DISTANCE MEASUREMENT DEVICE AND VEHICLE VELOCITY CONTROL DEVICE FOR MAINTAINING INTER-VEHICULAR DISTANCE

The computer (CPU) of a distance measurement device determines the inter-vehicular distance by applying a software filter (weighing means) upon successive values obtained directly from measurement. A vehicle velocity control device for maintaining the inter-vehicular distance include a distance measurement device for measuring the inter-vehicular distance, and the deviation .DELTA.R of the inter-vehicular distance with respect to the target inter-vehicle distance R.sub.S is determined. The vehicle velocity is controlled on the basis of the deviation .DELTA.R in accordance with the PID (proportion plus integral plus differential) control method, and the gains are varied in accordance with the current value of the inter-vehicular distance.