Tips on Choosing Inertial Navigation Systems

Inertial Navigation Systems (INS) are rising as their capabilities and applications increase. The increased availability and decreased cost of components such as accelerometers, magnetometers, gyroscopes, and processors have made inertial navigation systems indispensable in aerospace, military, and autonomous vehicles. These devices can measure speed, acceleration, orientation, and distance. The following are guidelines on how to select these systems.

Accuracy Is Key

Accuracy for inertial navigation systems can be described as the closeness of an observed value to its true value at a given point in time and space. Inertial sensors such as wheel odometers, magnetometers, and accelerometers provide measurements to update you relative to where you started. Each measurement update is an observation. It must be as close to the actual position as possible to ensure accurate navigation.

Accurate Velocity Information

The position and velocity components must be accurate when determining where you are relative to your starting point. To accurately represent the position, the inertial measurement unit (IMU) sensors typically used for navigation, such as wheel odometers and motion sensors, provide un-aided measurements of acceleration and angular rate. The measurements are inherently noisy and subject to errors in interpretation by the filter algorithms used by inertial navigation systems. They must be accurate to within an order of magnitude.

System Reliability

Due to their simplicity, inertial navigation systems are generally reliable and unaffected by communications issues that can affect more complex navigational systems. However, drift and bias errors that accumulate over time can affect inertial navigation systems. The key to inertial navigation systems is the algorithms’ ability to predict future positions based on current and past observations accurately. The systems are often integrated with other navigation-related sensors, such as a GPS receiver. The availability of this type of sensor is critical to accuracy.

The  systems are rugged electronic devices with no moving parts that measure speed along one or more axes. These devices are used in both commercial and military applications. They are also the foundation for inertial guidance systems used in many modern munitions.

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