Flight Measurement of a Ski Jumping using Portable Kinematic GNSS

Abstract

In order to improve the flight distance of a ski jumping, the lift-to-drag ratio must be maximized in all phases of the flight. Recently, high-accuracy positioning using kinematic GNSS becomes common, which achieves accuracy at centimeter-level by using carrier-phase enhancement. The purpose of this study is to apply the kinematic GNSS to analyze aerodynamic characteristics in all the flight phases of ski jumping. We have developed a wearable post-processed kinematic (PPK) GNSS receiver named AT-H-02 and measured a ski jumping at the Okurayama jump stadium in Japan. In order to improve the positioning accuracy, we have developed a select method of the GNSS satellites that can eliminate signals deteriorated by jumping hill. By using this method, the fix rate during flight of a ski jumping improved more than 20% and achieved 97.7%. Based on flight trajectory of the ski jump obtained from the AT-H-02, we have successfully calculated the aerodynamic characteristics in terms of lift force, drag force and lift-to-drag ratio.