A method and apparatus for spread spectrum distance and for spread spectrum velocity profile measurement is provided where the short pulse of traditional ultrasonic and radar level gauges is replaced by low peak power direct sequence spread spectrum (DSSS) modulated energy. An echo sequence subtraction process is provided that increases the signal to noise ratio of each echo sequence thus increasing the dynamic range of the system. In addition to providing a higher signal to noise ratio (SNR), better precision and accuracy in ranging Doppler applications and the ability to use lower peak power transmissions, the system is more immune to interference from the environment and allows for less expensive and less bulky ultrasonic transducers.