Geodetic Datum Transformation Using Residual Grids for Precise Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing navigation satellite systems face limitations in achieving precise geodetic datum transformations due to the integer ambiguity problem in carrier phase measurements, leading to suboptimal positioning accuracy and the need for efficient transmission of geodetic datum transformation information.
Innovation Solution
The method involves generating two- or three-dimensional similarity transformation parameters and post-fit transformation residuals based on reference stations' coordinates, distributing output points adaptively based on reference station density, and transmitting these parameters and residuals efficiently using quadtree data structures to enable precise geodetic datum transformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If carrier phase measurements are used to achieve high positioning precision, then position accuracy is improved, but the integer ambiguity problem arises making the measurements ambiguous
Solution Approach 1:
The patent introduces geodetic datum transformation parameters as an intermediary to resolve the integer ambiguity in carrier phase measurements. These parameters act as a mediator between the ambiguous carrier phase observations and the desired accurate position coordinates, enabling the resolution of ambiguities through transformation from one datum to another.
Solution Approach 2:
The patent replaces the traditional mechanical approach of directly measuring distances with a computational/geodetic approach using datum transformation. Instead of relying solely on direct carrier phase measurements, the system uses mathematical transformations between different geodetic datums to achieve both accuracy and unambiguity.
2Measurement precision
If geodetic datum transformation information is transmitted for all regions uniformly, then positioning accuracy is improved, but payload and bandwidth requirements increase
Solution Approach 1:
The patent applies local quality by providing geodetic datum transformation information selectively based on the specific region or area where positioning is needed. Rather than uniformly transmitting transformation data for all regions, the system identifies and transmits only the relevant transformation parameters for the local area of interest, reducing unnecessary data transmission while maintaining positioning accuracy.
Solution Approach 2:
The patent segments the global geodetic transformation information into regional or local portions. By dividing the transformation data into manageable segments corresponding to different regions, the system can transmit only the necessary segments for the current positioning location, thereby reducing overall payload and bandwidth requirements.
3Measurement precision
If reference stations are distributed uniformly across the region, then transformation accuracy is improved, but system complexity and setup cost increase
Solution Approach 1:
The patent applies local quality by concentrating reference stations in areas where high transformation accuracy is most critical, rather than distributing them uniformly across the entire region. This strategic placement ensures adequate accuracy in key areas while reducing the overall number of stations required, thereby lowering system complexity and setup costs.
Solution Approach 2:
The patent accepts partial coverage with strategically placed reference stations rather than attempting complete uniform coverage. By using a partial set of reference stations positioned optimally, the system achieves sufficient transformation accuracy for most applications without the complexity and cost of a fully uniform reference station network.
Data Source
AI summary
The invention relates to methods for providing geodetic datum transformation information applicable to a region of the Earth, for use by a navigation satellite system (NSS) receiver and/or a processing entity capable of receiving data therefrom. In one embodiment, the method comprises: generating (s10a) similarity transformation parameters and, for each of a plurality of reference stations in the region, post-fit transformation residuals applicable to the reference station; and sending (s20a) the transformation parameters and output residuals applicable to output points, wherein an output residual is one of the post-fit transformation residuals or derived therefrom; and the distribution of the output points in the region depends on the distribution of the reference stations. The invention also relates to variants of the above-mentioned method, to methods for receiving and processing the geodetic datum transformation information, and to systems, computer programs, and computer program products for carrying out such methods.