Radar Processing System for Multibounce Signal Ambiguity

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Solution Overview

Problem

Conventional radar systems fail to accurately identify and track objects in environments with multipath reflections, leading to incorrect object positioning and potential misidentification of vehicles' directions due to multibounce signals, which can cause inaccurate measurements and safety issues in autonomous vehicle navigation.

Innovation Solution

A radar processing system that utilizes known object locations from various sources, such as prior measurements, sensor data, and map data, to correctly associate and assign reflection signals to the correct objects, and iteratively calibrate object locations to remove false positives and improve measurement accuracy by using multibounce signals for high-resolution Doppler and range measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If radar systems use conventional signal processing to detect reflections, then the system can detect objects in the environment, but the system fails to accurately identify and track objects in environments with multipath reflections, leading to incorrect object positioning

Engineering Contradiction:
Improveobject positioning accuracyVSAvoidobject identification accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The radar processing system uses feedback from multiple reflections to iteratively refine object location estimates. By analyzing the time delay and amplitude of multiple reflected signals, the system adjusts and revises tracking information to converge on the correct object position, effectively resolving multipath ambiguity through iterative feedback processing.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transforms the problem from a single-dimensional range measurement to a multi-dimensional analysis by examining reflections across multiple paths and time delays. This dimensional expansion allows the system to distinguish between direct and reflected paths, enabling accurate object positioning even in complex multipath environments.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If radar systems process multibounce signals, then high-resolution Doppler and range measurements can be obtained, but the system may misidentify vehicles' directions due to multibounce signals

Engineering Contradiction:
ImproveDoppler and range measurement resolutionVSAvoiddirectional information accuracy
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The radar processing system segments the reflected signals into distinct components based on their time delays and amplitude characteristics. By separating direct reflections from multibounce signals, the system can process high-resolution Doppler and range measurements from direct paths while filtering out directional information corrupted by multibounce reflections.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system introduces an intermediary processing layer that analyzes the temporal and amplitude characteristics of reflected signals to identify and characterize multibounce paths. This intermediary analysis allows the system to preserve useful measurement information from direct reflections while excluding misleading directional data from multibounce signals.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If radar systems use conventional reflection processing, then the system can detect reflected signals, but false positives are generated leading to inaccurate measurements and safety issues

Engineering Contradiction:
Improvesignal processing speedVSAvoidmeasurement accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The radar processing system performs preliminary analysis of reflection characteristics before final object identification. By pre-processing signals to identify multipath patterns and potential false positives, the system can quickly filter out inaccurate measurements while maintaining high processing throughput, preventing safety issues before they arise.

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

The system effectively reduces ambiguity in object positioning and direction, enhancing the accuracy of radar imaging and obstacle avoidance in autonomous vehicles by correctly identifying and tracking objects, even in complex reflection scenarios.

Implementation Method 1

Radio detection and ranging (RADAR) systems can be used to actively estimate range, angle, and/or Doppler frequency shift to environmental features by emitting radio signals and detecting returning reflected signals

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

Distances to radio-reflective features can be determined according to the time delay between transmission and reception

Methodology Applied
Scientific EffectTime of Flight: Time of Flight

Implementation Method 3

Some systems may also estimate relative motion of reflective objects based on Doppler frequency shifts in the received reflected signals

Methodology Applied
Scientific EffectDoppler Effect: Doppler Effect

Data Source

PatentUS11435434B2Multibounce target additional data
Publication Date: 2022.09.06 WAYMO LLC
  • US11435434B2 patent drawing
  • US11435434B2 patent drawing
  • US11435434B2 patent drawing

AI summary

A method is provided that includes receiving reflections of a plurality of radar signals from an environment by a radar system. The method also includes determining, by a radar processing system, that two received radar reflections correspond to an object in the environment based on a location of the object, where at least one of the two received radar reflections had a reflection in the environment off of a secondary reflecting object. The method further includes revising a tracking for the object.