Conducting Aerial Surveillance With an RC Blimp

July 18, 2017

Base Station for an Aerial Surveillance Blimp

Blimps outperform alternative aircraft types in only a small set of areas. In particular, blimps can easily be optimized for lift capacity and endurance, but they will forever be constrained by slow speed. In the context of video surveillance then, the pros are optimal and the cons are inconsequential. Airship capabilities can most easily be understood by considering the iconic Goodyear Blimp: they advertise, and they’re notorious for broadcasting aerial video for sporting events. For now, we can ignore the advertising use cases.

Aerial surveillance has also long been a concern for military operations, and modern forward operating bases make use of aerostats, or tethered blimps, to easily deploy a heavy camera system that can take a vantage point hundreds of feet in the air.

The Goodyear Blimp carries with it a full crew and a hefty camera setup. Military aerostats carry components weighing hundreds of pounds. A more typical set of requirements for high altitude video surveillance system needs only a few pounds of materials, and therefore an RC Blimp or an aerostat to serve those needs can easily be delivered at a cost that’s dramatically cheaper than more permnanet infrastructure.

Video Components

Clients interested in video surveillance that have purchased systems from EBlimp typically have requirements that are composed of one or more of:

  • A 2-axis camera gimbal to control the pitch and yaw of the look point; our dirigibles have a low center of gravity and therefore naturally roll to a neutral position.
  • Remote video reception for real-time viewing
  • Remote zoom capabilties

Our Solutions

Camera gimbals are custom made and are optimized for stability and weight. Lighter sizes reduce the required buoyancy to provide sufficient lift, which in turn reduces the overall size of the final product. This in turn reduces operating costs incurred by helium consumption. Our camera gimbals are built from scratch using carbon fiber. Gyroscopes combined with gear boxes allow the entire setup to move and bounce while the camera look point remains stable. Coupled with an inherently stable video platform, we’re able to provide a smooth and reliable setup to allow a camera to record uninterrupted and continuous video.

Video broadcasting is also a fairly common requirement among our deliverables. In general, range requirements increase the cost of the entire setup. Standard video transmitters with an analog signal provide a straightforward method to abstractly take the RCA output of a camera and in transfer the video feed to an RCA input on the ground. Signal attenuation and interference from the environment can degrade the video quality. A more expensive but higher quality setup involves transmitting an HDMI signal. The video feed itself will inherently be capable of a higher resolution, and since the data is encoded into a digital format, degraded video quality is not possible. Instead, the signal will either be present or gone. Data at its lowest level is represented as a series of on or off bits, and therefore signal interference or any alteration in the amplitude of a data feed will not affect the underlying binary value of each bit. A clean set of data encoded onto radio waves is interpretted exactly the same as identical data encoded onto radio with fluctuations in overall amplitude for the high bits.

Camera Systems sometimes offer application programmer interfaces that allow an embedded device to programatically zoom in or out with a camera. Our solution is much simpler and therefore much cheaper with less maintenance. Our systems typically use a servo that physically manipulates the camera’s zoom control, and the servo itself is embedded into our radio transmitters the end client controls.

Tethered Video Systems

An example of a tethered video system is viewable below:

In most cases, it makes far more sense to provide aerial surveillance with a tethered balloon. Flight time can be indefinite since the aerostat is powered from its base, and the maximum altitude that can be reached by an aerostat is a function of its size.

Higher altitude tethered ballons require a longer tether which proportionally increase the overall resistance of the wire and the weight of the entire setup. Making the weight lighter will increase the resistance, and decreasing the resistance will increase the weight. Current is most efficiently pushed through high resistance wires by using a high voltage electrical signal, but there is a voltage ceiling at which electricity can be safely used. Therefore, the constraint that we eventually must succumb to is an increased weight from the wire, which then requires a larger aerostat with more lifting gas.

RC Blimp Surveillance

In cases where a video platform needs to be mobile, aerostats obviously become unfeasible. An example of a video system mounted on an RC Blimp is demonstrated below:

RC Blimps provide a few other advantages:

  • The overall setup is quiet and can therefore be useful when the surveillance should be stealthy.
  • If ground infrastructure is not possible, blimps can fly for 5 to 10 kilometers or higher if there’s an absolute need for it.
  • Completely mobile video systems.
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