METHOD AND DEVICE FOR MEASURING SHIP'S SPEED RELATIVE TO SEA BOTTOM Russian patent published in 2006 - IPC G01P5/24 

FIELD: designing hydroacoustic Doppler logs that can be used for measuring ship's speed relative to sea bottom.

SUBSTANCE: novelty in method and device for measuring ship's speed relative to sea bottom is introduction of unit for calculating sum power and difference energy of left- and right-hand spectrums relative to spectrum maximum, difference energy normalizing unit, integrator, multiplier, and adder; proposed method involves spectral analysis of echo signal received separately in frequency bands disposed either side of echo-signal maximum spectrum frequency, measurement of signal mean energy at desired time interval in mentioned frequency bands, and calculation of ship's true speed ν_true from formula ν_true = ν_meas [1 + K (E_l - E_r)/(E_L - E_R)], where ν_meas is measured value of speed; E_l, E_r is energy of left- and right-hand spectrums relative to spectrum maximum; K is constant depending on parameters of log equipment.

EFFECT: enhanced speed measurement accuracy due to compensating for error brought in by echo-signal spectrum relative to its design value.

2 cl, 4 dwg