FollowMe is a mobile real-time GPS tracking application (smartphone only) able to geolocate the user outside and send its position to a Geomatic's REST service.
FollowMe can run on iOS and Android smartphones and implements AppConfig standard (so can be manageable by various MDM).

Table of contents

• System overview
  • Real-time GPS tracking
  • Locations buffering
  • Battery saving mode
  • AppConfig implementation
  • Communication with the server
  • Logs
• Compiling and running
  • Preconditions
  • Project setup
  • Code quality
  • Compiling
• Troubleshooting
• Contributing
• Licence

System overview

FollowMe includes following features :

• Real-time GPS tracking
• Locations buffering
• Battery saving mode
• AppConfig implementation
• Communication with the server
• Logs

Real-time GPS tracking

Device location is recorded only with the GPS chipset in foreground and in background. The tracking can be deactivated by a switch on the main screen. In order to limit request and useless computation, the app filter each point received from the device chipset, by applying rules defined in settings (interval / distance).

Locations buffering

App send GPS point to the server on each tick. If the device can't reach the server, locations are stored in a sqlite local database until the connectivity is recovered.

Battery saving mode

The battery saving mode is enabled by default and can be disabled in settings. Eco mode's behavior is based on 2 battery's levels (inter / max) defined in settings. :

• If the battery level is below intermediate level : the GPS tracking will be less aggressive (depending on device capabilities)
• If the battery level is below max level : the GPS tracking is automatically stopped and the app don't send GPS location anymore

AppConfig implementation

In the current version, the app tries to get 2 variables from the MDM environment :

• disclaimer (String) : content displayed on the first launch or when the disclaimer is updated
• baseUrl (String) : REST API endpoint called by the application to send GPS locations

@see AppConfig.org for more information.

Communication with the server

The app send POST request to the baseUrl defined in the settings. Please find below parameters constituting the JSON object sent to the server :

Parameter	Type	Description
TIMESTAMP	Number	Location timestamp, in ms.
LONGITUDE	Number	Longitude, in deg.
LATITUDE	Number	Latitude, in deg.
ACCURACY	Number	Estimated accuracy of this location, in m. @see Android docs for more information. (docs for value on iOS devices is missing)
BEARING	Number	Bearing, in deg.
BATTERY	Number	Battery level, in %.
SPEED	Number	Speed, in m/s.
UUID	String	Device's Universally Unique Identifier (UUID). @see Android docs and iOS docs for more information.
ID_UNIQUE	String	Unique id (login name for example).
TRIGGER	String	HTPP POST can be trigger by settings update (UPDATE), a new location (MOVE) or a custom interval (SLEEP)
SENDING_INTERVAL	Number	If there is no new GPS point between this custom interval, app send the last point. In s.
SENDING_DISTANCE	Number	Minimum distance travelled by the user since the last point to record the GPS point. In m.
MODE_ECO	Boolean	Eco mode enabled/disabled.
SEUIL_LIMITE_INTER	Number	Eco mode inter level, in %.
SEUIL_LIMITE_MAX	Number	Eco mode max level, in %.

Logs

All locations, computations, settings modifications, tacking activation / deactivation are logged in local file. Path of current local file can be displayed by clicking on app version on settings screen. Log system limit file size to 1MB and global logs size to 5MB.

Compiling and running

Preconditions

The following software must be installed to compile and run the application :

• Node 10
• NPM 6

Project setup

Prepare the application (Ionic + Cordova + all dev dependencies) with NPM :

npm install -g @ionic/cli
npm install -g cordova@9
npm install

More info on Ionic can be found on the Installing Ionic page and the Ionic CLI repo.

Code quality

To run tests and generate code-coverage, use:

npm run test

To send code-coverage to Sonar, fill sonar-project.properties file and use:

sonar-scanner

Compiling

Android

Tested with :

• Android Studio 3.5.1

To package the Android app, first use:

npm run prepare-android

You are ready to build the apk:

ionic cordova build android --prod

Package is now available at : platforms/android/app/build/outputs/apk/debug/app-debug.apk To export signed apk, you can use Android Studio and open platforms/android/ folder.

iOS

Tested with :

• Xcode 12

To package the iOS app (on MacOS environment only), use:

ionic cordova platform add ios
ionic cordova build ios --prod

Package is now available at : platforms/ios/build/emulator/FollowMe.app To export signed ipa, you can use Xcode and open platforms/ios/FollowMe.xcworkspace project.

Troubleshooting

GPS tracking on Android

Some Android vendors (e.g. Xiaomi, Huawei, OnePlus or even Samsung…) implements their own battery savers with side effects on background activity of third-party apps like FollowMe. @see DontKillMyApp.
Luckily there are different workarounds for many platforms, described here.

Contributing

If you want to submit a contribution to this project, simply fork it on GitHub and submit your pull request. We will be glad to review it!

Licence

FollowMe application is released under AGPL 3.0.