The easiest guide to determine alignment angles

Automotive navigation systems, fleet management, sports and fitness tracking, and robotics applications all require accurate positioning. These applications achieve the precise location needed through a reliable GNSS (Global Navigation Satellite System) receiver, often supported by dead reckoning technology.  

As a design, development, test, or quality engineer, you may have experienced the thrill when a new dead reckoning product lands on your desk. Just like a Christmas present, you unbox and unwrap it, feeling excited at the sight of the new design. You’re enthusiastic about finally having access to the most advanced dead reckoning technology available on the market.

Integrating dead reckoning into your navigation system can be a straightforward process, especially with the user-friendly setup that modern dead reckoning products offer. Yet, in certain circumstances, it can become slightly more challenging. Here is where alignment angles come into play.

Alignment angles are among the most critical parameters for installing dead reckoning products. This alignment can be configured either manually or automatically, each method offering specific advantages.

But what exactly are alignment angles, what’s the difference between manual or automatic configuration, and why is it important to determine them correctly? If you are in the dark or just need a refresher, stick with us, and you’ll know in no time.

Alignment angles

Before implementing any dead reckoning technology, the DR system must be aligned with a reference coordinate system. The angles used for this alignment are called alignment angles.

Alignment angles typically ensure that a dead reckoning system is in sync with the direction and orientation of movement in an external environment. Without this alignment, accurate navigation and position tracking would simply be impossible.

Another, more technical way of describing alignment angles is in terms of the orientation of the Inertial Measurement Unit (IMU) and the vehicle’s reference frame. The orientation of an IMU is determined by data collected from its various sensors, including a 3D accelerometer and a gyroscope.  For a dead reckoning system to function correctly, it is necessary to align the orientation of the IMU with the vehicle’s reference frame.

Automatic alignment

Automatic alignment is the most straightforward way to set up a new dead reckoning product. It literally takes only a few minutes to install and start testing your applications. There are two main benefits to an automatic configuration:

• Simplified mounting process. A plug-and-play mode reduces installation complexity. Engineers or technicians installing DR products require no prior knowledge or training to ensure proper installation.
• Adaptability. Automatic configurations can easily adapt to changing requirements or environments. This is extremely useful for end users who regularly encounter different situations. The advantage of automatic alignment is that it can be implemented in any of these situations without requiring further configuration, resulting in greater flexibility.

Manual alignment

You may require manual alignment when there is an anomaly during the implementation of automatic alignment or when the application has a unified installation (typically in OEM/1st mount applications). Two-wheel applications, such as motorcycles or e-scooters, require manual alignment.

Figuring out the correct values of alignment angles is the trickiest step when properly configuring a dead reckoning product manually. Despite its potential complexities and time consumption, manual calibration offers several benefits, including:

• Precision. Design or development engineers can precisely tune alignment angles, eliminating potential sources of error and achieving higher precision than automatic methods. Still, if manual alignment is conducted incorrectly, it could be detrimental.
• Calibration time reduction. Manual calibration minimizes the time required to complete sensor calibration by eliminating the need to estimate alignment. In addition, the sensor fusion process takes less time after a cold start of the GNSS/DR receiver.

And what about two-wheelers?

As mentioned before, the automatic alignment feature is not available for two-wheelers. Manual configuration is always mandatory for these vehicles. Proper angle alignment is, therefore, essential for bicycle and e-scooter OEMs.

The primary reason for the mandatory manual alignment of two-wheelers is that they have more degrees of freedom in their movement compared to four-wheelers.

When a two-wheeler makes a sharp turn, both the vehicle and the rider's body tilt significantly. This extreme tilting poses challenges in estimating the alignment angles, obliging to manual determination.

You never ride alone

At u-blox, we understand the relevance of correctly setting up the alignment angles. For this reason, our engineers have created a step-by-step video that will guide you through all the nuances of the alignment angles process. Nothing else to say but enjoy.

Hold on. Actually, there is one more thing. If you’re looking for a reliable chip or module that incorporates dead reckoning technology, look no further. Just visit our website and make the best choice that fits your needs. And if in doubt, don’t hesitate to contact us.