Patent Application
20110186687
The following disclosure relates generally to unmanned aerial vehicles and, more particularly, to embodiments of a self-powered, unmanned airborne platform or “gyrokite” suitable for supporting various types of electronic systems, such as aerial surveillance systems.
The ability to provide continuous and sustainable intelligence, surveillance, and reconnaissance (commonly abbreviated as “ISR”) is highly valuable in both military and civilian applications. For example, in overseas military operations, the ability to conduct covert aerial surveillance of a designated geographical area has become increasingly useful for monitoring the movement of enemy combatants and for identifying potential threats, such as improvised explosive devices. Similarly, in the context of homeland security, the ability to maintain a widespread and continuous surveillance presence may help detect, and thereby discourage, the unauthorized transport of people and contraband across international borderlines. In the civilian sector, the ability to rapidly establish widespread monitoring of a geographical area can be critical after a large scale disaster, such as a hurricane, earthquake, or other natural disaster, to help support disaster relief efforts; e.g., to identify those in need of medical attention and/or to help coordinate search and rescue teams.
In recent years, Unmanned Aerial Vehicles (“UAVs”) have been increasingly employed to provide aerial ISR in military and certain civilian contexts. When utilized as a component of an Unmanned Aircraft System, UAVs enable real-time aerial observation of a designated geographical area without requiring the physical presence of a pilot or other human observer. The usage of UAVs thus helps to preserve the safety of aircrew and other personnel in the instances wherein the observed area is unsafe due to, for example, a hostile presence or environmental dangers. Furthermore, due to their airborne nature, UAVs are often able to monitor geographical areas that may be difficult to access by ground. As a still further advantage, UAVs equipped with specialized cameras can provide visual surveillance from a considerable distance thereby rendering visual detection of the UAV from an observed subject or subjects highly unlikely.
Although providing the above-noted advantages, UAVs are limited in certain respects. For example, Unmanned Aerial Vehicles, and more generally Unmanned Aircraft Systems, can be relatively costly to implement and maintain. In addition, the flight duration of an UAV is typically limited due, in part, to a current lack of inflight refueling capabilities. As a result, a single UAV generally cannot maintain a continuous, twenty-four hour ISR presence over a designated geographical area. Although a fleet of UAVs can be employed to provide such a continuous ISR presence, the maintenance, fueling, and overall operational costs of such UAV fleet are considerable.
There thus exists an ongoing need to provide embodiments of an unmanned aerial vehicle or other airborne platform capable of maintaining continuous and sustainable surveillance presence over a designated geographical area without refueling requirements. Ideally, embodiments of such an unmanned aerial vehicle or platform would be relatively inexpensive and straightforward to implement. It would also be desirable for such unmanned aerial vehicle or platform to be scalable and capable of being equipped with various types of mission-specific electronic systems to enable the vehicle to be adapted for both civilian and military uses including, for example, international border monitoring. Other desirable features and characteristics of the present invention will become apparent from the subsequent Detailed Description and the appended Claims, taken in conjunction with the accompanying Drawings and this Background.
Embodiments of an unmanned gyrokite for use in conjunction with a tether are provided. In one embodiment, the unmanned gyrokite includes an airframe configured to be attached to the tether, an autogyro rotor assembly mounted to the airframe and configured to generate lift when deployed in winds aloft, and a generator mechanically coupled to the autogyro rotor assembly and configured to be driven thereby. An electronic system coupled to the airframe is configured to be powered by the generator.
At least one example of the present invention will hereinafter be described in conjunction with the following figures, wherein like numerals denote like elements, and:
The following Detailed Description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding Background or the following Detailed Description. The following describes exemplary embodiments of an unmanned airborne platform that includes, among other structural elements, an autogyro rotor assembly and a tethered airframe. For ease of reference, and to emphasize the unique combination of an autogyro rotor assembly and tethered airframe, embodiments of the unmanned airborne platform are referred to below as an “unmanned gyrokite” or, more simply, as a “gyrokite.” The term “gyrokite,” therefore, is intended in a broad sense to encompass any aircraft or airborne platform having an autogyro rotor assembly and an airframe adapted to be attached, either directly or indirectly, to a tether.
With reference to
Rotor hub 24 and rotor blades 26 are free to rotate with respect to vertical mast 28. In contrast to the majority of rotary wing aircraft, rotor hub 24 is unpowered; that is, the rotation of rotor hub 24 is not driven by gas turbine engine or other onboard engine, at least during normal flight of gyrokite 10 (this is not to preclude the possibility that gyrokite 10 can be equipped with an auxiliary rotor drive system for assisted take-off purposes). Instead, when deployed in winds aloft, rotor hub 24 and rotor blades 26 autorotate and generate upward thrust and rotor torque. As air flows over and around rotor blades 26, the rotational rate of rotor blades 26 and rotor hub 24 increases until an equilibrium is reached between thrust and drag forces. When such an equilibrium is reached, rotor blades 26 and rotor hub 24 rotate at a substantially constant rotational speed and generate sufficient lift to maintain gyrokite 10 airborne. Notably, rotor blades 26 can be optimized to generate a considerable amount of upward thrust even when gyrokite 10 is deployed in moving air masses having low to moderate wind speeds. Consequently, by minimizing the weight of gyrokite 10 in an unloaded state (e.g., by forming airframe 12 from lightweight alloy or composite material), gyrokite 10 can be provided with relatively high weight-to-payload ratio can be achieved.
Rotor blades 26 may be formed from various rigid and semi-rigid materials. For example, rotor blades 26 can be formed from non-rigid materials to enable blades 26 to be folded or bent without structural damage. In embodiments wherein gyrokite 10 is relatively small in scale, this enables gyrokite 10 to be stored in a relatively compact container, such as a tubular canister, for physical protection and ease of transport. At the desired time of deployment, gyrokite 10 can be removed from the transport container and rotor blades 26 may unfurl, extend, or expand into the fully deployed position shown in
As indicated in
Empennage 16 is fixedly coupled to the aft end portion of a tail boom 34 included within airframe 12. In the illustrated example, empennage 16 includes first and second horizontal stabilizers 38, a vertical stabilizer or fin 36, and a rudder 40, which is hingedly coupled to fin 36. During flight of gyrokite 10, the angular position of rudder 40 is adjusted by an actuator (not shown in
In the exemplary embodiment illustrated in
Generator 52 is mechanically coupled to autogyro rotor assembly 14 and is driven thereby during flight of gyrokite 10. Collectively, generator 52 and autogyro rotor assembly 14 function as a vertical axis wind turbine that supplies the electrical components of gyrokite 10 with an environmentally-friendly and virtually inexhaustible power source. As indicated in
Energy storage device 54 provides a convenient source of auxiliary power if the electrical output of generator 52 should be temporarily insufficient to meet the electrical load placed on gyrokite 10 by the electrical components installed within SWAP package bay 62. Energy storage device 54 conveniently assumes the form of one or more super-capacitors or batteries that can be recharged by generator 52. As generically indicated in
Wireless transceiver 58 may assume any form suitable for enabling bi-directional communication with controller 50 including, for example, a C-band line-of-sight data link or a Ku-band satellite data link. In embodiments wherein gyrokite 10 is not fully autonomous, wireless transceiver 58 may be configured to receive flight control instructions and other data from a Ground Control Station (“CGS”) or other external control source (as indicated in
Mission-specific electronic system 56 may include any number of electronic components, which may be selectively installed within SWAP package bay 62 based upon the desired mission capabilities of gyrokite 10. A non-exhaustive list of electronic components suitable for usage as or inclusion within mission-specific electronic system 56 includes various sensor suites, data transmission packages, telecommunication nodes, radar systems, direction finders, weapons systems, targeting systems, and the like. In many embodiments, such as when gyrokite 10 is utilized for international border monitoring or other surveillance functionalities, electronic system 56 will typically include at least one optical sensor, such as a daytime camera or an infrared or near-infrared camera for nighttime observation. When included within electronic system 56, the camera or cameras deployed aboard gyrokite 10 are conveniently nose- or belly-mounted. Alternatively or additionally, electronic system 56 may include one or more synthetic aperture radars capable of providing pseudo-photograph images in adverse weather conditions. When electronic system 56 includes multiple cameras, wireless transceiver 58 may be configured to simultaneously broadcast multiple real-time camera feeds to a CGS or other external control source, depending upon available bandwidth.
Mission-specific electronic system 56 may also include various other sensors in addition to, or in lieu of, the optical sensors set-forth above. For example, electronic system 56 may include one or more chemical sensors, such as a laser spectrometer for analyzing air samples and identifying airborne pathogens, toxic gases, and other biological weapons. When utilized for military applications, electronic system 56 may include a weapons system and/or a targeting system, such as a laser-designator module. Furthermore, whether utilized for military or civilian applications, electronic system 56 may include sensors for gathering weather data, such as various types of barometers, thermometers, hygrometer, and the like. Electronic system 56 may further include one or more sensors for monitoring operational parameters related to gyrokite 10, such as an altimeter, a gyroscope, an accelerometer, or the like. As a still further example, electronic system 56 may also include a multi-mode receiver having global navigational satellite system (e.g., Global Positioning System) capabilities.
In embodiment wherein gyrokite 10 is deployed over a geographical area lacking a working telecommunications infrastructure due to, for example, the occurrence of a hurricane, earthquake, or other natural disaster, gyrokite 10 may serve as an ad-hoc telecommunication node. In this case, mission-specific electronic system 56 may include or assume the form of a radio repeater, a cellular site, or other telecommunications relay. Similarly, in instances wherein gyrokite 10 is intended to be utilized for disaster relief, electronic system 56 may include an electronic beacon, such as a radio, infrared, or sonar beacon, to provide a reference point for the coordination of search and rescue teams or other on-the-ground personnel.
Gyrokite 10 can further be equipped with a scanning device that includes a rotor-mounted antenna or antennae 64 (generally referred to herein as “scanning device 64”). For example, as indicated in
In embodiments wherein gyrokite 10 may be fired upon or otherwise subject to attack, such as when gyrokite is utilized for monitoring an international borderline or hostile forces, gyrokite 10 may be configured to perform evasive movements on its tether in the event of attack. In addition, gyrokite 10 may be equipped with a tether release mechanism 66, which is operatively coupled to controller 50 and which is mechanically coupled between tether 42 and airframe 12. Should gyrokite 10 be threatened, controller 50 can actuate tether release mechanism 66 to disengage airframe 12 from tether 42 and thereby permit gyrokite 10 to glide away from the threat and to a nearby area of safety. Gyrokite 10 may also be equipped with various other defense mechanisms including, for example, various non-lethal immobilizing devices, such as blinding lights and/or sonic or ultrasonic sirens.
The foregoing has thus provided an exemplary embodiment of an unmanned gyrokite that serves as a self-powered airborne platform for various electronic systems. Advantageously, the production and maintenance costs associated with above-described exemplary gyrokite are low due, in part, to the gyrokite's ability to maintain a continuous airborne presence without requiring refueling. The above-described exemplary gyrokite is particularly well-suited for usage as an aerial surveillance platform to provide continuous monitoring of a designated geographical area, such as an international borderline. This notwithstanding, the exemplary gyrokite is highly scalable and can be equipped with various mission-specific modules to enable the gyrokite to perform a wide variety of civilian and military applications. Although the foregoing described the exemplary gyrokite as a single unit, it should be appreciated that an array of gyrokites can be deployed over a designated geographical area to optimize lift and power generation characteristics of the gyrokite fleet, as a whole. In such an array, the gyrokites may be coupled in series, in parallel, or both in series and in parallel by a multi-point tether system.
While at least one exemplary embodiment has been presented in the foregoing Detailed Description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing Detailed Description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set-forth in the appended Claims.
