Emlid

Community Forum

PPK Setup


(Superblock Technologies) #1

Hi all,

I just send email to support team and the auto-reply requested me to send the inquiries in this forum for quicker response so hope experts here can help. Im pasting the email here

Blockquote We are BIM Solution provider in Malaysia. We have been looking at your products and need a few technical inputs to help us decide. Would be awesome if your team could enlighten us on your products regarding the following questions.
1. is it possible to use Mavic Pro;
2. Phantom 4 Pro is already discontinued as being claimed by local re-seller;
3. How many Ground Control Point are required if we use your product? Some websites claim need to establish 5 GCP for PPK or RTK purpose;
4. Your base have removable batteries or its a rechargeable built in batteries?
5. Do you have local support team?
6. Lets say we have 9km of road alignment to be surveyed and we break it into 500 meters for each survey. How to go about this?
7. We plan to extract point clouds, surface and monthly progress photo of the site for the whole project duration. We aim to collect the data every 2 weeks, 2 Drones, 1 on standby and 1 on duty with extra batteries of course and it will be 2 days field works.
8. Can you propose a setup for us because we need to provide details to our clients.

Regards


(Michael Lambert) #3

I don’t think this is the right forum for the majority of these questions as they appear to be much more pointed towards drone mapping. I will take a run at it though.

The first question that needs to be answered is what software are you going to use for photo capture? This will determine most of the specifications for what drone and the best flight characteristics to use. Generically though,

  1. A Mavic (2?) Pro is capable of mapping, but it is probably not the best choice for a PPK system due to how small it is. it’s number one selling feature is the portability correct?
  2. While it appears that the Phantom 4 has gone out of production, there are plenty of them left and the camera is still superior to the Mavic 2 Pro as far as mapping is concerned. It is also much more suitable for a PPK equipment installation.
  3. The more ground control points you use the better, but in my experience you can decrease the number of ground control points by 60 to 70% compared to non-PPK mapping without affecting accuracy. That said, house with pretty much any other mathematical process involving trigonometry you will want to have at least three ground control points at all times for maximum accuracy. The shape of the subject site will more likely determine the number of ground control points then anything else. I personally like to run 5 so that I can box in the site and have one in the center.
  4. The Emlid Reach RS+ and RS2 receivers have internal non-removable batteries. The M+ requires an external 5v power source.
  5. I don’t think so, but I will let Emlid answer this one.
  6. This is another question that will be determined by what flight software you use, but in my opinion it is always best to master plan and then subdivide.
  7. Sounds like a good plan to start with.
  8. I would recommend the Tuffwing Snap PPK set up for the Phantom 4 Pro. It will require the additional purchase of a reach RS+ receiver to be used as a base station, Reach M+ receiver for the drone, Tallysman antenna and 5 volt LiPo battery.

http://www.tuffwing.com/products/Phantom_Reach_PPK_Integration_kit.html

All said, you should be able to complete the setup including an extra battery for around $3,000 each. Hope this helps!


(Superblock Technologies) #4

Thanks @chascoadmin
with the setup at #8 does this means all M+ captured data is pushed to the image metadata?

My options or flight plan will be drone deploy and post-processing will be done in Agisoft


(Michael Lambert) #5

Ok, good I am a DroneDeploy Council Member as well. Agisoft is also a great product. The photos do not get tagged directly and this is the nature of a PPK solution. The final coordinates are not determined until after the fact. If you use the A-Shot then you could run RTK and tag the images, but I would not recommend RTK on a drone. Barely with a multi-frequency setup like the Phantom 4 RTK. I have the A-Shot and believe in the concept, but plan on plenty of testing and comparison to PPK before I ever try to implement it for business.


(Michael Lambert) #6

I guess that I could add that I have a great workflow for retagging the images in the PPK solution.

  • I would recommend an image editing software like ACDSee to eliminate the loss of a flight due to poor exposure. I am kind of picky on the “beauty” of the maps I put out so I enhance all my images to reduce blowout and shadows.
  • While the computer image enhancement is working you also process the GPS logs in RTKLIB. The goal is to acquire a GPX file.
  • The GPX file is then used in Geosetter to retag.

While it may seem like a bit of work it only takes me about 30 minutes to retag 300 images.


(Michael Lambert) #7

Cross-Post from the DroneDeploy Forum. @goetker did a great write-up on the P4RTK post-processing. Similar workflow, but also helpful if you decide to go the P4RTK route. RTK can be turned off and then data can be run with PPK.


(Tatiana Andreeva) #8

Hi @superblock.tech,

Just want to point out that DJI Mavic and Phantom cameras don’t have a hot-shoe, so there is no easy way to integrate them with Reach for saving time marks. With these drones, it’s better to use Reach RS+ survey kit for placing GCPs.

We don’t have local support teams. However, we’re always ready to help and answer all your questions here and at support@emlid.com.


(Superblock Technologies) #9

hi @tatiana.andreeva

If we setup another drone setup such as Matrice 100 and equip with a mirrorless digital camera with hot shoe using your Reach M+ means all GPS info will be pushed to the shots metadata automatically?


(Christian Grüner) #10

As far as I know, no such solution exists on the market, and probably never will for stand-alone cameras.
The root problem is the timing of the position.
While many cameras do accept an NMEA stream, that stream would be delayed at least 0.5 seconds. That amount of time is almost an eternity, when we talk about RTK/PPK photogrammetry. Here we deal in milliseconds, or even microseconds, if the position is to be within a few cm when processing (which is kinda the point).

We could try to dream some kind of functionality, where the M+ would send the camera a list of positions in order of when they were taken, and keep the image in memory until the position was given from the m+. However, 1 single missed trigger-event in the m+, and you’d have to inspect it all again.


(Michael Lambert) #11

Are you talking RTK now? I think I said it before, but there’s no sense in writing metadata to the image in a PPK scenario because the solution is not had until post-processing has completed. All the hot shoe does is write an event to the M+ so the events GPX file can be created later to retag the images.


(Tatiana Andreeva) #12

Hi @superblock.tech,

As was already mentioned above, Reach M+ can’t push position data to the camera directly. It just records time marks to raw data each time a photo is taken.

To get the centimeter accurate coordinates you need to PPK this raw data log with the base RINEX file. In the result, you get the solution file containing the precise position of each photo. You can then assign these coordinates to photos in special software.