The Coast Guard and Border Patrol need overhead EO/IR surveillance of outdoor venues, VIP events, border crossings, seaports, airports, etc. that is both less costly and intrusive than helicopters, while providing around the clock coverage. Law enforcement and emergency response agencies need a low cost, responsive, and mobile equipment for wide area resilient and durable communications after a natural disaster, major accident, or terrorist act that degraded existing communications systems.
Aircraft or Unmanned Aerial Systems (UAS) are expensive and have limited endurance. Mobile towers are height limited and provided only short range coverage. The most efficient means of meeting both these requirement is a low cost, mobile aerostat system.
However, traditional aerostats are large, manpower intensive and cannot operate in adverse weather conditions. This has limited their use to a few fixed sites flying large aerostats. Carolina Unmanned Vehicles (CUV) has developed the Lightweight Aerostat System (LAS), a solution that removes these limitations, resulting in a small, mobile and very cost effective system.
The Lightweight Aerostat System (LAS) consists of a small specially designed tethered blimp, called a Helikite, mounted on a trailer Carrier. The LAS blimp can be flown at several hundred to thousand feet altitude to provide coverage 24 hours a day for a week or more without maintenance or downtime. Operating and maintenance cost is a fraction of the cost of using aircraft or UAS to lift the surveillance or relay payloads. It does not require the complicated flight clearances
needed for UAS operations in civil airspace.
LAS can elevate a communications relay payload up to 4000 feet, providing extended communication coverage out to 60 or more miles from its location, or a circle 120 miles in diameter. Surveillance versions at 500 feet can cover a radius of 15 to 20 miles, depending upon terrain, while minimizing blind spots caused by trees, hills and buildings.
LAS consists of several unique components that, taken together, comprise a system far smaller and more versatile than any comparable unit. The patented Helikite combines aspects of kites and blimps to operate in much higher winds than traditional aerostat designs, improving system utility and capability in adverse
weather. LAS is very mobile and cost-effective through use of unique designs to reduce the need for ground crews to handle the blimp during launch and recovery. It is carried by a single trailer and operated by a two person crew. A small truck can tow the complete system. Prototype military and civilian security systems with communications and camera payloads have been delivered.
The key to making LAS a very compact but versatile system is the Helikite. Developed and patented by Allsopp Helikites Ltd. of Great Britain, Helikites combine a kite and a balloon, employing the advantages of both without incurring their disadvantages. The Helikite employs small flexible fabric wings and keel attached to the body of a helium balloon, combining helium and wind lift to operate easily in high wind speeds and at a fraction of the cost and trouble of traditional lighter-than-air designs.
Why does this Helikite design make a difference? An ordinary blimp in zero wind floats straight up from its tether location, with the helium exerting an upward force and
the tether an equal downward force. However, the tether cannot exert a sideward force to counteract wind forces, so traditional blimp shaped aerostats are driven into the ground by only moderate wind. To counteract wind drag traditional aerostats increase the buoyancy significantly beyond that required to lift the payload However, greater buoyancy requires a significantly larger blimp, resulting in greater cost, difficulty in ground handling and additional personnel.
It is a limited solution in any event. Wind drag increases with the square of the wind speed, so very large forces can be created at medium winds. Helikites are lighter-than-air like a balloon but are not knocked down by the wind. In fact, the opposite occurs – wind actually forces a Helikite up! Wind forces on the wings and the airfoil shaped balloon generate a force that maintains both the blimp body and Helikite wings at an angle of attack that generates additional lift to counteract the wind side force.
The Helikite is also far more intrinsically stable than traditional blimp designs. With this force to counteract the wind drag the Helikite does not need a large buoyancy margin and we can design the LAS to use modern lightweight electronics. The LAS Helikites will be able to fly in winds up to 70 mph. Other aerostats must be considerably larger to withstand wind forces, typically with buoyant lift of 200 to 300 pounds just for wind stability. This prevents them from being designed to small payloads, and makes them large, clumsy and expensive. Helikite performance is the key that allows LAS to be very compact, use minimum helium and be operable by only two people.
LAS will provide a unique and cost effective overhead capability for many electronic payloads. The main usage categories are communications, law enforcement surveillance and security, and atmospheric research. LAS basic simplicity and the modular design allows it to be manufactured at relatively low cost with minimum capital investment.
Communications Payloads In natural or man-made disasters LAS can act as a relay platform for emergency voice communications, as a network bridge for interconnecting ground computers and networks, and as relay point for dissimilar communications systems. With the Helikite at even a few hundred feet altitude an entire county or more can be covered. LAS can act as a communications relay platform for emergency response and law enforcement units, and as an airborne communications relay, particularly in mountainous or urban terrain. A commercial version of LAS could substitute for a cellular phone tower to increase local capacity during major events such as golf tournaments, etc. This version could also be used to temporarily replace towers damaged by hurricanes, earthquakes or tornadoes, providing emergency management communications to FEMA or other agencies at a critical time.
Relay Platform for Emergency Voice Communications In this role, the LAS payload could relay voice communications over a wide coverage area. The LAS would act as a transponder, and convert voice communications between frequency bands. In this manner, emergency responders would have seamless communications with remote emergency management personnel at extended ranges, with no dependence on (potentially) inoperative wired, cellular or point-to-point communications links.
Network Bridge Access to computer communications and emergency networks is critical for responders and emergency management. LAS can act as a network bridge in-the-sky, providing seamless connection of computer and network resources. Ground networks or individual computers would communicate to the bridge using inexpensive wireless network interface cards, bi-directional amplifier and antenna. A dedicated frequency band could be employed to ensure non-interference with any other ground assets. Field users would have complete access, as authorized, to all required emergency computer networks, with encryption and authorization techniques as required.