Gps goes Haywire And... lagging in reception.

Hi, I’m wondering why all of a sudden when I use Pix4D Catch it can make a jump and the GPS goes haywire. It jumps back and forth, causing me to see very strange point clouds.
(I drive with the phone’s own GPS only. ) But it jumps back and forth from full reception to i1 dash and switches back and forth. I love this app and think it’s great but on Android I wish there was a way to turn GPS off almost completely or something.

I have two different SIM cards in the phone that are on different “networks” but it should be there so you can only use GPS and remove other networks or whatever…

Because an entire scan can be destroyed because in the middle it starts to lag like this, for example. the wall becomes horizontal instead of vertical. and lots of different weird things. etc.

Is there any solution to this?
(Im fron sweden if that matters :wink: sorry for bad English)

Hi ola,
Are you making very fluid movements with your device? It is important to not be erratic when capturing data. This is because the IMU (inertial measurement unit) is tracking the fine movements of the device. If you are making quick movements or pivoting rapidly then the IMU cannot track what is happing, and the orientation data written to the image exif will not be correct. This will cause poor reconstruction. Thus, it is important to be very smooth when capturing.

No, I move very slowly.
I can even stand completely still and see when it suddenly jumps.

I have tried different settings and turning off e.g. mobile data and things like that (I was wondering if it made it switch between different cell towers or something?) But it’s the same thing for me all the time… It can work great for a while then all of a sudden after maybe 100 pictures it “jumps” like turns the whole pointclod up a notch…

VERY annoying when you get “two models in one” or whatever they say. I have also tried with different mobile phones.

2 different Samsung before but right now I use a Xiaomi T11.

But other than that, I really think you do a great job and I love the app! It’s the best! :slight_smile:

Hi @ola,

May I ask what version of PIX4Dcatch are you using? Can you make sure you are using our latest version of PIX4Dcatch?
Are you using the app indoors or near buildings?

Best,

This behavior sounds strange. Along with Nikoleta’s request. Can you please share a project/s along with the logs? We are very interested to see what could be happening here.

image

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I will send a shared drive link for you to use in a direct message for ease of transfer.

Regards,
Jon

I am using version 1.16.0 and last updated on December 16, 2022.

I recorded my screen using an app that is supposed to show my postion where it really looks like it’s jumping around!

I don’t think Pix4D is the problem here. But I would very much like to know if it can be solved somehow?

Because it doesn’t matter if I’m indoors or outdoors, it ALWAYS happens to me…
Here’s a link to the screen recording:

As you can see, I have made an X where I am.

As I wrote before, this is in a different app just so I could see if it behaved as strangely there…
and the answer is absolutely YES.

Very annoying. But I’ve tried to disable SIM card data and turned off WIFI and everything possible to see what could be interfering but I don’t know what else to do!?

Hi @ola,

Thank you for the video and welcome to the Pix4D Community :handshake:.

As you also noted, because the issue is also happening with other apps, this might not be an issue with PIX4Dcatch app.

From the video, I can see that the orientation of the device changes considerably within a few seconds. Were you moving the device during the screen recording?

I also see that you have already tried to disable cellular data and wifi.
Here is a list of actions that you could try:

Please let me know if any of these suggestions helped you.

Hi @ola,

I further discussed your issue with the GNSS location with the PIX4Dcatch product team. The behavior of the GNSS is indeed strange, but this should not result in "strange point clouds”.

This is because we only use one GNSS location with the best accuracy, so it doesn’t matter if the GNSS is jumping to many locations; the point cloud and reconstruction should be relatively good.
Maybe there is another factor causing the issue. For this, it would be great if you could send us some example projects.

Also, it is possible to turn off the GNSS completely for PIX4Dcatch. To do so, you need to disable PIX4Dcatch in the localization permissions of your device (this is also asked when the app runs at the first install).

Kind regards,
Daniele

Hi,

I found using a camera gimbal helps some with keeping the scan aligned.