Lidar Radar Fusion for Solid Object Detection in Autonomous Vehicles

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Solution Overview

Problem

Autonomous vehicles face challenges in distinguishing between solid and non-solid reflective features using LIDAR, leading to unnecessary maneuvers to avoid non-threatening obstacles like exhaust plumes and water splashes, which affects safety and fuel efficiency.

Innovation Solution

Combining LIDAR and RADAR sensors to determine the presence of solid materials by scanning a region with RADAR if a feature is indicated by LIDAR, using the absence of radio reflectivity to identify non-solid materials and thus safely ignore them during navigation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If LIDAR is used to detect reflective features, then the autonomous vehicle can identify obstacles in the environment, but it cannot distinguish between solid and non-solid materials leading to unnecessary maneuvers

Engineering Contradiction:
Improvematerial differentiation capabilityVSAvoidnavigation efficiency
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent combines LIDAR and RADAR sensors into a fused sensor system. The LIDAR provides high-resolution spatial mapping of reflective features, while the RADAR provides material classification through radio wave reflectivity analysis. By merging the data from both sensors, the system achieves both precise obstacle detection and accurate material differentiation, resolving the contradiction between measurement precision and navigation efficiency.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an intermediary classification system that processes LIDAR-detected features and uses RADAR reflectivity data to categorize them as solid or non-solid materials. This intermediary layer acts as a filter between raw sensor data and navigation decisions, enabling the vehicle to distinguish between threatening obstacles and non-threatening features like exhaust plumes or water vapor, thereby improving both detection accuracy and operational efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the vehicle avoids all LIDAR-detected features, then safety is maximized, but fuel efficiency decreases due to unnecessary maneuvers

Engineering Contradiction:
ImprovesafetyVSAvoidfuel efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by treating different detected features differently based on their material properties. Instead of applying a uniform avoidance policy to all LIDAR-detected features, the system uses RADAR data to identify local characteristics (solid vs. non-solid) and applies selective avoidance only to solid obstacles. This localized differentiation maintains safety for real threats while eliminating unnecessary maneuvers around non-solid features, thereby improving fuel efficiency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of obstacle classification from binary (obstacle/non-obstacle) to multi-class (solid/non-solid). By introducing material composition as an additional parameter for obstacle characterization, the system can make more informed navigation decisions. Solid obstacles trigger avoidance maneuvers while non-solid obstacles are ignored, optimizing the balance between safety and fuel efficiency.

Inventive Principle:
Principle #35Parameter changes

3Loss of information

If LIDAR scans the entire scanning zone, then complete environmental mapping is achieved, but the system cannot identify which features require avoidance

Engineering Contradiction:
Improveenvironmental information completenessVSAvoidobstacle identification accuracy
Core Design Contradiction:
Loss of informationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the environmental detection process into two distinct phases: first, LIDAR performs comprehensive scanning of the entire zone to capture all reflective features and build a complete environmental map; second, RADAR scans specific regions of interest to classify materials. This segmentation allows the system to maintain complete environmental awareness while focusing detailed analysis only where needed, resolving the contradiction between information completeness and identification accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds another dimension to obstacle detection by incorporating material composition analysis through RADAR. While LIDAR provides three-dimensional spatial information about reflective features, RADAR adds a fourth dimension of material characterization through radio wave reflectivity. This dimensional enhancement allows the system to process complete environmental maps and accurately identify which features require avoidance based on their material properties.

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

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

Enhances navigation by accurately differentiating between solid and non-solid features, reducing unnecessary maneuvers and improving safety and fuel efficiency by avoiding non-threatening obstacles.

Implementation Method 1

Individual points are measured by generating a laser pulse and detecting a returning pulse, if any, reflected from an environmental object

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

determining the distance to the reflective object according to the time delay between the emitted pulse and the reception of the reflected pulse

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 3

Individual points are measured by emitting a radio frequency radiation from a directional antenna and detecting a returning signal, if any, reflected from an environmental object

Methodology Applied
Scientific EffectRadio wave reflection: Reflection

Implementation Method 4

A RADAR actively estimates distances to environmental features while scanning through a scene

Methodology Applied
Scientific EffectRADAR: Radar

Data Source

PatentUS9097800B1Solid object detection system using laser and radar sensor fusion
Publication Date: 2015.08.04 WAYMO LLC
  • US9097800B1 patent drawing
  • US9097800B1 patent drawing
  • US9097800B1 patent drawing

AI summary

A light detection and ranging device associated with an autonomous vehicle scans through a scanning zone while emitting light pulses and receives reflected signals corresponding to the light pulses. The reflected signals indicate a three-dimensional point map of the distribution of reflective points in the scanning zone. A radio detection and ranging device scans a region of the scanning zone corresponding to a reflective feature indicated by the three-dimensional point map. Solid objects are distinguished from non-solid reflective features on the basis of a reflected radio signal that corresponds to the reflective feature. Positions of features indicated by the reflected radio signals are projected to estimated positions during the scan with the light detection and ranging device according to relative motion of the radio-reflective features indicated by a frequency shift in the reflected radio signals.