Dual-Element SATCOM Antenna Switching for Stable CDMA Links
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Solution Overview
Problem
Existing dual element SATCOM antennas require pilot intervention for real-time antenna element selection, leading to unoptimized gain at medium elevation angles and link failures due to out-of-service events, especially with CDMA waveforms, and replacing them with phased arrays is cost-prohibitive.
Innovation Solution
A UHF diversity combiner processes both antenna elements simultaneously, applying phase adjustments and signal weighting based on satellite view vectors, and a LNA diplexer assembly switches CDMA receive communications between SDRs, eliminating pilot interaction and enhancing antenna gain without requiring phased arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pilot selects antenna element based on operating location, then satellite communication can be established, but operator interaction is required and response time is delayed
Solution Approach 1:
The system performs self-service by automatically selecting the appropriate antenna element based on satellite elevation angle calculations. The processor computes the elevation angle using satellite orbital parameters and aircraft position data, then autonomously switches between high-angle and low-angle antenna elements without requiring pilot intervention or manual input.
Solution Approach 2:
The system implements feedback by continuously monitoring satellite orbital location and aircraft position to calculate real-time elevation angles. This feedback loop enables the automated antenna selection system to adapt dynamically to changing geometric relationships between the aircraft and satellite, ensuring optimal antenna element selection at all times.
2Reliability
If high angle antenna element is used for zenith satellite views, then zenith coverage is provided, but gain is unoptimized at medium elevation angles between 30 to 50 degrees
Solution Approach 1:
The system applies dynamics by dynamically switching between high-angle and low-angle antenna elements based on real-time elevation angle calculations. The processor continuously monitors the satellite-aircraft geometry and automatically selects the antenna element with optimal gain characteristics for the current elevation angle, ensuring maximum power efficiency across all operating conditions including medium elevation angles.
Solution Approach 2:
The system utilizes parameter changes by transitioning between different antenna elements with distinct radiation patterns. The high-angle element is optimized for zenith directions while the low-angle element provides superior gain at medium elevation angles (30-50 degrees). The automated switching system changes the active antenna parameter based on calculated elevation angles, maintaining optimal gain performance across the full range of satellite positions.
3Adaptability or versatility
If dual element antenna system is used, then satellite communication capability is provided, but link failures occur due to unoptimized gain relationships for CDMA waveforms
Solution Approach 1:
The system replaces manual mechanical selection with automated electronic control. Instead of relying on pilots to manually select antenna elements based on estimated satellite positions, the system uses a processor to automatically calculate elevation angles from satellite orbital parameters and aircraft position data, then electronically switches between antenna elements. This substitution eliminates human error and ensures consistent, optimal antenna selection for CDMA waveform reliability.
Solution Approach 2:
The system performs preliminary action by pre-calculating the optimal antenna element selection based on satellite orbital parameters and aircraft position. The automated system determines the appropriate antenna element before communication issues arise, preventing link failures rather than reacting to them. This proactive approach ensures that the correct antenna element is selected in advance to maintain optimal gain relationships for CDMA waveforms.
Data Source
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AI summary
A platform is provided which removes the need for the pilot to select between high angle and low angle antenna elements. By the automatic selection, the platform may improve BLOS connectivity during various phases of flight, such as during banking operations. The platform includes a SATCOM antenna (204) including first and second elements. The platform also includes one or more SDRs (202a, 202b) which provide receive and transmit functions for the BLOS waveform. The platform may also include either a UHF diversity combiner (208) or an LNA diplexer assembly (502). Thus, two methods are described for reducing out-of-service events for CDMA and legacy Narrowband UHF SATCOM.