## 3 Results and Discussion
### Summary  
This study investigated two methods, not previously used, for performance analysis in ski jumping, which will allow measurement of the kinematics and kinetics from the start of the in-run to the landing. The dGNSS was used to describe the kinematics and kinetics for the in-run and early flight phase to the landing, whilst the PosEst system was used to describe kinematics and kinetics of the take-off and early flight phase, using a body segment model. The study was separated into two parts, where the first part compared the agreement of the systems from 5 m before take-off to 20 m into the flight. Trajectory, velocity and acceleration components were compared between the systems for 16 jumps. Good agreement, within the uncertainty of the dGNSS, was found between the two methods from 5 and 20 m after take-off, indicating that the methods agree well in the flight phase, while PosEst performed better in the analysis of the take-off phase. The second part of the study served as a proof of concept of the sensor fusion application, showcasing the types of performance analysis that can be conducted with this system combination. For that purpose data from two jumps were extracted and used to illustrate how start gate, drag and lift influence the instantaneous velocity vector, altitude above ground and finally jump length. The study showed the complementary nature and validity of the methods and their usability in both research and practice.  
Conceptualisation, O.E., M.G. and G.E.; Methodology, O.E., and M.G.; Software, M.G, E.A.F.I, D.G. and O.E.; Formal analysis, O.E., G.E. and M.G.; Investigation, O.E., R.V., P.H. and M.G.; Resources, M.G., P.H., S.B. and G.E.; Data curation, O.E., M.G.; Writing--original draft preparation, O.E., G.E. and M.G.; Writing--review and editing, O.E., M.G., G.E., D.G., E.A.F.I., S.B., R.V. and P.H.; Visualisation, O.E.; Supervision, G.E., M.G., P.H. and S.B.; Project administration, M.G., P.H., G.E., S.B. and O.E.; All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The study was conducted in accordance with the Declaration of Helsinki, approved by the Norwegian Centre for Research Data and the ethical committee of the Norwegian School of Sport Sciences (Ref. number: 98-200619).  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study. All subjects gave their informed consent for inclusion before they participated in the study. The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Norwegian Centre for Research Data and the ethical committee of the Norwegian School of Sport Sciences (Reference number: 98-200619).  
The data presented in this study are available on reasonable request from the corresponding author.  
The authors would like to acknowledge the participation of all ski jumpers and coaches who voluntarily gave their time to this research and also the Norwegian Olympic and Paralympic Committee and the Norwegian Ski Federation for help before and during the data collection.  
No potential conflict of interest was reported by the authors.