How to Choose the Right IMU for UAVs?

As a UAV manufacturer or developer, you know how crucial it is to select the right Inertial Measurement Unit (IMU) for your UAV’s performance. Choosing the wrong IMU can affect everything—from flight stability to data accuracy. Believe me, I’ve seen firsthand how a miscalculation in sensor selection can compromise the entire mission, leading to not just monetary losses but also delays and frustration for your team.

So how do we make sure we pick the right IMU? That’s what I’m here to help you with.

UAVs (Unmanned Aerial Vehicles) typically use tactical-grade or industrial-grade IMUs depending on their application. Tactical-grade IMUs provide higher precision and stability, essential for military drones or those requiring accurate long-term navigation. In contrast, industrial-grade IMUs are more suited for commercial drones, offering a balance between cost and performance. Both types measure orientation, acceleration, and angular velocity to ensure stable flight and precise navigation in varying conditions.

Now, let’s dive deeper into the most important factors and questions you should be asking to make sure you choose the right IMU for your UAVs.

What is an IMU and Why Does It Matter for UAVs?

Before we get into the specifics of IMU selection, let’s make sure we’re all on the same page about what an IMU actually does.

IMU, or Inertial Measurement Unit, is a sensor suite made up of gyroscopes, accelerometers, and sometimes magnetometers. This device measures angular velocity, acceleration, and sometimes magnetic field strength—crucial data points for UAV flight control systems to maintain stability and precise movement.

In simple terms, your IMU is your UAV’s inner ear. Just as you rely on your inner ear to maintain balance and spatial awareness, a UAV uses its IMU to “know” where it is and how it’s moving, especially in GPS-denied environments.

What Accuracy Do You Need for Your UAV’s IMU?

Accuracy is probably the first thing that comes to mind when you think about choosing an IMU, and for good reason. The level of accuracy required for your UAV’s mission directly impacts what type of IMU you should consider. If you’re working with high-end UAVs used for critical tasks—such as military reconnaissance, mapping, or industrial inspections—then your IMU must deliver precise and reliable data.

Here’s a breakdown of what you should look for based on your application:

High-precision IMUs: These are needed for UAVs engaged in aerial mapping, surveying, or military operations where exact measurements of position and movement are crucial. You should aim for an IMU with a gyroscope bias stability of less than 1°/h and accelerometer bias stability below 0.1 mg.
Standard IMUs: For less demanding applications like consumer drones or light industrial use, where precision isn’t mission-critical, a more affordable IMU with moderate accuracy will do. The focus here is on maintaining stable flight rather than highly precise data.

The IMU you select must meet the accuracy demands of your application. You don’t want to overpay for a high-end IMU if you’re not utilizing its full potential, but you also don’t want to cut corners if your UAV’s performance depends on precision.

How Important is the Size and Weight of the IMU for UAVs?

Size and weight are critical factors, especially for smaller UAVs. Every gram counts when you’re trying to maximize flight time and maneuverability. The larger the IMU, the more it will weigh, and that means less room for payload or a shorter flight duration. On the other hand, reducing the IMU’s size too much might compromise performance, especially in rugged conditions.

In my experience, finding the right balance between size, weight, and performance is key. Here’s how to think about it:

Miniaturized IMUs: Ideal for small drones, these lightweight, compact IMUs offer reasonable accuracy and low power consumption. They’re great for consumer-grade drones or lightweight commercial applications where portability matters more than ultra-high precision.
Standard-sized IMUs: Best suited for medium to large UAVs where the additional weight and size of the IMU can be tolerated. These units often provide better accuracy and durability, making them ideal for professional applications like surveying or industrial inspections.

At GuideNav, we’ve worked with many clients who needed custom-sized IMUs to fit their specific UAV designs, ensuring they get optimal performance without compromising on weight or space.

How Durable Should Your IMU Be for UAV Applications?

Let’s be real here. UAVs, especially those used in industrial or military applications, don’t operate in ideal environments. Whether it’s extreme temperatures, high vibrations, or rough landings, your IMU needs to withstand a variety of stresses. Durability, therefore, should be a key consideration in your selection process.

Rugged IMUs: If your UAV operates in harsh conditions, such as in defense or heavy industrial environments, you need an IMU that can handle it. Look for units that have been tested for shock, vibration, and extreme temperatures.
Standard IMUs: For UAVs operating in more controlled environments, such as indoor use or recreational flying, a standard IMU with less emphasis on ruggedization will work just fine.

At GuideNav, we’ve supplied rugged IMUs to clients who operate in some of the world’s most demanding environments, from desert heat to freezing tundras, ensuring that their UAVs stay functional no matter what conditions they face.

What Impact Does Power Consumption Have on IMU Selection?

Power consumption is another critical factor, especially for UAVs that need to maximize flight time. The more power your IMU draws, the quicker it will deplete the UAV’s battery, limiting the operational time.

Low-power IMUs: These are ideal for UAVs that prioritize long flight times, such as those used for aerial surveillance or extended inspections. Low power consumption ensures that the IMU doesn’t drain the battery too quickly, allowing for extended mission durations.
High-performance IMUs: If you’re in a situation where accuracy and performance are more important than conserving power, you might opt for an IMU that consumes more energy but delivers the high-end performance required.

Balancing power consumption with the performance requirements of your UAV is key. You want to make sure your UAV can complete its mission without needing frequent recharges, but not at the expense of data accuracy or reliability.

How Much Should You Expect to Pay for a High-Quality IMU?

Let’s talk money. The cost of an IMU varies widely depending on its features, precision, and durability. While it’s tempting to cut costs, you should be cautious about under-investing in your IMU, as that could lead to suboptimal performance or the need for expensive replacements later on.

High-end IMUs: These are typically priced between $1,000 and $10,000, depending on the level of precision and ruggedness required. They’re used for professional applications like military drones, surveying, and industrial inspections.
Budget IMUs: On the other hand, consumer-grade IMUs range from $50 to $500. While more affordable, they come with trade-offs in terms of accuracy and durability, making them more suitable for hobby drones or non-critical applications.

Why You Should Consider Custom IMUs from GuideNav

If you’re struggling to find an off-the-shelf IMU that perfectly fits your UAV’s requirements, customization might be the answer. At GuideNav, we specialize in providing custom IMU solutions tailored to your specific needs. Whether you’re looking for ultra-precise sensors for military-grade UAVs or rugged, lightweight IMUs for industrial applications, we’ve got the expertise to deliver exactly what you need.

We understand that no two UAV projects are alike, and that’s why we work closely with our clients to develop IMUs that fit seamlessly into their systems, offering unparalleled accuracy, durability, and performance. With over a decade of experience in the field of inertial navigation, we’ve been trusted by leading organizations across more than 35 countries. If you want to ensure your UAVs are equipped with the best IMU for the job, don’t hesitate to get in touch with us.