Crowdsourced Ionosphere Map for GNSS Positioning Convergence
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Solution Overview
Problem
Precise Point Positioning (PPP) convergence time to centimeter-level accuracy is prolonged due to the time needed to estimate ionospheric effects, especially in global navigation satellite systems (GNSS), which can be improved but requires a dense network of base stations that is costly to establish and operate.
Innovation Solution
The system crowdsources atmospheric data from rovers to calculate and transmit ionospheric delay values, allowing a central server to generate an ionosphere map that corrects satellite range measurements, thereby reducing convergence time to achieve desired position accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a dense network of base stations is used to generate local ionospheric corrections, then PPP convergence time is reduced to 1-5 minutes, but the system cost becomes expensive to build and operate
Solution Approach 1:
The patent enables rovers to self-calculate ionospheric delay values using their own GNSS signal observations and dual-frequency measurements. Each rover independently estimates its own ionospheric correction without requiring external base station infrastructure, thereby eliminating the need for expensive dense base station networks while achieving fast convergence
Solution Approach 2:
The patent introduces a central server as an intermediary that collects ionospheric delay values from multiple rovers, generates a spatial-temporal ionosphere map, and distributes corrections back to rovers. This mediator enables rovers to benefit from aggregated crowd-sourced data without requiring direct peer-to-peer communication or expensive local base station infrastructure
2Device complexity
If traditional PPP method is used with sparse global network, then system cost is reduced, but PPP convergence time increases to 20-30 minutes
Solution Approach 1:
The patent implements a feedback mechanism where rovers transmit their calculated ionospheric delay values and position information to a central server. The server uses this feedback data to continuously update and refine the ionosphere map, which is then distributed back to rovers for improved positioning convergence. This closed-loop feedback enables accurate ionospheric correction without requiring expensive infrastructure
Solution Approach 2:
The patent makes each rover multi-functional by enabling it to not only receive positioning corrections but also to calculate and contribute its own ionospheric delay measurements to the central server. This universal participation of rovers in both consuming and producing correction data eliminates the need for dedicated base station infrastructure while maintaining fast convergence performance
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
This approach significantly reduces the convergence time to achieve centimeter-level positioning accuracy by utilizing crowdsourced ionospheric data, making it more efficient and cost-effective compared to traditional dense network methods.
Implementation Method 1
The ionosphere is a layer of the Earth's atmosphere that is ionized by solar and/or cosmic radiation and typically lies 75-1,000 km (46-621 miles) above the Earth's surface. Specifically, global navigation satellite system (GNSS) satellite signals interact with free electrons along the propagation path through the ionosphere leading to a group delay and phase advance proportional to the Total Electron Content (TEC).
Data Source
AI summary
A system and method crowdsources atmospheric data from one or more rovers. The rovers calculate an estimated ionosphere delay value that indicates an adverse effect of ionospheric activity on signals received from the GNSS satellite. The values and identifiers may be transmitted to a server. The server utilizes the received information to generate an ionosphere map that reflects the magnitude of ionospheric delay at different locations. The ionosphere map is transmitted to one or more rovers. The rover determines if a pierce point associated with a selected GNSS satellite in view of the rover falls within the boundaries of the ionosphere map. If so, a corresponding ionosphere delay value is obtained utilizing the ionosphere map and then applied as a correction to account for ionospheric activity. In addition, the central server and/or rover may transmit the estimated ionosphere delay values and identifiers to other rovers.