Adaptive Radar Height Estimation via Sliding Window

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Solution Overview

Problem

Existing methods for estimating the height of objects in multipath environments, such as those encountered by radar devices, face challenges due to interference from direct and indirect propagation paths, leading to inaccurate height measurements, which are insufficient for autonomous driving applications.

Innovation Solution

A method using a variable and adaptive sliding window to combine radar measurements, updating the window length based on current range and object height estimates, iteratively refining the height estimation by processing the spectrum of elevation angles to eliminate interference effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If radar measurements are processed using conventional methods in multipath environments, then processing speed is maintained, but height estimation accuracy deteriorates due to interference from direct and indirect propagation paths

Engineering Contradiction:
Improveheight estimation accuracyVSAvoidinterference from multipath propagation
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent segments the measurement data by introducing a sliding window that divides the range axis into discrete segments. Each window position processes only the relevant segment of data, allowing selective processing of measurements affected by different interference patterns. This segmentation enables the system to isolate and eliminate interference from direct and indirect propagation paths while maintaining processing efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary processing step that calculates a spectrum of elevation angles as an intermediate representation between raw radar measurements and final height estimation. This intermediary spectrum allows the system to identify and eliminate interference components before deriving the final height estimate, thereby improving accuracy without sacrificing processing speed.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a sliding window approach is used to combine radar measurements, then height estimation accuracy improves, but processing time increases

Engineering Contradiction:
Improveheight estimation accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements a dynamic sliding window approach where the window position and size are adaptively adjusted based on the current range and estimated height. Rather than processing all possible window positions, the system dynamically selects only the relevant window positions that contribute to the current measurement, significantly reducing processing time while maintaining accuracy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent performs preliminary calculations to determine which sliding window positions are relevant before executing the full processing algorithm. By pre-identifying and marking only the necessary window positions based on current range and height estimates, the system avoids unnecessary computations and reduces overall processing time while maintaining estimation accuracy.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If iterative refinement of height estimation is performed, then measurement precision improves, but complexity of the processing algorithm increases

Engineering Contradiction:
Improveheight estimation precisionVSAvoidalgorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements an iterative refinement process where each iteration uses the previous height estimate as feedback to improve the current estimate. The sliding window processing incorporates feedback from previously processed measurements to guide subsequent processing, allowing the algorithm to converge to accurate results while avoiding the need to process all possible combinations from scratch.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary processing to establish initial height estimates and identify relevant window positions before executing the iterative refinement. By preparing the data structure and identifying key processing points in advance, the system reduces the complexity of each iterative step while maintaining the benefit of iterative improvement.

Inventive Principle:
Principle #10Preliminary action

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 allows for quick and accurate estimation of object height, reducing interference-related errors and providing reliable height information even in complex multipath scenarios, enhancing the performance for autonomous driving systems.

Implementation Method 1

transmitting wave signals to be reflected by an object; receiving wave signals reflected by the object

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

radar device that transmits and receives radar waves

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 3

processing wave signals transmitted from a detection device to the object and reflected by the object, in the context of multipath propagation of the waves through reflection by reflecting surface(s)

Methodology Applied
Scientific EffectMultipath propagation: Reflection

Data Source

PatentEP4105688B1Method for estimating height of object
Publication Date: 2024.12.11 APTIV TECHNOLOGIES AG
  • EP4105688B1 patent drawingFigure 1~2
  • EP4105688B1 patent drawingFigure 3~4
  • EP4105688B1 patent drawingFigure 5

AI summary

The method is carried out by a detection device (1) that transmits wave signals to be reflected by an object (2) and propagating via a direct path and an indirect path via reflection over a reflecting surface (3). It includes: - measuring wave signals reflected by the object (2) and generating measurement vectors; - producing a spectrum of an estimated elevation angle (θ) of the object (2) over the range (R) by combining a plurality of measurement vectors over a sliding range window; and - estimating the height (h2) of the object (2) from the spectrum. The length of the window is variable and determined by estimating the range interval covered by a full phase cycle of a phase difference between the direct path and the indirect path, from a current value of the range and a current estimate (h2) of the height of the object.