Abstract: An accelerometer calibration system calibrates an accelerometer for use in, for example, an ocean wave environment in which the accelerometer will ergo generally oscillatory acceleration. The accelerometer calibration system includes an simple harmonic motion ("SHM")-derived accelerator and a processor. The SHM-derived accelerator applies an SHM acceleration to the accelerometer. The accelerometer generates an output signal having an amplitude related to the acceleration applied thereto. The processor controls the SHM-derived accelerator to apply selected accelerations to the accelerometer, receives the output signal from the accelerometer and generates a profile relating the accelerations applied by the sinusoidal acceleration means to the amplitude of the output signal.

Abstract: A wave measuring buoy for measuring ocean surface wave amplitude, frequency and direction of propagation is disclosed. The buoy includes a single-axis accelerometer suspended as a pendulum inside a water-proof housing. The water-proof housing is connected to and beneath the flotation hull of the buoy and is located at the center of rotation of the buoy assembly so that the accelerometer is substantially insensitive to roll and pitch motions of the buoy. An inclinometer and a compass are fixedly mounted inside of said flotation hull. Inasmuch as the inclinometer is fixed in the water-proof housing it responds to the pitch and roll motions of the buoy and the compass indicates the direction of said roll and pitch. The output of the accelerometer is an analog signal proportional to the vertical (heave) acceleration of the buoy. The outputs of the inclinometer and the compass are analog signals which indicate the pitch and roll of the buoy and the magnetic heading of said pitch and roll.

Abstract: A wave measuring buoy for measuring ocean surface wave amplitude and frequency is disclosed. The buoy includes a single-axis accelerometer suspended as a pendulum inside a water-proof housing. The waterproof housing is connected to and beneath the flotation hull of the buoy and is located at the center of rotation of the buoy assembly so that the accelerometer is substantially insensitive to roll and pitch motions of the buoy. The output of the accelerometer is an analog signal proportional to the vertical (heave) acceleration of the buoy. A frequency transfer calibration can be applied to the accelerometer output to compensate for the mass, size and resonant heave behavior of the buoy.