Phased Array Antenna Pointing Control for Moving Satellite Links
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Solution Overview
Problem
Mechanically steered directional antennas on moving vehicles are bulky, require significant clearance, and are expensive due to precision rotation mechanisms, making them impractical for applications like satellite communication, especially when the satellite is also moving.
Innovation Solution
A phased array antenna system with a digital phase shifter array and a controller that adjusts the antenna's direction using a local search algorithm and inertial navigation, coupled with a Kalman filter to maintain alignment with a moving satellite by predicting and adjusting the pointing direction based on vehicle orientation and satellite movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanically steered directional antennas are used, then directional communication capability is achieved, but the system becomes bulky and requires significant clearance
Solution Approach 1:
The patent replaces the mechanical steering system with an electronic phased array system that uses digital phase shifters to control the direction of the antenna pattern. This eliminates the need for bulky mechanical components, precision rotation mechanisms, and servo motors, thereby reducing the overall volume and clearance requirements while maintaining directional communication capability.
Solution Approach 2:
The antenna system is divided into multiple antenna elements arranged in an array, with each element controlled by independent digital phase shifters. This segmentation allows electronic beam steering without mechanical movement, reducing the physical size and clearance needs of the system.
2Ease of operation
If mechanically steered directional antennas are used, then directional communication is enabled, but the system becomes expensive due to precision rotation mechanisms
Solution Approach 1:
The patent substitutes expensive mechanical precision rotation mechanisms, servo motors, and associated electronics with a digital phased array system. The digital phase shifters and signal processing electronics are significantly less expensive than precision mechanical steering components, thereby reducing the overall system cost while maintaining directional communication capability.
3Productivity
If high gain directional antennas are used, then link budget is improved and higher data rates are achieved, but the antenna must be precisely pointed which is difficult on moving vehicles
Solution Approach 1:
The patent implements a dynamic electronic beam steering system that can rapidly adjust the antenna pattern direction in real-time to track moving satellites. The digital phase shifters allow instantaneous repositioning of the beam without mechanical inertia or lag, making it feasible to maintain precise pointing accuracy on moving vehicles communicating with non-geosynchronous satellites.
Solution Approach 2:
The system incorporates feedback mechanisms including local search algorithms and inertial navigation data processed through a Kalman filter to continuously estimate and correct the antenna pointing direction. This feedback loop maintains accurate tracking of moving satellites despite vehicle movement, enabling sustained high data rate communications.
4Measurement precision
If mechanical steering systems are used, then directional control is achieved, but the system requires bulky components and extra clearance
Solution Approach 1:
The patent replaces the entire mechanical steering system with an electronic phased array configuration. By using digital phase shifters to control the phase and amplitude of signals at each antenna element, the system achieves precise electronic beam steering without any moving parts, thereby eliminating the volume and clearance requirements associated with mechanical components.
Data Source
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AI summary
Systems for maintain pointing of a phased array antenna in a direction maximizes to an extent possible the effective antenna gain is provided. The system includes a gyroscope and a Kalman Filter. The Kalman filter estimates an antenna pointing direction for each successive time step based on gyroscope readings and based on the results of a local search for maximum gain performed in the neighborhood of a previous antenna pointing direction.