A free course for parents, teachers and students
Twice a second, each aircraft broadcasts a 112-bit radio message: who it is, where it is, how high and how fast. The technique is called ADS-B. Understanding it means understanding satellites, radio waves, the curvature of the Earth, digital coding and the speed of light. This course takes you through all of it, at three levels.
For most of aviation's history, the only way to know where an aircraft was from the ground was to bounce a radar beam off it and time the echo. Since 2020, nearly every airliner in Europe and North America does something different: it works out its own position from navigation satellites and then simply announces it, by radio, to anyone who cares to listen. That announcement is ADS-B, Automatic Dependent Surveillance - Broadcast. Air traffic control uses it. Other aircraft use it to avoid each other. And because the messages are sent in the clear, a receiver the size of a USB stick on a school roof can hear them too.
That makes ADS-B an unusually good teaching subject. It is real, it is happening above every classroom right now, it can be observed with cheap equipment, and to understand it properly you have to pass through a large part of the physics curriculum: electromagnetic waves and the spectrum, frequency and wavelength, the speed of light, line-of-sight propagation on a curved Earth, the inverse square law, antennas and resonance, timing and the geometry of satellite positioning, binary coding and error detection.
The course is written in two voices. The reference course is the complete explanation for any adult, whatever their background: twelve chapters from "why do we need to know where aircraft are" to "how does one receiver's data become a live map of Europe". The three kits then take the same material to a family, a primary class and a secondary class. Each kit has an adult page, which explains the theory at that depth and shows how to teach it, and a child page, which tells the same story directly to the learner.
Reference course
Twelve chapters. Radar before ADS-B, the idea, satellite positioning, the anatomy of a message, three chapters of physics, receiving and decoding, networks and multilateration, uses, limits and history. Read this first.
Kit 1 - at home
For a child of about 5 to 12 and an adult. The parent's page explains the theory in plain language with the analogies that work, and why they work. The child's page is an illustrated story in six chapters.
Kit 2 - primary school
The teacher's page is a course in itself: what to explain, in what order, at what depth, with the demonstrations that carry each idea and the misconceptions to expect. The student's page is the course told to the class.
Kit 3 - secondary school
A physics and computing course built on one real system: c = f x lambda, the radio horizon, path loss, pulse position modulation, error detection, satellite timing and multilateration, with worked examples and a receiver project.
Part 5 - hands-on
The practical end of every kit: exactly what to buy for 100 to 150 euros, which antenna to choose and where to place it, how to prepare a Raspberry Pi and install the Dataero feeder, and how to claim your station. An afternoon's work; no radio or Linux experience needed.
Every lesson and the workshop can be downloaded as a PDF, laid out for printing, with the course address on every page: for the classroom, the kitchen table, or a colleague.
Every level of the course follows the same thread, because the thread is the logic of the system itself. An aircraft needs to know where it is (satellites and air pressure). It needs to say so (a digital message). The message needs to travel (radio waves). Something needs to hear it (an antenna and a receiver, limited by the horizon). And many listeners together make a picture (a network and a map). The depth changes with age; the order does not.
| Thread | Told to a 7-year-old | Told to a 10-year-old | Told to a 16-year-old |
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Yes. ADS-B messages are broadcast unencrypted on purpose, so that other aircraft and ground stations can use them. Receiving them is legal in Belgium and across the EU. Transmitting on aviation frequencies is not, and none of the equipment in this course transmits. The data identifies aircraft, never passengers.
Every kit ends on the live map, built from receivers hosted by volunteers, airports and schools. A school that hosts a small receiver on its roof sees its own patch of sky appear on the map.
