Distributed Timing Calibration for Phased Array Radars
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Solution Overview
Problem
The distribution of timing signals in large-scale phased array Radars is challenging due to the need for precise knowledge of RF path delays, synchronization of sample clocks, and maintenance of centralized calibration systems, which are costly and sensitive to environmental factors, especially in undeveloped or ecologically diverse locations.
Innovation Solution
A method and system using bi-directional fibre optic SFPs and digital dual mixer time difference circuits to continuously monitor and adjust signal delays, creating a phase-stable fibre optic network that automatically accounts for temperature variations and fibre length differences, enabling distributed reference networks for phased array Radars.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If centralized distribution with stabilised equi-length coaxial cable or differential pair runs is used, then timing synchronization is achieved, but device complexity and maintenance difficulty increase for large-scale arrays
Solution Approach 1:
The patent replaces the mechanical/electrical centralized distribution system (coaxial cables, differential pairs, central calibration equipment) with an optical fiber-based distributed system. Each remote unit independently measures its own cable length and calculates timing offsets using light-time corrections, eliminating the need for complex centralized calibration infrastructure while achieving precise timing synchronization across large-scale arrays.
2Length of stationary object
If RF-over-Fibre is used for timing distribution, then signal transmission over long distances is improved, but sensitivity to environmental factors and maintenance requirements worsen
Solution Approach 1:
The patent implements self-service through automatic cable length measurement and timing offset calculation at each remote unit. The system autonomously compensates for environmental variations (temperature, cable expansion) by continuously measuring actual cable lengths and recalculating light-time corrections, eliminating the need for manual environmental control or sensitive equipment protection while maintaining long-distance transmission accuracy.
3Measurement precision
If centralized calibration distribution is used, then timing accuracy is maintained, but capital expense and installation requirements increase for new sites
Solution Approach 1:
The patent segments the centralized calibration function into distributed autonomous units. Each remote unit independently performs cable length measurement, timing offset calculation, and synchronization without requiring centralized calibration equipment or specialized installation procedures. This segmentation enables straightforward installation in diverse locations while maintaining timing accuracy through local autonomous operation.
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 solution simplifies calibration and timing distribution, reduces maintenance complexity, and allows cost-effective installations in diverse environments by maintaining phase stability and automatically compensating for signal delays, reducing the need for specific manufacturing and installation requirements.
Implementation Method 1
sending an optical timing pulse from the optical transmission point to each of the series of remote optical receiver points and back; determining a round trip time of the timing pulse
Implementation Method 2
optical conversion unit for receiving and converting the optical timing signals into corresponding electrical timing signals
Data Source
AI summary
A method of distance synchronization of a series of remote optical receiver points with an optical transmission point, the method including the steps of: (a) sending an optical timing pulse from the optical transmission point to each of the series of remote optical receiver points and back; (b) determining a round trip time of the timing pulse; and (c) storing an indicative measure of the roundtrip time of the timing pulse and utilising the indicative measure to adjust the timing of signals at the remote optical receiver points to determine the relative reception time of signals received by the series of remote optical receiver points.