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New to Litchi - I lost my drone :(

Tonyf85

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Apr 16, 2020
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Hello,
I have been using my Spark with DJI 4 for about a year manually flying. Today I decided to take a dip into the world of automated flying with waypoints. Sounded very cool. I did some reading up on it and decided on installing Superpatcher 2.02 and purchased Litchi. Superpatcher installed without a hitch. I read through the guide for Litchi and figured I was ready to take the plunge. I installed the Litchi app on my Samsung Galaxy S8. I logged into the Litchi Hub online and created a simple mission with 3 way points; 2 about 100 meters away, and the 3rd back at my home. Default height for waypoints was 100 ft. I had the finish action set to RTRH. I saved the mission in the hub then loaded it on my phone. I manually launched the drone to about 20 feet, then pressed the 'play' button in Litchi app on my phone to initiate the mission.
The drone raised to the default hieght of 100 ft, took off toward the 1st waypoint, and thats the LAST I SAW OF IT. I went searching at its last known location according to the map, but never found it. I was very sad.
According to the map, it just went straight and kept going. I don't know what I did wrong. I had high hopes for this Litchi app, it seems really cool. I intend to invest in another Spark, but don't want to risk losing another one.
I have so many questions...
Maybe someone can shed some light on what I did wrong in order to prevent this in the future.
Also, is there any way to look at logs to determine where the drone might have gone? I may go looking for it again tomorrow.
I thought this drone was smart enough to return to home if it was lost, lost connection, low battery, etc?

I have attached a pic of the map. It shows the waypoints and where the drone disappeared off radar.

Screenshot_20200416-190902_Litchi.jpg
 

Tonyf85

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Thanks for the reply. Attached is the Litchi flightlog csv file from the doomed flight. I wasn't sure if you wanted me to paste the entire file contents into this post (it's 1800+ lines), or just attach the file.

Tony
 

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jrhoffman75

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The mission looks strange. It‘s not a closed loop; it doesn’t show flying from Home to WP1. It also says mission length is 2450 feet.
 

Tonyf85

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I see what you mean... odd. Doesn't the mission start at WP1? I do notice a small piece/tail of the mission path hanging off WP1; that seems odd also. On the Litchi map the last known position (LKP) is slightly off from the Google Earth map. Any idea which one is more accurate? For example, I drew a 1 and a 2 on this map; 1 is the Google Earth LKP, and 2 is the Litchi map LKP.

spark LKP.png
 

Tonyf85

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Also I see at time 1m 42.6s , the 'Message' column says 'Go home command failed (reason: Execution of this process has timed out).'. Any idea why this would happen?
 

jrhoffman75

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I see what you mean... odd. Doesn't the mission start at WP1? I do notice a small piece/tail of the mission path hanging off WP1; that seems odd also. On the Litchi map the last known position (LKP) is slightly off from the Google Earth map. Any idea which one is more accurate? For example, I drew a 1 and a 2 on this map; 1 is the Google Earth LKP, and 2 is the Litchi map LKP.

View attachment 12705
Litchi has a popup at the start of a mission to allow the pilot to select at what waypoint the mission should start. I haven't been flying lately so I don't know what the default WP is. I haven't been flying lately, so I forget. Can you load your mission in Mission Hub on your PC and see if there is perhaps a bogus WP4 that the aircraft was trying to fly to?

Are there any obstructions out past where you are that are higher than your altitude; maybe aircraft impacted one of them?

You can download Virtual Litchi Mission to your computer and fly the mission on the computer. I tried to fly your mission by using the file you posted (deleting .txt converted it to a CSV file) but VLM reports that it is an unrecognizable CSV file.
 

RotorWash

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Sorry for your troubles. There must have been little wind as it drifted away slowly in atti mode and with the battery down to 12% at the last known position it can't have gone very far from that point. With the craft in atti mode RTH won't work.
 

Tonyf85

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Litchi has a popup at the start of a mission to allow the pilot to select at what waypoint the mission should start. I haven't been flying lately so I don't know what the default WP is. I haven't been flying lately, so I forget. Can you load your mission in Mission Hub on your PC and see if there is perhaps a bogus WP4 that the aircraft was trying to fly to?

Are there any obstructions out past where you are that are higher than your altitude; maybe aircraft impacted one of them?

You can download Virtual Litchi Mission to your computer and fly the mission on the computer. I tried to fly your mission by using the file you posted (deleting .txt converted it to a CSV file) but VLM reports that it is an unrecognizable CSV file.

Here is the Litchi mission csv i exported from the misson hub. It's just 3 waypoints. Doesn't show a 4th one. There were some trees, but not higher than the 100 ft altitude. I'll try the VLM. Thanks.
 

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Tonyf85

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Sorry for your troubles. There must have been little wind as it drifted away slowly in atti mode and with the battery down to 12% at the last known position it can't have gone very far from that point. With the craft in atti mode RTH won't work.
Yes it was a bit windy (10-12 mph). I'm trying to figure out the behavior it would have followed. I had SuperPatcher installed with the Smart Battery Mod. The battery last reported at 12%. At what battery percentage would it start the emergency auto landing (if at all)? Or would it just drift at that altitude (atti mode) until it fell out of the sky?
 

RotorWash

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Yes it was a bit windy (10-12 mph). I'm trying to figure out the behavior it would have followed. I had SuperPatcher installed with the Smart Battery Mod. The battery last reported at 12%. At what battery percentage would it start the emergency auto landing (if at all)? Or would it just drift at that altitude (atti mode) until it fell out of the sky?
It will usually hit critical battery at 10% but it can start before that depending on altitude. It will autoland at this point. That's why I figure with the slow movement of the craft it probably didn't go too much further in the direction it was going given the level the battery had left.
 

Tonyf85

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It will usually hit critical battery at 10% but it can start before that depending on altitude. It will autoland at this point. That's why I figure with the slow movement of the craft it probably didn't go too much further in the direction it was going given the level the battery had left.
At time 1m 42.6s , the 'Message' column says 'Go home command failed (reason: Execution of this process has timed out).'. Since the battery was still at 15%, I believe that was me pressing the RTH button on the controller (which obviously failed). Any idea why this 'command failed' msg would happen?
 

RotorWash

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When the drone goes into ATTI mode it drops GPS hold/nav and without GPS no form of RTH will function as it needs GPS to work. About your only course of action in such a situation is to fly back manually if possible or land somewhere safe asap. Looking at your speed data again, it doesn't appear correct for the time/distance traveled so if the drone was traveling faster than indicated it could be further out from the LKP than I first thought. It may have autolanded right in the general area where it lost connection for the last time or maybe drifted, I'd guess, for up to another minute or so at whatever speed the wind pushed it before autolanding in that SE direction. Doesn't look to be an easy place to find a small drone either but wishing you luck.
 

ndaru

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I see what you mean... odd. Doesn't the mission start at WP1? I do notice a small piece/tail of the mission path hanging off WP1; that seems odd also. On the Litchi map the last known position (LKP) is slightly off from the Google Earth map. Any idea which one is more accurate? For example, I drew a 1 and a 2 on this map; 1 is the Google Earth LKP, and 2 is the Litchi map LKP.

View attachment 12705
Sorry for your loss. I also had my drone lost before, so I know the feeling.

Anyway, your flight record is a bit strange. Looks like the drone didn't go through the waypoints, but went straight south east all the way to Terry Rd.

But since your drone is above Terry Rd when her battery was down to 12% and her speed was 0 km/h (she was hovering), I'm guessing that she was still at around the same spot when the battery reached 10% and triggered the autolanding. Factor in the wind speed, and the 30 meter altitude, then the actual landing spot should be around Terry Rd or Inggrid Ct.
 

Tonyf85

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When the drone goes into ATTI mode it drops GPS hold/nav and without GPS no form of RTH will function as it needs GPS to work. About your only course of action in such a situation is to fly back manually if possible or land somewhere safe asap. Looking at your speed data again, it doesn't appear correct for the time/distance traveled so if the drone was traveling faster than indicated it could be further out from the LKP than I first thought. It may have autolanded right in the general area where it lost connection for the last time or maybe drifted, I'd guess, for up to another minute or so at whatever speed the wind pushed it before autolanding in that SE direction. Doesn't look to be an easy place to find a small drone either but wishing you luck.
I would like to know why it went from waypoints mode to GPS mode, then to atti mode. If I inadvertently hit a joystick, would that immediately stop the mission and put it in atti mode?
 

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