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Objective
This is a collaborative project to incorporate demonstrated effects of predictable global atmosphere and ocean conditions in the NPS National MDP Modeling and Gaming Laboratory. The project includes analysis of the current state of threat and own force detection in the National Maritime Domain Protection system with regard to including atmosphere and ocean surface conditions influencing radar (refractivity profiles) and IR (refractivity profiles, thermal contrast, absorption, and aerosol scattering) sensor performance.
Background
Performance predictions for surveillance sensors and some communication systems are in the “dark” unless effects of atmosphere and ocean effects are taken into account. Threat surveillance, detectability of own forces and general maritime domain protection can be vastly improved when lower atmosphere, surface conditions, and time of day are known and considered when responding to threats.
Incorporation of such influences on surveillance sensor performance and of the threat characteristics will become essential in the design of a “test bed” for CONOPS in Maritime Domain Protection.
Method
Researchers are studying variations on radar and IR surveillance sensor performance caused by lower atmosphere and ocean surface conditions. Emphasis is placed on low radar cross section and low thermal cross section targets.
The project is based on transitions of models and procedures developed for U.S. Navy (USN) sensor performance prediction, to apply in port and coastal surveillance and also in response detection estimations. The U.S. Coast Guard, Research and Development Center (USCG/R&DC) is also adapting USN propagation effects tools in initiated programs to account for atmosphere and ocean surface effects in Search and Rescue Operations Planning Software (SAROPS). SAROPS uses a Multi-Sensor Performance Prediction (MSPP) toolset based on USN radar and IR effects models .
NPS experience in supporting field tests on radar/IR sensor performance suggests that, for port and coastal security, surveillance has to consider atmosphere and ocean surface effects. The recent Northern Arabian Gulf incidents with low radar cross section and low thermal contrast small boats indicate that knowledge of such influences on surveillance sensor performance, and of the threat characteristics, will become essential in the design and selection of different procedures and assignments of resources. The environmental conditions affecting sensors, the targets involved, and the threat procedures important to Maritime Domain Protection are very different from ship self-defense against mach-1 surface-skimming missiles. Hence, special integration of models and testing of approaches are necessary.
The planned MDP measurement and data transmission system/network systems/procedures will be designed on the basis of field collection that occurred with NAVSPECWARCOM combatant craft radar signature tests and in SOCOM/3rd Fleet endorsed overland network and surveillance systems demonstrations in several locations:
• Dam Neck , Virginia , August 2002
• San Clemente Island , California , June 2003
• NPS Surveillance, Targeting Acquisition Network (STAN-5) field test, Camp Roberts , California , February 2004
Continuous small vessel measurements in the combatant craft target signature tests provided information on non-radar cross-section related variability in target range. Although fielded for target signature verification/validation, the combatant craft test involvement provided an excellent demonstration of application of sensors and propagation models for real-time descriptions for radar. Continuous multilocation measurements of the lower atmosphere and surface in STAN-5 NETWARCOM based demonstration provided a measure of the value of wireless network links between the field sensors to a Tactical Operations Center .
In a MDP NETWARCOM operation, the atmosphere data would be derived from deployed sensor nets to provide a Common Operating Picture (COP) of surveillance capabilities, and response detection that varies with conditions.
The Applied At-Sea Technology Research article in SITREP IV (Applied At-Sea Technology Research, Estimation of Atmosphere and Ocean Surface Influence on Radar and IR sensor Performance for MDP) describes littoral region distance versus time-of-day variability of predicted two-way loss, exclusively caused by measured variability of atmosphere and ocean surface condition, during an August field test off Dam Neck, Virginia. Unclassified effects for a test of radar signatures of low cross section combatant craft are shown.
However, the significant variability shown in these results was confirmed in the actual detection results, for S- as well as X-band radars. Knowing the variations during execution of the described surveillance detection in the Northern Arabian Gulf or, better, forecasting the variation 24 hours in advance, would be critical to MDP operations. The influencing condition in the Dam Neck tests was associated with warm surface temperature (~26 C) that occurs in the Arabian Gulf and in the vicinity of Singapore , another MDP region of interest. An additional feature of this field test and a similar test off San Clemente Island , California , was to assess the value of mesoscale model 24-hour predictions for estimating the changes and, hence, participating in mission planning.
The comprehensive approach followed in the MDP-TF effort encompasses five components:
• Integration of operational/near-term in situ and remote METOC measurement and prediction systems, including real-time satellite retrievals (3-D) and mesoscale model predictions (4-D).
• Data transfer from surface platforms to a tactical operations center to produce a Common Operating Picture (COP). The building blocks of the proposed mobile network include: Wireless data transmission unit in a forward (field) measurement vessel linked to base METOC receiver unit on the command platform; and Software/hardware interface between the base METOC receiver installed with multi-agent architecture for 2-way information exchange via network to Tactical Operations Center (TOC).
• Adapt and integrate physical environmental models (developed and verified) that produce radar refraction profiles and clutter and IR refraction, absorption, and turbulence (scintillation) from available METOC data sources (platform-measured, mesoscale model and satellite-based).
• Selection and adaptation of operational propagation models that use atmospheric descriptions (3-D refractivity profiles and 2-D surface roughness) to determine propagation characteristics.
• Selection of surveillance/detection Tactical Decision Aids (TDAs), which predict detection range probabilities for various sensors and targets and can be available both on operational platforms themselves and at a C4I center.
Integration of existing technologies for MDP purposes must be based on:
• Present remote and in situ measurement of atmosphere and ocean surface properties
• High resolution model prediction and assimilation of dynamic processes of both the atmosphere and ocean
• Open-ended information systems architecture
• Radar and IR sensor modeling/representation
• Full evaluation of threat concepts and capabilities
This project will integrate existing technology and provide surveillance operations information on the detectability of low cross section and low thermal contrast targets by radar and IR, and eventually by acoustic sensors. The outcome of this effort will be a highly modular set of components that can be “shaped together” in a variety of operational configurations for multiple uses, including port security surveillance and small unit response team C4I support.
FY04 Field Tests
METOC surveillance effects awareness and estimation for MDP purposes, on the basis of existing tools, are critical objectives in the MDP-TF Applied At-Sea Technology project. In FY04, this has been accomplished by becoming a component of field experiments and fleet exercises in which radar detection of low radar cross-section targets was under evaluation. The NPS MDP-TF provided resources which were used as cost share for participation in the following field test/fleet exercises with collection of appropriate surface layer and upper air data from the provided platform. The data relate to detection, and will be validated by the partnering organization.
ESM Vulnerability Study (EVS). EVS was conducted as part of the PASCEX 1-04 Shallow Water Workup "COMSUBRON 12 OP ORDER 9-04." It occurred in the Pacific Ocean , in the vicinity of San Clemente Island , California . Multiple platforms with varying radar-cross-sections were involved in PASCEX 1-04, surface and subsurface. In EVS, personnel and equipment from the Naval Postgraduate School made surrogate vessel based measurements to establish impacts on radar propagation in the lower atmosphere from fixed sensors on the vessel and from balloon-borne rawinsondes. In EVS, Rf propagation was a factor in system performance assessments, so refractivity profiles were desired from measured pressure, air temperature and humidity, sea surface temperature, and wind speeds. Profiles from both immediately above the surface, and through the entire boundary layer, were required to evaluate a vulnerability system.
Surveillance, Targeting, Acquisition, and Network (STAN-8) Field Demonstration. The STAN field demonstrations are focused on SOCOM objectives including SOCOM assets. Efforts in STAN-8 will be to collect (mid-August) METOC descriptions from a surrogate vessel, the Cypress Sea, in Monterey Bay, in conjunction with low radar cross section and special unit (SOF) penetration. This field test will evaluate the ability to estimate detection (target and communications), and then to link information to a TactiCalifornial Operations Center (TOC). The METOC on the surrogate vessel will have continuous transmission via the on-board "hub" to the TOC. The descriptions would relate to METOC effects on COMS and radar/IR detectability, own and threat forces. The calculations that lead to the real-time assessment of radar detection would be done in the TOC in real-time, and varying conditions will be available to exercise controllers and to SOF units working maritime operations.
Trident Warrior/Silent Hammer (TW/SH) Fleet Exercises. Personnel and equipment from the Naval Postgraduate School will take surrogate-vessel based measurements of the atmosphere and ocean surface (METOC) properties that affect EM/EO propagation during the TW/SH fleet battle experiments. TW/SH will occur in the vicinity of San Clemente Island (SCI), California , in September-October 2004. Fleet Information Warfare Command (FIWC) initiated requirements for METOC measurement within TW/SH to support the Electromagnetic Spectrum Management using the Afloat Electromagnetic Spectrum Operational Planer, AESOP. TW/SH arrangements made in the NPS involvement are adjustments/extensions to the FIWC requirements. These extensions are to examine detection of low cross section targets within a time/region ( Santa Ana airflow regime) where refractive effect impacts will be large. Also, the region occurs in the SOCALIFORNIAL area, which is a focus area for NORTHCOM littoral surveillance initiatives.
MDA and Coalition Partner Interaction
Interaction with MDA and intelligence community groups is occurring. An invited classified presentation, “Estimating Radar Detection Variability for Small Vessels,” was presented at the White Shipping and Maritime Interdiction Workshop held at the Space and Naval Warfare (SPAWAR) Systems Center , San Diego (SSC-SD) from 02-04 June, 2004. The presentations showed results from field tests on how surveillance variability can be accounted for by sensor (radar and IR), data (atmosphere and ocean surface), and information fusion. It was suggested that performance predictions for both own and threat forces surveillance sensors would be in the “dark” unless time and space varying atmosphere and ocean effects are taken into account. This is believed to be the first time that MDA persons in the Intelligence Operations had given a presentation of the demonstrated impact of METOC on surveillance of low cross section targets.
Results Regarding Detection Variability
Estimation of detection variability was included in a list of deficiencies identified during the workshop. A significant increase in collaboration is occurring with groups in the Singapore Ministry of Defense. This includes planning for future collaboration and the actual performance of special joint analysis/interpretation with several groups on influence on radar/IR surveillance in the vicinity of Singapore and in the Straits of Malacca. Joint activities in MDP related areas have occurred, through an end of July, 1 ½ week assignment of K. L. Davidson to the National University of Singapore (NUS) for short course lectures, and to the NUS Temasek Laboratories, for research collaboration. Two time-critical opportunities have arisen to contribute to MDP activities with respect to Singapore .
The first opportunity falls within the recently announced initiative by the Pacific Command (PACOM) for ambitious and complicated ventures to prevent seaborne terrorist and criminal assaults on nations bordering the Pacific and Indian Oceans (Washington Times, May 10, 2004 , page 15). This initiative, known as the Regional Maritime Security Initiative, was created in response to several known instances of maritime terrorism, including prevention of the seizure of a vessel loaded with liquid natural gas for purposes of slamming it into a pier and exploding in Singapore , and preventing terrorists from scuttling a tanker in the Straits of Malacca to close a vital waterway. Technology assets mentioned in regards to the PACOM initiative included radar, radio communications, and transponders emitting signals to disclose a location. A primary task is to pull that information together swiftly, so that law-enforcement agencies, coast guards, and navies can intercept any suspicious vessels. Predicted and observed influencing METOC factors can and should be included in this information.
The second opportunity arises from the need to create partnerships with other countries as part of this initiative. Admiral Thomas Fargo, PACOM, stated that the goal is to forge a partnership of nations willing to identify and intercept "transnational maritime threats." In this regard, NPS MR is scheduled to participate in the National University of Singapore Defense Technical Short Course (DTSC), for the fourth consecutive year, presenting lectures on atmosphere factors in radar and IR sensor performance. Professor Lim Hock, Director of the Temasek Laboratories, has requested that Project Leader, Dr. Kenneth Davidson, spend three days with his team to address the detection issue.
As part of the MDP effort, NPS/MR performed analyses and interpretations on the Comprehensive Ocean and Atmosphere Data Set (COADS) for the Singapore Straits , Straits of Malacca, and the Karimata Strait . These were for the evaporation duct height and surface based duct. The climatological values indicate that both Rf and IR detection is greatly influenced, relative to normal. Since the COADS data set is heavily averaged, statistics of variability with time of day is missing. Further, COADS is derived from volunteer ocean shipping, so it may have biases for application to critical calculations for the evaporation duct. The Temasek Laboratories (Ministry of Defence) requested a meeting with Dr. Davidson and the Director of the Singapore Meteorological Service to explore their interest in this issue.
Meetings were conducted with persons from the NUS Temasek Laboratories, the Singapore Ministry of Defence DSO National Laboratories, and the Singapore Defence Science and Technology Agency (DTSA) to explore the characterization and prediction of atmosphere and ocean conditions of the Singapore Straits with regard to impacts on radar/IR surveillance. Model evaluation and field tests are being planned for a mid-2005 start time. Singapore officials will come to NPS in mid-August and in mid-November and these collaborative efforts will be discussed.
Former NPS student, LCDR Jorge Vazquez-Zarate, Mexican Navy, completed a thesis under the direction of Dr. Davidson. It is titled, “The Relevance of METOC Factors in the Expected Performance for ES Systems Against Low RCS and Low IR Contrast Targets in a Warm Water Littoral Environment.”
NPS Team Members
Professor Kenneth L. Davidson
Professor David Tucker
Professor Rex Buddenberg
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