Position Estimation Using Velocity Vector Integration
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Solution Overview
Problem
Existing mobile object positioning technologies, such as those described in JP-A No. 2006-208392, face challenges in accurately estimating the position and movement direction of mobile objects due to inconsistencies in position estimation accuracy and errors at epoch intervals, primarily because they rely on pseudo-ranges for position estimation without effectively integrating velocity information.
Innovation Solution
A position estimation apparatus that acquires transmission source information including position, distance, and relative velocity data from multiple information sources, calculates the mobile object's trajectory by integrating velocity vectors over a predetermined duration, and translates this trajectory to minimize distance differences with the information sources, thereby estimating the mobile object's position accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If position estimation is performed using only pseudo-ranges from navigation satellites, then the positioning navigation section can output positioning navigation positions, but errors occur at epoch intervals and accuracy of position estimation is inconsistent
Solution Approach 1:
The patent combines trajectory information from inertial navigation with position information from satellite positioning to create a hybrid position estimation system. The trajectory calculation section integrates velocity vectors to generate trajectory data, which is then combined with satellite pseudo-range measurements in the position estimation section, resolving the inconsistency between epoch-based satellite positioning alone
Solution Approach 2:
The trajectory calculation section acts as an intermediary that processes velocity vector information to generate trajectory data. This trajectory information serves as a bridge between the inertial navigation system and the satellite positioning system, enabling consistent position estimation across different epoch intervals by providing continuous trajectory constraints
2Loss of information
If the inertial navigation section estimates the trajectory of the mobile object, then velocity information is obtained, but the movement direction of the mobile object cannot be estimated
Solution Approach 1:
The patent adds the dimension of trajectory geometry to the velocity information from inertial navigation. By integrating velocity vectors over time to create trajectory paths and analyzing the geometric characteristics of these trajectories, the system extracts movement direction information that was not directly available from velocity measurements alone
3Productivity
If positioning navigation section only inputs pseudo-ranges for estimating positions, then position estimation can be performed, but errors occur at epoch intervals
Solution Approach 1:
The trajectory calculation section performs preliminary integration of velocity vectors to generate trajectory information before the position estimation process. This pre-computed trajectory data provides continuous positional constraints that bridge gaps between satellite epoch measurements, preventing errors from propagating between epochs
Data Source
AI summary
The present invention provides a position estimation apparatus, mounted at mobile object, including: an acquisition section that acquires transmission source information transmitted from each plural information transmission sources including, information relating to a position of information transmission source, information relating to a distance between information transmission source and mobile object, and information relating to a relative velocity of mobile object with respect to information transmission sources; a trajectory calculation section that calculates, over predetermined duration, a trajectory of mobile object by integrating velocity vectors of mobile object obtained based on transmission source information; and an estimation section that estimates, as a position of mobile object, a position for which trajectory is translated such that a difference between, distances between a plurality of points at different times on trajectory and respective information transmission sources, and acquired distances between respective information transmission sources and mobile object, is minimum.