Geopositioning Confidence Index via Satellite Validation
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Solution Overview
Problem
Current satellite geopositioning systems, such as GPS, face challenges in providing accurate position estimates in constrained environments like urban areas due to multipath and masking issues, and existing augmentation systems are not effective for land-based users without inertial units, requiring a method to assess the quality of position measurements.
Innovation Solution
A satellite geopositioning method that calculates a confidence index by comparing pseudo-distance measurements from additional satellites in a different constellation to those used for position estimation, allowing for the determination of position accuracy and error estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If satellite geopositioning systems are used in constrained environments, then position estimation is provided, but measurement accuracy deteriorates due to multipath and masking issues
Solution Approach 1:
The patent uses an additional satellite as an intermediary reference point to validate position measurements. By calculating pseudo-distances to this independent satellite and comparing them with expected values, the system can detect and flag inaccurate measurements caused by multipath and masking effects without being directly affected by these harmful factors themselves.
Solution Approach 2:
The system implements feedback by continuously monitoring the consistency between position estimates derived from primary satellites and pseudo-distance measurements from additional satellites. When discrepancies exceed thresholds, the system adjusts its confidence index and can exclude unreliable measurements, creating a self-correcting mechanism that improves accuracy in constrained environments.
2Reliability
If augmentation systems are used to improve position accuracy, then integrity information is provided, but effectiveness deteriorates for land-based users in urban environments due to local propagation phenomena
Solution Approach 1:
The patent enables the receiver to autonomously perform integrity monitoring by using additional satellites as self-generated reference points. The system calculates expected pseudo-distances based on known satellite positions and compares them with actual measurements, allowing land-based users to self-validate their position accuracy without relying on external augmentation systems that cannot account for local urban propagation effects.
Solution Approach 2:
The system dynamically adjusts operational parameters including the selection of additional satellites, confidence index thresholds, and measurement weighting based on real-time signal quality and geometric configuration. This adaptability allows the system to maintain effectiveness across varying urban environments by changing its monitoring strategy according to local conditions.
3Measurement precision
If RAIM algorithm is used to detect satellite failures, then measurement consistency is verified, but applicability deteriorates in the presence of strong masking due to requirement for large number of measurements
Solution Approach 1:
Instead of requiring a large number of satellites for full RAIM operation, the patent applies partial action by using a minimal set of additional satellites specifically for validation purposes. The system performs targeted consistency checks on critical measurements rather than requiring comprehensive redundancy, making it operable in masked environments where only a few satellites are visible.
Solution Approach 2:
The patent extracts the essential integrity monitoring function from the full RAIM algorithm, separating the validation step from the primary position calculation. By taking out only the necessary consistency verification using additional satellites, the system achieves measurement consistency checking without requiring the excessive number of measurements that full RAIM demands.
4Measurement precision
If batch-type technologies with inertial sensors are used to accumulate measurements, then position can be determined from small number of GNSS measurements, but device complexity increases due to requirement for inertial units
Solution Approach 1:
The patent uses additional satellites as intermediary reference points that enable validation of position measurements without requiring inertial sensors. These intermediary satellites provide the necessary geometric reference to accumulate and validate measurements over time, replacing the function that would otherwise require complex inertial measurement units while maintaining position determination capability.
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 method provides users with a reliable confidence index on the accuracy of their position, improving accuracy in challenging environments without the need for inertial units, by using additional satellite constellations like Galileo or GLONASS to validate GPS measurements.
Implementation Method 1
calculate the position of the receiving terminal by measuring the propagation time of signals emitted by positioning satellites between the satellites and the receiving terminal
Implementation Method 2
the geopositioning terminal measures the time elapsed between transmission and reception of the coded message and thereby deduces the distance separating it from the satellite
Data Source
Figure 1~2
AI summary
The present invention relates to the field of satellite geolocation. More particularly, it relates to a geopositioning method with a confidence index implemented by a geopositioning terminal 10. According to the method, the positioning of the terminal 10 is estimated using geopositioning satellites 11, and said confidence index is provided by comparison with at least one pseudodistance measurement 13 obtained using at least one additional geopositioning satellite 12 different from those used to calculate the position of the terminal 10.