About the Tracker App

This app started life as a normal phone app and has transitioned to a web-app to avoid the cost and maintenance associated with dealing with Apple and Google approved apps.

It's primary poropose started out being to provide race officials with information to better track cars on track. It has transistion to also be used as a 'Navigator' and provide some basic timing functionality. It will NOT reliabily get you real close on time. But it may be an acceptable replacement to a consumer GPS that shows average MPH to the 10th.

The app loads all data when you start it, so it will function in those areas without cell coverage. It does periodically report your location/speed to race officials. It also monitors G-forces/Direction (if available on your device) and will try to differentiate between a car that came to a normal stop on track and one involved in an incident. Speeds collected are not used to DQ participants, but if you are way over/under your allowable speed it may draw attention to you.

The app now allows you to add notes to areas on coarse. You can use these to remind yourself of desired corner entry speed, up-coming timing landmarks or anything else important to you.

Why is the time not more acurate?

There are a few reasons why your phone/this app are not as acurate as the custom electronics used by some racers:

  1. Your phone likely does not use GPS time
    Typically a phone uses the carrier's network time. This will not be exactly the same as the GPS time that timing equipment uses. Since the app uses the your phone's time, a 'perfect' finish according to the app would be off however much your phone time differs from GPS time.
  2. Your phone likely only gets GPS updates once a second
    Most consumer devices receive updates once a second. More expensive GPS equipment often receives updates 10-50 times a second. The app calculates when you cross the finish line by extrapolating where the finish line was between 2 GPS updates. At 150mph you are traveling 220 feet each second. That is a significant distance to assume your speed/direction was constant.
  3. Delays between GPS updates and Web-App notifications
    There is some delay between when your phone receives a GPS update and when the browser on your phone provides that update to the App. The amount of this delay varies by phone/OS version and may even be inconsistent on a single phone. No attempt has been made to account for this delay.

How acurate is it?

Typically we see real world results of about 4 seconds (round trip). Your mileage will vary!