Hi,
I have been loving using Litchi with my Phantom 4 Advanced and my missions around the house have been going well. I just took it out on the farm (what I bought it for) and sent it on a hilly mission that I had carefully planned and double checked with Google Earth.
It seems it disconnected and crashed pretty shortly thereafter. It seemed too low just before it disappeared.
I'm thinking either Google Earth altitudes are out by 10m or so OR it goes to each waypoint and then changes altitude (and I had assumed a straight line between the two). Can anybody help? This would help me decide where to search.
I will go and hunt for it in the gorse in the morning. I had so much work planned for it and it was going so well!
Litchi Learning Curve:
My first Litchi flight was a waypoint mission over 100 acres and a lake. I had planned it in Mission Hub in the comfort of my home. The property looked flat from satellite maps (duh). I did not think of Google Earth. My Waypoint mission started from a 400 ft panorama and went to waypoint 2 at 125 ft by the lake, then waypoint 3 at 85 feet and by the lake shore. On the way to WP 3, I lost video signal and then RC signal and the last thing I saw was a tree, way higher than the drone. I was 1/2 mile from the lake and started my hike to try and find my Mavic Pro in the trees. 200 yards up the trail, I got a video signal again. Again all I could see was a pine tree. I finally angled the camera down and saw a road. The Mavic was hovering above the road where my truck was parked but up close to a pine tree and the obstacle avoidance had stopped it.
My stomach stopped aching and I landed my drone and said a prayer of thanks.
It turned out a ridge was between me and WP 3 and I didn't know it since I hadn't checked Google Earth terrain map.
The Mavic had completed it's programmed flight, took beautiful video and when the mission ended and it had no signal, it returned to home and hovered. It missed home by 20 feet and ended up against a tree.
I had not even accounted for the difference in tree height from ground height.
I was SO lucky.
A couple of weeks later. flying my
P4P (see, I know this is a Phantom forum
), on a 200 acre parcel, I had added 100 feet to each waypoint altitude to account for trees; I thought.
1/2 way through the mission, while watching the video monitor, I saw a tree higher than the drone go by and hit the abort button and shot straight up. Since the waypoint mission was still on the monitor, I finished flying the mission manually and got good footage.
Back home and checking the terrain maps again, if I drew a straight line between the 2 waypoints where I had the tree problem, I saw it passed over a ridge at an altitude lower than the possible tree height. I had programmed a waypoint 100 feet over the river to 100 feet over a distant ridge not counting on a straight line between the two crossing too low over a ridge in between.
I just shot another property where the measured tree height was up to 130 feet. My 100 foot "guess" would have had me in trees again.
So what have I learned? Trees are higher than I thought and I can't just trust Litchi Mission Hub altitudes to be safe. Maybe that sounds dumb, but I had to learn it by making mistakes.
I don't know any solution to just using Litchi Mission hub to plan in advance without doing a flying survey of the property once you get on site to see if your plan makes sense altitude and obstacle wise.
