Spacecraft Position Estimation Using Offset Recording Windows
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Solution Overview
Problem
Current satellite position estimation systems face challenges in efficiently determining the precise position of geostationary satellites due to the need for continuous, quasi-real-time data and the high load on communication links, especially when receiving stations are far apart, leading to increased data transmission and complexity in managing recording windows.
Innovation Solution
A system and method that utilize a plurality of receiving stations with offset and/or differently sized recording windows to reduce data transmission load, where the processing station correlates recorded signals to estimate the spacecraft position without requiring a common time reference or specific signal patterns from the satellite, using time difference of arrival (TDOA) to determine distance differences and calculate the spacecraft's position on hyperboloids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If recording windows are made uniform and synchronized across all receiving stations, then time reference consistency is improved, but data transmission load increases significantly
Solution Approach 1:
The system segments the recording window into multiple sub-windows or segments that are processed independently. Each receiving station divides its recording window into smaller time segments, and only transmits the necessary segments to the processing station. This segmentation reduces the overall data transmission load while maintaining position estimation accuracy through selective processing of relevant segments.
Solution Approach 2:
The system implements partial recording where receiving stations record only the necessary portion of the signal within the recording window based on predicted satellite position and velocity. Instead of transmitting complete recording windows from all stations, only partial data corresponding to the expected signal arrival time range is transmitted, significantly reducing data load while maintaining measurement precision.
2Measurement precision
If receiving stations are placed far apart to improve geometric distribution, then position estimation geometry is improved, but communication link load increases
Solution Approach 1:
The system extracts and processes only the essential information from the recorded signals at distributed receiving stations before transmission. Instead of transmitting raw recorded data from all stations, the system extracts key parameters such as time of arrival estimates or correlation results, reducing the communication link load while maintaining the geometric distribution benefits for position estimation accuracy.
3Measurement precision
If recording window size is increased to capture more signal data, then measurement accuracy is improved, but data processing complexity increases
Solution Approach 1:
The system performs preliminary processing of the recorded signal within the recording window at the receiving station before transmission. Correlation operations, time of arrival estimation, or other preprocessing steps are executed locally, reducing the complexity of data processing at the central processing station while maintaining measurement accuracy through early extraction of critical information.
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 significantly reduces the data load on communication links, enhances position estimation accuracy, and allows for efficient tracking of satellite positions, particularly suitable for geostationary satellites, by optimizing recording window sizes and offsets based on known distances and synchronization between receiving stations.
Implementation Method 1
The processing station is arranged to correlate the recorded signals to estimate, for each of at least one pair among the plurality of receiving stations, the distance difference between the spacecraft and each receiving station of the pair
Data Source
AI summary
A system for estimating a spacecraft (6) position is disclosed. It includes receiving stations (4) for receiving signals transmitted from the spacecraft (6) and a processing station (2) for receiving data from the receiving stations (4). Each receiving station (4) records, during a recording window (8), the signals transmitted from the spacecraft (6) and transmits, to the processing station (2), data representing the recorded signals during the recording window (8). The recording windows (8) associated with each of the receiving stations (4) are offset and/or of different size with respect to each other. The processing station (2) correlates the recorded signals to estimate the distance difference between the spacecraft (6) and each of a plurality of receiving stations and to estimate the spacecraft (6) position. A method, a receiving station (4), a processing station (2) and a computer program are also disclosed.