In , Watson-Watt hoped to go to work for the War Office, but no suitable position in communications was available there, so he joined the Meteorological Office.
He was put to work developing systems for detecting thunderstorms. Lightning ionizes the air and generates a radio signal, which Watson-Watt could detect to map the positions of thunderstorms.
The Air Ministry had already offered pounds to anyone who could demonstrate a ray that could kill a sheep yards away. In February Watson-Watt demonstrated to an Air Ministry committee the first practical radio system for detecting aircraft. The Air Ministry was impressed, and in April Watson-Watt received a patent for the system and funding for further development.
Soon Watson-Watt was using pulsed radio waves to detect airplanes up to 80 miles away. These stations, known as Chain Home, successfully alerted the Royal Air Force to approaching enemy bombers, and helped defend Britain against the German Luftwaffe in the Battle of Britain. The Chain Home system worked fairly well, but it required huge antennas, and used long wavelengths that limited ability to pinpoint enemy aircraft accurately.
During the day, fighter pilots could see enemy bombers. But soon the Germans began nighttime bombing missions, so to help fighter pilots locate enemy aircraft at night, the British needed a shorter wavelength radar system that was compact enough to install in planes.
This became possible when British engineers Harry Boot and John Randall invented the cavity magnetron in early The magnetron generated about hundred watts of power at wavelengths about 10 centimeters, enough to produce echoes from airplanes many miles away.
The MIT Radiation Laboratory, was set up and quickly became one of the largest wartime projects, employing about people. Radar detectors and CB radio sales skyrocketed.
The high demand brought many new players to the game. K40 Electronics came into the game with a game-changing CB Antenna in and introduced its first radar detector in This dash-mounted unit detected both X and K-band police radar and weighed almost 3 lbs!
In , the FCC allocated the spectrum from Today, X-band police radar enforcement is almost non-existent. But the biggest source by far is the vast amounts of vehicles on the road with radar-based safety features such as Collision Avoidance, Blind Side Assist, and Lane Departure Warning. Today, there are only a handful of manufacturers left in the game. K40 has been a trailblazer in this industry with many firsts such as The first Ticket-Free Guarantee in The first custom-installed remote radar detector.
This was the first radar detector system that hid most of the components, except for an externally mounted control head. Individuals who complete the course program can earn up to 0. Institutions interested in the program can contact an IEEE account specialist to learn more. To learn more about how digital transformation can impact your company, register for The Benefits of Digital Transformation for Organizations , a free virtual event to be held on 16 November at noon New York time.
The session will be available on demand two hours after the live event concludes. It turns out that you don't need a lot of hardware to make a flying robot. Flying robots are usually way, way, way over-engineered, with ridiculously over the top components like two whole wings or an obviously ludicrous four separate motors.
Maybe that kind of stuff works for people with more funding than they know what to do with, but for anyone trying to keep to a reasonable budget, all it actually takes to make a flying robot is one single airfoil plus an attached fixed-pitch propeller. And if you make that airfoil flexible, you can even fold the entire thing up into a sort of flying robotic swiss roll.
This type of drone is called a monocopter, and the design is very generally based on samara seeds, which are those single-wing seed pods that spin down from maple trees. The ability to spin slows the seeds' descent to the ground, allowing them to spread farther from the tree.
It's an inherently stable design, meaning that it'll spin all by itself and do so in a stable and predictable way, which is a nice feature for a drone to have—if everything completely dies, it'll just spin itself gently down to a landing by default.
F-SAM stands for Foldable Single Actuator Monocopter, and as you might expect, it's a monocopter that can fold up and uses just one single actuator for control. There may not be a lot going on here hardware-wise, but that's part of the charm of this design. The one actuator gives complete directional control: increasing the throttle increases the RPM of the aircraft, causing it to gain altitude, which is pretty straightforward.
Directional control is trickier, but not much trickier, requiring repetitive pulsing of the motor at a point during the aircraft's spin when it's pointed in the direction you want it to go. F-SAM is operating in a motion-capture environment in the video to explore its potential for precision autonomy, but it's not restricted to that environment, and doesn't require external sensing for control. While F-SAM's control board was custom designed and the wing requires some fabrication, the rest of the parts are cheap and off the shelf.
If you look closely, you'll also see a teeny little carbon fiber leg of sorts that keeps the prop up above the ground, enabling the ground takeoff behavior without contacting the ground. You can find the entire F-SAM paper open access here , but we also asked the authors a couple of extra questions. IEEE Spectrum: It looks like you explored different materials and combinations of materials for the flexible wing structure.
Why did you end up with this mix of balsa wood and plastic? Shane Kyi Hla Win: The wing structure of a monocopter requires rigidity in order to be controllable in flight. Although it is possible for the monocopter to fly with more flexible materials we tested, such as flexible plastic or polymide flex, they allow the wing to twist freely mid-flight making cyclic control effort from the motor less effective.
The balsa laminated with plastic provides enough rigidity for an effective control, while allowing folding in a pre-determined triangular fold. Can F-SAM fly outdoors? What is required to fly it outside of a motion capture environment? Yes it can fly outdoors. It is passively stable so it does not require a closed-loop control for its flight.
The motion capture environment provides its absolute position for station-holding and waypoint flights when indoors. For outdoor flight, an electronic compass provides the relative heading for the basic cyclic control. We are working on a prototype with an integrated GPS for outdoor autonomous flights.
A camera can be added we have done this before , but due to its spinning nature, images captured can come out blurry. A conventional LiDAR system requires a dedicated actuator to create a spinning motion.
Your paper says that "in the future, we may look into possible launching of F-SAM directly from the container, without the need for human intervention. Currently, F-SAM can be folded into a compact form and stored inside a container. However, it still requires a human to unfold it and either hand-launch it or put it on the floor to fly off. In the future, we envision that F-SAM is put inside a container which has the mechanism such as pressured gas to catapult the folded unit into the air, which can begin unfolding immediately due to elastic materials used.
The motor can initiate the spin which allows the wing to straighten out due to centrifugal forces. F-SAM could be a good toy but it may not be a good alternative to quadcopters if the objective is conventional aerial photography or videography. However, it can be a good contender for single-use GPS-guided reconnaissance missions. As it uses only one actuator for its flight, it can be made relatively cheaply.
It is also very silent during its flight and easily camouflaged once landed. Various lightweight sensors can be integrated onto the platform for different types of missions, such as climate monitoring.
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