Starting Fusion Indoors

This feature is available from 2.102.1

Introduction

Prior to this feature, the Fusion engine could only be initialized if correction data of RTK Fix quality was received. With this Save / Load feature, it is now possible to initialize the Fusion engine by loading a previously saved position even in areas with GNSS degraded or denied reception.

Usage

On the 'Status > Fusion' page you will see an 'Actions' button page of the Web Interface (Fig. 1). Once pressed, a pop-up will appear with three options: 'Reset', 'Save', and 'Load'. You can use the 'Save' option to store the current Fusion position and internal state. In total, you are able to store and label up to 5 positions here.

Note that Fusion must be fully initialized for this to work. Once 'Save' is pressed after labelling the position, wait a few seconds before powering off the device or stopping the Fusion engine. When fusion is started again, press the 'Load' option to initialize the device using the previously stored state and continue your operation seamlessly.

As best practice, we recommend saving the last stationary position every time you turn off Fusion or the VRTK-2 overall and not to move the robot afterward.

Please note that the sensor must remain stationary when saving or loading the Fusion state. In addition, when loading the state, please ensure the device is in the same position and orientation as it was saved.

Known Limitations

The Fusion engine can be initialized indoors now; This means covariances estimation, and fusion outputs are available but it the IMU convergence is flagged as ‘warmstarted’, or ‘rough converged’. With that, one can already use the position data.
However, to achieving reliable high precision positioning, we recommend moving the platform into open sky to verify the global positon under RTK Fix as well as the IMU convergence, before operating in longer outages. At the moment, we recommend using this feature for, e.g., moving the robot from its docking station in a garage out to the field under open sky, but not for direct prolonged indoor operations.

Lastly, it is essential to ensure the Vision-RTK 2 has some sort of time synchronisation (NTP or GNSS) before attempting to load a position.