Much has been made about the GPS and website leaderboard at Primal Quest. As a volunteer for both the Lake Tahoe and San Juan Islands races, I’ve got some experience in the technology they are using. I’ll explain a little about how it all works.

GPS: Each team carries a GPS device that is equipped with a satellite phone. In Lake Tahoe, the device was housed in a little dry bag with an antenna sticking out. Obviously the antenna had to have a hole to come out of the bag, so the dry bag wasn’t entirely waterproof. A ton of them stopped working on the first paddle leg on Lake Tahoe so they moved the working units up to the leaders and then had to dry the rest of the units before redeploying them back to the teams. I didn’t really see the units in the San Juan Islands race so I’m not sure if they changed or not. The antenna is attached to the pack of one racer and they are instructed to try to keep the antenna facing the sky at all times. At certain TAs, the Competitio staff replaces the batteries of the GPS and satellite phones.

The GPS records their position in one minute intervals (if I recall correctly) and then every hour transmits the data via the satellite phone up to the database where it becomes live for everyone to see. When you see a team disappear on the GPS or stop moving, it could be that they antenna doesn’t have a clear view of the sky, the unit is having some type of problem, or the team stopped to rest. The satellite phone can also be used in case of an emergency.

Website leaderboard: The website leaderboard is not in any way linked to the GPS data. The website leaderboard is powered by data received from checkpoint staff. Each CP/TA has its own PDA with a custom leaderboard application built in. The leaderboard application shows the time each team reached the most recent CP and shows their team status (Unranked, withdrawn, etc). When a team checks into a CP, the staff records their time into the PDA. When the staff has some free time, they hook the PDA up to a satellite phone and send their data off to the database. Once the data hits the database, it’s live for everyone to see.

Occasionally teams will switch between withdrawn and active, or vice versa, on the leaderboard. This is most likely due to checkpoint staff accidentally changing the team status on the leaderboard application and sending the data in. A simple wrong click on the leaderboard application can change the status of a team. You sometimes will see a team skip a checkpoint on the leaderboard but later on it shows the team having reached that CP. If two checkpoints are close together and the later checkpoint sends in the data from the PDA before the previous checkpoint, this can happen. Once the earlier checkpoint sends in their data, the website leaderboard will be updated. That’s the gist of the system.