wave_height_from_IMU

(DEPRECATED REPOSITORY) Note: For actual implementation see: https://github.com/bareboat-necessities/bbn-wave-period-esp32

Calculate sea wave height from IMU

Algorithm description:

https://bareboat-necessities.github.io/my-bareboat/bareboat-math.html

Kalman filter based on

https://www.researchgate.net/profile/Mehdi-Hendijanizadeh/publication/264713649_A_Novel_Kalman_Filter_Based_Technique_for_Calculating_the_Time_History_of_Vertical_Displacement_of_a_Boat_from_Measured_Acceleration/links/53ec88db0cf24f241f1584c5/A-Novel-Kalman-Filter-Based-Technique-for-Calculating-the-Time-History-of-Vertical-Displacement-of-a-Boat-from-Measured-Acceleration.pdf

And another model is based on vertical acceleration of trochoidal waves

TODO:

generate NMEA 0183 sentence for wave height
run this code as part of pypilot server

MWH - Wave Height NMEA 0183 Approved by the NMEA 0183 Standard Committee as of October 1, 2008

$--MWH,x.x,f,x.x,M*hh
Wave height, meters
Wave height, feet

XDR - Transducer Measurement Talker ID - 'YD' - Transducer - Displacement, Angular or Linear

        1 2   3 4            n
        | |   | |            |
$YDXDR,a,x.x,a,c--c, ..... *hh<CR><LF>

Field Number:

    Transducer Type

    Measurement Data

    Units of measurement A = Amperes B = Bars B = Binary C = Celsius D = Degrees H = Hertz I = liters/second K = Kelvin K = kg/m3 M = Meters M = cubic Meters N = Newton P = % of full range P = Pascal R = RPM S = Parts per thousand V = Volts

    Name of transducer

There may be any number of quadruplets like this, each describing a sensor. The last field will be a checksum as usual.

Example for (reporting displacement of a vessel from mean sea surface due to a wave of -0.33 m height):

$YDXDR,W,-0.33,M,VERT_DISPLACEMENT*<checksum>

Or something like this from Autopilot:

$APXDR,A,-0.087,M,VDIS*<checksum>
$APXDR,A,0.08,,VVEL*<checksum>
$APXDR,A,-0.087,,VACC*<checksum>
$APMWH,3.44,f,1.05,M*<checksum>

VDIS - vertical displacement (m)
VVEL - vertical velocity (m/s)
VACC - vertical acceleration (m/s^2)
$--MWH - wave height (feet and meters)

bareboat-necessities / wave_height_from_IMU

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wave_height_from_IMU