DTIC ADA426507: Remote Characterization of Littoral Dynamics in Support of Expeditionary Warfare

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Remote Characterlzation OF Littaral Dynamics In Support Of Expeditionary 1 _—_—_
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of Tituruf dynamics in support of expedisiomary warfare

Remote ebiaractertrat
K. Todd Lolland. Jack Polen. and Nauhaniet Plant

Naval Kescarch Laboratory — Code 7440.3
Stennis Sprce Center. MS 39529
[phone]. thllandif wilsse.navy mit

Abstract — Over tae last decade there has boon an inereasing interest in conducting.
cexpediionary warfare operations in very shallew valor and suef zone regions, with
‘ej typically less than 1m. The couseqquences of inadequately estimating littoral
environmental conetions in tbe salscantal to aaliacy systema
yeifarmance. latercstingly. the spatial diversity aud dsnamie nature of titoral processes
that have a diroet impact on expeditionary warlure operations are often Simited 103
particular leeation (em the endee of 100s of meters) aneor a relatively stort tire terval
on the anker of haus ty days). Given this complexity. traditional soltions for
‘eavionmental charactetization involving historia slatabeses or elimaualogies are
vlequate la contrast, an adaptive solution for nowcasting Uidoral condidons in high
is requires» provide» wetical_ organic. eeconnaissauce capability in support
‘cuntermeasuees. Such a solution known asthe
1 applivations are

nig

resolu
‘af amphibious opceations ane! 1
Litoral Ensironimental Nowsasting System (LENS) ard its poten

sdesevibed Ire,

Fatruduetion
Environmental processes in Rita regis eect over «variety of temporal and spatial

scales. Txnmples elude ides, waves. curtents, and bathymetric changes vin sediaent
Innnsporl. These processes are dynamic such that enviromnental cluracterizations have a
limited “shelt life". typically le than a feo days, in that condition eau change quickly.
‘As examples. broaker wave heights clearly are altered by the vasiation in depth over a
tidal cycle and changes in beach profiles of arore than a mcter have beou observed veer
time spans as shart as afew fours. Also these processes are site sporific in Ua closely
Facmted urea may shone simlaites. but often have. importnt differences such as ip
ats o¥ particularly high wave enc ns

‘These dynam enviraminental condiGins can have a diel impact on systems develope
For use in expeditionary wartaee, particularly with respect to mine coulermcasuTes
‘operations, For example, planned use of autonomous systems including Unoranned
Underwater Velicles (LIUV) and “crawler” deployments for wine detection will be
dependent upon wave and eurcent crndilions to avoid being either damaged or
transported away fren he interfer survey atea. Also choosing efficient survey routes.
relative 1a existing bully metiy andr stuf Zone Jocations can reduce survey firme. Mine
buco is highly dependent upon sediment typs-and bottom curroar magnitudes,
Operations occurring during amphibious Favelings including lane marking aud previsio

Funcling for this work was provided! hy the Olive of Naval Research through 6.2 base
funding of the Naval Reseurch | abwvalory, PERKO2ASSN, to support the Orgame Mine
(Countermeasaues (MCN Tutuce Naval Capability (ENO.

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savigilion can be impacted by ueurshore wave and current comlifons. Also. rapid
‘environmental assessment isiniportantto prepare the VSW:S7. batlespace for
littoral penetration. tn essence. many elements of Ship Ta

follow-on clearance) will bencft from knonledye of Koval enviconmental coneitons.
Precise knowledge of Littoral cavirruunent alles tactical decisions resulting in

ower assets required.
(Optimal deployment of assets (vchietes &
Rednco (ime to seeurelclear op arca
Higher confidence in force protection
Safest methodsirautes 10 necamplish objectives

‘This capability is particulsrly imprint iu the very shallow water, suf, each. eval
Janding. ana beach exit anes (VSW i SZ BZ? CLT! BZ).

LLnfortunaely, existing environmental ion in Forward areas is usually sparse,
sometimes outdated, and cfton inuccorute making assessment of potemtia? impacts on
expediionary warfare uperatians challenging. Traditions? survey operations typically
have a long turi-uroend time. Additionally, relevant cnviresonental information is
dliffignt to nequice im hostile/denicd arcs ismg iste neasimements of covert
reutmnaissance. In is publication, we present 1 derupnstaled capability for providing
stich environmental inforaation as part af a tactical operation. This eapabilty results
Front the Fusion of sulvanced nuencrical modeling with al-time infonnation derived from
inagery obtained by Unmanned Actial Vehicles (UAVs). Basically, we bave aiepred an
‘existing numerical circulation made for simulating hydrodynamic and morphological
ppracesses in littoral environment for use with remotely sensed mearsore
channeterizations, This approach, known a8 LENS for Littoral Rvirnmvental Novweasting
System, has heen demonstrated at four scienriie experin itary excreises and
shows meh promise for adaptation to Meet use,

Littoral Envirunmental Noneasting System (LENS)
“The objective of the Laroral Environmental Novteasting System program is ta develop
and demonstrate technology and techniques that will coxble a rape and tactical
reconnaissance enpability using Uamanned Acrial Vehieln (LIAW' inmagery fou
‘chaeteri cing Boral processes trom very shallewe te

previously mentioned, this capahility is critical to several aspects of expeditionary
‘warfare including autonamens vehicle operations invelved in Mins Counter Measunes
(MED, locating mines { minetilis fabatacles, and cfficicatly conducting amphibivus
Toning’. There is a cleat operational need for such elnrucLeication in at few present
ccouatermeasute systems are designed te operate inthe SZ region, in planing this
solution, we decide to collet cata at high density as pant of ongoing operations.
‘Resqireiment inclaule being minimally intrusive such that thon: is file interference with
the primary missiou, wo alterations eesulUng in a cormpeomise of platform safety and the
‘capability should be largely automated ta peecluls the weed for specially vained
aperatos.
Spsteen Description
The LENS program ix moGivated by the fact that in-<trde neutralization of mines amt
prediction of wine busial in VSWISZ regians equines up-uralate knowledge of

‘environmental conditions in these dywamic areas. Since wave and bathymetric conditions
in hese ateas can vary dramutically overtime periods as short asa few hours. a coupled
rete sensing and numerical forecasting approach is required, Based upoe receat
‘advances iu imaging sensors, signal processing, and numerical modeling. LENS isa
software systema Ihal uses temofely acquired, reenporally and spatially variant information
from clecire-npieal sensors to provid high resolution noweasts for VSW and SZ.
regio. Betimates of breaker hight, dr

lacadian, bar location, surf ame width. and the number of wv
provided, in sddiion wi standard meteorological

imagery. Baihy:etry and fittoral eutents ean also be deter
prrvucts relating to vessel tacking and submerged object detection

“The system (diagramed in Figure 1} primarily consists of an clecre- optical (EO)
ry sume that provides time sequential ("vick-like”) imagery. Visible band
ry as been typically useel although these eapabilitiesare-applicable to
Snfraved, raueispeewal, or even hyperspecteal sensors. A Tndamental requirement of the
data collection is tha he imagery be asoviated with additional motive to alone
photogrammetric extificaien uf pixel information to werld coordinates such as UTM.
‘his metadata is typicwfly provided by external hardware that meusurex caraera postion
pitch roll rnd yur, bu these angles can also be determined using slereomietvic processing
‘a cantol poiets of the ground using methods established for application to field sensors:
Littoral charseterization algorians are them applied tothe imagery dats sires to
determine the hourulary and forcing conditions (namely bathymetry aud veean wave
clusteterstics) dhat can be wsed todrive numerical kydradgnamic and circulation models
Figute I Schematic showi al nerwcasting,

LENS coupled systems apprewch to i

‘The firal chamneterization algorithms were developed usiog EO
fixed platforms, such as in towers, lighthonses, oF 09 hilltops, ‘These installations affered
she advantages of long-term sarupling with minina dificulies retaing to system size,
Tower dla soraye. Additianally, the viewing geometry generally remains tried
allowing sepeared pixel based snalyses to he highly automated. Subsequently. the
alsarithms were tested an imagery collected fromm aisborue platforms, such us UAVS.
which typically bus much higher viewing angle resulting in # nue consistent pixel
Footprint through the coverage atea. One advantage uf the LAY approach is that imagery
can le rapidly collected ata numb of spain! Ingutions, and is generally more suite
foe covert mifitary operations. One iisadvantage of airborue traagery is tht the geo
(ransformation bereeen image nnd ‘saondiaates has to be Feealculafe foreach
ine Fen. bt that process bas becn automated. Collections using arbome vehicles are
_penerally preferable Ce space-based platforens given the olfen lower pixel resolution and
Shorter temporal dave ofthe satellites.

sors deplayed from

[Nurwerical models of nearshore processes (waves, curren) have reached an advanced
stage of sophistication and accuracy wo inake their use as predietion Cools tenable. For the
simulation of nenrsbone wave nw] curent fields. ¢ypleal input includes bathymetry (ata
resolition sufficient tp include maja features such as bars)and offshore wave conditions
(spectral parameters such as poak perio, Height and dlietion or Tull dieetional spectra
Generally, a coupled wave and hydeslynamie riidel npproach is used. with the wave
field over larger rozion calenlated from the intial condition and the resuting forcing
information provided to the civealaion ruodel which operates over a smaller region. The
‘athymettic resolution requirements are usually similar between the two mel. An
example nearshore characterization produet for La Jolla, CA is shown in Figure 2

Figure 2 Example noweast prover showing wave height anil curvent paters fora 1.2.x
4.3 km nemshore region, Depth conto

‘An important part of the technical approach bass been ta vida te TENS protedype as
part of scientific experiments and military exereises using inuyery [rom TUAY and LAY
Surtogates. Validation of these capabilities using in-situ measurements such as
fydrogiaphie surveys and directicmal ware buns hay sbewen excellent agreement at a
variety nf locations Ge Figure 3)
Figure 3 Remotely sensed estimates af bathymetric prolites (blue) at 4 afongshore:
locations eennysined te surveyed profiles (magenta) ubuained at Duck, NC.

Operational Concept

Prior to an amphibious assault, ral time reconnaissance including detseting and locating
mines, minefields. and obstacles often nceurs using autonomous vahicles that will be:
impacted by adverse occanogeaphic cousitions suchas breaking waves. strony currents
‘or abrupt changes in bathymetry. For example. remotely operated. undentaer, ive
honting vehicles eamnol easily Ganst against littoral current exceeding thle maxtnaira
navel speed, Similacy. vehicles entering the suef ove reyiom mray be stranded oF
rendered inoperable, In addition, the sucess of follow on mine clearing operations wcill
itr many ways depend upon siwilar knowledge of the litora! envirguunntal conditions.

‘The LENS operational concept therefore isto process. in wcur veal
imngery obined fom an organic UAV and tctemetcred te the ground (ar recordec! on
Fowl: The major hardware rcquircmemts sre ta sufficient navigational data (such as
platiorm location and sensor healing) are provided to allow for image co-royistation and
220 rectification. Analysis of the imagery time series provides the hoondary and forcing
‘oncltians (such as bathymetry and wave spectra) neceswary to inilalize hyerady antic
anil mphedyamic medals t allow estimation of Tinoral conditions. Es adlition. hese
estimates can be update periodically to provide continued forecasting abilities over x 2—
3 day period, The fil ouput car he used to design UU ancl LAY deploy nen

uation points, and help the comumander deteruine
the most successful min a! neaching aud‘or elcacing approaches. The various imagery
preducts available From the LENS analysis arc algo useful in iewsifying miine-tike
‘objects and for sucveillance of moving vehicles (Figure 4), Many of these develepanents
are relevant 1o velted technology plac for tactical UTAY employments inc
roellispectralhyperspectcat (UV-VIS-NIR-SWIR-LWIR) cameras sith co
Inser Murninatoxs,

Figure 4— Pstimates of AAW tacks obtained from a variance expen
yy eoonpared 19 sampled GPS coorlinates (aigenta and Ulue lines),

ing motion

Disenssion

xnmples of how the environment can impart expeditionary warfare operations are listed

in Table F LENS ca be used adress many oF these missions.
able 1 -

Bnei Proce Traian

ietnseity 7 Sen State “Amphibious landings TRICK
Littoral Dynamnies (Carma? Sui} "| UUV snaneuveratuiy / EOD
‘ysical Processes (Density "Teph ‘Marine mammal systems

Seaflonr and Tensain Charaetyigice Mine deci FT

Targeing 741 Os Maan ‘Neutralization! Obstele avoidance
‘Bese? iiveting Chametonsiow Special pert —

An inmpertant concept selating wo literal characterization is Hea the sizeof necessary
‘coverage region decreases while required resolution of eotditions inereases as time
towards nssion progresses. For example, planning decisions made several days priar 1a
an assault involving generlized wave conditions (such am expacted mani
high require only come estates (2. ariel spoeings of 100s of meters) of the regional
bathymetric stance. Hinrever these forecasts nel be made over a sizenble spatial
dori (perhaps S00 ku page environ ents Kaiabiity associate with vlple
‘Potent fora penewrtion pois. fu cowlast_ determination of survey routes for MCM.
Iision regions of SO km sic necessitates knowledge of bathymetric varstons to
‘within TOs cf meters, Furthormons, accurate estimation of surf zone conditions pertaining
{ea specitc 50 m wide nscale lane could iavelve having Talyrelty measurements
spaced by as litle as afew meters.

Fin,
%,

<
Miss,
iy

Spatial Domain

Nowcast Resolution

Figure 5 — Schematic showing relmionship hetween spatial coverage and reson
requires as tims towards mission prowresses,

Although complete characterization over these inquired scales is a forradsble challenge,
Us ceniept has signiticant implications towars BICM inission planning and 93321
deployment. Primarily, these mguirements ate achievable if» nested al sequentiad
approach to linoeal chacacterization i pursued, Ideally, low density bul regicmal
bathynrrie measurennenls provided by historic databases such a» DDBY are sufficient
tw define the bettom boundary uscd by numerical medels such as WaveWatch II 0
ssdimate large coverage wave vnrintions used during planning stages, As likely littoral
penetration aroas are chosen. atiqaal aul theater capabilities can be tesked to me
Accurately estimate haikymeiry within more constrained regions. These measurements
fan then he used to dive higher resolution munesical simalations (such as SWAN) that
nile inthe optimal deploymicot of tactical assets sueh as VOWS and UAWS, The sensors
‘in these vebicles provide even higher eselition bofhymnetry estimates, along wath
allowing even greater ficlty in the Salowing numerical noweast such as Delia. By
fhe time of the ssn 1 higteresolution depiction ofthe environmwata conditions within
a reasonably sill, bul especially velevant litaral region is avilable

‘Theve is atleast one significant imnpelimen I successtuliayplementation of ths scheme,
Prinvatily.as tho distance to the “pointy end of the speat”, where the most wctically
felevant environmental inforranton is required, Increases. the om seeue expertise
available Wo process data and perform
swarfighter is involved in a number of wher activities more pressing 1
Tiuoral noweast, However. since we believe that a great partion of the mission sucress
will depend on fittaral environmental conditions, we propose an alvanced sohwtion to ths
a

Summary
“The: LENS operational concopt therefore is to proces, i near ral time, stabilized motion
imayery obtained ftom an organic UAV and telemetered tothe ground (or recorded on-
Inoand). The major hardware rcauirements are that sufficicnt navigation data (such as
platform tocation und senso beading) are provided to allawe lar iraage co-tegistration anal
£20 rectification. Analysis of Unc imagery time series provides the boundary and Forcing
Conditions (such as hathymetry and wave species) necessary to initialize hylrody mimic
and morpharlywimic models to allow estimation of Tivoral conditions. In addition. these
tstinstes can be updated periodically provide continued foterasting shilivies over a2 —
3 day period. The final ourpat ea he used to design ULIV andl UAY deployment
‘Svategies.fotate optimal liuoral penettation points. andl help the comuauder deteemie
he most cueeessful mix of breaching andor clearing approaches,