Astronavigation

Though Federation space is littered with sensor platforms, transmitter beacons and route markers, spacecraft still use certain astronomical features to orientate themselves, this redundancy in flight navigation is essential outside of Federation territory and allows for craft use in emergency crises where standard navigation nets have been shut down. Spacecraft are apt for finding their own way about in space, they are covered with powerful accurate sensors, which are sensitive to a whole host of different navigational cues. Some of the commonly used natural phenomena are shown below, along with the astrogation techniques that make use of these phenomena.

Star spotting

For supra light vehicles knowing the positions of the stars is not so immediately helpful as traveling across many light years the positions of stars will shift, instead computers will scan the skies for certain unusual stars. An unusual star may be a star with exceptional brightness or peculiar spectral class, by comparing the spectra of these unusual cases a computer can estimate from the known coordinates of these stars whereabouts the ship is. The use of these known standards is at least useful within federation space, and as these stars are observed at distances thousands of light years away from federation space they also provide useful navigational tools outside of familiar space.

Pulsars

A simple sensitive radio telescope will be able to detect and determine the source of these cyclic radio patterns, these astoundingly regular features make exceptionally good beacons. Using the positions of known pulsars the position of the ship can again be calculated. There are however a few problems with this method. The first is that some pulsars have similar frequencies, a problem that is exacerbated when the ship is moving at relativistic speeds as correcting for ‘real’ rate is troublesome. Another problem is that signal strength may vary as the ship’s angle to the pulsar changes (directional beams), another minor problem is the slow spin down of pulsars as one approaches the pulsar (and the radio waves received are therefore younger) the pulsar seems to spin down, this in itself is not a problem if there is certainty of the right object, but such differences can confuse two similar frequency pulsars if other factors do not aid differentiation.

Gravitational wave sources

Using a completely different type of instrument again, mass sensors are able to pick up these tell tale waves, and like pulsars are for the radio spectrum, there are some sources that generate cyclical gravitational waves, such as close binaries or black hole pulsar systems. By tracing the direction of these signals and measuring their telltale frequency to identify them the positions of these sources can be used to extrapolate the position of the space craft. Like with pulsars the direction of these waves tend to be propagated along a particular plane, and attenuation will occur if the space craft is not in a similar plane, using one source alone this may give a false approximation of distance. A feature of this system is that every spacecraft has a good system to detect these signals as the asymmetric propulsion field is uniquely sensitive to these kind of spatial disturbances.

Nebulae

Using the structure of nebulae for navigation is particularly troublesome, they tend to be diffuse and indistinct systems with complex topology, but they have few unique identifiers, mostly their spectrum which serves to fingerprint them. Astrogation based on nebulae alone is imprecise and troublesome, but it does give supporting evidence to other methods. All that is needed for this method is a database of the nebulae fingerprints and a simple scanning spectrometer (infra red usually).

Galaxies.

As these objects are so far away there abilities to determine position within our own galaxy is next to useless, but they do provide that ultimate last resort just to prove that the spacecraft is after all in the correct galaxy. Of more use is using our galaxy's attending satellites, most notably the Magellanic clouds to triangulate some relative positioning of the spacecraft, but again this is imprecise and would only be ever used if the spacecraft was to accidentally transport itself to some far flung corner of our own galaxy (as inevitably happens when poking around with mysterious ancient artifacts).

These methods alone can be used as astronavigation tools, but more commonly an onboard computer will use these techniques simultaneously and a combination of other techniques available to it (comparing the properties of local space with known navigation data, such as particle abundance) as well as comparing to charts from a series of known standards in space and grading similarity to reach conclusive decisions on its whereabouts.

A ship should never really have to perform this task from scratch as it will continuously record its flight path, but occasional checks are made to correlate its apparent movements with real space. The only time where the navigational computer will perform a whole navigational location sequence is either where it had suffered complete system failure and had therefore been traveling blind for a while, or where a phenomena had obscured all its usual sensors and again the ship would have not been able to observe its relative position with space.