Up Periscope-Down Periscope; Sub­ma­rine’s Eye at Sea

The periscope is the eye of the sub­ma­rine and is meant to keep a watch on the sur­face with­out it being de­tected by sur­face craft or from the air. Modern op­tronic masts in­clude pre­cise, high-res­o­lu­tion op­tics and in­te­grated sen­sor pack­ag­ing.

SP's NavalForces - - FRONT PAGE - LT GEN­ERAL NARESH CHAND (RETD)

The periscope is the eye of the sub­ma­rine and is meant to keep a watch on the sur­face with­out it being de­tected by sur­face craft or from the air. Modern op­tronic masts in­clude pre­cise, high-res­o­lu­tion op­tics and in­te­grated sen­sor pack­ag­ing. Lt Gen­eral Naresh Chand (Retd)

the PERISCOPE IS the eye of the sub­ma­rine and is meant to keep a watch on the sur­face with­out it being de­tected by sur­face craft or from the air. the prin­ci­ple of the de­sign of a periscope is sim­ple and based on re­flec­tion of ob­jects through mir­rors or prisms but it is ac­tu­ally a com­plex piece of equip­ment. ear­lier periscopes had mir­rors held at 45 de­grees but th­ese were later on re­placed by prisms. they were also rigidly fixed but soon periscopes were de­signed to be man­u­ally low­ered, raised and ro­tated. thus the or­ders down periscope and up periscope was dra­mat­i­cally shown in war movies. Stand­ing watch at the periscope is thus called danc­ing with the gray lady. at greater speeds the periscope tended to bend due to pres­sure thus they were placed in dou­ble tubes, where the outer tube with­stood the pres­sure. another prob­lem was that the ro­ta­tion of the up­per prism caused the im­age to be seen up­side down which was cor­rected later with bet­ter de­sign. Ger­many was largely re­spon­si­ble for mod­ernising the sub­ma­rine periscope. Length of periscopes could be as much as 18 me­tres (60 feet) thus when a sub­ma­rine is submerged at depth equal to the length of the periscope, it is called periscope depth. Due to such large lengths, an ef­fec­tive periscope will re­quire more com­plex ar­range­ment of lenses and prisms and twin tele­scopes fit­ted inside the periscope tube.

the US term sail or the Bri­tish term ‘fin’ of a sub­ma­rine is the tower-like struc­ture lo­cated on the top­side of the sub­ma­rine. ear­lier sub­marines housed the con­ning tower which in­cluded the com­mand and com­mu­ni­ca­tions data cen­tre, periscopes, radar and com­mu­ni­ca­tions masts. now most of the func­tions are car­ried out from the hull thus sail is no longer con­sid­ered as the con­ning tower but the tower is still in use for other pur­poses. Modern sub­marines are equipped with two types of periscopes, one on the right (star­board) side and one on the left (port) side like Los an­ge­les-class nu­clear pow­ered sub­ma­rine USS Spring­field which has a Type 2 at­tack scope on the star­board side and a type 18 search scope on the port side. the type 18 scope is lim­ited to op­er­a­tions in the day­light and takes pho­to­graphs with a 70mm dig­i­tal cam­era which are then dis­played on a tele­vi­sion mon­i­tor. Some periscopes also have night vi­sion ca­pa­bil­ity, a still cam­era, a video cam­era and can mag­nify im­ages. con­ven­tional op­ti­cal periscopes have a few dis­ad­van­tages. first one is that when the periscope is in use then the sub­ma­rine has to op­er­ate at periscope depth which is just be­low the sur­face thus it is easy to de­tect. also a con­ven­tional opti- cal periscope runs the en­tire height of the ship to house the periscope thus it lim­its the space of the sail and in­te­rior com­part­ments. Lastly it can ac­com­mo­date only one per­son at a time. to over­come th­ese dis­ad­van­tages a new an/BVS-1 pho­ton­ics mast has been de­vel­oped which made its de­but in 2004 in Vir­ginia class of uS sub­marines.

Pho­ton­ics Mast

elec­tro-op­tic sen­sors are re­plac­ing the mir­ror-cum-lens ar­range­ment of the con­ven­tional tele­scopes which have done valu­able ser­vice for al­most 80 years. the pho­ton­ics mast (also called op­tronic mast) has a ro­tat­ing head which emerges over the sur­face of the wa­ter and houses mul­ti­ple elec­troop­ti­cal sen­sors. the masts are equipped with a set of sep­a­rate cam­eras in­clud­ing a colour cam­era, a high-res­o­lu­tion black-and- white cam­era and an in­frared cam­era. there is also a mis­sion crit­i­cal con­trol cam­era housed sep­a­rately in a pres­sure-proof and shock-hard­ened cas­ing. an eye safe laser range finder which pro­vides ac­cu­rate tar­get range and as­sists in nav­i­ga­tion, just about com­plete the sen­sor com­po­nents of the pho­ton­ics mast. the elec­tro-op­ti­cal sen­sors are con­nected by fi­bre op­tics cable to twin work sta­tions and the com­man­ders con­trol panel. the pho­ton­ics masts can be con­trolled by a joy­stick from any of th­ese sta­tions. each sta­tion con­sists of two flat-panel dis­plays with a stan­dard key­board. in­ter­face is through a track­ball and im­ages are recorded on both video cas­sette and cD-roM. the smaller size of the periscope al­lows more flex­i­bil­ity in the lo­ca­tion of the con­trol room. in the Vir­ginia class of sub­marines, the con­trol room is lo­cated in the more roomy se­cond deck in­stead of the crowded up­per deck. Pho­ton­ics mast with its elec­tro-op­ti­cal sen­sors pro­vide imag­ing, nav­i­ga­tion, elec­tronic war­fare and com­mu­ni­ca­tions func­tions. they also do not re­tract into the sub­marines hull but open up like a cars ra­dio an­tenna. Pho­ton­ics mast also pro­vide the sub­marines cap­tain space, bet­ter lay­out and im­proved sit­u­a­tional aware­ness.

Global Sur­vey

the pop­u­la­tion of con­ven­tional and nu­clear sub­marines is mi­nus­cule as com­pared to sur­face ships thus the re­quire­ment of peri-

Pho­ton­ics mast with its elec­tro-op­ti­cal sen­sors pro­vide imag­ing, nav­i­ga­tion, elec­tronic war­fare and com­mu­ni­ca­tions func­tions

scopes/pho­ton­ics mast is small. it is also high-tech niche busi­ness. thus there are only few com­pa­nies who de­velop and make periscopes/pho­tonic masts. the com­pa­nies and their prod­ucts are given in suc­ceed­ing para­graphs.

Air­bus DS Op­tron­ics

carl Zeiss op­tron­ics Gmbh has changed to cas­sid­ian op­tron­ics Gmbh from oc­to­ber 1, 2014. cas­sid­ian op­tron­ics is a 100 per cent sub­sidiary of air­bus De­fence and Space and op­er­ates as air­bus DS op­tron­ics Gmbh. Brief de­tails of its prod­ucts are:

Sub­ma­rine periscopes. air­bus DS periscope sys­tems con­tain a high-qual­ity op­ti­cal ob­ser­va­tion chan­nel with a binoc­u­lar tube. their lines of sight are sta­bilised in el­e­va­tion and az­imuth by means of gy­ro­scopes. ob­ser­va­tion and op­er­a­tion are con­trolled di­rectly on the periscope or from a com­bat sys­tem con­trol con­sole. the periscope sys­tems are equipped with var­i­ous high-res­o­lu­tion cam­eras. the stan­dard con­fig­u­ra­tion in­cludes a colour TV cam­era, a resid­ual light tV cam­era and a dig­i­tal cam­era. highly ac­cu­rate long-range and eye safe laser rangefinder can also be in­te­grated in ad­di­tion to the pas­sive op­ti­cal rangefinder sys­tem.

SERO 400 with OMS 100. the Sero 400 periscope sys­tem can be in­stalled and used in com­bi­na­tion with the oMS 100 op­tron­ics mast sys­tem. the oMS 100 op­tronic mast sys­tem is a com­pact state-of-the-art op­tron­ics mast which re­quires no hull pen­e­tra­tion. it is fully au­to­matic thus ideal for mis­sions where the sen­sor is ex­posed for an ex­tremely short time.

SERO 250. the Sero 250 is a com­pact, state-of-the-art periscope sys­tem that was specif­i­cally de­signed for retro­fit pro­gramme so­lu­tions. it can make use of ex­ist­ing hoist­ing mech­a­nisms, periscope bear­ings, seals, etc. its small size makes it ideal for boats where space is at a pre­mium. the Sero 250 is avail­able in an at­tack and search ver­sion and the search ver­sion in­cludes a ther­mal im­ager.

Sagem

Briefly their sys­tems are:

Se­ries 20 At­tack Periscope Sys­tem. Se­ries 20 aPS at­tack periscope sys­tem is highly re­li­able and can be fit­ted on all types of con­ven­tional and nu­clear pow­ered sub­marines. It is also pos­si­ble to retro­fit them. the sys­tem can carry out mul­ti­ple roles like sur­veil­lance, at­tack, nav­i­ga­tion safety, in­tel­li­gence gath­er­ing and elec­tronic war­fare self-pro­tec­tion. its mod­u­lar de­sign en­ables the sys­tem to com­bine high-qual­ity di­rect op­ti­cal chan­nel with four mag­ni­fi­ca­tions and the lat­est tech­nol­ogy op­tronic sen­sors with GPS/eSM-eW an­ten­nas. in ad­di­tion, the periscope in­cludes a low head di­am­e­ter and stealth features. it has low neck cross-sec­tion, high-def­i­ni­tion op­tics, dig­i­tal op­tronic sen­sors sup­port and can be re­motely con­trolled. op­tronic sen­sors are low light level tV anti-bloom­ing cam­era and a hDtV colour cam­era. ir cam­era is an op­tional sen­sor.

Se­ries 30 Search Op­tronic Mast (SOM). Se­ries 30 SoM is a modern which can be fit­ted on all con­ven­tional and nu­clear pow­ered sub­marines or can be retro­fit­ted. it has stealth features and can carry out mul­ti­ple roles like panoramic de­tec­tion and iden­ti­fi­ca­tion, nav­i­ga­tion safety, in­tel­li­gence gath­er­ing and elec­tronic war­fare/ op­tron­ics self-pro­tec­tion. the sys­tem is mod­u­lar in con­struc­tion, is non-hull pen­e­trat­ing, can si­mul­ta­ne­ously ac­com­mo­date up to four ad­vanced op­tronic chan­nels and a full range of elec­tro­mag­netic an­tenna. its op­tronic sen­sors are third-gen­er­a­tion high-def­i­ni­tion 3-5 mi­cron ther­mal im­ager, hDtV colour cam­era, low light level tV anti-bloom­ing cam­era and eye-safe laser range finder.

Se­ries 30 At­tack Op­tronic Mast (AOM). Based on the Se­ries 30 Search op­tronic Mast de­sign, it is a dis­creet non­pen­e­trat­ing at­tack op­tronic mast which is suit­able for con­ven­tional and nu­clear pow­ered sub­marines. it is mod­u­lar in de­sign, can si­mul­ta­ne­ously com­bine up to four op­tronic sen­sors and an eSM/GPS an­tenna. the Se­ries 30 aoM features very low sig­na­ture due to its small size above the wa­ter sur­face. its fully dig­i­tal tech­nol­ogy al­lows a high level of op­tronic per­for­mances. the op­tronic sen­sors fit­ted are third-gen­er­a­tion high-def­i­ni­tion 3-5 mi­crons ther­mal im­ager and a hDtV colour cam­era. op­tional op­tron­ics are eye-safe laser range finder, short wave in­frared ther­mal im­ager and day/night backup cam­era.

L-3 KEO

L-3 Keo (for­merly Koll­mor­gen elec­troop­ti­cal) is the sole de­signer and man­u­fac­turer of all uS op­tronic mast sytems. in ad­di­tion, L-3 Keo has in­stalled op­tronic masts on many in­ter­na­tional plat­forms. th­ese sys­tems in­clude pre­cise, high-res­o­lu­tion elec­tronic imag­ing and in­te­grated sen­sor pack­ag­ing. in­te­grated sen­sor op­tics can in­clude elec­tronic sup­port mea­sures, di­rec­tion find­ing , copla­nar strip ( CPS) or com­mu­ni­ca­tion an­ten­nas, and low ob­serv­ables tech­nol­ogy. L-3 Keo has also de­signed and pro­duced the uni­ver­sal Mod­u­lar Mast (uMM) which has been cho­sen as com­mon equip­ment for above wa­ter sen­sors on many uS and in­ter­na­tional sub­marines. cal­zoni, a sub­sidiary of L-3

The Vir­ginia class is one of the first sub­marines with­out a tra­di­tional op­ti­cal periscope that pen­e­trates the ves­sel’s pres­sure hull but ex­tends up­ward to en­able com­man­ders of submerged sub­marines to view the sit­u­a­tion on the sur­face

Keo, de­signs and man­u­fac­tures sub­ma­rine masts, in­clud­ing snorkel masts, as well as hull in­duc­tion valves, gas ex­haust valves and sea­wa­ter hull valves.

Uni­ver­sal Mod­u­lar Mast (UMM) made by L-3 Cal­zoni. the uMM has been in­te­grated and tested with the op­tronic, com­mu­ni­ca­tions, sat­com high data rate and elec­tronic war­fare un­der­wa­ter sen­sors. it is mod­u­lar in de­sign, re-con­fig­urable with dif­fer­ent sen­sor pack­ages, has built-in clo­sure doors ac­tu­a­tion sys­tem, op­er­ate at high speed at periscope depth, high el­e­va­tion stroke, noise­less rais­ing/low­er­ing con­trol, radar ab­sorb­ing ma­te­rial coat­ing is op­tional, drop-in/dropout in­stal­la­tion, re­quires no align­ment and has low life-cy­cle costs.

Dur­ing april 2014, uS navy con­tracted for 16 uMM sys­tems for the navys Vir­ginia class sub­ma­rine fleet. The Vir­ginia class is one of the first sub­marines with­out a tra­di­tional op­ti­cal periscope that pen­e­trates the ves­sels pres­sure hull but ex­tends up­ward to en­able com­man­ders of submerged sub­marines to view the sit­u­a­tion on the sur­face. They are also being fit­ted on Ohio class cruise mis­sile sub­marines. The UMM can host five dif­fer­ent sen­sor con­fig­u­ra­tions: the pho­ton­ics mast, the multi-func­tion mast, the in­te­grated elec­tronic mast, the high-data-ratemast, and the pho­ton­ics mast vari­ant. the navys Vir­ginia class at­tack subs each have a bank of eight of th­ese sen­sor masts, while the ohio class cruise mis­sile subs each have banks of four uMMs.

Sub­ma­rine Periscopes. L-3 Keo is the sole de­signer and man­u­fac­turer of all uS periscope sys­tems. in ad­di­tion, L-3 Keo has in­stalled periscopes on sev­eral in­ter­na­tional plat­forms, in­clud­ing the tr1700, the t209, the Wal­rus, the a-19 and the Sauro class sub­marines. th­ese sys­tems in­clude pre­cise, high-res­o­lu­tion op­tics, and in­te­grated sen­sor pack­ag­ing. in­te­grated sen­sor op­tions can in­clude elec­tronic sup­port mea­sures, di­rec­tion find­ing, GPS, com­mu­ni­ca­tions an­ten­nas, ther­mal imag­ing, low­light imag­ing or im­age in­ten­si­fied cam­eras and low ob­serv­ables tech­nol­ogy.

PHO­TO­GRAPH: Daniel Linares/Sagem/Safran

Se­ries 20 APS at­tack periscope sys­tem can carry out mul­ti­ple roles like sur­veil­lance, at­tack, nav­i­ga­tion safety, in­tel­li­gence gath­er­ing and elec­tronic war­fare self-pro­tec­tion

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