Abstract: A gaseous detection system for detecting the existence of a certain gas and further detecting a certain level or percentage of that certain gas within a prescribed environment. An example is the use of the gas detection system in a motor vehicle or elsewhere to determine when the driver of the motor vehicle may be driving under the influence of alcohol, and alternatively, for providing signals that may be used for evidentiary purposes of the alcohol content in the breath of the driver. The system includes a sensor unit for sensing ethanol in the atmospheric contents of the test person's breath and utilizing fresh air and a reference gas to determine the amount, if any, of blood-alcohol content of a person for evidentiary or other purposes.

Abstract: Apparatus for sensing distances between two objects by using multiple pulses from the detector and from the object to be detected by using a transmitter and not using any reflected waves the reliability and the ability to reject clutter is improved. The periods between transmission are accurately controlled so that there is no signal returned until the object to be detected generates such a signal. As a result it is possible to accurately measure the distance between two objects and indeed the system may be used between two objects when both are in motion.