developed although thetechnical difficulties arestillfarfromsolved. 92.Withregardtodetection, radarremains theprimary sensorabovethesurface. Therearemanytypesofradar: surface andairsurveillance, height-finding, navigational andsoforth. Withair-borne radarsurveillance, surface ship formations areabletoestablish adetection zonearoundthemselves reaching out morethan700km.Withtheuseofintegrated computers, targetidentification and tracking datainformation issenttoatactical information processing systemthat canindicate theoptions ofweapons appropriate todealwiththethreat. Thereis nowalsoincreasing useofsatellites fordetection purposes, eitherfor photographic intelligence usinghigh-resolution camera equipment orusingadvanced technologies suchasheat-sensing devices orverysensitive radar. 93.Belowthesurface, sonaristhemostimportant detection system. Modern active sonarequipment canbeoperated fromships, submarines, helicopters or devices dropped byaircraft. Whether thesonardevices areship-borne ortowed (sonardevices towedbelowthesurface soastoavoidsurface layers wheresound transmission isbad),active sonarrangecanreachover30kmunderfavourable conditions. Whereas activesonartransmits underwater pulses andthencollects I...A/40/535 EngliSh Page31 returnresponses, passive sonarisineffect alistening devicethatdoesnotmake itsowntransmissions. Passive sonarenables submarines tolistentoexternal underwater noiseswithout revealing theirownpresence through transmissions. In general, passive sonarhasamuchlonger underwater rangethanactive sonar. However, theseaenvironment issodiverse thataqUietsubmarine hidingina cold-water layerstillhasagoodchanceofeluding detection. Inpractice, nuclear submarines areoftenthebestvehicles tocarryoutanti-submarine operations, andseveral countries havedeveloped specially designed classes of submarines forthispurpose. Inordertoincrease theirchances ofavoiding detection, submarines aresometimes coatedwithaspecial anechoic surface material thatabsorbs someofthesonarstriking it,and any internal machinery thatmay vibrate issuspended onspecial mountings. 94.Theelectronic revolution hasalsogivenbirthtoanother veryimportant facet ofnavalwarfare, electronic countermeasures (ECM),byuseofwhichpotential targets endeavour toevadedetection, ortoconceal theirtruepositions and movements ortoconfuse incoming attacks bymissiles orotherweapons insuchaway astorendertheattacks unsuccessful. ECMdevices andtechniques varywidely. Somearecomparatively simple, suchasthejamming ofenemyradartransmissions, whileothers demand averyhighdegreeoftechnology andextremely speciali~ed eqUipment. Various electronic countermeasures existWhich,ifusedintime,can seektoturnmissiles asidebutwhichcanalsobeneutrali~ed byelectronic counter-countermeasures (ECCM). D.Weapons systems 95.Technological developments baveprofoundly altered theweapons carried by warships. Themissile isnowottenthestandard mainweapon, replacing thegun, andtherearemanytypeswithawidevariety ofmissions. Sincethefirstmodels wereintroduced inthe1950s,missiles havebecome muchlighter andbeenmuch improved. Deployed insubmarines, surface vessels, helicopters andaircraft, they canbeusedagainst surface, air,sub-surface andlandtargets. Therearealso missiles thatchangetheirmedium, forexample, starting offasmissiles abovethe surface andbecoming torpedoes belowthesurface. Missiles havevarious typesof guidance systems, ranging frominertial systems toradarorinfra-red sensors, usually withanactive homingdeViceforthefinalapproach. 96.Missiles canbeentirely independent oncetheyarefired, knownas "fire-and-forget", ortheymaybeguidedforpartofthetrajectory, either bythe initial launching platform orbyarelayguidance vehicle, suchasahelicopter. Eachtypehasadvantages anddisadvantages. Thefire-and-forget missile islimited inrange(outtothe hori~on, i.e.40km)anditstrajectory cannot becorrected, butitallowsthelaunching platform tominimi~e itsexposure tocounter-attack by
**Analysis**
The text appears to be discussing the technological advancements and capabilities of naval warfare, including radar, sonar, and missiles. It highlights the importance of electronic countermeasures and the development of specialized equipment for detection and tracking. The text does not mention economic, environmental, or social aspects, but rather focuses on the technological aspects of naval warfare.

**Category**
Science and technology, Industry