Many disabilities may impair a disabled wheelchair-user's capability in maintaining an accurate course using the conventional joystick controls. This paper describes systems being developed, using low cost ultrasonic sensors, to provide additional data to supplement that derived from the joystick whilst still leaving the user in overall control. Methods are described for following a straight course parallel to a wall, which is one aspect of an ongoing research project to provide comprehensive low-cost navigational assistance for disabled wheelchair-users.