action by adjusting the RADAR altimeter's time window configuration before terrain measurement. By pre-configuring the first time window to capture sling load reflections and the second time window for terrain reflections, the system proactively prevents false indications rather than requiring complex post-processing or hardware modifications to handle interference.
2Measurement precision
If desensitizing signal return from sling load is applied, then false indication is reduced, but sensitivity of RADAR altimeter deteriorates
Solution Approach 1:
The patent implements dynamic time window adjustment where the RADAR altimeter's processing parameters are adaptively configured based on the operational context. The system dynamically opens a first time window for sling load detection and a second time window for terrain measurement, allowing the sensitivity to be optimized for each specific measurement target rather than requiring fixed desensitization that would reduce overall system sensitivity.
3Loss of information
If passive modulator is placed on sling load, then presence of sling load is indicated, but device complexity and cost increase
Solution Approach 1:
The patent extracts and isolates the sling load reflection signal by dedicating a specific first time window to capture it, separating it from the terrain measurement process. This extraction approach allows the system to identify and ignore sling load reflections without requiring any physical modulators or additional sensors, achieving detection capability through signal processing alone.
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 provides a cost-effective and accurate method for determining vehicle altitude and sling load range without diminishing the RADAR altimeter's sensitivity, effectively addressing interference from sling loads.
Implementation Method 1
If the airborne vehicle utilizes a RAdAR altimeter to measure the vehicle's height above terrain
Implementation Method 2
the sling load can interfere with the operation of the RADAR altimeter by presenting a false indication of range to, or height above terrain. RADAR altimeter may also be referred to as a Radio Altimeter.
Data Source
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AI summary
A method and apparatus are provided to determine a range of a sling load from a vehicle. In one embodiment, an FMCW RADAR altimeter generates an altitude history image that is used to determine the range of the sling load from the vehicle and an altitude of the vehicle.