Turning the Frequency Up

Turning the Frequency Up

When someone turns on their radio to listen to their favorite song, they rarely ever think about how that song reaches their ears. But when they do, they enter into a fascinating world full of radio waves that exist beyond the naked eye. This is the world that the Landmines Team encountered when they listened to presentations from Dr. Kevin Giovanetti and Dr. Thomas Alberts about radio frequencies and their application to drones.

Dr. Giovanetti began his presentation by explaining the general characteristics of waves. He discussed how frequency (the rate at which a wave occurs) and amplitude (the length of the wave) are used to measure different wave types. He then explained how humans perceive sound and color through waves that operate at different frequencies.

The presentation then turned toward the most applicable form of waves for drones: radio waves. Dr. Giovanetti discussed how drones communicate different forms of data through certain AM frequencies, much like a radio. The two different types of data drones communicate are telemetry and control. Telemetry data communicates positional characteristics such as speed or direction, while control data deals with the communication between the drone and the receiver that controls it.

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Dipole antenna pattern

 

Dr. Thomas Alberts then took the floor to discuss different ways drones can send and receive radio waves. He described how different devices are used to transmit different radiation frequency patterns. For example, the receiver that controls the drone uses a dipole antenna pattern, which emits radio frequencies omnidirectionally, leading to better control over the drone. The pixhawk, on the other hand, generally uses a single horizontal dipole pattern allowing it to communicate information over farther distances. These patterns can be altered so that the drone can more successfully perform certain tasks.

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Single horizontal dipole pattern

 

Radio waves and how they function is something the Landmines Team needs to consider when constructing their drone. They will be using a lot of different sensors that will need to communicate information to computers over long distances. The detonation system is also controlled remotely by a computer, so radio waves will have to be used to activate the pneumatic system. They also need to use radio frequencies to control their drone using both telemetric and control data.

The Team is currently using a traditional receiver and pixhawk to communicate with their drone, meaning radio frequencies will be travelling in both a dipole antenna pattern (with the receiver) and a single horizontal dipole pattern (with the pixhawk).

The Team will have to keep these patterns in mind, especially with information being communicated from the pixhawk. Since the device is transmitting only a single horizontal pattern, if they get into distances of up to five miles away there’s going to be certain places they will have trouble getting a signal. They could consider using a dual perpendicular horizontal pattern to increase their coverage, but the Team doesn’t see that as necessary at this stage.

The journey into the complex and magical realm of radio waves was quite a trip for the Landmines Team, but it’s time to get back to the perceivable world. Now they will have to use what they’ve learned about invisible waves to create some real visible explosions. They’re going to need to turn up the frequency to bring down the landmines.

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