A Novel Method For Improving Aerostat Endurance Using Microprocessor Controlled Feedtube (Patent Applied)
Enhanced 24X7 surveillance has become a pre-dominant part of country’s strength and the same been realized using various platforms. Presently platforms such as satellites, Unmanned Aerial Vehicles(UAV), aircrafts, Lighter Than Air(LTA) vehicles are used widely to gain intelligence gathering and monitoring applications. Of all the above platforms the LTA vehicles are gaining much importance due to its inherent stability characteristics, loitering capabilities with minimum disturbance and 24X7 continuous monitoring capability. The aerostat vehicle is one of its kind in LTA widely used for surveillance and monitoring. The aerostat is a balloon filled with LTA gas(helium/hydrogen) to provide the lift and it is moored to the ground using an electromechanical cable called tether. The aerostat works on the principle of buoyancy and the lift is generated by helium/hydrogen gas lighter than air. One of the important aspects considered during design of LTA based surveillance system is its endurance. The endurance primarily de-pends on its gas leakage, impurities adding up to lift gas due to various phenomenon. The buoyancy/lift force produced is directly proportional to the purity of lift gas, volume of gas and aerostatic parameters based on environmental conditions. For a given altitude, considering the environmental perturbations as constant the buoyancy force or lift produced depends on the volume of gas present. The lifting gas leaks due to fabric porosity and joints present in the system. The gas need to be re-furbished periodically to regain the calculated buoyancy force. For re-filling the system needs to be lowered which is a major drawback. Also the surveillance gets interrupted during lower-ing. To overcome this drawback refilling of gas need to be online. Tethers can be broadly classified based on the applications with reference to its features supported. A simple-tether available worldwide supports strength, electrical and optical coupling feature. Recently researchers are working on a concept-tether where a feedtube is embedded to support online top of lift gas. The novel-tether presented in this paper is a novel design of feedtube tether which supports more features than simple-tether and concept-tethers. In this paper the conceptual design and architecture of noveltether, advantages and disadvantages, its interface with a microprocessor controlled valves and various operational modes are explained. A micro algorithm and flowchart depicting various mission scenarios and valve control is also discussed. By adopting the novel-tether technology the aerostat system endurance can be improved from weeks to months. This is discussed in detail in the sections below.