NASA's Jet Propulsion Laboratory (JPL) has developed a compact, low-power, self-contained instrument that provides the equivalent of GPS throughout the solar system without the aid of an artificially provided infrastructure. The state-of-the-art X-ray navigation instrument is also able to determine the position of a spacecraft anywhere in the solar system, but it cannot provide this information relative to the Earth, the Sun, or any other remote target body (the equivalent of GPS providing a user's position relative to a vehicle, a second user, or any other moving target). JPL's uniquely capable deep-space positioning system determines the position and the target-relative position of a spacecraft anywhere in the solar system using optical navigation, which makes it ideally suited for any spacecraft requiring deep-space navigation services.
JPL's deep-space positioning system (DPS) consists of narrow- and wide-angle cameras, a coelostat, an S- or X-band receiver and patch antenna, and a central processor that hosts the navigation computations and controls the coelostat. The DPS instrument determines the location of the hosting spacecraft via images of solar system objects and, optionally, via one-way radio to the Earth or another known object from which Doppler observables are extracted. To make the instrument as small and lightweight as possible, a single mechanism combines the pointability of the coelostat with that of the antenna. Additional mass and volume are saved because the wide-angle camera is placed behind the secondary reflector of the narrow-angle camera. That way, the wide-angle camera shares the precise field of the narrow-angle camera, and can provide accurate pointing information for the narrow-angle camera. The DPS is also advantageous because the coelostat can be used to relieve the pointing requirements of the host spacecraft with respect to navigation imaging and radiometric link closure. Most missions require either a reorientation of the spacecraft or a cessation of science activities in order to obtain navigation data when the desired science and navigation targeting are different.
The DPS can be used in deep-space navigation instruments, asteroid reconnaissance and mineral prospecting missions, and the human missions to Mars.