A method and apparatus are described for controlling the attitude of a vehicle in a space having at least two opposed viewable regions, each region being viewed by a respective first sensor for sensing a first frequency band of electromagnetic radiation and a respective second sensor for sensing a second frequency band of electromagnetic radiation, wherein respective first and second data sets from the first and second sensors for each regions are produced, these second data sets are subsequently modified and combined with the first data sets to form respective third data sets for each region. The attitude of the vehicle is then adjusted until the third data sets are substantially equal.