Litchi Erroneous Center of Orbit

[John]

1. Has anyone experienced the UAV (Inspire 1) start a Litchi orbit with an actual orbit center that does not match the planned center point placed on the Litchi satellite image?
2. If so, what was the cause & prevention for recurrence?

I ask because I set a 36' radius orbit around a center point and the UAV flew an orbit where the center point did not match the point on the map, resulting in a crash into a tree. Seemed like the actual center point was off by about 30'.

Thanks.

 

[SanCap]

1. Has anyone experienced the UAV (Inspire 1) start a Litchi orbit with an actual orbit center that does not match the planned center point placed on the Litchi satellite image?
2. If so, what was the cause & prevention for recurrence?

I ask because I set a 36' radius orbit around a center point and the UAV flew an orbit where the center point did not match the point on the map, resulting in a crash into a tree. Seemed like the actual center point was off by about 30'.

Thanks.

I may be wrong but you need to give yourself some leeway with altitude. Then do a practice orbit and then grab the orbit point on the map and move it to fit the orbit you need.

 

[The Editor]

1. Has anyone experienced the UAV (Inspire 1) start a Litchi orbit with an actual orbit center that does not match the planned center point placed on the Litchi satellite image?
2. If so, what was the cause & prevention for recurrence?

I ask because I set a 36' radius orbit around a center point and the UAV flew an orbit where the center point did not match the point on the map, resulting in a crash into a tree. Seemed like the actual center point was off by about 30'.

Thanks.

This is why I never use anything that run waypoints etc.
Depending on where and how many satellites are being received (and can change during the course of the flight) the HDOP/VDOP (Horizontal and Vertical dilution of precision) can mean GPS positional accuracy can easily be many feet off.
Although you may start a flight with 12 satellites (or more) these may be clustered low on the horizon with only a few nearer to overhead. This will dramatically alter the accuracy for waypoint flying.

 

[Kilrah]

I may be wrong but you need to give yourself some leeway with altitude. Then do a practice orbit and then grab the orbit point on the map and move it to fit the orbit you need.

I'd suggest that as well, satellite imagery is not always precise enough to exactly match visual objects down to this level of precision since it may have been captured with an angle and stretched to be remapped more or less correctly.

 

[Leszek Kedziora]

Here is the answer:

 

[John]

Thank you for the responses. Up completion of the mission post mortem, the risk mitigation steps we will implement include: a practice flight above the structure along the lines of SanCap's comment and before running new control apps, be sure to understand the app-specific process for aborting a mission immediately. Though am still disappointed that the flight plan did not work as expected and learning of potential inaccuracies in waypoints, including orbital. The purpose of the orbital mission was to capture images of a structure at at controlled speed and interval to facilitate creation of a 3-D model. Comments on how to fly such a mission with that degree of precise control are welcome.

 

[LoudonMacReady]

Share your mission on Hub so we can see what you tried to do.