GNSS-INS In-Motion Initialization for Vehicle Orientation Changes
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Solution Overview
Problem
Existing navigation systems face challenges in initializing and re-initializing the Global Navigation Satellite System (GNSS) and Inertial Navigation System (INS) combination while a mobile device is in motion, due to changing orientations and lack of stationary periods for calibration.
Innovation Solution
A method for in-motion initialization and re-initialization of the GNSS-INS system using gyroscope and accelerometer measurements to determine the gravity, forward, and north vectors, allowing calibration while the vehicle is moving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor calibration is performed using traditional stationary methods, then calibration accuracy is improved, but the system cannot be re-initialized when the mobile device orientation changes during motion
Solution Approach 1:
The patent transforms the static calibration process into a dynamic one by enabling calibration during vehicle motion. The system uses accelerometer and gyroscope measurements taken while the vehicle is moving to determine gravity, forward, and north vectors, allowing the GNSS-INS filter to be initialized without requiring stationary periods. This resolves the contradiction by making the calibration process adaptable to motion conditions while maintaining accuracy through sensor fusion algorithms.
Solution Approach 2:
The system changes the operational parameters of calibration from stationary conditions to moving conditions. By collecting sensor data during vehicle motion and processing it through the GNSS-INS filter, the system adapts the calibration parameters (gravity vector, forward vector, north vector) to dynamic environments. This allows re-initialization after orientation changes without requiring the vehicle to stop, thus maintaining both accuracy and adaptability.
2Reliability
If the mobile device is mounted in a fixed structure in the vehicle, then initial calibration can be performed, but re-initialization becomes difficult when orientation changes occur during travel
Solution Approach 1:
The system performs self-re-initialization by automatically detecting orientation changes through sensor measurements and executing calibration without user intervention. When the mobile device orientation changes during motion, the GNSS-INS filter uses accelerometer and gyroscope data to重新 determine the device orientation and recalibrate, maintaining reliable positioning without requiring manual re-initialization or stationary periods.
Solution Approach 2:
The system implements continuous feedback monitoring of device orientation using accelerometer and gyroscope measurements. By comparing current sensor readings with stored calibration data, the system detects when orientation changes occur and triggers automatic re-initialization of the GNSS-INS filter. This feedback mechanism ensures the system maintains reliability while adapting to orientation changes during vehicle travel.
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
Enables accurate positioning and heading updates for mobile devices in dynamic environments by effectively calibrating the GNSS-INS system during vehicle motion, maintaining position history and reducing the need for stationary periods.
Implementation Method 1
gyroscope measurements made while the vehicle is turning
Implementation Method 2
accelerometer measurements while the vehicle is traveling straight
Data Source
Figure 1~2B
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AI summary
A mobile device (100) in a moving vehicle (102) initializes a Global Navigation Satellite System (GNSS) - Inertial Navigation System (INS) system while the vehicle (102) is in-motion with the orientation of the mobile device (100) with respect to a global reference frame. The mobile device (100) uses gyroscope (312) measurements made while the vehicle (102) is turning to determine a gravity vector. The gravity vector and accelerometer (311) measurements may be used to determine a forward vector for the mobile device (100). A north vector is determined using the GNSS (110) measurements. After the GNSS-INS system is calibrated, the mobile device (100) may be positioned with respect to the vehicle (102). The orientation of the mobile device (100), prior to repositioning, may be compared to a current orientation, determined while the vehicle (102) is in motion, in order to determine whether the GNSS-INS system should be reinitialized.