RaceCapture CustomTrackBestPractices

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Walking/Building a Course - Best Practices

Whether you are doing an autocross, rally, karting or whatever else you may race, sometimes you need to create your own course. Fortunately Autosport Labs has you covered for this very scenario with our custom course design tool. Using a GPS enabled tablet or phone with the RaceCapture App, you can define start & finish points as well as sector points along your track.

This page goes over the best practices in creating a course as well as in covers course setup to ensure that you get the best performance from your RaceCapture device.

Basic System Overview

In order to understand these recommendations, its best to first understand how RaceCapture works internally. Below is a brief definition of concepts used internally.


A Geo-Circle is simply a gps point and a distance. We use this information to draw a circle on the map. This is how we implement start, finish and sector points in RaceCapture firmware. When you enter the circle, you have reached that particular point. By default, the radius of a Geo-Circle is 11 meters (~36 ft). Here is what it looks like conceptually:

Race Track StartFinish GeoPoint.png


Geo-Triggers are like Geo-Circles in that they have a gps point and a distance, but they also have one more element: a boolean indicating when the object has been triggered. We use Geo-Triggers on top of Geo-Circles in RaceCapture to prevent false positives results. Here is what it looks like conceptually:

Race Track StartFinish GeoPoint with GeoTrigger.png

Sector Counting

Sectors work like sequential counters. So when you start a lap with sectors on the track, RaceCapture will look for the first sector. When you reach it, it will search for the next. This process repeats until there are no more sectors, at which point it uses the finish point as the last sector point.

Best Practices

Now that you are armed with a basic understanding of how the internals work, these best practices are hopefully very reasonable.

Avoid Overlapping Geo Circles With Other Parts of the Track

Because Geo-Circles are triggered when a vehicle enters them, we must be careful in where we place them. Overlapping Geo-Circles can cause unpredictable results such as early finishes, early sector time values. This often occurs because drivers can take different drive lines. Some lines may trigger the event while others miss the Geo-Circle, and thus don't trigger the event. If there is a chance that a Geo circle overlaps an earlier part of the track, adjust its position away from the overlapping portion to prevent a false trigger. Here is what an overlapping Geo-Circle might look like:

Geo Circle Overlapping.png

In Stage Mode, Drive 25 M From Start Before Next Run

Start/Finish points in RaceCapture are protected by a Geo-Trigger. Geo-Triggers are present to prevent false triggering of Geo-Circles when start and finish locations are close together. The Geo-Trigger radius is configured to be 2x the Geo-Circle radius. This means the default trigger radius is 22 meters (~72 ft) since the default Geo-Circle radius is 11 meters. In order to trigger a Geo-Trigger, you must leave the boundary it covers. Thus, if you on a Stage course (like for autocross), then after you finish you must ensure you drive than 72 feet away from the start point before you make your next run. Otherwise, RaceCapture may not trigger the start event.

Use RaceCapture's Launch Control Feature

Since the release of 2.8.0 firmware, RaceCapture has supported Launch Control, a feature that allows you to start from a dead stop in the start Geo-Circle and have RaceCapture properly record the start timing. This feature is available for the first lap on Circuit tracks and for every lap on Stage tracks. On Stage tracks, see the previous note about driving 25 M from the start point before your next run after finishing your previous run.