Has anyone tested newer cellphones with dual-frequency GNSS/GPS with Collector? Any noticeable improvement in accuracy?

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10-18-2019 01:44 PM
KyleLandon
New Contributor II

Here's an overview of phones with the dual-frequency chips:

https://medium.com/@sjbarbeau/dual-frequency-gnss-on-android-devices-152b8826e1c 

It's hard to find good info and nothing with respect to Collector. People using gps testing apps were still getting 4m at best.

The pixel 4 was just announced with this note:

⁸Dual Band (L1+L5) or (E1 +E5a). Support - coming soon

So maybe the phones right now don't have proper software support?

10 Replies
DougBrowning
MVP Notable Contributor

Yes we have been testing but so far not many devices tested are actually using it.   I have a S10+ and a Note 9 test device but no Note 10.  I have a personal Pixel 1 but not a 4.

I asked our tester and he said this...

As far as Dual band L1/L5 frequency chipset use we have confirmed that the S9 does have the chip but the firmware does not support it. We have not heard any updates as to whether the current fleet of Galaxy S/Note devices will use any dual band chips, after doing our accuracy testing there were no significant improvements in either the S10 or S10 plus devices under heavy canopy where the dual band is really supposed to shine, however the Note 10 device really seemed to be significantly better under canopy than the other devices we tested. It came out at about 6-7 meters in heavy canopy situation and seemed more consistent as well than most of the other devices. It's possible this device may have firmware to utilize the new chip set, but this is not verified as of yet....

DanAllen
Occasional Contributor III

The December update for the Pixel 4 is supposed to add the dual band support.  I downloaded the GPSTest app and it shows my phone tracking the L1 and L5 US satellites.  Collector for ArcGIS app still shows 12 foot "reported" accuracy, which is probably a value it picks up from the GPS string as an estimate value.  Not sure if there is additional setup in Collector that has to happen to use the dual band, similar to a high accuracy GPS profile you need to use a high accuracy Bluetooth GPS receiver.

I also noticed using the GPSTest app on android, it seemed to show my spot on the aerial very close to where I was standing.  When i switched to Collector (on my pixel 4) it jumped my position a good 10 feet from where I was standing relative to the aerial photo.

DougBrowning
MVP Notable Contributor

Dan I just got a Pixel 4 and have used GPS Test before.  How do you tell it is using the 2 bands?

Our org did a lot of testing trying to get the Note and S10 to work in dual band but with no luck.  It has the chip but no firmware to support dual bands.

Thanks

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DanAllen
Occasional Contributor III

Hi Doug,

I am not an expert by any means but I read in another post if on the "status" tab in GPSTest if the CF field shows "L5", then your device is seeing the second band.  Right now I am seeing 23 of 40 total satellites L1 & L5 inside my office.  That number went up a bit outside.  Now whether apps outside of google maps or GPS status can actually do anything with that extra L5 info is outside my area of knowledge.  If I recall these apps usually get some kind of core location NMEA GPS string from the device that give a position and an estimated error value, if I remember from previous reading on this topic.  There are NMEA string recording apps out there to create a log file of what your device is reporting to the apps.  Might be worth seeing trying to see what it is reporting.

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DougBrowning
MVP Notable Contributor

Thanks I am not seeing a CF anywhere.  I do see two different symbols under the satellites.  I will ask our device testers and see how they checked.

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DanAllen
Occasional Contributor III

Hit the button in the top left of the app, then select status.  you should see a row of ID numbers, flags, then next field is CF.  Also, assuming your phone is on the december update for the pixel.  Although, i still don't see and "official posts on the google pixel forum about this feature being active, despite seeing a few android news outlets reporting it was turned on with the december update.  so who knows.

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DougBrowning
MVP Notable Contributor

Turns out I was using the app GPS Test by Chartcross Limited (space) but you are using GPSTest by barbeauDev (nospace).  I got GPSTest (nospace) going and my Pixel 4 is using L1 sand L5.

But as you say it does not seem to actually improve anything.  GPS Test stops getting lower at 3m and never better.  GPSTest goes down to 3.8 and never any better.  This could just be Android reporting a min of 3m ever.  I read somewhere once it will never actually report better than 3m in the software (liability?).

Both Collector and 123 are both reporting 12.4 feet - so right at the 3.8 m.

Hope that helps?

See this article for more info

https://medium.com/@sjbarbeau/dual-frequency-gnss-on-android-devices-152b8826e1c  

Other quote

"There is a bit/lot of confusion because chips report “theoretical” accuracy and that’s now under 1 meter with DF, however no one’s seen anything better than 3/5 meters I believe with actual testing. It’s not hard to see why, tiny GPS antennas, interference, etc…DF on smartphones is going to be mostly useful on smartphones to eliminate “bounced” signals in deep urban canyons."

In my last job we did a lot of testing and in the end it had way more to do with the size of antenna then anything else.  This is why a bad elf is no better for example.  Once we added a antenna the size of a dinner plate it got way better.

DanAllen
Occasional Contributor III

Using the GPSTest app you can put in the location of a known point and it will tell you how far you are from it.  Using my Pixel 4 I went out in the parking lot at work, where I have a sewer grate I located with our survey trimble r10.  I input those coordinates to GPSTest, and it said my pixel 4 was 7 to 8 feet away when i was standing with the phone over the sewer grate.  I stayed there for a good 5 minutes and the accuracy valued pretty much stayed in that range.  The skyplot said I was tracking 24 satellites, including three US L5's

I flipped over to the Collector app (Beta version), and it jumped about 20 feet away, then slowly came back to roughly were I was.  I collected three points about a minute apart with collector.  Looking at them back in the office.  the spread between the three points was only 0.4 feet, but they were 13 feet away from the survey point reference I was using.

So at this moment, the Collector app does not appear to be taking advantage of the L5 band like the GPSTest app is, just based on the location shifting without me moving going back and forth between the apps.

Anyone care to suggest if I am doing something wrong in this testing?

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MichaelDavis3
Regular Contributor

We have tested pretty extensively with a Xiaomi Mi8 and the Collector Beta - and no, despite verifying that L5 signals are in use there is no real improvement in accuracy so far.

We've been testing on and off for a couple of years now whenever a major Android update rolls in.  At this point I'm fairly convinced dual-frequency GNSS on mobile isn't really going to live up to the marketing hype from the chipmakers and manufacturers.