Satellite Acquisition Guard Time Reduction via Single Terminal Ranging
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Solution Overview
Problem
Existing satellite communication systems face challenges in determining accurate acquisition guard times, leading to large guard times, especially for satellites with high orbit inclination, which can result in inefficient network synchronization and increased latency.
Innovation Solution
The implementation of single terminal ranging and triangulation methods to determine satellite positions and acquisition control parameters within the satellite communication network, allowing for the reduction of acquisition guard times by selecting a ranging terminal based on orbit inclination and adjusting acquisition control parameters for other terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large acquisition guard time is allocated based on worst-case satellite motion parameters, then transmission overlap is avoided, but network synchronization efficiency deteriorates and latency increases
Solution Approach 1:
The patent changes the parameter for determining acquisition guard time from fixed worst-case satellite motion parameters to dynamic ranging measurements. By measuring the actual time difference of arrival of synchronization signals from the satellite at different terminals, the system obtains real-time range information that reflects actual satellite position, replacing the conservative fixed-parameter approach with adaptive parameter adjustment based on measured values.
Solution Approach 2:
The patent implements a feedback mechanism where terminals measure the time difference of arrival of satellite signals and report ranging information back to the network. The network controller uses this feedback to calculate accurate acquisition guard times for each terminal based on its actual distance from the satellite, continuously adapting to satellite motion without requiring large fixed guard times.
2Measurement precision
If external TTC stations and SOCs are used to determine satellite position accurately, then acquisition guard time can be reduced, but system complexity and cost increase
Solution Approach 1:
The patent enables the satellite communication network to determine its own satellite position using internal terminals as ranging references. Instead of relying on external TTC stations and SOCs, the system uses signals already transmitted by the satellite and received by terminals to calculate range differences. This self-service approach eliminates the need for complex external infrastructure while achieving accurate satellite position determination.
Solution Approach 2:
The patent makes the satellite signals serve multiple functions: both communication data transmission and ranging measurement. The same satellite signals used for normal communication operations are also utilized for determining satellite position and calculating acquisition guard times, eliminating the need for separate dedicated ranging infrastructure and reducing overall system complexity.
3Ease of manufacture
If acquisition control parameters are computed for each terminal based on nominal satellite position, then computation is simplified, but accuracy deteriorates leading to larger guard times
Solution Approach 1:
The patent performs preliminary ranging measurements by having terminals measure the time difference of arrival of satellite synchronization signals before actual data transmission begins. These preliminary measurements provide accurate range information that is used to compute precise acquisition control parameters for each terminal, ensuring both accuracy and computational efficiency without requiring complex real-time calculations during operation.
Data Source
AI summary
Embodiments provide systems, devices, and methods for determining acquisition guard times and acquisition control parameters or distance metrics for terminals in a satellite communication network using triangulation and single terminal ranging. A terminal or multiple terminals from the network may be selected as ranging terminals; the terminals may include normal user terminals used for determining a satellite position or a satellite distance. Ranging terminals may first enter a network and synchronize to TDMA frame timing by adjusting the acquisition control parameters. An adjusted acquisition control parameter may also be called a transmit timing control parameter. A satellite position or a distance difference between a real-time and a nominal satellite position may be estimated from timing control parameters. Information about the satellite position and/or the distance difference in satellite position may then be used to reduce acquisition guard times for other terminals using various techniques to compute acquisition control parameters.