Navigation Receiver Orbital Model Generation Without Broadcast Ephemeris
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Solution Overview
Problem
GPS receivers face challenges in determining their position accurately and quickly when they do not have access to current ephemeris data, especially due to power outages or weak signal conditions, leading to increased Time-To-First-Fix (TTFF) and reduced position estimation accuracy.
Innovation Solution
A navigation receiver system that generates satellite orbital models using a small set of parameters obtained from a server, including solar radiation pressure and initial condition parameters, allowing for numerical integration to predict satellite positions with low computational load and without the need for historical ephemeris, enabling accurate position calculation even without broadcast ephemeris.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complete ephemeris data is transmitted to the receiver, then position accuracy is improved, but communication resources and data transmission requirements increase significantly
Solution Approach 1:
The patent extracts only the essential initial condition parameters (position and velocity at a reference time) from the complete ephemeris data, eliminating the need to transmit the full ephemeris dataset. This extraction approach maintains sufficient position accuracy while dramatically reducing communication resource requirements.
Solution Approach 2:
Instead of transmitting the complete ephemeris data directly, the patent creates a simplified copy containing only the necessary initial conditions and force parameters. This reduced copy is then used by the receiver to generate satellite orbit predictions through numerical integration, achieving both data reduction and functional equivalence.
2Measurement precision
If historical ephemeris data is collected and stored, then position estimation accuracy is improved, but device complexity and data storage requirements increase
Solution Approach 1:
The patent extracts only the essential initial condition parameters (position and velocity at a reference time) from the complete ephemeris data, eliminating the need to store the full ephemeris dataset. This extraction approach maintains sufficient position accuracy while dramatically reducing storage requirements.
Solution Approach 2:
The receiver uses the received initial parameters and force models to autonomously generate satellite orbit predictions through numerical integration. This self-service approach eliminates the need to store and process historical ephemeris data, reducing device complexity while maintaining position estimation accuracy.
3Measurement precision
If numerical integration is performed with high precision, then satellite position prediction accuracy is improved, but computational load increases
Solution Approach 1:
The patent changes the parameters from complete ephemeris datasets to simplified initial condition parameters (position and velocity at reference time) plus force parameters. This parameter transformation enables high-accuracy position prediction through numerical integration while significantly reducing computational requirements compared to processing full ephemeris data.
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 approach reduces communication resources required for data transmission, enhances TTFF, and provides accurate receiver position calculations for several days without the need for current ephemeris, improving navigation efficiency and reliability.
Implementation Method 1
the receiver uses the set of parameters to compute an integration that predicts the satellite orbit
Implementation Method 2
the force parameter includes solar radiation pressure
Data Source
AI summary
Provided herein are methods and system for enabling a navigation receiver to generate receiver specific satellite orbital models based on relatively small sets of parameters obtained from a server. In an embodiment, a set of parameters for a satellite includes a force parameter (e.g., solar radiation pressure), initial condition parameters (e.g., satellite position and velocity at a time instance) and time correction coefficients, which the receiver uses in a numerical integration to predict the position of the satellite. The set of parameters needed for the integration is small compared to current methods which require transmission of a complete set of ephemeris and other parameters for each satellite. Since the set of parameters is relatively small, it requires less communication resources to transmit compared to current methods. Further, the integration based on the small set of parameters enables the receiver to predict satellite orbits with low computational load.