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How does your Smartphone Know your Location?

Deguzman, 412th SFS, Security Forces Squadron, installation security technician. “This would allow us to cover more than 20 kilometers of terrain with a single piece of technology. Given the amount of manpower the squadron has as compared to the amount of terrain that needs to be covered. It would be extremely difficult for a patrol to effectively monitor the lakebed”.

The base poses several challenges to its security force: primarily the rugged terrain in the large area to cover. Edwards AFB is approximately three hundred and eight thousand acres. The driving need for this system is to proactively defending Edwards AFB. “We need a system that can overcome the difficulties of patrolling the vast amount of land, Edwards’s presence to our patrols”, the government said. According to Edwards, dot F dot mill, the Raptor system is one of the few current technologies that the squadron is exploring to enhance security. We are currently looking for commercial off-the-shelf smallunmanned aerial systems, vehicle and body cameras and a renovation to our current emergency command center. All of these proposed technologies will help with our security and overall command and control the 412th SFS leadership along with wing leadership will now decide whether the Raptor system should be fielded at Edwards.

How does your Smartphone Know your Location?

How does your smartphone know exactly where you are? The answer lies 12,000 miles over your head in an orbiting satellite that keeps time to the beat of an atomic clock powered by quantum mechanics. Phew. Let's break that down. First of all, why is it so important to know what time it is on a satellite when location is what we're concerned about? The first thing your phone needs to determine is how far it is from a satellite. Each satellite constantly broadcasts radio signals that travel from space to your phone at the speed of light. Your phone records the signal arrival time and uses it to calculate the distance to the satellite using the simple formula, distance = c x time, where c is the speed of light and time is how long the signal traveled. But there's a problem. Light is incredibly fast. If we were only able to calculate time to the nearest second, every location on Earth, and far beyond, would seem to be the same distance from the satellite. So in order to calculate that distance to within a few dozen feet, we need the best clock ever invented. Enter atomic clocks, some of which

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are so precise that they would not gain or lose a second even if they ran for the next 300 million years. Atomic clocks work because of quantum physics. All clocks must have a constant frequency. In other words, a clock must carry out some repetitive action to mark off equivalent increments of time. Just as a grandfather clock relies on the constant swinging back and forth of a pendulum under gravity, the tick tock of an atomic clock is maintained by the transition between two energy levels of an atom. This is where quantum physics comes into play. Quantum mechanics says that atoms carry energy, but they can't take on just any arbitrary amount. Instead, atomic energy is constrained to a precise set of levels. We call these quanta. As a simple analogy, think about driving a car onto a freeway. As you increase your speed, you would normally continuously go from, say, 20 miles/hour up to 70 miles/hour. Now, if you had a quantum atomic car, you wouldn't accelerate in a linear fashion. Instead, you would instantaneously jump, or transition, from one speed to the next. For an atom, when a transition occurs from one energy level to another, quantum mechanics says that the energy difference is equal to a characteristic frequency, multiplied by a constant, where the change in energy is equal to a number, called Planck's constant,times the frequency.That characteristic frequency is what we need to make our clock. GPS satellites rely on cesium and rubidium atoms as frequency standards. In the case of cesium 133, the characteristic clock frequency is 9,192,631,770 Hz. That's 9 billion cycles per second. That's a really fast clock. No matter how skilled a clockmaker may be, every pendulum, wind-up mechanism and quartz crystal resonates at a slightly different frequency. However, every cesium 133 atom in the universe oscillates at the same exact frequency. So thanks to the atomic clock we get a time reading accurate to within 1 billionth of a second, and a very precise measurement of the distance from that satellite. Let's ignore the fact that you're almost definitely on Earth. We now know that you're at a fixed distance from the satellite. In other words, you're somewhere on the surface of a sphere centered around the satellite. Measure your distance from a second satellite and you get another overlapping sphere. Keep doing that, and with just four measurements,and a little correction using Einstein's theory of relativity,you can pinpoint your location to exactly one point in space. So that's all it takes: a multibillion-dollar network of satellites, oscillating cesium atoms, quantum mechanics, relativity,a smartphone, and you. No problem.

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Nasa Mars 2020: First Aircraft to Fly on Another Planet

Digital Electronic Warfare System Overview

The Digital Electronic Warfare System, or DEWS, fuses legacy systems into one digital suite to defeat evolving threats across the global airspace. The system protects new and legacy aircraft with enhanced detection range, high fidelity identification, all aspect electronic attack, and countermeasures response. DEWS constantly listens across an entire frequency band to provide the aircrew with complete situational awareness. The system is already in production and supported by skilled employees and a modern facility. DEWS provides offensive and defensive support against modern air defense systems in the battlefield of today and tomorrow

Electronic Warfare Technology

Electronic warfare (EW) is any action involving the use of the electromagnetic spectrum (EM spectrum- a collection of energy waves emitted from the Sun).

Military operations are executed in an information environment increasingly complicated by the electromagnetic spectrum. The recognized need for military forces to have unimpeded access to and use of the electromagnetic environment creates vulnerabilities and opportunities for electronic warfare in support of military operations. There are three capability areas from which military assets consist. They are electronic support, attack, protection.

Electronic support intercepts , identifies and locates energy signals emitted from threats. Electronic attack (or jamming) directs energy toward threats to disrupt and neutralize their effect. Electronic protection protects personnel facilities and equipment from an enemy. By the way, there is a world leader in the EW it is BAE system, which brings our pilots home. So this is how the electronic warfare technology affects us and our world.

Nasa Mars 2020: First Aircraft to Fly on Another Planet

This is Ingenuity and it’s going to Mars. NASA hopes it will give us a different view of things and allow us to study cliffs and craters and all the other places that rovers, like this one, simply can get to.

It’s got these carbon fiber blades and they can spin eight times faster than the blades on the helicopter here, on Earth, at around two thousand four hundred

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revolutions per minute. It’s got solar cells, batteries, two cameras (one black and white and one in colour), computer systems, navigation systems: all of these in a helicopter, that’s only the size of a Chihuahua.

It’s so small, it’s actually travelling in the belly of another piece of scientific equipment that Nasa is sending to Mars. All parts of this 2020 mission to the Red planet.

Now, because Mars is so far away from Earth, there’s too much of a delay for you to be able to control this thing with a joystick. So what’s happening is scientists are sending commands way-way-way in advance. So, essentially, this machine will be taking off by itself, flying by itself and landing by itself. And flying there won’t be easy: the atmosphere is a hundred times thinner that it is here, on Earth. But if it works, we could be sending more flying robots to Mars in the future. And, possibly, using them as scouts for human missions one day.

The Brilliant Engineering of First Flight!

On December, 17, 1903, the history of the aviation was changed forever when the Wright brothers made the world's first successful flight. You might think that they're design was so simple. The propellers move the aircraft forward, the wings produce the lift and the aircraft stays in the air. But when you examine it closely, you will be amazed by the numerous ingenuous technologies these high school dropouts developed 100 years ago. Their design was so complete that even the current modern aircraft used the same principles of flight.

First thing's first, to make an aircraft fly you have to first overcome the pull of gravity, or in other words, you have to produce a lift force. The Wright brothers borrowed the idea of lift generation from their own earlier experience on gliders. They knew that when air floated over a curved surface, it generated a lift force. The higher the speed, the more would be the lift force. An increase in angle of attack also increased the lift force. How is this lift generated? That's a topic for another video. To make the aircraft move forward, two propeller blades were used. They produced thrust force, again, from the same airfoil principle. The thin propeller blades were a clever design choice. Until then, the common belief was that an aircraft propeller should be something like that of a ship's propeller. However, the Wright brothers proved that to work efficiently in air, a high speed narrow blade was the ideal choice. Moreover, you will notice that the blades were rotating in opposite directions. This was another crucial design

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The Brilliant Engineering of First Flight!

decision. Without this, control of the aircraft would not have been possible. We will learn about that at the end of the video. The blades were driven by an engine which sat on the wing. To fly an aircraft, you have to obey the following force equations of flight. To come up with an aircraft design which satisfied these equations, the Wright brothers developed their own lift data by abandoning all the wrong lift data that was available at that time. The Wright brothers' wing had a top point near the leading edge. This design produced much more lift than the top at centre design used at that time.

With an optimized wing design alone, this aircraft would not lift from the ground.

The Wright brothers realized that the existing heavy automobile engines being used were the main villains. They had to make the engine lighter without compromising its power output. Only a powerful engine could give the aircraft a good speed. As explained earlier, the more the speed the more the lift. Unable to find any such engine, with the help of their mechanic, the Wright brothers designed and built their own engine. A light-weight, 12 horsepower petrol engine. Even before the new engine development, the Wright brothers had calculated that they needed an engine of less than 200 pounds in weight, with at least 8 horsepower to meet the equations of flight. To reduce weight, they even cast the crank case with aluminum, first at that time. They painted the crank case black so that their competitors would not know about the construction material. You can see the details of the chain and sprocket mechanism used to transfer power from the engine to the propeller blades.

With this design, at proper airplane speed, the lift force would overtake the gravitational pull and they would have take-off. Did you notice a rail track in this visual? That was another clever design decision from the Wright brothers. They knew that it was impossible to get a good airplane speed in the sandy terrain, so they used a 60 foot long rail track arrangement for a smooth take-off. The Wright brothers' main innovation was the development of successful flight controls.

Aircraft crashes were a common issue in those days, and nobody knew how to control them. To have a successfully controlled flight, the Wrights had to control their plane in three axes: pitch, roll, and yaw. They again relied on the principles of the airfoil to accomplish this task. To pitch the airplane, the right flyer had an elevator arrangement at the front. You can see that by moving this lever, a rope mechanism changed the angle of the elevator. If the elevators rotated up, there would be an upward lift force as per the airfoil principle. The

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torque produced by this lift force could push the whole aircraft up as shown. To push the aircraft nose down, they just did the reverse. In modern airplanes the elevators are fitted at the back. To roll the aircraft, Wilbur Wright had a great idea: wing warping. It was clear that by twisting the wing along its length at one end, the angle of attack would be positive and at the other end, it would be negative. This would obviously create a lift differential and the airplane would roll. To understand how the Wright brothers practically achieved the wing warping, let's have a look at this animation.

The pilot controls a cradle, using its hip, which in turn controls two separate cables attached to it. The cable movement makes the wing warp through a clever mechanism. This is a brilliant mechanism. We need a separate, dedicated video to understand the details of it. In modern aircraft, ailerons are used to generate the lift differential. However, when the Wright brothers first tried to roll the aircraft using wing warping, the result was disastrous. They noticed that along with the rolling, the airplane took an unintended turn as shown. They called it a “steering reversal problem.” This phenomenon is now called, “adverse yaw.” The physics behind the adverse yaw are now well understood. The airflow above the high angle wing region produces high drag. On the other tip, the drag force is low. The difference in the drag force makes the airplane yaw as shown. The Wright brothers overcame this issue with the help of a rudder arrangement. If the aircraft was yawing in this way, they turn the rudder as shown, in such a way that the torque produced by the rudder would exactly cancel the adverse yaw torque. Here the Wright brothers made another smart move. Since the rudder had to be operated whenever there was wing warping, they connected the rudder and wing warping controls together. Both these motions were simultaneously operated from the hip control. By using these controls effectively, the Wright brothers were able to give the aircraft the stability needed. Pitch the aircraft to climb up or climb down, and make a smooth turn by banking the aircraft.

Now back to the interesting question posed in the middle of the video. Why did the Wright brothers use opposite direction of rotation for the blades? This was to cancel the gyroscope effect of a rotating wheel. Any rotating object has an angular momentum. Assume the Wright brothers designed the aircraft with the blade spinning in the same direction. Now the pilot decides to pitch the aircraft by lowering the elevator. The lowering of the elevators would obviously produce a torque as shown. However, the airplane would not pitch upwards as

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How Does the Power Grid Work?

expected due to the angular momentum of the blades. Instead, it would take an unexpected side turn as shown. This unexpected phenomenon is known as gyroscopic procession. Gyroscopic procession conforms perfectly with Newton's second law of motion. You can see that the direction of change in angular momentum is the same as that of the torque applied. The only way to overcome such unexpected behavior is by eliminating the very cause of it: the angular momentum of the spinning blades. That is exactly what the Wright brothers did with two blades spinning in opposite directions. It is astonishing to discover that the Wright brothers thought about such detailed engineering points, despite their limited formal education. Did you notice that the pilot's position was not in the middle of the aircraft? Please support us by clicking the help button if you are astonished by the marvelous engineering feats that the Wright brothers accomplished. Also, let us know in the comments box why you think the Wright brothers decided to position the pilot slightly off-center. Thank you.

How Does the Power Grid Work?

The modern world depends on electricity. It’s not just a luxury we use to power our devices and enjoy our free time. It’s not even just a convenience of having light, heating and cooling in our buildings. Electricity is a crucial resource, especially in urban areas, providing public security, safety and health, and making possible everything from emergency response to modern medical care in hospitals to even the other utilities we require, like fresh water and sanitation systems.

But unlike those other utilities, electricity can’t be created, stored and used at a later time. The instant it’s produced, it’s used, no matter how far apart the producer is from the user. And the infrastructure that makes all this possible is one of humanity’s most important and fascinating engineering achievements.

Hey, I’m Grady and this is Practical Engineering. On today’s episode we’re talking about the power grid.

This video is sponsored by NordVPN. Visit NordVPN.com/practicalengineering to get 75% off a 3-year plan. More on that later!

Like most people, you probably take the grid for granted. Electrical infrastructure is so ubiquitous, it’s easy not to notice that the most of our power grid is out in the open for anyone who wants to have a look. I happen to be one

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of those people who does want to have a look, and hopefully by the end of this video series on the electrical infrastructure, you will be too. This video is geared toward North America, but most of the concepts will apply to any other part of the world. And just to give you a sense of scale, there are only four distinct electrical grids that service essentially all of North America. You have the two big ones, Western and Eastern, and the two electrical separatists: Quebec and Texas.

Depending on your definition, an electrical grid can be considered one of the world’s largest machines. So how does this machine work? The basic function of generating electricity and delivering it to those who need it may seem simple. I can hook up a small generator to a light and, boom, power grid. With the cost of solar panels reaching record lows, many are exploring the possibility of generating all the power they need at home and forgoing the grid all together.

But a wide area interconnection (that’s the technical term for a power grid) offers some serious advantages in exchange for increased complexity.

Here’s a simplified diagram showing the major components of a typical power grid, and we’ll follow the flow of electrical current as it makes its way through each one.

We start with generation where the electricity is produced. There are many types of power plants, each with their own distinct advantages and disadvantages, but they all have one thing in common: they take one kind of energy and convert it into electrical energy. Most power plants are located away from populated areas, so that electricity they create needs to be efficiently transported. That’s handled by high-voltage transmission lines. At the plant, transformers boost the voltage to minimize losses within the lines as the electricity makes its way to the areas that need it. Once it reaches populated areas, transformers then step down the power back to a safer and more practical voltage. This is done at a substation, which also has equipment to regulate the quality of the electricity and breakers to isolate potential faults. Some energy customers draw power directly from transmission lines, but most are served from feeder lines that carry power from the substation. This part of the system is called distribution. From the feeders, smaller transformers step down the voltage to its final level for industrial, commercial or residential uses before the electricity reaches its final destination.

Rather than a constant flow of current in a single direction (called direct current, or DC), the vast majority of the power grid uses alternating current, or

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How Does the Power Grid Work?

AC, where the direction of voltage and current are constantly switching, 60 times per second in North America. The major advantage of AC power is that it’s easy to step up or down voltages, a critical part of efficiently and safely moving electricity from producer to consumer.

The device that performs this important role, called a transformer, is as simple as a pair of coils next to each other. A varying voltage in one coil induces a voltage in the other coil proportional to the number of turns in each one. If the current doesn’t vary, like in direct current, the transformer can’t do any transforming.

It’s helpful to think about the grid as a marketplace. Power producers bring their electricity to the market by connecting to the power grid, and power consumers purchase that electricity for use in their home or business. The economics and politics of the grid are so much more complicated than this, but the important part of the analogy is that, in many ways, the power grid is a shared resource. Because of that, it needs organizations to oversee and establish rules about how each participant in the producing, transmitting and consuming of power may use it.

And there are three overarching technical goals that engineers use to design and maintain the power grid.

The first one is power quality. Our electrical devices and equipment are designed, assuming that the power coming from the grid has certain parameters, mainly that the voltage and frequency are correct and stable. Some devices even count the oscillations in the AC grid power to keep track of time, so it’s critical that the grid frequency not deviate. Changes in voltage can lead to brownouts or surges that damage connected equipment. One of the benefits of a large power grid is electrical inertia. All those huge spinning generators connected together provide momentum that smooths out the ripples and spikes that can occur from equipment faults or quickly changing electrical loads.

The next technical goal of the grid is reliability. If, like most people, you take the constant availability of power for granted, that’s by design. Much of the grid’s complexity comes from how we manage faults and provide redundancy so that you’re rarely faced with blackout conditions. It’s another inherent benefit of a grid that electricity can be rerouted when a piece of equipment is out-of- service, whether it was planned or otherwise.

The final goal of a power grid is simply that the supply meet demand. Electricity production and consumption happens on a real-time basis. That

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means, if it’s plugged in, the light from the screen you’re watching right now was a drop of water in a turbine or a breeze across a windmill just microseconds ago.

And by the way, did you call your utility and let them know that you were going to be turning on your computer or phone to watch this video? I’m willing to bet you didn’t, which means not only did they have to adjust their production up to match the extra load, but they had to do it immediately without any warning whatsoever. Luckily, having millions of people connected to the same grid smooths out the demands created by individuals, but load following is still a major challenge.

For the most part, electrical demand follows a fairly consistent pattern, but factors like extreme weather can make it difficult to forecast. Grid operators balance demand by dispatching generation capacity in real time. The cheapest sources of power are used t fulfill the base load that’s more consistent, and higher cost sources are used for peaking when demand exceeds the base.

But it’s not as simple as flipping on a switch. Large power plants can take hours, days or even weeks to start up and shut down. Equipment needs to be taken out of service for maintenance. Fuel costs fluctuate. Renewable sources, like wind and solar, can have massive and unpredictable variations in capacity, providing irregular sloshes of power to the grid. You can see why balancing electricity supply and demand is this fantastically complex job of taking into account all these considerations, some of which are predictable and some of which aren’t.

That’s part of the reason we are trying to make the grid smarter by using software, sensors and devices capable of communicating with each other. On the supply side, this can allow computers and software to do what they do best: take in tremendous amounts of data to help us make decisions about how to manage the grid. But a smart grid can also help on the demand side as well. Unlike most of the goods we buy, consumers don’t have a keen understanding of power, how much we’re using or how much it should cost depending on the time of day or year. A smart grid can take away some of the obfuscation, allowing us to male better decisions about how we use electricity in our day-to-day lives. Ultimately, a smart grid can help us use and take care of this huge machine – this shared resource we call the power grid – more effectively and efficiently now and into the future.

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