RTK Positioning Terminal Using Antenna Azimuth to Narrow Ambiguity Search

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Solution Overview

Problem

In urban areas with significant shielding, the rate of float solutions calculated in RTK calculations tends to increase, leading to reduced accuracy and reliability in positioning.

Innovation Solution

A positioning method and terminal that utilize multiple antennas and inter-antenna distance and azimuth angle to narrow the search range for integer ambiguity estimation, quickly converting float solutions to fixed solutions by leveraging fixed solutions from other antennas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If RTK calculation is performed in urban areas with shielding, then positioning service is provided, but the rate of float solutions increases reducing accuracy

Engineering Contradiction:
Improvepositioning accuracyVSAvoidshielding effect
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the positioning calculation into two independent parts: float solution calculation and integer ambiguity resolution. By segmenting the search space for integer ambiguity based on float solution results and using constraints from one antenna pair to narrow the search for another, the system can maintain accuracy despite shielding. This segmentation allows the system to process each antenna pair's data independently while using cross-validation to overcome individual float solution failures caused by shielding.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If multiple antennas are used for positioning, then positioning accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the processing of multiple antenna pairs by using the float solution and integer ambiguity results from one antenna pair to constrain the search space of another antenna pair. This combining approach allows the system to leverage information from all antennas collectively, improving overall positioning accuracy while avoiding the need for completely independent processing of each antenna pair, thus managing system complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If integer ambiguity search range is reduced, then calculation speed is improved, but reliability of ambiguity resolution decreases

Engineering Contradiction:
Improvecalculation speedVSAvoidambiguity resolution reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent performs preliminary float solution calculation for each antenna pair before conducting integer ambiguity resolution. The float solution results are used to pre-constrain the integer ambiguity search range, creating a narrower but more reliable search space. This preliminary action ensures that the reduced search range is based on accurate float solutions, maintaining ambiguity resolution reliability while achieving faster calculation speeds.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from float solution quality and cross-validation between multiple antenna pairs to dynamically adjust the integer ambiguity search strategy. When float solutions are reliable, the search range is narrowed significantly; when float solutions are uncertain, the search range is maintained larger or alternative resolution methods are employed. This feedback mechanism ensures calculation speed is optimized without sacrificing reliability.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3647821B1Positioning method and positioning terminal
Publication Date: 2021.12.15 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3647821B1 patent drawingFigure 1~2
  • EP3647821B1 patent drawingFigure 3
  • EP3647821B1 patent drawingFigure 4A~4B

AI summary

In a case where a first RTK positioning solution (X1) is a fixed solution and a second RTK positioning solution (X2) is a float solution, a processor estimates a position of a second receiver (antenna A2) based on the first RTK positioning solution (Xl), inter-antenna distance L, and antenna azimuth angle θ to set an area within a circle with radius R centered on the estimated position as a search range. Next, the processor calculates an integer ambiguity within the search range obtained in the RTK calculation as the second RTK positioning solution (X2)' (estimated fixed solution). Then, the processor outputs the first RTK positioning solution (X1) and the second RTK positioning solution (X2)' as positioning solutions (current coordinates of a moving object).