franchise-star-trek-tng-technical-manual1

10.3 NAVIGATIONAL SENSORS10.3 NAVIGATIONAL SENSORSA terrestrial bird, a living organism, is aware of itssurroundings and uses its senses to find its way from one pointto another, frequently guided by stars in the night sky. Thecomparison of the USS Enterprise to the bird here is an aptone. In much the same way, the Enterprise system constantlyprocesses incoming sensor data and routinely performs billionsof calculations each second, in an effort to mimic thebiological solution to the problem of navigation. While anequivalent number of Enterprise sensors and simulatedneurons (and their interconnections) within the main computersare still many orders of magnitude less efficiently designedthan the avian brain, nonetheless the Enterprise system ismore than adequate to the task of traversing the galaxy.Sensors provide the input; the navigational processorswithin the main computers reduce the incessant stream ofimpulses into usable position and velocity data. The specificnavigational sensors being polled at any instant will dependon the current flight situation. If the starship is in orbit abouta known celestial object, such as a planet in a charted starsystem, many long-range sensors will be inhibited, and shortrangedevices will be favored. If the ship is cruising ininterstellar space, the long-range sensors are selected and amajority of the short-range sensors are powered down. Aswith an organic system, the computers are not overwhelmedby a barrage of sensory information.The 350 navigational sensor assemblies are, by design,isolated from extraneous cross-links with other general sensorarrays. This isolation provides more direct impulsepathways to the computers for rapid processing, especiallyduring high warp factors, where minute directional errors, inhundredths of an arc-second per light year, could result inimpact with a star, planet, or asteroid. In certain situations,selected cross-links may be created in order to filter outsystem discrepancies flagged by the main computer.Each standard suite of navigational sensors includes:• Quasar Telescope• Wide-Angle IR Source Tracker• Narrow-Angle IR-UV-Gamma Ray Imager• Passive Subspace Multibeacon Receiver• Stellar Graviton Detectors• High-Energy Charged Particle Detectors• Galactic Plasma Wave Cartographic Processor• Federation Timebase Beacon Receiver• Stellar Pair Coordinate ImagerThe navigational system within the main computersaccepts sensor input at adaptive data rates, mainly tied to theship's true velocity within the galaxy. The subspace fieldswithin the computers, which maintain faster-than-light (FTL)processing, attempt to provide at least 30% higher proportionalenergies than those required to drive the spacecraft, inorderto maintain a safe collision-avoidance margin. If the FTLprocessing power drops below 20% over propulsion, generalmission rules dictate a commensurate drop in warp motivepower to bring the safety level back up. Specific situations andresulting courses of action within the computer will determinethe actual procedures, and special navigation operating rulesare followed during emergency and combat conditions.Sensor input processing algorithms take two distinctforms, baseline code and rewritable code. The baseline codeconsists of the latest version of 3D and 4D position and flightmotion software, as installed during starbase overhauls. Thiscode resides within the protected archival computer coresegments and allows the starship to perform all general flighttasks. The Enterprise has undergone three complete reinstallationsof its baseline code since its first dock departure. Therewritable code can take the form of multiple revisions andtranslations of the baseline code into symbolic language to fitnew scenarios and allow the main computers to create theirown procedure solutions, or add to an existing database ofproven solutions.These solutions are considered to be learned behaviorsand experiences, and are easily shared with other Starfleetships as part of an overall spacecraft species maturingprocess. They normally include a large number of predictiveroutines for high warp flight, which the computers use tocompare predicted interstellar positions against realtime observations,and from which they can derive new mathematicalformulae. A maximum of 1,024 complete switchable rewriteversions can reside in main memory at one time, or a maximumof 12,665 switchable code segments. Rewritable navigationcode is routinely downloaded during major starbaselayovers and transmitted or physically transferred to Starfleetfor analysis.Sensor pallets dedicated to navigation, as with certaintactical and propulsion systems, undergo preventative maintenance(PM) and swapout on a more frequent schedule thanother science-related equipment, owing to the critical natureof their operation. Healthy components are normally removedafter 65-70% of their established lifetimes. This allowsadditional time for component refurbishment, and a largerperformance margin if swapout is delayed by mission conditionsor periodic spares unavailability. Rare detector materials,or those hardware components requiring long manufacturinglead times, are found in the quasar telescope (shiftedfrequency aperture window and beam combiner focus array),wide angle IR source tracker (cryogenic thin-film fluid recirculator),and galactic plasma wave cartographic processor (fastFourier transform subnet). A 6% spares supply exists forthese devices, deemed acceptable for the foreseeable future,compared to a 15% spares supply for other sensors.