new smartphone, LMP recording very few points. CAT S42 from CAT S41

[pat22043@gmail.com]

I have just replaced my old CAT S41 with a new CAT S42. I've been using Locus Map Pro for ages and love it. But its not happy on my new phone. I'm running version 3.49.1 of LMP. The phone runs Android 10

Over a 3+ hour ride, Locus Map Pro recorded only 100 points. I also run a Garmin GPSmap 64ST to record the track, and it recorded 1353 points. The LMP recording missed a lot of points, it says that the track is about 7 miles long, while the Garmin track says it was 18.8 miles. Clearly the LMP missed a lot.

I am guessing that this is either a setting on the LMP app, or on my S42 smartphone. But I have no idea what could do this.

I've attached the two GPS files

How can I debug this?

[balloni55]

Hello
main problem on new devices are the aggressive akku save options
please take a lock at
https://docs.locusmap.eu/doku.php?id=manual:faq:gps_lost_fix_android6
your device isn´t listed there till now but the path should be clear when you have read this.
Exclude LMP from all those "save" options!

And additional on android10 there you have to allow use "location always" for locus, not only while use,
inside settings of your device.
Wolfgang

[pat22043@gmail.com]

OK, I've read the links. changed the settings for the battery optimization
So for a CAT S42 the battery optimization is controlled by:

setup -> apps & Notification  -> advanced-> special app access -> battery optimization ->all aps-> locus map ->don't optimize

I've changed it and will check next time I hit the trails.

Thanks

[michaelbechtold]

PS: do not forget Wolfgangs "allow use "location always" for locus,"

[pat22043@gmail.com]

I have the Android "location permission" set for Locus to "allow all the time"
and I set the power-saving options to "not optimized"
The attached GPX is better, but still is missing a lot of points (you can see straight lines)

I must be missing something
Thanks

[balloni55]

now it looks better already...
the question is,
what was different in the time from 15:33:19 to 16:47:37 and from 17:16:13 to 17:40:40
and why were the reception conditions worse between 17:9:42 and 17:10:39?

- what are the settings in the recording profile? i have good experience when cycling with: distance interval=10m, time interval=5s, recording condition = distance and time

- for monitoring it is also helpful to record NMEA data while recording >  settings/GPS and sensors/NMEA recording = track recording

[pat22043@gmail.com]

I have no idea why some times were just thrown out. I was also recording a track on my Garmin GPSmap 64ST, and it had no issues, no missed points. It was set to the default "car" setting. I'll change it to your values for my next session.

I've riding a dirt motorcycle. The land is old coal mine land, valleys and ridges. No buildings at all. Usually open sky for good satellite visibility. Of course, sometimes you are along the side of a ridge, so there is solid rock blocking sky visibility to one side

I'm running LMP "as a service" if that makes any difference. I thought it might help keep the operating system from messing with it.

I can try turning on NMEA style output. Other than the format of the data file, what difference does that make?

[michaelbechtold]

The NMEA data is RAW data, coming from Android level, BEFORE interpretation by Locus.
I once had a phone that had a faulty GPS module (or wiring after a repair) and would deliver only 30% of the expected points, and also with huge delays.

[pat22043@gmail.com]

That is a good point. I've also been having the same issue (missing points, long time between locations) on Glympse, another Android application

[pat22043@gmail.com]

Not good news. I got a replacement S42, and setup power and location. Rode my motorcycle on a nearly four hour ride with LMP recording. Over 3:41 there were only 22 "trkpt" entries in the GPX file. I've attached the entire file (its small, since it has very few points)

When I test on local trips around the neighborhood, LMP seems perfect. But when the phone is not powered by a USB feed, and its 100 miles from home, it only occasionally records points.

I'm at a loss. I was sure that getting  a replacement smartphone would solve my problem.

[michaelbechtold]

The GPX file is not relevant in the analysis of your case.
Did you have a look at the NMEA log file? If that has the missing points, then share it with Menion.
If that also has only few (VALID!) entries, then go check ANY power saving setting your device may have.
I know from own experience, that Huawei is BRUTAL when it comes to killing background processes. Samsung is quite decent. LG also OK.
The vendor policy is quite different and may be the key to your issue.

[pat22043@gmail.com]

Sorry, I did not have NEMA turned on for this session.

I have noticed that the GPS works fine when on USB power, such as when I'm using Waze to navigate to the riding area. Most of the trip is on Interstates and there is always good coverage.

When I'm riding, there is no external power, and there is effectively no cell coverage. Its in the middle of nowhere, old coal mining area where the mines closed down decades ago. A big town in the area has maybe 10,000 people, the little ones have a few hundred folks. Not enough population to encourage the big cell phone services to cover the area.

[pat22043@gmail.com]

Did you have a look at the NMEA log file? If that has the missing points, then share it with Menion.

I turned on the NMEA log. How do I access the resulting file?
The track "share" options say "share as GPX" but there is no mention of any other format file
Where might it be?

[michaelbechtold]

On internal SD look for /Locus/data/nmea
Those files can be big, but they are text files.
To understand the format you may look at https://www.gpsworld.com/what-exactly-is-gps-nmea-data/
A message with a valid GPS position looks like $GPGGA,181908.00,3404.7041778,N,07044.3966270,
W,4,13,1.00,495.144,M,29.200,M,0.10,0000*40
You can search in this file for ",N," if you are in the northern hemisphere and ",S," if in the south.

[pat22043@gmail.com]

Got it. It was 4.5 mb in a short run
I don't have any of your $GPGGA sentences, but I've got thousands of $GNRMC

I made this test driving to my grandkid's house to pick them up. Phone using battery. LMP on "run as service" There is great cell service, most of the trip is along Interstate I76 into Philadelphia.