GNSS Position Updates Using Delta Carrier Range Corrections
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Solution Overview
Problem
Traditional GNSS positioning techniques that rely on pseudorange and carrier range measurements are computationally expensive, leading to high power consumption and latency in position updates, making them unsuitable for frequent and efficient tracking of GNSS receiver movements.
Innovation Solution
A method that calculates a first position solution based on pseudorange measurements and subsequent position updates using delta carrier range measurements, corrected for satellite motion and ionospheric delay, allowing for rapid and accurate position updates without full recalculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full position fixes are calculated frequently using pseudorange and carrier range measurements, then positioning accuracy is improved, but computational complexity and power consumption increase
Solution Approach 1:
The positioning calculation is segmented into two distinct types: full position fixes (computed less frequently using all measurements including pseudorange and carrier range) and position updates (computed frequently using only carrier range measurements). This segmentation allows the system to maintain high positioning accuracy through full fixes while reducing computational complexity during frequent updates by using a simplified calculation method that processes only the necessary carrier range data changes.
2Measurement precision
If full position fixes are calculated frequently, then positioning accuracy is improved, but power consumption increases
Solution Approach 1:
The power consumption is segmented by separating full position fix calculations from position update calculations. Full fixes, which consume the most power, are performed less frequently. Position updates, which consume significantly less power as they use simplified carrier range only calculations, are performed frequently to maintain positioning accuracy. This segmentation directly reduces overall power consumption while preserving positioning accuracy.
3Measurement precision
If full position fixes are calculated frequently, then positioning accuracy is improved, but latency increases
Solution Approach 1:
Processing latency is reduced by segmenting the calculation types: full position fixes are computed less frequently with higher accuracy, while position updates are computed frequently with lower latency using simplified carrier range measurements. This allows the system to provide timely position information through frequent updates while maintaining accuracy through periodic full fixes, thereby reducing overall latency.
4Device complexity
If carrier range measurements are used for position updates, then computational complexity is reduced, but measurement precision requirements increase
Solution Approach 1:
The position update calculation uses feedback from the previous full position fix by incorporating the satellite position and velocity information. The carrier range measurements are processed as changes relative to the known satellite states, allowing the system to maintain measurement precision requirements while reducing computational complexity. The feedback mechanism enables accurate position updates using simplified calculations.
Data Source
AI summary
A GNSS receiver, a method of estimating position, and an associated computer program are provided. An example method includes calculating a first (full) position solution based on pseudorange measurements made at a first time. One or more position updates are then calculated based on the first position solution, using delta carrier range measurements which compare first carrier range measurements, made at the first time, with second carrier range measurements, made at a second time. When calculating the one or more position updates, the delta carrier range measurements may be corrected to compensate for satellite motion between the first time and the second time. Corrections may also be made to compensate for changes in ionospheric delay.