Carrier-Phase DGPS Relative Position Calculation
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Solution Overview
Problem
Conventional methods for calculating the relative position between two vehicles based on navigation satellite signals have significant calculation errors, ranging from several meters to scores of meters, which are not sufficient for precise applications.
Innovation Solution
A relative inter-vehicle position calculation apparatus that determines the carrier wave phase of radio waves from multiple navigation satellites and calculates the relative position based on the difference between the carrier wave phases received by two vehicles, employing Carrier-Phase DGPS positioning to achieve precision up to one meter or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the relative position is calculated based on the difference between two radio wave propagation times from GPS satellites, then the calculation method is simple to implement, but the calculation precision deteriorates with errors ranging from several meters to scores of meters
Solution Approach 1:
The patent changes the measurement parameter from radio wave propagation time to carrier wave phase. By using the phase information of the carrier wave instead of the propagation time, the system achieves millimeter-level precision in relative position calculation while maintaining the simplicity of GPS-based measurement approaches
Solution Approach 2:
The patent introduces carrier wave phase as an intermediary parameter between the GPS satellite signal and the final position calculation. The phase difference of the carrier wave serves as a precise mediator that enables accurate determination of relative position between vehicles without directly measuring propagation time
2Device complexity
If the relative position calculation uses conventional radio wave propagation time difference method, then the system complexity remains low, but the measurement precision deteriorates to several meters or more error
Solution Approach 1:
The patent transforms the measurement parameter from time-based (propagation time) to phase-based (carrier wave phase). This parameter change enables the system to achieve millimeter-level precision without significantly increasing system complexity, as the phase information is already contained within the GPS carrier signal
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
Improves the precision of relative position calculation between vehicles to an order of millimeters, significantly enhancing the accuracy compared to conventional methods.
Implementation Method 1
a phase determination unit for determining a carrier wave phase of a radio wave through reception of the radio wave from a plurality of navigation satellites
Data Source
AI summary
An on-board communication equipment on each of two vehicles receives a radio wave from two or more GPS satellites, and determines a carrier wave phase of the received radio wave. Then, the on-board communication equipment on one vehicle receives, from the other vehicle, information on the carrier wave phase observed in the other vehicle. Further, the on-board communication equipment calculates a relative position of a self vehicle relative to the other vehicle by a Carrier-Phase DGPS positioning based on a difference between two carrier wave phases (e.g., single difference, double difference or the like), that is, one from the self vehicle and one from the other vehicle, both having the same observation time, from among the available carrier wave phases.