Zero Hz on the GPS page after using Map view

[gplracerx]

I made a comment on the XGPS160 thread using Google maps, but now I've been able to reproduce this inside HLT. The XGPS160 is connected to HLT (iPhone 4s, iOS 7.1.2) and shows 10Hz on the GPS page. I switch to Map and drive around. I get the green markers on the map. I switch back to the GPS page and it shows 0Hz, but the latitude and longitude continue to update. The XGPS160 is using the latest firmware 1.3.5, but it did the same thing with 1.3.0. Is this iOS or HLT? How would I go about generating a connection log file for this particular situation?

[Harry]

I assume that's a problem with parallel access to the XGPS by both iOS (Location Service triggered indirectly by Apple Map View) and LapTimer (using the direct accessory access). In case you can reproduce it, please log the situation from GPS/OBD Buddy following the viewtopic.php?f=8&t=1933 how-to. GPS/OBD Buddy includes the Map View and accesses the XGPS160 just like LapTimer. So it should be the same. Please turn on the following Trace Classes: GPS/GLONASS Sensor, Sensor Timing, Accessories, Timer.

Please check if you can get the update rate back to 10 Hz by sending LapTimer to background and pull it forward again too. This resets the sensor connections and probably works around the problem.

- Harry

[gplracerx]

I've sent a trace. It took a while to reproduce the problem.

Unfortunately, once the problem started again, I couldn't get rid of it. Sending the program to background didn't work. Killing and restarting the app didn't work. Rebooting didn't work. I could sometimes get the device to show a 10Hz update rate on the GPS page, but the date and time windows were orange and on the timer page, there's a pause marker on the checkered flag icon at the top rather than a rotating line. Sometimes there's a 10Hz update rate but the date and time frames alternate between orange and white. Sending the program to background tends to toggle between the various modes. The sensor list shows the XGPS160 as connected and the satellite view works. The SkyPro app shows the XGPS160 connected and functioning.

I'm going to leave everything off overnight and see if that helps.

[Harry]

Hi,

Thanks for sending. Can you please verify the time you logged that data has been around 00:52 am UTC? Any unser interactions while you log that data (going to Map etc), or is this simply viewing the GPS View? Thanks!

- Harry

[Harry]

Hi again,

At least I see the symptom that makes update rate counters and time stamp warning color show yellow... LapTimer tries to keep a measure for system time / UTC time deviation (including work arounds for run time effects on system time level). This is a rather cumbersome area but allows mixing of user and automatic timing operations. I see an underflow in timestamps here that creates the issue. I have added a work around already (v18.3.1) but would like to understand how this configuration can occur.

So in case you can reproduce the issue again, can you please include a "LapTimer wake up" into the logging? So the procedure would be to reproduce the issue (GPS view), turn logging on, send LapTimer to background, wait a few seconds, pull it forward again, verify the issue is still visible, finish log, and send it again.

Thanks a lot!

- Harry

[gplracerx]

After sitting overnight, the problem went away. I'm going to leave it on for several hours in map view to see if it comes back. I have some screen shots of the GPS page during the problem that I will upload shortly. Considering that altitude, heading, latitude, longitude, date and speed update on the GPS page but slope doesn't, which I presume is calculated from the speed and the rate of change of altitude, timing does seem to be the issue.

The UTC time stamp appears to be correct, but I'll check the screen shots to be sure.

[gplracerx]

Here are screen shots taken during the problem:





It's hard to reproduce. It may take several hours with both the XGPS160 and the BT1 connected and spending lots of time in map view. Local time is US Eastern Daylight, so -4 hours from UTC.

[bulls23]

These problems kind of sound like the ones I've been having with my VBOX Sport for quite a while now. Although in my case I can't say it's due to the use of the map view but simply a connection or initialization problem. Everything from turning on / off the VBOX and the iPhone, unpairing / pairing, sending to background or restarting the App...sometimes one of these actions will eventually succeed and I can connect to the VBOX, sometimes (like at the moment) it simply won't work for days, despite all I try...really learning to hate the VBOX...passionate hate! But even in this situation the VBOX will work and connect to the Racelogic Apps without a problem...but not to Laptimer. I even sometimes get the combination of the pop-up connection error in Laptimer but 10Hz GPS through the internal GPS in Laptimer. 99% of the time I immediately get the connection error pop-up when starting the App. Would it be useful to log with GPS Buddy while it's in this condition (meaning not connecting to HLT)?

[Harry]

Here are screen shots taken during the problem:
t's hard to reproduce. It may take several hours with both the XGPS160 and the BT1 connected and spending lots of time in map view. Local time is US Eastern Daylight, so -4 hours from UTC.

Yes, I'm aware of the symptom, I could see this from the logs. The time field coloring and update rates are based on system time and that is the part that "underran". Btw. as LapTimer uses UTC NMEA time for recording, it is well possible everything works fine even when displaying something like the snapshots.

In case you can reproduce it, please send the log including the app startup as requested, otherwise LapTimer version 18.3.1 should have this fixed from the workaround I have added. Not the nicest solution, but it should work. So please so not spend to much time on it (although I appreciate it).

- Harry

[Harry]

These problems kind of sound like the ones I've been having with my VBOX Sport for quite a while now. Although in my case I can't say it's due to the use of the map view but simply a connection or initialization problem. Everything from turning on / off the VBOX and the iPhone, unpairing / pairing, sending to background or restarting the App...sometimes one of these actions will eventually succeed and I can connect to the VBOX, sometimes (like at the moment) it simply won't work for days, despite all I try...really learning to hate the VBOX...passionate hate! But even in this situation the VBOX will work and connect to the Racelogic Apps without a problem...but not to Laptimer. I even sometimes get the combination of the pop-up connection error in Laptimer but 10Hz GPS through the internal GPS in Laptimer. 99% of the time I immediately get the connection error pop-up when starting the App. Would it be useful to log with GPS Buddy while it's in this condition (meaning not connecting to HLT)?

Hi Alex,

These items are not related. The problems you mention should be fixed in version 18.3 (a question of days, submitted since last Friday). While your item is purely on connection making, gplracerx's is a LapTimer internal processing issue. To be fair, yours is not a VBOX problem, it is simple some unexpected behavior during interaction. I think it needs to be named an "incompatibility". But again, I could reproduce the named issues. After applying the tweak to 18.3, I have tested all kinds of power on/off and app start / background / kill variations I could think of - and I did not get an error again. Keep my fingers cross.

- Harry