Coarse Position Injection for Satellite Navigation Systems
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Solution Overview
Problem
Position determination systems (PDS) face delays and failed initial searches due to the use of inaccurate seed locations, especially when receivers transition from one location to another, as they rely on outdated or unreliable external sources for initial positioning.
Innovation Solution
Implementing a method where a satellite positioning system (SPS) receiver gathers location information from multiple sources, analyzes consistency, and injects a derived seed location into the positioning process, using a weighted mean or multilateration based on signal strength and proximity data to ensure accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the SPS receiver uses standalone acquisition process without external location information, then the positioning calculation can be performed accurately, but the acquisition and positioning time becomes quite long during cold start operation
Solution Approach 1:
The patent applies preliminary action by obtaining coarse location information from external sources (cell towers, wireless access points, femtocells) before the SPS acquisition process begins. This pre-acquisition location data is used to initialize the receiver's position estimate, allowing the SPS receiver to start with a warm start rather than cold start, thereby significantly reducing the acquisition and positioning time while maintaining accurate positioning through the subsequent SPS calculation process
2Productivity
If the SPS receiver uses stored seed location information from previous operations, then the acquisition process is accelerated, but the initial search may fail when the seed location is no longer accurate
Solution Approach 1:
The patent obtains fresh coarse location information from external sources immediately before the SPS acquisition process, rather than relying on stored seed location information from previous operations. This preliminary update ensures the location data is current and accurate for the present geographical context, maintaining both high acquisition speed and high initial search success rate
Solution Approach 2:
The patent implements feedback by continuously monitoring the receiver's movement and updating the coarse location information from external sources before each SPS acquisition attempt. This feedback mechanism ensures that the seed location information remains accurate even when the receiver has moved to a new geographical area, preventing initial search failures while maintaining fast acquisition
3Loss of time
If the SPS receiver relies on external sources for seed location information, then the initial positioning is accelerated, but the positioning may fail when external sources provide incorrect or outdated information
Solution Approach 1:
The patent uses coarse location information from external sources as an intermediary to initialize the SPS acquisition process, but the final accurate positioning is achieved through the SPS satellite signal calculations. The external source information serves only as a starting point to reduce search space, not as the final position source, thereby maintaining positioning reliability even when external information is incorrect
Solution Approach 2:
The patent applies partial action by using external source location information only for the initial coarse positioning and search window establishment, while the complete and accurate positioning is performed through the full SPS satellite signal processing. This partial use of external information accelerates initial positioning without compromising final positioning reliability
Data Source
AI summary
A position determining system (PDS) receiver gathers independent location information from multiple sources. These multiple pieces of location information are analyzed to determine consistency of location. If the location is consistent among the various independently gathered location information, then the location information is injected into the PDS positioning process for more efficient acquisition and positioning. Otherwise, if inconsistency is found, then no location information is injected into the PDS positioning process.