GlideTrack is a simple mobile tracker for glider flying. It works in conjunction with the GlidePort.aero track visualization and analysis web app. It sends high-resolution flight track data to GlidePort.aero so that spectators can view your flights in real-time (or later). GlideTrack also allows you to send text messages that can be seen in GlidePort.aero.
This is a minimal functionality reference implementation, it illustrates how to use the GlidePort.aero API. GlideTrack source code is available at github.com/glideport/GlideTrack. However, GlideTrack is fully functional, you can use it to track your flights in real-time!
Create a GlidePort.aero user account if you do not already have it. To create a user account go to GlidPort.aero and register. When you submit your registration information you will receive an activation email. Click the link in the email to complete the registration process. If you don't receive the registration email, check your spam folder.
Once you have your GlidePort.aero account, run GlideTrack on your mobile phone, enter your GlidePort login name (your email), and click save. If needed, update the glider information that will be associated with this tracker.
Prior to your flight, if you need to update your glider information, tap "Settings". Alternatively, you can edit your track in GlidePort.aero after the flight.
When you tap "START" to start tracking, GlideTrack uses the phone GPS to record your track and to periodically send it to GlidePort.aero, nominally every 2 minutes. If there is no cellular phone connectivity, it will keep retrying until it is able to successfully send data. If you stop tracking and start again within 15 minutes, the old track will be continued.
To send a message, enter your message and tap "Send". To resend a recent message, tap the message so that it appears in the message box, and tap "Send". Note that messages can only be sent when tracking is ON.
Tap "STOP" when back on the ground.
- It is recommended to run the app and start tracking a few minutes before you fly. That way the GPS will have time to get a good position lock.
- It is important that your phone has a good view of the sky in order to get a good quality track. For example, if you keep the phone in your pocket, you will not get a good quality track.
- GlideTrack is not optimized for battery life. It is recommended that you plug it into an external battery if you plan to do long flights. E.g., you can buy cheap 12V-to-USB adapters and phone cradles on eBay.
Here is what my setup looks like -- the phone is plugged into the main battery and has a good view of the sky.
iPhone mount and power cord.
Side view. The USB power adapter is visible in the bottom left.
GlideTrack is tolerant to poor cell-phone coverage. When there is no coverage, GlideTrack keeps recording tracking data. When it is finally able to send data, it sends everything that has been collected up to that point.
Note that mobile tracking will not be as reliable as satellite tracking (e.g., SPOT or inReach). However, mountain flight tests in Colorado Rockies indicate that mobile tracking works suprisingly well. Here are two typical mountain flights at high altitudes. The pink/red circles indicate locations where GlideTrack was able to successfully send tracking data.
| 
The quality of current phone GPSes for flying applications is not as good as flight recorder. For example, it is not uncommon see erratic GPS altitudes and GPS "teleporting". One thing thing that makes phone GPS perform poorly is the internal phone GPS filter which is designed and tuned for walking and driving; e.g., you don’t see erratic altitude when you drive around. Note that it does get better as you run your phone for a while, provided the phone has a good view of the sky.
The location of the phone is very important --- it must have good and consistent view of the sky in order to produce good quality fixes. The GPS quality degrades if it has to switch lock to a different set of satellites, e.g., you get one view of the sky when you are straight and level, and a different view of the sky if you are banked.
Note that GlideTrack has no GPS filtering whatsoever since its primary intent is to be an example app how to use the GlidePort API, and thus simple. Third-party flying/tracking apps using GlidePort API should have filtering to improve track quality. In any case, iPhone 6 will reportedly have a pressure sensor, so at least that will fix the erratic altitude problem completely.
The diagnostic mode can be turned on in the Settings screen. In the diagnostic mode successful data transfer events are recorded in the flight track. This is useful for analyzing mobile coverage in your flight area. Also, in this mode all GPS fixes (typically at 1s interval) are sent, as opposed to fixes interpolated at 4s interval.
The GlidePort.aero API is open! Any gliding software can use the API to send high-resolution track data to GlidePort.aero so that spectators can follow flights in real-time.
The GlidePort hi-res track API is described in API.md. The heart of
the api is the gt call. It is designed to be as minimal and as simple as
possible. You essentially pass IGC data (fragment) in the body of an http POST
request. See Track.js for how it is used.
GlideTrack is implemented in HTML5/JavaScript for simplicity. It does not use any third-party libraries. It can be built into a native app using Cordova/PhoneGap. The API can of course be used from any language.
NOTE: GlideTrack currently only keeps tracks in memory, it does not save them. In other words, if you kill the app or if the app crashes all tracking that has yet not been sent will be lost.
There are a lot of defines in Manager.js, Settings.js, and Track.js. The important development mode defines are:
DBGINFOin Track.js: Switch to true to include transfer info in the track. This is useful for analyzing mobile coverage in your flight area.LOG_ALLin Manager.js: Switch to true to send raw GPS fixes to the ground. The default is to send fixes at 4s interval.API_URLin Settings.js: Change tohttp://test.glideport.aero/apifor development.- In Manager.js init() method, uncomment line
this.geoloc=(new gt.Sim)....to feed in simulated flight track locations instead of using the phone GPS.
Important: These four values should be switched to default for deployment.
See TERMS.md.
Copyright (c) 2014 TipTop Software, Inc., All Rights Reserved.