Precision Landing isn't Precise

Joined
Aug 30, 2016
Messages
182
Reaction score
59
Age
79
Location
Morgan Hill, CA
Second day flying with new P4P. Landing/takeoff pad is 43" bright orange and white. Settings made for precision landing. At auto takeoff, (yep, home point had been recorded), I checked box for precision landing. Drone rose to about 20'. I let it stay there for about 15 seconds. Went and flew around.

Pressed the RTH button and RC announced returning to home. Got a yellow announcement on my tablet during the landing saying something about landing with 0.3' and did I want to continue... I slid the bar over indicating "yes". As the drone descended, clearly, the bird was not going to land on the pad, so I aborted and manually landed.

OK, this occurred on every landing today and there were at least six of them. All were 3 to 5 feet from the takeoff point.

I calibrated the VPS using Assistant 2 last night. IMUs were calibrated. Any ideas as to what is going on? Whatever help you can give would be much appreciated. My friend's P4P hit his landing pad dead center every time today. Maybe I need his landing pad..... ;o)

Thanks!!
 
Although I have often gotten better, 3-5 ft (less than 2 m) is pretty much the gps accuracy of the system.
 
Thanks, Richard... Except the P4P also uses the vision positioning system in conjunction with GPS. Pretty sure it should easily hit a 4' diameter landing pad.
 
Drone rose to about 20'. I let it stay there for about 15 seconds. Went and flew around.
Try ascending straight up until the Phantom is at least 30 feet over top of the takeoff point. There's no need to pause at the top.
 
Second day flying with new P4P. Landing/takeoff pad is 43" bright orange and white. Settings made for precision landing. At auto takeoff, (yep, home point had been recorded), I checked box for precision landing. Drone rose to about 20'. I let it stay there for about 15 seconds. Went and flew around.

Pressed the RTH button and RC announced returning to home. Got a yellow announcement on my tablet during the landing saying something about landing with 0.3' and did I want to continue... I slid the bar over indicating "yes". As the drone descended, clearly, the bird was not going to land on the pad, so I aborted and manually landed.

OK, this occurred on every landing today and there were at least six of them. All were 3 to 5 feet from the takeoff point.

I calibrated the VPS using Assistant 2 last night. IMUs were calibrated. Any ideas as to what is going on? Whatever help you can give would be much appreciated. My friend's P4P hit his landing pad dead center every time today. Maybe I need his landing pad..... ;o)

Thanks!!

John,
Beyond demonstrating to friends how well it works, I don't often use the precision landing feature, however when I have, it's accuracy has always been measured in inches, not feet. So although I can't recommend a fix for why yours is so far off, I would recommend a little trouble shooting thought.

When I observe it in action, I see that GPS brings it to the general location, then it appears that VPS kicks in and results in some minor adjustments on the final path to the ground. So if you VPS is not seeing straight, perhaps it is actually guiding it to the wrong spot. Maybe some comparative test would help determine if the VPS is the cause. Try doing some RTH landings with and without the precision landing feature. If it is actually better with just GPS, then I think you need to look at the possibility that you have a defective VPS or your calibration was not that accurate.

Hopefully this may help you discover if a problem exist.

Cheers.
 
John,
Beyond demonstrating to friends how well it works, I don't often use the precision landing feature, however when I have, it's accuracy has always been measured in inches, not feet. So although I can't recommend a fix for why yours is so far off, I would recommend a little trouble shooting thought.

When I observe it in action, I see that GPS brings it to the general location, then it appears that VPS kicks in and results in some minor adjustments on the final path to the ground. So if you VPS is not seeing straight, perhaps it is actually guiding it to the wrong spot. Maybe some comparative test would help determine if the VPS is the cause. Try doing some RTH landings with and without the precision landing feature. If it is actually better with just GPS, then I think you need to look at the possibility that you have a defective VPS or your calibration was not that accurate.

Hopefully this may help you discover if a problem exist.

Cheers.

Thanks, Traveler... First, I'm going to make sure I go to 30' at takeoff. If that's not the answer, I'll give it a shot with vps turned off. When I calibrated vps, Assistant 2 reported the calibration as successful.

My flying buddy mostly uses Litchi and he's the one who lands within inches every time. I'll also be giving it a shot using Litchi and see how it does.
 
Thanks, Traveler... First, I'm going to make sure I go to 30' at takeoff. If that's not the answer, I'll give it a shot with vps turned off. When I calibrated vps, Assistant 2 reported the calibration as successful.

My flying buddy mostly uses Litchi and he's the one who lands within inches every time. I'll also be giving it a shot using Litchi and see how it does.

Welcome,
Be sure to let us know how your test goes. BTW, I use Litchi too, but I have only used DJI Go 4 for precision landings.
 
Welcome,
Be sure to let us know how your test goes. BTW, I use Litchi too, but I have only used DJI Go 4 for precision landings.

I've used Litchi quite a bit with my P4. Mostly for waypoint missions. Love it! Had the P4P not behave very well on a simple mission yesterday. Going to try a new mission this coming Thursday. Keeping my fingers crossed.

Don't like having the thought that I might have a bad bird.
 
I've used Litchi quite a bit with my P4. Mostly for waypoint missions. Love it! Had the P4P not behave very well on a simple mission yesterday. Going to try a new mission this coming Thursday. Keeping my fingers crossed.

Don't like having the thought that I might have a bad bird.

With respect to using Litchi, same here, almost exclusively for Waypoint missions.

I am curious if you are on the newest FW, 1.04.xx.xx?

It has had its share of reported bugs, while others report being happy with it. For myself, I downgraded to 1.03.xx.xx. I think I'll wait for the next version.

I'm keeping my fingers crossed that you didn't get a bad bird. I had problems day one with my P3P and my personal experience with DJI's customer service wasn't good.
 
Don't be so quick to suspect one's equipment when using 3rd party add-ons. Evaluate the suspected equipment on its own merits.
 
With respect to using Litchi, same here, almost exclusively for Waypoint missions.

I am curious if you are on the newest FW, 1.04.xx.xx?

It has had its share of reported bugs, while others report being happy with it. For myself, I downgraded to 1.03.xx.xx. I think I'll wait for the next version.

I'm keeping my fingers crossed that you didn't get a bad bird. I had problems day one with my P3P and my personal experience with DJI's customer service wasn't good.

Yes, I upgraded to the latest fw when I got the P4P. I talked with my flying pal and he was using that fw. It is the 1.04.xx.xx version. If I have issues on Thursday I'll probably downgrade one version. Bought bird from Amazon. Have 30 days to return it.

I believe the RC version didn't change with latest update. Can you confirm that?

Thanks!
 
Yes, I upgraded to the latest fw when I got the P4P. I talked with my flying pal and he was using that fw. It is the 1.04.xx.xx version. If I have issues on Thursday I'll probably downgrade one version. Bought bird from Amazon. Have 30 days to return it.

I believe the RC version didn't change with latest update. Can you confirm that?

Thanks!

There was a RC update too. I recall that when we went to 1.04 on the AC, we had to update the RC before it would connect properly. However when I downgraded the AC to 1.03, the connection was fine on the RC with the new FW, but I downgraded that too. You can use the assist to do the AC and the Go app for the RC, but again I don't think you have to downgrade the RC.
 
There was a RC update too. I recall that when we went to 1.04 on the AC, we had to update the RC before it would connect properly. However when I downgraded the AC to 1.03, the connection was fine on the RC with the new FW, but I downgraded that too. You can use the assist to do the AC and the Go app for the RC, but again I don't think you have to downgrade the RC.
There was a RC update too. I recall that when we went to 1.04 on the AC, we had to update the RC before it would connect properly. However when I downgraded the AC to 1.03, the connection was fine on the RC with the new FW, but I downgraded that too. You can use the assist to do the AC and the Go app for the RC, but again I don't think you have to downgrade the RC.

Thanks, Traveler... I'll see how it goes on Thursday.
 
Don't be so quick to suspect one's equipment when using 3rd party add-ons. Evaluate the suspected equipment on its own merits.

Agree, but I think the OP said that it was his friend who was having success on precision landing and Litchi. I have never evaluated precision landing with Litchi as the active app, only DJI Go 4. If there is a problem anywhere I'd put my money on the newest FW vs hardware. I guess we'll find out more after Thursday.

A potential FW bug like this could have easily have gone unnoticed as I am doubtful that precision landing is all that popular of a feature. Hand catch and manual landings is probably the norm for most.
 
Although I have often gotten better, 3-5 ft (less than 2 m) is pretty much the gps accuracy of the system.
Ascended from a football field from the intercection of two white lines on the grass. Went vertical for 10 metres then out 200 metres and hit RTH it landed within an inch of the take off point. It even rotated during landing so it was pointing in the same direction at takoff. Yes I know it was matching the take off image. Very impressed.
 
Second day flying with new P4P. Landing/takeoff pad is 43" bright orange and white. Settings made for precision landing. At auto takeoff, (yep, home point had been recorded), I checked box for precision landing. Drone rose to about 20'. I let it stay there for about 15 seconds. Went and flew around.

Pressed the RTH button and RC announced returning to home. Got a yellow announcement on my tablet during the landing saying something about landing with 0.3' and did I want to continue... I slid the bar over indicating "yes". As the drone descended, clearly, the bird was not going to land on the pad, so I aborted and manually landed.

OK, this occurred on every landing today and there were at least six of them. All were 3 to 5 feet from the takeoff point.

I calibrated the VPS using Assistant 2 last night. IMUs were calibrated. Any ideas as to what is going on? Whatever help you can give would be much appreciated. My friend's P4P hit his landing pad dead center every time today. Maybe I need his landing pad..... ;o)

Thanks!!
Did the going on up 30 ft help? I usually go more like 100ft straight up. That might be more than i need but the only time mine hasnt landed under a foot was after trying the poi and then it was about 2' off.
 
I would suggest calibrating the compass. I also agree with ascending to at least 10 metres before flying away.
 

Members online

No members online now.

Forum statistics

Threads
143,054
Messages
1,467,297
Members
104,919
Latest member
BobDan