To measure low-level angular vibrations such as 10.sup.-6 radians at frequencies from zero to 10 kHz in a small device two embodiments of vibrators are used: one having two parallel spaced-apart steel plates connected at their bottom end to a platform through a magnetic path and aligned with the direction of an axis of rotation of the plate and the other having a tuning fork. Between the steel plates at their upper end in the first embodiment is mounted a source of magnetic flux which, when ener...

A velocimeter being readily adaptable for measuring the magnitude and direction of velocity of a moving element. A transducer is responsive to the moving element and produces an output signal having frequency variations proportional to the transducer velocity. A circuit is provided for measuring the variations in frequency and producing a DC output signal as a function thereof.

The present invention relates to velocity measuring devices wherein the center frequency of a pattern of backscattered energy, proportional to the relative velocity between two objects, is detected. In particular it improves the accuracy of prior art systems by desensitizing the device to variations in distance between the device and the reflecting surface. This is achieved by interposing in the receiving section of the device a limiting aperture which restricts the backscattered energy contribu...

An apparatus for detecting the speed information of an object comprises a light source device, a frequency shifting device for shifting the frequency of a light flux from the light source device, a light-flux dividing device for dividing a light-flux whose frequency is divided by the frequency shifting device, one of the divided light fluxes divided by the light-flux dividing device being projected onto an object to be measured and the other light flux being projected in a direction other than t...

A heterodyne velocimeter system includes an illumination laser that illuminates a moving object with a coherent, laser beam. The laser illumination is reflected from the object as separate wavefronts (referred to as the signal light) and is passed through a range-focus lens pair, a polarizer element and through a partially reflective, partially transmissive element onto a plurality of separate light sensitive elements of a sensor which are referred to as pixels. A second source of laser illumina...

A Doppler velocimeter includes an illuminating system for projecting a light beam for measurement onto an object to be measured at a predetermined working distance, and a light-receiving system for receiving light from the object illuminated with the light beam by the illuminating system. Information relating to a speed of the object is detected by a Doppler shift of the light received by the light-receiving system. The Doppler velocimeter further includes a changing device for changing the work...

A muzzle velocimeter comprising a pair of sensors positioned adjacent to the path of a projectile containing magnetic material wherein each of the sensors includes a permanent magnet having a wire coil wound thereon. The magnets provide magnetic fields which are disturbed by magnetic materials in a passing projectile causing each of the sensor coils to develop signal pulses. The distance between the sensor coils and the amount of time between the sensor coil pulses are used to calculate the velo...

A velocity measuring system utilizes a pair of magnetic sensors each moun in a displaced location with respect to the other on a vehicle whereby such sensors passing over the same stationary base location at different times provide geomagnetic field signals to a correlator circuit for producing a value for the ground speed of the vehicle.

An aircraft velocimeter comprises means for projecting three pairs of independently generated ribbon-shaped laser beams to a measurement volume located at a predetermined distance from the aircraft with a predetermined separation being maintained between the two ribbon-shaped laser beams of each pair at the measurement volume. The times of flight of atmospheric aerosol particles between the two ribbon-shaped laser beams of corresponding pairs of laser beams are measured as the aerosol particles ...

This optical velocimeter may be installed in an aircraft to measure the true airspeed and the angles of attack and of sideslip of the aircraft. Alternatively, the velocimeter may be mounted in a wind tunnel to measure the velocity of the airstream passing through the wind tunnel. In either case, the points of reference for measurement are the large number of aerosol particles that are entrained in the air and are assumed to have the same velocity as the oxygen and nitrogen molecules of the air i...