Sports Telemetry
July 11, 2013, Motion Tracking Developers’ Conference, San Francisco—David Troup from Xensr talked about the telemetry needs for extreme sports. This area calls for much more than just adding sensors and an RF link to a person or a piece of equipment.
Data for extreme sports have special requirements. The gross quantification of data has to take into account environmental variables, precision, sensor fusion, high data rates to capture the rapidly changing forces, and high dynamic range. Essentially, the sports are not able to GPS for anything except gross initial localization, since the GPS updates too slowly to be of any use.
The evolution of the sensor package started with an iPhone as the sensor hub. A dongle held the combo sensors on a small PCB. They found that the sensors had to align with the iPhone sensors to get realistic results. Nevertheless, when they used the first systems in a Red Bull windsurf contest, the results were impressive. The riders changed their behaviors with their knowledge of placing and event readings, and the dynamics of the competition changed when everyone could get real-time height measurements.
The integrated apps and data display changed the event, while also highlighting the need for sensor alignment as the alignment errors were easily detected. They found that they needed an integrated multi-axis, multi-sensor platform that included a CPU, GPS, barometer, accelerometer, and gyroscope.
Other efforts showed that there are no common variables across the extreme sorts spectrum. As a result, they collect lots of extra data and compensate in the CPU. They can now provide real-time data to the contestants that is meaningful and, through links to the phones, to the event officials. Even though they have gone to a complete sensor package on a separate board, they still have to deal with sensor saturation in many of their sports. Momentary forces can exceed 20 Gs in various sports.
Their next step is to integrate the sensor data with other apps and video and provide real-time data through the phones. The spectators can become involved through the social media components of the apps. They also want to synchronize the video of the event with the sensor timelines to reduce the editing efforts.
In all of their extreme sports instrumentation, they consider the jump measurements the hardest. There is a lot of noise and loading of 14-22Gs on the landings, and in some events, the launch point is not level with the landing point. Every event and sport requires real-world testing to ensure realistic measurements.
The next generation will be smaller, wearable, and wireless, and not depend upon the smart phone as a platform. Video integration with the sensor data need a lot of work. they have a SDK to help others with localization, data processing, and managing raw data.
