Speed sensor and head-mounted data display

摘要

A transmitter is mounted for movement with a skier or other self-propelled sportsman and transmits ultrasonic or electromagnetic waves toward the stationary medium over which the skier or sportsman is moving. An element of the same transmitter or a separate transducer detects waves reflected from the stationary medium. A computer calculates the speed of the skier or sportsman from the Doppler shift of the reflected waves and actuates a readout unit to indicate the speed to the skier or sportsman. The readout system has a head-mounted display including a character generator and a semitransparent reflector in which the character generator is viewed so that the speed indication appears superposed over the normal background in the viewing direction.