A system and method of controlling operation of a host device in real-time, the host device operatively connected to an optical device and a radar device. The optical device is configured to obtain visual data of at least one object. The object is located at an incline, relative to the host device, the incline being characterized by an elevation angle (ϕ) and an azimuth angle (θ). The radar device is configured to obtain radar data, including a radial distance (r) of the object from the host device, the azimuth angle (θ), and a range rate (dr/dt). The controller is programmed to determine a time-to-contact for the host device and the object based at least partially on a 3-D position and 3-D velocity vector. The operation of the host device is controlled based at least partially on the time-to-contact.