Rapid GNSS Inertial Initialization via Target Point Detection

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Solution Overview

Problem

Existing navigation systems require extensive initialization time for inertial and GNSS subsystems, which delays the provision of accurate navigation information, especially in dynamic motion scenarios, and often necessitate stationary conditions for precise alignment.

Innovation Solution

A navigation system that utilizes a constellation of target points with transmitters broadcasting their positions, combined with detector systems like Lidar, sonar, or radar, to quickly calculate the absolute position and orientation of a vehicle, allowing the INS subsystem to initialize without relying on GNSS initial positioning and aiding the GNSS subsystem in signal acquisition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the inertial and GNSS subsystems use traditional initialization methods, then the initialization is performed with standard procedures, but the initialization time is extended and accurate navigation information is delayed

Engineering Contradiction:

Improveinitialization timeVSAvoidnavigation information accuracy

Core Design Contradiction:

Loss of timeVSMeasurement precision

Solution Approach 1:

The system performs preliminary actions by pre-calculating position and orientation information using the detector system and target points before the GNSS subsystem completes its traditional initialization. This allows the INS subsystem to initialize with accurate preliminary data, significantly reducing initialization time without compromising navigation accuracy.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If the system requires stationary conditions for initialization, then alignment precision can be maintained, but the system cannot operate in dynamic motion scenarios

Engineering Contradiction:

Improvedynamic motion capabilityVSAvoidalignment precision

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical requirement for stationary alignment conditions with an optical/detector-based system. The detector system captures images of target points and calculates position and orientation information through image processing, eliminating the need for physical stationary conditions while maintaining alignment precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Loss of time

If the INS subsystem waits for GNSS initial positioning, then positioning accuracy can be ensured, but the initialization process is delayed

Engineering Contradiction:

Improveinitialization delayVSAvoidpositioning accuracy

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The system introduces an intermediary solution by using the detector system and target points as a intermediate positioning mechanism. This intermediary system provides the INS subsystem with sufficient position and orientation information to initialize independently, eliminating the waiting delay while maintaining positioning accuracy through the combination of detector-based preliminary data and subsequent GNSS data.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Productivity

If detector systems are used to calculate position and orientation, then initialization speed is improved, but system complexity increases

Engineering Contradiction:

Improveinitialization speedVSAvoidsystem complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The detector system serves multiple functions: it captures images of target points for position calculation, provides orientation information, and can be used during both initialization and operational phases. This multi-functionality justifies the added complexity by providing sustained benefits throughout the system's operation, not just during initialization.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 significantly reduces the initialization time for navigation systems, enabling them to operate in dynamic conditions without the need for stationary alignment, thereby providing faster and more accurate navigation information.

Implementation Method 1

determine how long it takes for the beam to bounce back or reflect from the rendezvous site to the detector system to determine relative distances from the targets

Methodology Applied

Scientific EffectTime of Flight: Time of Flight

Data Source

PatentEP3056926B1Navigation system with rapid GNSS and inertial initialization

Publication Date: 2018.12.19 NOVATEL INC

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AI summary

A navigation system for use with moving vehicles includes target points proximate to a rendezvous site located on a first moving vehicle. One or more transmitters broadcast target point positioning information. A navigation unit on a second moving vehicle utilizes a camera to capture images that include the target points or a detector system that emits one or more beams to the target points. The navigation unit determines the relative position and orientation of the rendezvous site at the second vehicle. The navigation unit utilizes the relative position and orientation and an absolute position and orientation of the rendezvous site calculated from the target position information and calculates an absolute position and orientation corresponding to the second vehicle. The navigation unit then initializes its component inertial subsystem using a local position and orientation that are based on the calculated absolute position and orientation of the second vehicle.