P4M is still pretty new but I am wanting to know how to execute a Mapping mission using P4M with RTK ground station where the agricultural field is NOT flat.


A paddock with a uniform slope from 0 to 90m vertically over 1000m will mean the drone will be at a relative height of only 10M to the ground IF the mission height is a uniform 100m from the ground at take-off to completion.

Surely the P4M was designed to not only undertake missions on land that is flat like irrigated corn and wheat crops as in the sales videos. What about Macadamias, Avocados, tea or a significant number of other agricultural crops grown on sloping land?

The P4R has the ability of Terrain awareness but from what I understand this is not able to be used with the P4M.
I am using P4M, RTK, GSP for the mission and DJI Terra for the post flight processing.

Is this problem solved using other non DJI tools/ mission control apps?

Thanks in advance

  

No answers from moderators ..Nice

I came  here to ask roughly the same question. I see you got nowhere. I am still in the setup stage and have not flown it yet. I am flying woodland rehabilitation and analog plots over steep territory. I am assuming, from Terra and GS Pro, that I cannot follow terrain. My other constraint is I will be setting up the ground station away from the plots and at a different altitude. Terra seems to address it by having  settings for mission altitude and relative altitude. It does not show up in GS Pro. Maybe it does when I link the ground station to the RC. So if you find anything on your question I would be interested in the answer.
I was also told to add an altitude error to the ground station of 1.807m. I assume that is the height of the receiver. My sense tells me it would be -1.807. Waiting on an answer from the supplier on that.

Euc Posted at 9-18 05:45
I came  here to ask roughly the same question. I see you got nowhere. I am still in the setup stage and have not flown it yet. I am flying woodland rehabilitation and analog plots over steep territory. I am assuming, from Terra and GS Pro, that I cannot follow terrain. My other constraint is I will be setting up the ground station away from the plots and at a different altitude. Terra seems to address it by having  settings for mission altitude and relative altitude. It does not show up in GS Pro. Maybe it does when I link the ground station to the RC. So if you find anything on your question I would be interested in the answer.
I was also told to add an altitude error to the ground station of 1.807m. I assume that is the height of the receiver. My sense tells me it would be -1.807. Waiting on an answer from the supplier on that.

You are correct - this is still an unanswered question. I have flown several missions on gently sloping terrain (height variation 50 m) an have had no problems reconstructing maps with this data flying at 120 m. I did compensate to some extent by flying the high and low areas with a 25M differential in altitude.
In Australia we are able to access geodetic survey data providing terrain height, but I have not yet found a way to incorporate this into a mission plan.
You will be aware that you can fly point-to-point and re-set your altitude at each point, but I don't think that you can take mapping pictures between points in this mode.
The 1.807m seems over-accurate to me and is probably a conversion from 6 ft to metric. If you have a ground point elevation you need to ADD the height of the GS to that figure to obtain the elevation of the GPS sensor. If you are using the GPS indicated GS elevation you would subtract the 1.8m from that to get the ground elevation. Does that make sense to you?
I think it's only relevant if you are surveying, making volumetric assessments or 3D modelling and for agricultural work not so important.
If I find a work-around I will post it here.

djiuser_3b2SInTyI3Bz Posted at 9-18 13:25
You are correct - this is still an unanswered question. I have flown several missions on gently sloping terrain (height variation 50 m) an have had no problems reconstructing maps with this data flying at 120 m. I did compensate to some extent by flying the high and low areas with a 25M differential in altitude.
In Australia we are able to access geodetic survey data providing terrain height, but I have not yet found a way to incorporate this into a mission plan.
You will be aware that you can fly point-to-point and re-set your altitude at each point, but I don't think that you can take mapping pictures between points in this mode.

Thanks. iThings and using DJI software is new to me despite having DJI gear for the last 5 years.
I purchased the drone through a Sydney company. They use the importer for support I believe, and they were great. It is just a steep learning curve particularly since I am using it for a different scenario than it is aimed at, particularly in terms of landscape and vegetation. Support told me there may be a follow terrain update.
I am in Aus as well. QLD. I can access 1m contours  for some areas (QLD Data), otherwise,  5m contours. So I can figure the Alt difference between my base location and the mission area.
Yes thanks, I understand your explanation. I take it the value would be input into the base station Z value? And it did seem pretty precise to me as well.
I have asked elsewhere, but doesn't hurt to ask...If my base /home is some distance from the mission area (say 100m) do you know if the drone flies up to mission alt then to the mission start point or does it fly diagonal to the mission area altitude (start point)?
Other than the moderator, responses seem pretty quiet on Multispectral threads.

Euc Posted at 9-19 00:52
Thanks. iThings and using DJI software is new to me despite having DJI gear for the last 5 years.
I purchased the drone through a Sydney company. They use the importer for support I believe, and they were great. It is just a steep learning curve particularly since I am using it for a different scenario than it is aimed at, particularly in terms of landscape and vegetation. Support told me there may be a follow terrain update.
I am in Aus as well. QLD. I can access 1m contours  for some areas (QLD Data), otherwise,  5m contours. So I can figure the Alt difference between my base location and the mission area.

Hello Euc. I too am Qld - Brisbane, with our survey ares of interest in N. NSW.
I did see an interesting DJI drone video taken in Colorado (I think) with very rugged terrain. It seemed to be flown at a height sufficient to clear the highest peaks and I was not looking at terrain detail when I saw this so cannot comment on GSD details.
Our seller too has been most helpful, but DJI is less forthcoming. A bit like the early days of computers - "it's in development"!
On a mission the drone will climb vertically to its set altitude then fly a direct line to the mission start point. On completion it will fly a direct line to above the base station then descend vertically. You can program the RTB height independently of the mission altitude - handy if you are doing a 3D building survey! I can recommend buying (or making) a 'target' landing zone. Having a bullseye or cross makes it much easier for the vision system to home in om the target for precision landings.
If you would like to contact me directly it's jamesauld@bigpond.com

Thanks. I’ll send an email.