Wikipedia
Navcam, short for navigational camera, is a type of camera found on certain unmanned rovers or spacecraft used for navigation without interfering with scientific instruments. Navcams typically take wide angle photographs that are used to plan the next moves of the vehicle or object tracking.
The Mars Curiosity rover has two pairs of black and white navigation cameras mounted on the mast to support ground navigation. The cameras have a 45 degree angle of view and use visible light to capture stereoscopic 3-D imagery. These cameras, like those on the Mars Pathfinder missions support use of the ICER image compression format. European Space Agency Rosetta spacecraft uses single camera with 5 degree field of view and 12 bit 1024x1024px resolution allowing for visual tracking on each of spacecraft approaches to the asteroids and finally the comet.