Home Forums 3d Race Replay How RaceQs calculates Wind, VMG and Mark Locations

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    I found the following post on By Natalie Mand on LinkedIn useful:

    1) Wind direction. The app uses a rule based algorithm which assesses the likely wind direction based on the tacking / gybing angles and course shifts on close hauled POS (likely headers and footers). Estimated margin of error is about 3 – 5 degrees in the single boat mode and 1 degree with 5 or more boats are on the race course. This method of calculating VMG although not exact, incorporates the current impact and is more accurate than VMG toward wind without adjustment for the current. The biggest challenge we had faced is how to compare distance between boats with the wind direction slightly different at each boat location. Any ideas how to solve this problem would be highly appreciated.

    2) Mark location. For the “stationary marks” we use NOAA database of all navigation marks in the US and we working to build such database worldwide. For the “temporary marks” the rule based engine “estimates” the mark location based on the boat(s) mark rounding pattern. The same logic as above a single boat will have about 95% accuracy rate guessing the mark location and with several boats on the race course it is 99 % accurate. The users can add, delete and modify mark location during the race replay as necessary. The key element for both wind direction and mark recognition is correct location of the start line, which needs to be provided by at least one boat either during the race of after the race during the race replay. The start line tells the program:
    a. The fact that that a boat is in the race and we can utilize mark / wind recognition algorithm.
    b. The fleet – all the boats who crossed the line with you, therefore we can use multiple boats wind / mark detection.

    3) The iPad release with the NOAA charts is scheduled to be released April next year. The beta version is coming out Jan 2014. Please let us know if you would like to be a beta users for the upcoming release.

    Thanks for your feedback, any farther questions / comments are always welcome.

    • This topic was modified 2 years, 1 month ago by Profile picture Paul White.

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