Terrain Following - Limits

Owned by Matt Skelton
Last updated: Sept 20, 2023
2 min read

About

The terrain following feature has limits to the capability. Understanding these limits will ensure the feature is used correctly.

Limits

Obstacles

The terrain following feature is not an obstacle avoidance feature. It will not account for, detect, or avoid obstacles such as trees, buildings, and powerlines.


New construction or recent elevation changes may not be captured in the terrain elevation database. Use caution when using the terrain following feature near recent construction (or similar) areas.

 

Accuracy

The terrain following feature is limited in accuracy by the supplied terrain elevation data and the accuracy of the aircraft navigational sensors.

What about RTK?

The accuracy of the terrain following feature cannot be improved with RTK GPS. The PHX does not currently use RTK GPS information for navigation. RTK GPS information may improve the height above ground information in the image metadata but will not improve GSD consistency.

 

Flight Plan Size

When the terrain following feature is enabled more waypoints are added to the mission plan to command the changes in altitude. The number of added waypoints is dependent on the tolerance setting described in Defaults section and the terrain elevation variation of the area being flown over. See the example mission plans below.

It is recommended not to exceed 2000 waypoints when planning a mission for the PHX.

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