Vehicle Pose Estimation Using LiDAR Point Clouds and UKF

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Solution Overview

Problem

Existing navigation systems for autonomous vehicles face accuracy degradation in complex urban environments due to poor GPS satellite signals, leading to positioning errors and global inconsistency in high-resolution maps.

Innovation Solution

The implementation of a navigation system that combines LiDAR, GPS, IMU sensors, and camera data with Unscented Kalman Filter (UKF) and Normal Distributions Transform (NDT) for improved vehicle pose estimation, using trajectory interpolation and pose graph optimization to reduce error accumulation and enhance positioning accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GPS, IMU, and wireless base stations are used for vehicle pose estimation, then positioning accuracy of about 10 cm is achieved in normal conditions, but positioning accuracy is greatly degraded in complex urban environments with poor GPS satellite signals

Engineering Contradiction:
Improvepositioning accuracyVSAvoidpositioning reliability in complex urban environments
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent combines multiple sensors (LiDAR, GPS, IMU, cameras) to capture features and aggregate point cloud frames. By merging data from these diverse sensors, the system achieves robust positioning that maintains accuracy in complex urban environments where GPS alone fails, directly resolving the contradiction between normal-condition accuracy and urban-environment reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces point cloud frames and pose graph optimization as intermediary elements between the sensors and the final positioning result. These intermediaries process and integrate sensor data to produce accurate pose estimates even when GPS signals are poor, thereby maintaining reliability in complex environments

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If real-time point clouds are introduced to improve positioning accuracy, then positioning accuracy is enhanced, but error accumulation still occurs due to poor GPS satellite signals

Engineering Contradiction:
Improvepositioning accuracyVSAvoiderror accumulation
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent implements pose graph optimization that uses feedback from multiple point cloud frames to correct positioning errors. The system continuously compares estimated poses with observed point cloud features and adjusts the pose estimates to minimize errors, preventing error accumulation even when GPS signals are poor

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary pose estimation using point cloud frames before final map aggregation. By pre-processing and optimizing poses using point cloud data and pose graph methods, the system eliminates positioning errors in advance, preventing their accumulation in the final map product

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If high-resolution maps are generated by aggregating multiple point cloud frames based on 3-D pose information, then map resolution is improved, but global inconsistency occurs due to positioning errors

Engineering Contradiction:
Improvemap resolutionVSAvoidglobal consistency of map
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent uses pose graph optimization with feedback loops to ensure global consistency. The system continuously refines pose estimates by comparing point cloud features across multiple frames and adjusting poses to maintain consistency, allowing high-resolution map aggregation without global inconsistency

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary pose optimization and error elimination before aggregating point cloud frames for map generation. By pre-processing the pose data to eliminate errors and ensure consistency, the system enables high-resolution map aggregation while maintaining global consistency throughout the final map product

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 provides high-accuracy vehicle positioning and point cloud data aggregation, reducing error accumulation and ensuring consistent map generation even in challenging environments.

Implementation Method 1

a LiDAR radar, to capture features of the road on which the vehicle is driving or the surrounding objects

Methodology Applied
Scientific EffectLight Detection And Ranging (LiDAR): LIDAR

Data Source

PatentEP3612854B1Vehicle navigation system using pose estimation based on point cloud
Publication Date: 2023.03.15 BEIJING DIDI INFINITY TECH & DEV CO LTD
  • EP3612854B1 patent drawingFigure 1
  • EP3612854B1 patent drawingFigure 2
  • EP3612854B1 patent drawingFigure 3

AI summary

Embodiments of the disclosure provide systems and methods for positioning a vehicle. The system includes a communication interface (202) configured to receive point cloud frames with respect to a scene and initial pose data of a vehicle captured by sensors (150) equipped on the vehicle as the vehicle moves along a trajectory. The system also includes a storage (208) configured to store the point cloud frames and the initial pose data. The system further includes a processor (204) configured to estimate pose information of the vehicle associated with each of the point cloud frames based on the initial pose data and the point cloud frames. The processor (204) is also configured to adjust the estimated pose information of the vehicle based on a model. The model includes a spatial relationship and a temporal relationship among the plurality of point cloud frames. The processor (204) is further configured to position the vehicle based on the adjusted pose information.