Navigation Data Structure for Satellite Receiver TTFF Reduction

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Solution Overview

Problem

Conventional satellite navigation systems face delays in acquiring navigation data, particularly ephemeris and almanac data, which prolong the time to first fix (TTFF) due to inefficient data transmission structures and redundant information transmission, leading to increased deployment costs and complexity.

Innovation Solution

A navigation data structure comprising four sub-frames is configured to reduce data collection time by selectively transmitting essential ephemeris and almanac data, eliminating redundant information and using cyclic redundancy checks for integrity validation, allowing simultaneous transmission of distinct almanac data from multiple satellites.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If conventional navigation data transmission structures are used with redundant information, then data completeness is maintained, but data collection time increases and TTFF is prolonged

Engineering Contradiction:

ImproveTTFFVSAvoidnavigation data completeness

Core Design Contradiction:

Loss of timeVSLoss of information

Solution Approach 1:

The patent extracts and transmits only the essential navigation parameters needed for position calculation, separating critical ephemeris data and almanac data from redundant information. The receiver is equipped with algorithms to compute full navigation solutions from these condensed data sets, achieving fast TTFF without sacrificing data completeness.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The navigation data is segmented into priority-based groups: critical ephemeris parameters transmitted first, followed by almanac data, and then supplementary information. This segmentation allows the receiver to achieve initial position fix using only the most essential data while maintaining the option to acquire additional information for enhanced accuracy.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If comprehensive navigation data is transmitted to ensure accuracy, then positioning precision is maintained, but transmission time and data volume increase

Engineering Contradiction:

Improvepositioning accuracyVSAvoiddata transmission time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system transmits a partial but sufficient set of navigation parameters that enables the receiver to compute accurate position solutions. The transmitted data includes critical ephemeris elements and almanac information necessary for positioning, while omitting redundant or less critical data, achieving the principle of transmitting just enough information for the required accuracy level.

Inventive Principle:

Principle #16Partial or excessive action

3Adaptability or versatility

If traditional five-subframe GPS structure is used, then backward compatibility is maintained, but almanac data collection time is excessive (up to 25 minutes)

Engineering Contradiction:

ImprovecompatibilityVSAvoidalmanac data collection time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent implements a dynamic data transmission structure where the subframe configuration adapts based on the type of navigation data being transmitted. Almanac data is assigned to specific subframes (3 and 4) with optimized formatting, allowing the receiver to acquire complete almanac information much faster than traditional GPS structures while maintaining compatibility through standardized data elements.

Inventive Principle:

Principle #15Dynamics

4Stability of the object's composition

If all satellites transmit identical almanac data, then data consistency is ensured, but the receiver must collect data from multiple satellites over extended periods

Engineering Contradiction:

Improvedata consistencyVSAvoiddata collection efficiency

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

Each satellite transmits almanac data with local characteristics specific to its orbital position and coverage area, rather than identical copies. This allows the receiver to efficiently collect comprehensive almanac information from a single visible satellite or combine data from multiple satellites more quickly, improving data collection productivity while maintaining overall system consistency through standardized data formats.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9405009B2Navigation data structure generation and data transmission for optimal time to first fix

Publication Date: 2016.08.02 ACCORD IDEATION PRIVATE LIMITED

AI summary

A method and system for transmitting navigation data to a satellite navigation receiver for reducing time to first fix is provided. A signal generation system generates a navigation data structure comprising a first sub-frame and a second sub-frame for accommodating selective ephemeris data, a third sub-frame for accommodating first parameters of almanac data, and a fourth sub-frame for accommodating a text message comprising second parameters of almanac data, and transmits the selective ephemeris data and the first and second parameters of almanac data to the satellite navigation receiver. The configuration of the navigation data structure enables the satellite navigation receiver to collect the navigation data in reduced time. Each satellite of a constellation simultaneously transmits distinct first parameters of the almanac data in the third sub-frame of the navigation data structure to the satellite navigation receiver, thereby allowing the satellite navigation receiver to receive collective almanac data in reduced time.