Satellite Positioning Using Prediction Error Correction
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Solution Overview
Problem
Current satellite positioning methods, such as GNSS, require lengthy processing times for acquiring satellite signals, which is unacceptable for miniaturized portable applications and results in poor first fix accuracy due to inaccuracies in satellite orbit and clock predictions.
Innovation Solution
A satellite-based positioning method that involves obtaining predicted satellite data, calculating satellite prediction error data, and using a processing unit to calculate parameters based on these errors to enhance the accuracy of satellite positioning, thereby improving the first fix process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stand-alone mode is used to acquire satellite signals, then the system operates independently without external assistance, but the time-to-first-fix is excessively long and battery life is greatly limited
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing satellite orbit and clock prediction data before the receiver needs to acquire signals. The server performs offline computations of satellite ephemeris and clock corrections, then provides these pre-processed data to the receiver, eliminating the need for the receiver to perform time-consuming signal search and acquisition from scratch.
Solution Approach 2:
The patent introduces an intermediary server that acts as a bridge between the satellite system and the receiver. This server computes satellite prediction data using reference ephemeris and clock information, then delivers pre-computed orbit and clock data to the receiver, reducing the computational burden and time requirements of the standalone receiver.
2Loss of time
If assisted mode with pre-computed orbit data is used, then the time-to-first-fix is reduced, but the accuracy of satellite positioning deteriorates due to prediction errors
Solution Approach 1:
The patent implements feedback by computing prediction errors between pre-computed orbit data and reference ephemeris data, then using these errors to generate correction terms. The receiver applies these correction terms to the pre-computed data, forming a feedback loop that continuously improves positioning accuracy based on the difference between predicted and actual satellite positions.
Solution Approach 2:
The patent changes parameters by introducing prediction error metrics and correction coefficients that dynamically adjust the pre-computed orbit and clock data. The system modifies the orbital parameters and timing data based on computed errors, transforming static prediction data into dynamically corrected data that maintains high accuracy.
3Loss of time
If extended prediction orbit is used for long-term satellite trajectory prediction, then the time-to-first-fix is improved, but enormous errors occur between predicted and actual satellite orbits
Solution Approach 1:
The patent applies partial action by using extended prediction orbit data only for satellites and time periods where the prediction accuracy is sufficient. The system selectively applies EPO data based on computed prediction errors, using it partially rather than universally, thereby avoiding the enormous errors that would occur with long-term predictions for all satellites.
Data Source
AI summary
A satellite-based positioning method includes: obtaining predicted satellite data for at least one satellite vehicles (SVs) in a global navigation satellite system (GNSS); obtaining reference satellite data for the at least one SV; calculating satellite prediction error data for each of the at least one SV according to the predicted satellite data and the reference satellite data; and utilizing a processing unit to calculate a parameter for each of the at least one SV based on the satellite prediction error data. An associated satellite-based positioning apparatus is also provided.