Vive trackers losing tracking / dongle placement

[Thor777]

I need some help with Vive tracker (2018) tracking issues. I use 3 trackers along with the Index for full body tracking. I have tracking issues on all 3 trackers and am trying to troubleshoot. I've done all of the usual troubleshooting steps....no reflective surfaces, turning off WiFi, changing USB ports (2.0, 3.0, 3.1), testing one tracker at a time, swapping dongles, etc....I also purchased the Inateck USB 3.0 PCI-E card. But so far nothing has fixed the tracking issues. I'm trying different locations for dongle placement now. I made sure they are at least 3 feet away from the PC. But does it matter where the dongles are placed elevation wise? The trackers are used on my waist and feet, so would it benefit to have the dongles on the ground?

Edited May 24, 2021 by Thor777

[HackPerception]

@Thor777 With this level of troubleshooting, I would suspect only a few options

• You have very strong RF/Bluetooth interference in that local environment which is preventing the trackers from talking to the dongles. Radio Towers, Strong WiFi 2.4 signals, etc...
• Your base stations are on the same channel (more common than you'd think).
• You have some weird SteamVR/PC-specific thing. Try on a friends VR setup if possible.
• Could be software. Nuclear option is reinstalling Windows - if it survives that then that rules out alot of things.
• You actually do have a reflection in the environment that's not obvious because the object is reflective only in IR

 

Test for a reflection using the following method:

Quote

Reflective surfaces" in practice are extraordinarily hard to track down without specialized equipment because materials interact differently with IR light than optical light. A material may not be reflective in the visible spectrum but may be highly reflective in the IR spectrum; the same is true with opacity, some visibly opaque materials will be complete transparent in IR and vice versa. To detect reflections, generate a system report or open up the SteamVR web console and search for the term "back-facing". I'll post an example of what a reflection looks like in the logs below.

• Sun Jun 26 2016 23:02:09.676 - lighthouse: LHR-4E8EF209 H: Dropped 32312 back-facing hits, 2069 non-clustered hits during the previous tracking session

 

[Thor777]

Dropped 1648 rejected updates, 11698 back-facing hits, 9350 non-clustered hits during the previous tracking session

Dropped 1200 back-facing hits, 1 non-clustered hits during the previous tracking session

I have 53 of these in my latest system report. So I guess there is/are IR reflective items in my playspace?

Are these back-facing hits caused only by reflections and not something software related? If so, it would save me a lot of time by stopping my troubleshooting on the PC and focus on physical objects in my room.

Edited May 26, 2021 by Thor777

[HackPerception]

11698 back-facing hits would be a moderate reflection issue. It depends on how long that session covers. That's definitely enough to cause multiple seconds of complete tracking loss.

Back-facing hits are definitely physical reflections. This error code is derived the laser's time of flight calculations and a bunch of other complex sensor maths.

You for sure have some sort of IR reflective surface - so you'd want to try to debug that and see if the behavior improves. There's not a great way to do this without specialized optics. Using a LED flashlight is the best way to do it without special equipment:

 

[Thor777]

I have headlamp I can use to test in the same fashion as in the video. Thank you so much for the help!

[Thor777]

One more question, is a small amount of back-facing hits acceptable, or should I troubleshoot until I no longer get any more of these errors?

[HackPerception]

@Thor777 Depends on how quickly the reflections happen. The tracking system is 120hz interleaved so 100 reflections all in succession is enough to trigger tracking loss. A few hundred in a session isn't bad - when you start getting into the thousands you'll probably notice it. The number in your case is moderate. Over 100,000 in those reports is severe (like a mirror)

I also recommend disabling 2.4Ghz WiFi in your area if possible and seeing if sticking to 5Ghz WiFi helps.

Wood floors can be shiny enough to cause problems.

Try to get that number down and see if that affects your problem. Happy hunting.

[Thor777]

OK, so I've narrowed it down to occlusion. It happens most on my foot trackers. The drifting happens consistently when either of my legs is blocking the line of sight from the basestation behind me. What can I do at this point? Is upgrading to 3 2.0 basestations my only course of action?

Edited June 15, 2021 by Thor777

[HackPerception]

@Thor777 - Depends on if you've squeezed the most of our your current

1.0 basestations needed to be mounted in opposite diagonal corners above head level.

2.0 basestations have none of those limitations. You can move the stations around in whatever way you find maximizes their 120 degree FOV covering as much of your space as possible. In fact, if you mount a 2.0 basestation in a right angle corner - you're actually wasting 40 degrees of it's FOV (see how the stations are inset in the last photo)

Adding a third station would probably help if occlusion is right and truly your problem; but maybe first experiment to see if reposition your two stations helps.

Also be sure to use base station power management, especially if you add a third station. It will prolong their lives greatly. I use an app called BS Companion on iOS since I have multiple HMD.

[Thor777]

I cannot add a third station, I have the original Vive 1.0 ones. They are in opposite corners about 8 feet high. I've already tried reducing the diagonal distance between the basestations. I stand and play in the middle, where it should have the most coverage, and yet the trackers on my feet lose tracking whenever a basestation is blocked from view. So it's not possible to move the 1.0 basestations into different layouts other than in the corners diagonally?