Single Frequency GNSS Positioning via Interpolated Delay Correction
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Solution Overview
Problem
Current single frequency GNSS positioning methods using the RTK scheme face challenges in achieving high accuracy beyond a few kilometers due to large ionospheric and tropospheric delay errors, making it impractical for inexpensive single frequency receivers to determine ambiguity accurately.
Innovation Solution
A positioning method and apparatus that estimate satellite clock errors, code biases, ionospheric, and tropospheric delays at the reference station, and use pseudo and phase distance observation formulas to determine carrier phase ambiguity, allowing for accurate positioning with a single frequency receiver by transmitting correction information from the reference station to the mobile station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dual frequency GNSS receiver is used to determine carrier phase ambiguity, then positioning accuracy is improved, but device cost increases
Solution Approach 1:
The patent introduces a reference station as an intermediary that collects dual-frequency observations and computes carrier phase ambiguity parameters. The mobile station using single frequency receives these pre-computed parameters from the reference station, enabling high-accuracy positioning without requiring expensive dual-frequency hardware. The reference station acts as a mediator that transforms dual-frequency information into single-frequency usable parameters.
Solution Approach 2:
The patent creates a copy of the dual-frequency observation results by having the reference station compute and transmit carrier phase ambiguity parameters to the mobile station. Instead of requiring the mobile station to perform dual-frequency measurements itself, it receives copied/derived parameters from the reference station, achieving the same positioning accuracy with simpler single-frequency hardware.
2Device complexity
If RTK positioning scheme is used with single frequency, then device cost is reduced, but positioning accuracy deteriorates when distance exceeds a few kilometers
Solution Approach 1:
The reference station serves as an intermediary that collects dual-frequency observations and computes correction parameters for carrier phase ambiguity. These parameters are then transmitted to the mobile station, enabling it to achieve high-accuracy positioning beyond a few kilometers without requiring dual-frequency hardware. The reference station mediates the distance limitation by providing pre-computed ambiguity parameters.
Solution Approach 2:
The patent changes the parameter transmission approach by having the reference station compute and transmit not just standard correction data but specifically pre-solved carrier phase ambiguity parameters. This parameter transformation allows the mobile station to overcome the distance limitation inherent in traditional single-frequency RTK, extending accurate positioning beyond the typical few-kilometer range.
3Measurement precision
If reference station is located in vicinity of mobile station for single frequency RTK, then positioning accuracy is improved, but adaptability deteriorates
Solution Approach 1:
The patent fundamentally changes the parameter transmission content by having the reference station compute and transmit carrier phase ambiguity parameters derived from dual-frequency observations. This parameter transformation enables the system to overcome the distance limitation, allowing the reference station to be located far from the mobile station while maintaining high positioning accuracy, thus greatly improving system adaptability and versatility.
Data Source
AI summary
A positioning signal from a satellite positioning system is received at a mobile station, correction information from a reference station is used, a pseudo distance observation formula using a code and a phase distance observation formula using a carrier wave are used to perform positioning using single frequency at the mobile station, and these observation formulas are expressed by a satellite clock error, clock errors at the reference station and the mobile station, a ionospheric delay and a tropospheric delay, and a code bias and a phase bias of single frequency at the reference station, the mobile station and a satellite.