A highly robust communication system capable of stably realizing a three-dimensionalized network over a wide area can be provided, in which a propagation delay is low, a simultaneous connection with a large number of terminals in a wide-range area and a high-speed communication can be performed, and a system capacity per unit area is large, in radio communications with terminal apparatuses including devices for the IoT, in mobile communications of the fifth generation or the like. The communication system comprises a plurality of radio relay for relaying a radio communication between a terrestrial base station and a terminal apparatus. The plurality of radio relay stations include a plurality of first radio relay stations capable of communicating with each other, each first radio relay station being provided in a floating object controlled to be located in a floating airspace with an altitude less than or equal to 100 [km] by an autonomous control or an external control, and a second radio relay station for relaying a communication between the plurality of first radio relay stations and the terrestrial base station, the second radio relay station being provided in a floating object moored on the ground or the sea so as to be located in a floating airspace with an altitude less than or equal to 100 [km].

In one aspect, an example system includes: (i) a base including a bottom surface and a first coupling-point; (ii) a vertically-oriented elongate structure comprising a lower end, an upper end, and an inner channel, wherein the inner channel comprises an upper access-point disposed proximate the upper end, wherein the base is coupled to the elongate structure proximate the lower end; (iii) a deployable cushioning-device coupled to the elongate structure; and (iv) a tether comprising a first portion, a second portion, a third portion, and a fourth portion, wherein the first portion is coupled to the first coupling-point, the second portion is coupled to a second coupling-point of the UAV, the third portion extends through the inner channel, the fourth portion extends from the upper access-point to the second coupling-point, and the fourth portion has a length that is less than a distance between the upper access-point and the bottom surface.

In one aspect, an example system includes: (i) a base including a bottom surface and a first coupling-point; (ii) a vertically-oriented elongate structure comprising a lower end, an upper end, and an inner channel, wherein the inner channel comprises an upper access-point disposed proximate the upper end, wherein the base is coupled to the elongate structure proximate the lower end; (iii) a deployable cushioning-device coupled to the elongate structure; and (iv) a tether comprising a first portion, a second portion, a third portion, and a fourth portion, wherein the first portion is coupled to the first coupling-point, the second portion is coupled to a second coupling-point of the UAV, the third portion extends through the inner channel, the fourth portion extends from the upper access-point to the second coupling-point, and the fourth portion has a length that is less than a distance between the upper access-point and the bottom surface.

The invention relates to a method for landing a tethered aircraft (90), comprising the steps of approaching a ground site with said aircraft, thereby shortening free length of tether (92) between the aircraft and the ground site until said free length of tether reaches a predetermined value, further approaching the ground site with said aircraft, thereby keeping free length of tether fixed at said predetermined value, retaining the tether to form a loop, wherein the loop is tensed and tightened by the moving aircraft, and damping said tightening of said loop in order to decelerate the aircraft until it stands at the ground site. The invention further relates to a launch and land system (1) for a tethered aircraft comprising a runway (12) for the aircraft, a winch (62) for the tether, and a retention system (42,46) for forming a loop of the tether between the winch and the aircraft approaching the runway, wherein said retention system features a damping device (41) for damping a tightening of said loop caused due to movement of the aircraft upon approach and landing in order to decelerate said aircraft.

The invention relates to a method for landing a tethered aircraft (90), comprising the steps of approaching a ground site with said aircraft, thereby shortening free length of tether (92) between the aircraft and the ground site until said free length of tether reaches a predetermined value, further approaching the ground site with said aircraft, thereby keeping free length of tether fixed at said predetermined value, retaining the tether to form a loop, wherein the loop is tensed and tightened by the moving aircraft, and damping said tightening of said loop in order to decelerate the aircraft until it stands at the ground site. The invention further relates to a launch and land system (1) for a tethered aircraft comprising a runway (12) for the aircraft, a winch (62) for the tether, and a retention system (42,46) for forming a loop of the tether between the winch and the aircraft approaching the runway, wherein said retention system features a damping device (41) for damping a tightening of said loop caused due to movement of the aircraft upon approach and landing in order to decelerate said aircraft.

A kite launch device that includes a kite, a mast, a guide device coupled to the mast, and a winch. The kite includes a canopy, a base structure for at least one device, a plurality of support lines coupled to the canopy and the base structure, a guide line coupled to the canopy, and a tether coupled to the base structure. The guide device is configured to grab the guide line. The winch is coupled to the tether of the kite. The winch is configured to extend and retract the tether. The kite includes a guide element coupled to the base structure and the guide line. The guide device is configured to encircle the guide element in order to grab the guide line.

A kite launch device that includes a kite, a mast, a guide device coupled to the mast, and a winch. The kite includes a canopy, a base structure for at least one device, a plurality of support lines coupled to the canopy and the base structure, a guide line coupled to the canopy, and a tether coupled to the base structure. The guide device is configured to grab the guide line. The winch is coupled to the tether of the kite. The winch is configured to extend and retract the tether. The kite includes a guide element coupled to the base structure and the guide line. The guide device is configured to encircle the guide element in order to grab the guide line.

Offshore airborne wind turbine systems with an aerial vehicle connected to an undersea anchor via a tether are disclosed. A floating landing platform may be coupled to the tether and be dragged along the surface of the water along with the tether. The landing platform may be designed such that the tether can freely pass through the platform, allowing the aerial vehicle to ascend, descend, move laterally, and in crosswind flight, without creating a significant tension load on landing platform. The landing platform may also include a tether drive mechanism that can actively move the tether through the platform, thus changing the platform's location along the length of the tether.

The present disclosure relates to an anchoring platform for captive aircraft that addresses one of the main problems when handling captive aerostats, which is the excessive workload required to switch between flying and anchored states. The technology disclosed herein requires only one person to install the structure and the operation can be performed remotely or by a person. Additionally, cords, together with the confluence point, are wound into the anchoring device, the winch. The structure for anchoring the captive aircraft is the cradle which bears the aerostat, while the winch exerts tension to hold same static in the structure.

The present disclosure relates to an anchoring platform for captive aircraft that addresses one of the main problems when handling captive aerostats, which is the excessive workload required to switch between flying and anchored states. The technology disclosed herein requires only one person to install the structure and the operation can be performed remotely or by a person. Additionally, cords, together with the confluence point, are wound into the anchoring device, the winch. The structure for anchoring the captive aircraft is the cradle which bears the aerostat, while the winch exerts tension to hold same static in the structure.