We're starting a brand-new chapter now — Chapter 18, Inertial Navigation… — Page 226, Lesson 268

We're starting a brand-new chapter now — Chapter 18, Inertial Navigation Systems. This is a big one, and I want to give you the lay of the land before we dive into the physics. Here's the roadmap I'm going to take you through. We open with an introduction, then get straight into the basic principles of INS. From there, we build up the hardware: the accelerometer and its integrators, then the accelerometers themselves, and a critical topic — how gravity affects an accelerometer. After that comes the integrating gyroscope, and then we put it all together on the platform. We'll look at how the system orients itself to the Earth, and the concept of apparent wander. Then we cover alignment of the system, the Schuler period, and the errors of INS — split into bounded errors, unbounded errors, and inherent errors. Finally, we get into the pilot-facing part: the INS control and display panels, the summary INS warning lights, the LED display, and manual and automatic system checks. The chapter closes with practice questions and answers. So the whole arc is: principles, then the sensors, then how they're mounted and aligned, then the errors you have to live with, and finally the controls and indications you'll actually use in the cockpit. Let's start with the introduction and the basic principles. An Inertial Navigation System — INS — is a self-contained navigation system. That's the key word: self-contained. It needs no external references at all. No radio signals, no ground stations, no satellite. It works purely by sensing acceleration and integrating it to get velocity and position. The core idea is simple in principle. If you know where you started, and you measure every acceleration you experience, then by integrating that acceleration once you get velocity, and integrating velocity again you get displacement — your change in position. Add that to your starting point, and you know where you are. That's the whole philosophy. The accelerometer measures acceleration, and the integrators do the math to turn that into velocity and distance. That's our foundation. Next, we'll get into the accelerometer itself and how those integrators actually work.