# Multi-Sensor System for Analysis of Maneuver Performance in Olympic Sailing
## 1 Introduction to Olympic Sailing Research  
Following the research on the International Laser Class Association (ILCA) Olympic dinghy class from [PERSON] et al. [1] and [PERSON] et al. [2], this paper presents a system for multi-sensor measurement and analysis of maneuver performance, utilizing motion sensors such as global navigation satellite systems (GNSS), inertial measurement units (IMU), and potentiometers for rudder and mast angle measurements.  
Dinghy sailing is a technical sport with high demands for tactics, technique, and physical endurance to respond effectively to wind, waves, and current changes [3, 4]. Olympic sailing regattas are carried out on predefined race courses consisting of upwind (towards the wind), downwind (away from the wind), and broad reach (perpendicular to the wind) sections [1, 5]. During upwind legs, the sailors perform a course change through the main direction of the wind. These maneuvers, called \"tacking\", are made to approach the top mark against the wind [6, 7]. Olympic sailing typically involves fleet competitions with mass starts over 10-12 races before gold finals.  
ILCA 6 and 7 are Olympic sailing classes in the single-handed dinghy category, requiring simultaneous adjustment of the rudder, sail, and body position to optimize propulsion toward the desired direction. A detailed description of the tacking maneuver for the ILCA 7(formerly called the Laser) can be found in [8]. Among Olympic classes, ILCA sailers are considered to have the highest demand for physical fitness, as they dynamically adjust their hiking position without the aid of a trapeze (contrary to the 49 er skiff, etc.) [3; 9; 10; 11]. In addition to physical load, continuous analysis of wind changes, waves, and competitors makes ILCA sailing mentally demanding [12].  
Maneuvers, physical fitness, boat speed, and tactics are the main contributors to sailing performance in Olympic competitions [4; 13; 14]. Velocity Made Good (VMG, defined as the relative velocity vector towards an upwind mark) and distance traveled have been shown in analysis to be of great importance [4; 15]. Further, a range of studies have employed simulated, numerical, or controlled environments to analyze ILCA sailing performance [5; 16; 17; 18; 19]. A range of studies investigate the physical demands of dinghy sailing [3; 9; 10; 13; 20]. The tactical and technical aspects, on the other hand, have received less attention in research. This is largely due to the lack of in situ sailing data available for analysis and difficulties in replicating realistic conditions in a simulated environment [16; 21]. High-quality scientific research demands repeatability, an inherent challenge of in situ testing in marine environments. However, a recent comprehensive review of sports performance research highlights that athletes and their teams are more interested in research directly applied to the sport in the field, recognizing that performance limits are ultimately tested in real-world conditions, not in the lab [22].  
A recent study on the frequencies of motion for the ILCA 6 included the in situ testing and data collection of global positioning (GNSS) and inertial measurement unit (IMU) data to identify the amplitude and frequency of boat roll in medium-wind conditions [2]. Modern sailing computers include GNSSs and IMUs for calculating the roll and pitch of a boat [23], allowing analysis of speed and orientations as demonstrated in [2]. Looking at the available data for analysis, there is a need for more sensors to expand our understanding of the physical-technical details in sailing. We present a setup for multi-sensor measurement and analysis of tacking technique and performance in elite dinghy sailors. The main aim of this study is to increase the understanding of how different actions, such as rudder movement and mast rotation, influence tacking performance. The setup is demonstrated in situ with an elite ILCA 7 sailor.