Optimized Teardrop Satellite Orbits for Signal Availability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional land mobile satellite systems use suboptimal orbits that result in lower elevation angles and reduced signal availability, leading to higher system costs and increased probability of signal blockages, especially in urban environments.
Innovation Solution
The implementation of a spacecraft constellation with teardrop or oval-shaped orbits, optimized using non-linear methods to achieve higher elevation angles and improved signal availability, featuring apogee longitudes between 90° and 100° west, semi-major axes of approximately 42,164 kilometers, and inclinations between 40° and 60°, which reduces system costs and enhances service quality by maintaining higher signal strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional HEO orbits with 63.4° inclination are used, then coverage of continental United States and Canada is provided, but elevation angles droop when spacecraft is near apogee due to high latitudes, reducing signal availability
Solution Approach 1:
The patent changes the orbital parameters from conventional 63.4° inclination HEO to optimized orbits with inclinations between 40°-60° and eccentricities between 0.16-0.40, with apogee positioned at 90°-100° west longitude. This parameter optimization eliminates the elevation droop effect while maintaining coverage, directly resolving the contradiction between signal availability and elevation angle stability.
2Reliability
If higher power and heavier satellites are used to overcome signal blockages, then service quality improves, but system cost increases substantially
Solution Approach 1:
By optimizing orbital parameters to maintain consistently high elevation angles, the patent reduces signal blockage probability without requiring increased satellite power or weight. This resolves the contradiction by achieving improved service quality through orbital geometry rather than increased system resources.
3Duration of action of stationary object
If conventional figure-eight ground track orbits are used, then 24-hour repeating coverage is achieved, but the pronounced loop over northern Canada reduces elevation angles to the coverage region
Solution Approach 1:
The patent modifies the ground track shape by optimizing orbital inclination and eccentricity parameters, transforming the conventional figure-eight pattern into a teardrop or oval shape. This maintains the 24-hour repeating coverage duration while eliminating the northern Canada loop that causes elevation angle reduction, thus resolving the contradiction between coverage period and elevation angle quality.
Data Source
AI summary
A constellation, including a plurality of spacecraft, including a first, second and third spacecraft, each of the plurality of spacecraft including a broadcast capability, and each of the plurality of spacecraft in its own approximately 24-hour orbit. Each of the orbits has a substantially teardrop-shaped or oval-shaped ground track, is optimized based upon elevation angle or probability of signal availability, and has an apogee longitude of approximately 90° west to approximately 100° west. Each of the orbits has a semi-major axis of approximately 42,164 kilometers, an argument of perigee of approximately 270°, an inclination of approximately 40° to approximately 60°, and an eccentricity of approximately 0.16 to approximately 0.4. The orbits of each of the plurality of spacecraft are selected to bring each of the spacecraft to apogee at time increments of approximately eight hours.