Dynamic EIRP Spectral Density Control for Aeronautical Satellite Links
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Solution Overview
Problem
Aeronautical satellite broadband communication systems face challenges in maintaining regulatory compliance with EIRP spectral density limits while minimizing satellite bandwidth waste and ensuring consistent service across varying aircraft positions and orientations, leading to high operational costs.
Innovation Solution
An adaptive single channel per carrier link system with dynamic EIRP spectral density control, utilizing an antenna controller connected to an inertial navigation system to adjust transmit gain patterns and carrier bandwidth in real-time, ensuring compliance with regulatory limits and optimizing satellite coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the beam width is increased to improve coverage area, then the satellite coverage is enhanced, but the interference with adjacent satellites increases
Solution Approach 1:
The patent applies dynamic EIRP spectral density control that continuously adjusts transmission parameters based on real-time aircraft position, orientation, and antenna skew angle. This dynamic adjustment allows the system to expand coverage when conditions permit while automatically reducing power spectral density when skew angles approach limits that would cause adjacent satellite interference, thus resolving the contradiction between coverage area and interference prevention
Solution Approach 2:
The system changes the EIRP spectral density parameter dynamically based on operating conditions including skew angle, elevation angle, and aircraft maneuvers. By modifying this key parameter in response to changing conditions, the system can maintain adequate coverage while preventing harmful interference to adjacent satellites when the antenna beam width would otherwise cause such interference
2Object-generated harmful factors
If the EIRP spectral density is reduced to comply with regulatory limits, then adjacent satellite interference is prevented, but the satellite bandwidth efficiency decreases
Solution Approach 1:
The patent implements dynamic adjustment of EIRP spectral density that adapts to real-time operating conditions. When the aircraft is in stable position with favorable skew and elevation angles, the system operates at higher power spectral density for efficient bandwidth utilization. When maneuvers cause skew angles to approach regulatory limits, the system dynamically reduces EIRP spectral density to maintain compliance, thus optimizing bandwidth efficiency while preventing interference
Solution Approach 2:
The system periodically reassesses operating conditions including aircraft position, antenna orientation, and skew angle, and adjusts EIRP spectral density accordingly. This periodic control ensures that the system operates at maximum efficiency during favorable conditions while maintaining regulatory compliance during maneuvers, resolving the contradiction between bandwidth efficiency and interference prevention
3Duration of action of stationary object
If the antenna skew angle is increased to maintain coverage during aircraft maneuvers, then service continuity is improved, but regulatory compliance deteriorates
Solution Approach 1:
The patent employs dynamic EIRP spectral density control that responds in real-time to changes in antenna skew angle during aircraft maneuvers. When skew angles increase during maneuvers, the system dynamically adjusts the EIRP spectral density to maintain compliance with regulatory limits while preserving service continuity. This dynamic control allows the system to operate successfully during maneuvers that would otherwise violate fixed skew angle constraints
4Object-generated harmful factors
If a fixed EIRP limit is applied to ensure regulatory compliance, then adjacent satellite interference is prevented, but the operational flexibility and service consistency decrease
Solution Approach 1:
The patent replaces fixed EIRP limits with dynamic control that continuously adapts to changing operating conditions including aircraft position, orientation, antenna gain pattern, and skew angle. This dynamic approach maintains regulatory compliance by preventing adjacent satellite interference while simultaneously improving service consistency across varying flight conditions, as the system optimizes parameters for each specific operating state rather than adhering to conservative fixed limits
Data Source
AI summary
An aeronautical satellite broadband communications system has an antenna defined by a transmit gain pattern varying according to an orientation relative to a geostationary orbit satellite. An antenna controller unit is connected to an aircraft inertial navigation system and receptive to navigation data therefrom, and a set of antenna orientation data is derived from the navigation data on a real-time basis. A broadband controller connected to the antenna controller unit generates a set of output variables as a function of normalized equivalent isotropic radiated power spectral density values of the antenna and the set of antenna orientation data. The set of output variables controls the output power and carrier bandwidth of transmissions from the antenna within predefined limits of equivalent isotropic radiated power spectral density that vary with values of the set of antenna orientation data.