Two questions. Does the P4 Pro see the sun as an obstacle, and Litchi pause at waypoints?

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Hello,

Sorry if this should be two threads, however I noticed both issues this morning while doing some test flights.

Firstly, I was doing a little warm-up sight flying using DJI GO and kept getting strange "obstacle detected" warnings at 60 m AGL with nothing but blue sky around the P4 Pro. As I continued these warnings became more frequent until the bird came to a complete halt a couple of times, always while facing directly into the low morning sun coming over the nearby mountain ridge. As I normally use Litchi Waypoint for all my longer flights, I am now concerned that the P4 could be stopped by the sun beyond video or Tx range, and just sit there with me unaware of any issue until it ran out of battery or too little to RTH, etc.

Another thing I noticed today, that I had missed previously, is that the bird seems to pause/slow down at each Litchi waypoint before resuming cruise speed. The possible issue with this is I was planning on dealing with flying long missions over irregular mountain terrain by using lots of waypoints i.e. every 30 to 50 m over rough ground, then using the batch edit of altitude relative to ground to create a terrain-following track. This will not work if the bird has to slow down and accelerate at each of a hundred or so waypoints, as it will burn up the battery much faster than flying at cruise speed with only a few waypoints to deal with. Does this mean I am back to creating a track using fewer waypoints at all the high and low points using Google Earth then importing it? I was hoping to use Litchi Hub directly using the "high-density" waypoints idea to avoid having to transfer from GE to Litchi.

Sorry for the long-winded post. Any ideas?
 
Try turning off OA if you are happy with not hitting anything on the mission. The sun can confuse the OA (does on my P4).
Unless you are setting up actions at each WP, use 'curved' instead and the quad will continue at the preset speed. I set mine to 30 kph and it is fine for the video I use. If you are using straight lines at each WP, the quad will have to slow down as it is not possible to perform at the preset speed without flying to pieces.
 
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In addition to tevek's good suggestions you may encounter an additional issue with your proposed mission, the max number of waypoints is 99.
 
Also, any actions programmed at waypoints (such as "take photo") will not occur on a curved path because the bird never actually reaches the waypoint. It smoothly flies by it. In order for actions to work, the flight must be set to "straight lines" but then the bird will briefly stop at each waypoint. Also, when using straight lines, the added time due to stopping and starting is not calculated into the estimated mission time.
 
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Also, any actions programmed at waypoints (such as "take photo") will not occur on a curved path because the bird never actually reaches the waypoint. It smoothly flies by it. In order for actions to work, the flight must be set to "straight lines" but then the bird will briefly stop at each waypoint. Also, when using straight lines, the added time due to stopping and starting is not calculated into the estimated mission time.
I don't like the way that sounds, could easily program a mission that might exceed available battery capacity with that iissue- how hard could it be for litchi devs to fix that problem? I moved from litchi to autopilot initially as the iOS litchi app had a lot less features than the android version (that doesn't seem to be the case now). The est mission times in autopilot are spot on actual with the exception of flying in windy conditions.
 
Thanks guys.

I had forgotten about using curves because I was setting up start/stop video at various waypoints and as mentioned I couldn't do that without straight lines. No problem, I will just switch to manual recording control and that should solve the "flow" issue.

As for my question about the sun being sensed as an obstacle, I think I will just fly when the sun is more overhead (or cloudy), so as not to loose the OA capability, should it ever be needed. I am still not sure if the bird will ever stop completely if OA is invoked during a Litchi mission, as it did when manually flying using GO. I hope that the P4 would attempt to fly itself out of trouble and either continue the mission or RTH, however I am not sure how to test this safely.
 
Thanks guys.

I had forgotten about using curves because I was setting up start/stop video at various waypoints and as mentioned I couldn't do that without straight lines. No problem, I will just switch to manual recording control and that should solve the "flow" issue.

As for my question about the sun being sensed as an obstacle, I think I will just fly when the sun is more overhead (or cloudy), so as not to loose the OA capability, should it ever be needed. I am still not sure if the bird will ever stop completely if OA is invoked during a Litchi mission, as it did when manually flying using GO. I hope that the P4 would attempt to fly itself out of trouble and either continue the mission or RTH, however I am not sure how to test this safely.
You could try a smaller mission that is within sight of you to test out the effect, if any, of the sun interacting with OA. An issue may be that if the sun is triggering OA and does continue on its mission, your battery life will be affected. Low battery RTH may kick in and the unit will return, however it will be at slower speed with OA turned on. I always limit my mission time to 10-12 mins as I need to factor in wind where I fly and have never had an issue...yet...
 

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