Jolla: GPS Navigation (updated: bug located)

Update 2:  Navfree above version 2.1.14 doesn't get GPS connection.

Recommended not to update above this version (2.1.14), which seems to be the latest working one.

Update: Location data bug located - I call it a GPS Velocity Bug

User have been wondering why several Android Navigation Apps running on Jolla shows the car location at closeby roads and crossings, or shows you driving sideways / backwards. I've been observing this behaviour the best I can, and by that I'm pretty sure that there is a bug in the velocity data calculation, calculated from the gps data.

Jolla uses OpenSource code Geoclue, originally contributed by Garwin, for location data handling. This code should provide all the needed data very well, so the problem is within Qt or Sailfish code. My findings are based on observations only, so I can only share some possible options for the type of this bug. Either:

•  Location is shown in the Navi app before the direction calculation is done. In this case, the Navi App would assume the direction sometimes as 0 (pointing to North)
• Direction is calculated with inaccurate data. It should be calculated from the last two readings provided by gps, and if either of these readings is occasionally missing or old, the direction could show anything (e.g. making the Navi app to circle the map)
• Direction data is not calculated at all. In this case the Navi app might show it as north all the time. 

In a modern smartphone there are three ways to determine the phone current direction: (1) Directly from the magnetometer data, (2) calculated from that and the accelerometer data, or (3) calculated from two data readings received from GPS. Navi apps are using this method.

Some Navi apps are able to use compass (Magnetometer sensor) as a supportive reading for the direction (e.g. when gps data is missing). Jolla's compass should work fine, but it's currently providing data to only some of the Android apps. (This is another known bug already under work. I'm expecting it to be fixed after Qt 5.3. release). However, this is not related to the velocity bug.

We are also looking forward for a native Navi application for Jolla phones, but it's not expected to be released yet in the next update. I'm not expecting a fix to the velocity bug either unless it's very small, as it was just discovered (well, I suppose some coders have noted this earlier)

Original article 12-Dec-2013

While waiting for updates to HERE Maps features, here's a simple HowTo for installing GPS Navigation to your Jolla smartphone. Voice navigation included, tested to work myself.

INSTALLING

1. Register a Jolla account (needed to access Jolla store in the phone)
2. Open Jolla store and install Android Support (close the store)
3. Open your phone browser, go to address m.aptoide.com/installer.* Install Aptoide store (close browser)
4. Open Aptoide store and search Navfree. Install the application (close the store)
5. Open Navfree, follow the instructions and load your countrymap into the phone. WLAN recommended - e.g. road map files for Finland were 180Mb
   
   *Note: I made a typo (missing e) in the store installing address before. Corrected now.

USAGE

1. Enable Location in your Jolla settings
2. Start the app, wait for GPS lock and on to the road.

TEST NOTES

1. User inteface works perfectly. Navfree has a nice set of settings.
2. Supports voice navigation, POI's, speed cameras, speed limits (in selected countries) etc.
3. Full offline support. To navigate, no connection or SIM card needed. 
4. Sound (finnish tested) was loud and clear, instructions ok too. No need to use with max volume.
5. In my first time, driving was shown in reverse on the map. Restarting the phone fixed this.
6. If you navigate without internet connection, the phone might ask for it. This doesn't prevent the navigation app to talk, but the question screen hides the map. Tap to clear, but it appears again.
7. You can drop the app to your home screen (swipe from left/right). Voice navigation keeps on running, but the map doesn't update in the active cover screen. Tapping the active cover opens the app and updates the map again.
8. Landscape mode works well, even when dropping the app to home screen.
9. If you close your screen yourself (swipe from up), navigation stops talking. I haven't tested if it stops talking when the screen is closed automatically.
10. Navfree offers free map update download 4 times a year

Coming up...

My next app related blog post will reveal how to enable Adobe Flash Player on Jolla, with no special tricks needed. Comments are welcome, if you have wishes for the one after that. Thanks for your visit.