Final answer:
To determine the altitude when operating an sUAS without GPS or an installed altimeter, one could use visual perspective comparison with known heights on the ground, fly a second sUAS with an altimeter alongside, or maintain level flight near a 400-foot tower.
Step-by-step explanation:
When operating an sUAS (small Unmanned Aircraft System) without GPS or an installed altimeter, determining the altitude can be tricky. Here are methods that can assist in this situation:
- Gaining a visual perspective of what 400 feet looks like on the ground before the flight. This could be through comparing the sUAS's height with a structure of known height or using reference points in the environment.
- Operating a second sUAS that has an altimeter to gain a visual perspective of 400 feet from the air. This would provide a live reference for the altitude.
- Operating the sUAS in close proximity of a tower known to be 400 feet tall. By flying near the tower and maintaining a level altitude in relation to the top, you can ensure you are not exceeding 400 feet.
Understanding techniques such as parallax or estimating distance outdoors using landmarks can also be of assistance. Parallax is the apparent change in direction of a remote object due to a change in the observer's vantage point and can be used to estimate distances. These are practical methods surveyors use, and operators of sUAS can apply similar principles.