Rapid GNSS Inertial Initialization via Target Point Detection
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Solution Overview
Problem
Existing navigation systems require lengthy initialization processes for inertial and GNSS subsystems, which delays the provision of accurate navigation information, especially in dynamic environments where continuous GNSS satellite visibility is not guaranteed.
Innovation Solution
A navigation system that utilizes a constellation of target points with transmitters broadcasting their positions, allowing a navigation unit on a second vehicle to quickly determine its absolute position and orientation using camera or detector systems, thereby initializing the inertial subsystem without relying on initial GNSS positioning and aiding in faster GNSS signal acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the inertial/GNSS receiver uses traditional initialization processes, then the subsystems can be initialized, but the initialization time is lengthy and delays navigation information provision
Solution Approach 1:
The system performs preliminary actions by using inertial measurements during the initialization period to predict and fill in navigation information before GNSS subsystem is fully initialized. This allows the system to provide navigation information immediately rather than waiting for complete GNSS initialization, thereby reducing initialization time and improving productivity.
Solution Approach 2:
The inertial subsystem acts as an intermediary during initialization, providing bridge navigation information while the GNSS subsystem is being initialized. The inertial measurements serve as a temporary substitute that maintains navigation functionality, resolving the contradiction between quick information provision and complete system initialization.
2Reliability
If the inertial/GNSS receiver waits for sufficient GNSS satellite signals during initialization, then positioning accuracy is ensured, but the system cannot operate in dynamic environments where satellite visibility is not guaranteed
Solution Approach 1:
The system uses its own inertial sensors to self-service during initialization, generating navigation information from inertial measurements without relying on external GNSS signals. This self-service capability ensures continuous operation in dynamic environments where satellite visibility cannot be guaranteed, while maintaining reliability through the use of accurate inertial data.
Solution Approach 2:
The system dynamically adapts its initialization process by switching between inertial-only mode and combined GNSS-inertial mode based on satellite availability. This dynamic approach allows the system to operate reliably in both static and dynamic environments, improving adaptability without sacrificing reliability.
3Ease of operation
If the system requires dynamic motion during initialization, then the inertial/GNSS receiver can calculate navigation information, but the system cannot initialize in static or near-static conditions
Solution Approach 1:
The system replaces the mechanical requirement for dynamic motion with an computational approach using inertial measurements and mathematical algorithms. Instead of requiring physical movement to initialize, the system uses inertial sensor data processed through initialization algorithms, thereby improving ease of operation while maintaining fast initialization completion.
Solution Approach 2:
The system changes the initialization parameters from motion-dependent to measurement-dependent by using inertial measurement data as the primary initialization source. This parameter change allows initialization to proceed regardless of vehicle motion state, improving operational flexibility without sacrificing initialization speed.
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 time to first fix and enables uninterrupted navigation by initializing the inertial and GNSS subsystems quickly, even in dynamic conditions, without compromising accuracy.
Implementation Method 1
A navigation unit on a second moving vehicle utilizes a camera with known properties to capture an image that includes the constellation of target points
Implementation Method 2
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
Data Source
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.