GNSS Receiver Clock Bias Correction for Lane-Level Positioning
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Solution Overview
Problem
Current positioning systems using GNSS receivers face challenges in achieving high precision due to receiver clock bias errors, especially with low-cost single-frequency receivers, which require accurate correction to enhance positioning accuracy beyond road-level precision.
Innovation Solution
A positioning device that includes a code positioning part, a receiver clock bias error correction part, and a code positioning correction part to calculate and correct receiver clock bias errors using a corrected pseudorange and orbit data from GNSS satellites, thereby improving positioning precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a low-cost single-frequency GNSS receiver is used, then device cost is reduced, but positioning precision deteriorates due to receiver clock bias error
Solution Approach 1:
The patent introduces a base station as an intermediary that provides correction signals to compensate for receiver clock bias errors. The base station calculates precise clock bias corrections using its more stable clock and transmits these corrections to mobile receivers, enabling accurate positioning without requiring expensive atomic clocks in each receiver unit
Solution Approach 2:
The patent changes the time parameter by using differential time measurements between the base station and mobile receiver. By measuring the time difference of arrival (TDOA) of signals and applying clock bias corrections, the system transforms the positioning problem from absolute time measurement to relative time difference measurement, thereby eliminating the need for high-precision clocks in mobile receivers
2Measurement precision
If a high-precision clock is used in the GNSS receiver, then positioning precision is improved, but device cost increases
Solution Approach 1:
The base station acts as an intermediary that performs the high-precision time measurement function centrally. Instead of equipping each mobile receiver with an expensive high-precision clock, the system uses the base station's precise clock to generate correction signals that compensate for receiver clock errors, achieving high positioning precision at low cost
Solution Approach 2:
The patent creates a virtual reference time source by having the base station calculate and broadcast corrected timing information. Mobile receivers copy this reference time information from the base station signals, effectively replicating the high-precision time reference function without physically possessing expensive atomic clocks
Data Source
AI summary
A code positioning part calculates a position of a subject vehicle and a receiver clock based on an orbit of a GNSS satellite in which an error indicated by a positioning reinforcing signal is corrected and a first corrected pseudorange being a pseudorange of the GNSS satellite in which an error indicated by the positioning reinforcing signal is corrected. A receiver clock bias error correction part determines a difference between a two-point range between a position of each of a plurality of GNSS satellites and the position of the subject vehicle and the first corrected pseudorange as an unknown error, and determines a receiver clock bias error of the pseudorange based on the unknown error. A code positioning correction part recalculates the position of the subject vehicle, using a second corrected pseudorange that is obtained by correcting the first corrected pseudorange using the receiver clock bias error.