> For the complete documentation index, see [llms.txt](https://docs-7.phoenixlidar.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs-7.phoenixlidar.com/lidarmill-desktop/workflow-kk/lidarsnap-v4/trajectory-optimization/airborne-trajectory-optimization.md).

# Airborne Trajectory Optimization

The airborne trajectory optimization preset uses a **Bias optimization model** with only the **Up** parameter enabled for optimization:

<figure><img src="/files/0RhL6kem6oJl9aAsYHfy" alt=""><figcaption></figcaption></figure>

This will result in a single vertical adjustment for each flight line. This works well to correct for vertical drift between different flight lines in an aerial data set. Applying only a single adjustment per flight line restricts the optimizer from applying sudden adjustments along the trajectory, and ensures that ample observations are used when computing each adjustment.&#x20;

{% hint style="info" %}
Aerial data sets may require optimization of **Yaw**, in addition to **Up**. Determination of heading (or yaw) with most lidar systems utilizes the system's course-over-ground as determined by GNSS (kinematic alignment). This process can sometimes result in a poor heading determination, and thus yaw should possibly be considered for optimization.&#x20;
{% endhint %}