Position Measurement Device Using Time Feedback for Error Correction
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Solution Overview
Problem
Existing position measurement methods, such as those using GPS signals, may produce erroneous results due to signal errors or invalid assumptions about satellite radio waves, leading to incorrect positioning and potential erroneous control of moving objects like trains, especially when determining stopping positions.
Innovation Solution
A position measurement apparatus comprising a radio wave receiver, memory, speed measurer, time measurer, upper limit error determiner, and position determiner, which evaluates and corrects positioning errors by calculating the upper limit of error in the positioning result using navigation satellite signals and track information, ensuring accurate positioning even if the assumption of single satellite error is invalid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If GPS signal reception level is used to determine position accuracy, then position measurement can be simplified, but erroneous positioning results cannot be detected when error-causing signals have sufficient reception level
Solution Approach 1:
The patent implements feedback by comparing the time information calculated from GPS satellite signals with the time information measured by an independent time measurement device. This feedback mechanism enables detection of positioning errors even when GPS signal reception levels appear normal, resolving the contradiction between measurement simplicity and positioning accuracy.
Solution Approach 2:
The patent introduces time information as an intermediary parameter to verify positioning accuracy. By using time information from both GPS calculations and independent time measurement as mediators, the system can detect erroneous positioning results without complicating the overall measurement process, thus maintaining simplicity while improving reliability.
2Productivity
If assumption of single satellite error is made, then position measurement can be performed, but erroneous results occur when multiple satellites transmit error-causing radio waves
Solution Approach 1:
The system uses feedback comparison between independently measured time information and GPS-calculated time information to detect when multiple satellites are transmitting error-causing signals. This allows the system to maintain position measurement capability while identifying when results should be rejected due to multiple satellite errors.
Solution Approach 2:
The patent performs preliminary verification by comparing time information before finalizing position measurements. This preliminary action checks whether the assumption of single satellite error is valid, preventing erroneous results from being accepted while maintaining the ability to perform position measurements under normal conditions.
3Device complexity
If position is determined based on GPS signals alone, then measurement process is simple, but stopping position control may be erroneous due to undetected positioning errors
Solution Approach 1:
The patent applies feedback by continuously comparing time information from independent time measurement with time information calculated from GPS signals. This feedback mechanism ensures stopping position accuracy without significantly increasing system complexity, as the same time comparison methodology is used for both position verification and stopping control.
Solution Approach 2:
Time information serves as an intermediary parameter that verifies both position accuracy and stopping position control validity. By using this intermediary, the system ensures precise stopping position control while maintaining relatively simple measurement system architecture, as the intermediary already exists from the position measurement process.
Data Source
AI summary
A position and time calculator, based on a navigation satellite signal, calculates a position of a navigation satellite and a position and a time where an antenna receives the navigation satellite signal. An upper limit error determiner evaluates an upper limit of error caused in positioning a reception position of the antenna based on an amount obtained by multiplying a difference between the time calculated based on the navigation satellite signal and the time measured by a time measurer by a coefficient determined based on arrangement of navigation satellites, and information on the position on the track stored in a memory. A position determiner corrects the moved distance measured by the speed measurer based on the evaluation of the upper limit of error in positioning, and determines the position of the antenna.