Browse Publications
2008 Reports
Note: Unless linked to the full text, reports are only available to NATO member nations from designated distribution centres.
LIDAR: an assessment of port protection capabilities. Brooke, G. NURC-SP-2008-004. December 2008.
This report provides an introductory survey and background to LIDAR (Light Detection and Ranging) as a non-acoustic means for detecting and tracking underwater intruders in ports. It was found that commercial use of LIDAR is mature. Applications such as conducting coastal and forest surveys and sea-mine detection with air- or ship-borne LIDAR are most similar to sea surveillance in port protection, but there are important differences. Surveillance for intruder detection requires constant watch on a fixed body of water in a port, with provisions for tracking intruders after they have been detected, rather than merely passing over an area to generate a one-time still image of a swathe below or ahead of the LIDAR. The LIDAR must remain on station in the port, mounted to a hovering aerial platform (a balloon) or to a tower. This report was commissioned from General Dynamics Canada (Garry Brooke) as part of NURC project 3J1 (Port Protection), Ref: GDC PO:40800736, 31-Oct-08, No.:EYK. A follow-on feasibility study will consider LIDAR coverage in more detail, based in part on the technology survey presented here.
NATO Undersea Research Centre Marine Mammal Risk Mitigation Rules and Procedures. Marine Mammal Risk Mitigation Project. NURC-SP-2008-003. December 2008. Superseded by NURC-SP-2009-002.
The goals of the NATO Marine Mammal Risk Mitigation include the development of risk mitigation protocols, computer tools, and in-water devices to provide risk mitigation before sonar experiments so to avoid potential negative impact on marine mammals. This document outlines the procedures and marine mammal risk mitigation protocols that are in use by NURC at this time. This is an updated, public release version of the NURC Staff Instruction 77. These procedures are reevaluated and modified as new information becomes available from continued research by the Marine Mammal Risk Mitigation project as well as other documented sources.
Target tracking in large sensor networks. Coraluppi, S.; Guerriero, M.; Willett, P.; Carthel, C. NURC-FR-2008-032. December 2008.
The NURC distributed multi-hypothesis tracker (DMHT) technology has been developed over the past several years. Recent application of the DMHT in the context of sub-band processing has suggested that there are limits in surveillance performance in large sensor networks. This report develops a tracker performance model to study this phenomenon. Further, we introduce a fuse-before-track (FbT) processing architecture and provide simulation-based validation of its improved performance over single-stage processing in large sensor networks.
Response Against Diver Intrusions (RADI): Imaging Sonar Exercise, Analysis, and Results. Kessel, R.T.; Pastore, T.J.; Crawford, A.; Crowe, V. NURC-FR-2008-031. December 2008.
A top-down approach, from concept to experimentation, working toward new capability for enforcing an underwater security exclusion zone is given. The concept builds on the assumption that response will be a self-defensive measure, bounded by a duty therefore to warn, to prove intent, and to use proportional force. One key task within such capability is treated here; namely, the task of classification and close observation of an underwater intruder while issuing warnings to prove intent and justify the use of force. A methodology for evaluating imaging sonars is developed and applied to seven different commercial sonars, six of which were exercised during the experimentation against actual divers, both open and closed-circuit breathers, under realistic conditions. The imaging sonar under experimentation was mounted to a response boat, both manned and unmanned, and vectored into position during experimentation by an underwater surveillance system. Both forward- and side-looking sonars were considered. They are compared and found to be complementary for the mission in several respects. The experimentation substantiated the methodology and generated many system requirements and lessons learned. The methodology and system requirements should be of use to system developers and security providers in port protection.
Bathymetry estimation by fusing multi-spectral satellite data and depth samples from autonomous underwater vehicles. Grasso, R.; Pennucci, G.; Trees, C.; Le Gac, J.-C.; De Marte, M. NURC-FR-2008-030. December 2008.
This report approaches the problem of estimating shallow water bathymetry in denied areas by fusing high resolution multi-spectral satellite imagery in the visible through regression algorithms trained by using depth in situ measurements collected by autonomous underwater vehicles (AUVs) used in covert missions. The methodology uses top of the atmosphere (TOA) satellite data in high visibility conditions avoiding the use of atmospheric correction procedures. The depth from TOA sensor radiances is estimated by means of empirical regression algorithms trained by in situ samples collected by an AUV on the area of interest. Algorithms based on multi-linear regression (ML) and Radial Basis Function Neural Networks (RBF-NN) are considered. A data set collected along the southern Tyrrhenian Sea coasts during the NURC BP07 experiment has been used to test and validate the proposed methodology. Comparisons show good correlation with the retrieved depths with the RBF-NN algorithm outperforming the ML regression in terms of mean square error which is of the order of 0.5 meter for the RBF-NN one.
Characterisation and mode coupling of internal waves in the Strait of Messina. Casagrande, G.; Folegot, T.; Stephan, Y.; Warn Varnas, A. NURC-FR-2008-029. December 2008.
The internal waves in the south of the Strait of Messina (Italy) are studied using observational data and numerical simulations. The observational data consisted of SAR images, XBT/CTD measurements and thermistor string measurements from the Coastal Ocean Acoustic Changes at High frequencies (COACH'06) cruise. The numerical model used was the Lamb [1994] model, which solves the fully nonlinear, nonhydrostatic Boussinesq equations on a f plane. The model is 2.5 dimensional with spatial variation in a vertical plane along depth and range, and neglect of derivatives in direction perpendicular to vertical plane. Eleven out of fifteen SAR images contained internal wave events for the month of October 2006. From these images, some of the internal wave characteristics were estimated: a least square fit of the front positions of the southwards propagating internal wave trains gives a propagation speed of 1.00 m/s and a time of release of the bore of about 2 hours after maximum northwards tidal flow at Punta Pezzo. The frequency dispersion of the waves gives a wavelength increase between the first two internal solitary waves of the trains of 40m/km. The in-situ data were used to initialize and evaluate the Lamb model. An Empirical Orthogonal Function (EOF) analysis was applied to the data and the model outputs. The first three empirical functions contain over 99% of the variability. The data and the model are in very good qualitative and quantitative agreement, giving a propagation depth of the internal solitary waves train around 90m with a density gradient oscillating from 80 to 130m. An original method for detecting internal waves was developed by analyzing the scatter diagram formed by the first EOF projection coefficient versus the second EOF projection coefficient. This distribution has a specific crescent shape illustrating that the first two projection coefficients are not independent in the presence of internal wave events. The crescent shape signature of the internal waves can be used as an internal wave detector.
Local bottom characterization using an Autonomous Underwater Vehicle (AUV).Nielsen, P.L.; Harrison, C.; Holland, C. NURC-FR-2008-028. December 2008.
The bottom properties in shallow water regions are key parameters for optimum predictions of acoustic propagation, reverberation, and particularly clutter signals which may arise from local bottom features. The use of Autonomous Underwater Vehicles (AUV) for environmental characterization gives the possibility to perform detailed inspection of such local underwater features of interest which may be very difficult to obtain from a surface vessel. The CLUTTER'07 experiment was conducted on the Malta Plateau in 2007 with one of the objectives to characterize the underwater environment using an AUV. The AUV was deployed at a particular site to demonstrate the feasibility to infer bottom geoacoustic properties using such an autonomous platform. The AUV was equipped with 2 sound sources covering a frequency band 800-3500 Hz, and the transmitted signals were received on a bottom moored vertical array. The individual time-separated multi-path arrivals are used to calculate the bottom reflection as a function of grazing angle and frequency. The results obtained by using the AUV to characterize the bottom properties are compared to independent findings from different experiments using various types of equipment at different seasons in the same area.
Buried mine countermeasures in ports. Groen, J. NURC-SWP-005. December 2008.
Buried mines in ports constitute a significant problem in mine countermeasures operations, because of the hard detection and classification. At present, in most NATO nations there is no practical solution if a port mine threat comes about, which most certainly results in expensive closedown of the port. This report is based on a literature study on NATO documents and open literature focused on recent developments in the field. The relevant research and state-of-the-art systems available within NATO are reviewed in order to come up with a solution for the authorities responsible for port security. An overview is given of the sensors that are successfully employed for buried mine detection and classification, i.e. predominantly magnetic and acoustic and to a lesser extent chemical sensors. The different advantages and disadvantages of the sensors, which are discussed in detail, emphasise the expectation for notable gain when sensor information is fused. Excessive false alarm rates are an important concern for buried mine hunting in general, but particularly in the case of a port due to the increased density of man-made clutter. A clean port and regular monitoring of the port can reduce the false alarm rate. It is concluded that the buried mine problem is rather a financially viable than a conceptual problem, because it shows that performance of a multi-sensor systems can be pushed as far as necessary to ensure sufficient port security. The operational problem of time is also still an issue, because periodical scanning of the port interferes with regular port traffic. It is recommended that the sensor suite of such system consists of a sonar array and a magnetometer at minimum.
Rapid strategic positioning to counter underwater intruders. Pastore, T.J.; Kessel, R.T. NURC-FR-2008-027. November 2008
As previous work has shown, detection sonars that can detect and track an underwater threat are available commercially. Granted that a detection has been made, there are a series of steps which must generally occur before the threat can be deterred or eliminated. These steps of course require time, during which a genuine threat would presumably continue to advance toward its target or try to evade prosecution. This report characterizes the response time quantitatively, on the basis of empirical measurements made during the Response Against Diver Intrusions (RADI) sea trial conducted by NURC, November 2007. It also characterizes the overall effectiveness observed for the steps involved in response. A number of candidate system components and their combinations were exercised during the sea trial, including four surface response crafts, manned and unmanned, each exercised in turn, and four high-resolution imaging sonars to classify, observe, and thereby prove the intent of intruders. Different combinations of response craft and imaging sonar gave different candidate response systems for testing. The key determinants of response time are treated parametrically here. A companion report will consider the merits of the associated classification sensors.
On Multi-View Mine Classification with SAS Imagery. Williams, D.P. NURC-FR-2008-026. November 2008
This work proposes an elegantly simple solution to the general task of classifying the shape of an object that has been viewed multiple times. Specifically, this problem is addressed in the context of underwater mine classification where the objective is to discriminate targets (i.e., mines) from benign clutter (e.g., rocks) when each object is observed in an arbitrary number of synthetic aperture sonar (SAS) images. The proposed multi-view classification algorithm is based on finding the single highest maximum correlation between (i) a set of views of a training shape of interest and (ii) a set of views of a given testing object. Classification is performed by using this measure of similarity, which we term the affinity, directly. This approach obviates the need for explicit feature extraction and classifier construction. Moreover, the framework induces no constraints on the number of views that each object can possess. Promising experimental results using both simulated and real SAS imagery demonstrate the feasibility of the proposed approach for multi-view classification of underwater mines. In particular, it is shown that classification performance improves dramatically as the number of views of the objects increases.
Bayesian Data Fusion of Multi-View SAS Imagery for Seabed Classification. Williams, D.P. NURC-FR-2008-025. November 2008
A Bayesian data fusion approach for seabed classification using multiview synthetic aperture sonar (SAS) imagery is proposed. The principled approach exploits all available information and results in probabilistic predictions. Each data point, corresponding to a unique 10mx10m area of seabed, is represented by a vector of wavelet-based features. For each seabed type, the distribution of these features is then modeled by a unique Gaussian mixture model. When multiple views of the same data point (i.e., area of seabed) are available, the views are combined via a joint likelihood calculation. The end result of this Bayesian formulation is the posterior probability that a given data point belongs to each seabed type. It is also shown how these posterior probabilities can be exploited during an autonomous mine countermeasures (MCM) mission to determine the most useful additional data to acquire. Promising experimental results of the proposed multi-view classification framework are shown on real, multi-view SAS imagery collected during the Colossus II sea trial.
Super-ensemble forecasts and resulting acoustic sensitivities in shallow waters. Rixen, M.; Le Gac, J.-C.; Hermand, J.-P.; Peggion, G.; Ferreira-Coelho, E. NURC-FR-2008-024. October 2008
Multi-model Super-Ensembles (SE) which optimally combine different models, have been shown to significantly improve atmospheric weather and climate predictions. In the highly dynamic coastal ocean, the presence of small-scales processes, the lack of real-time data, and the limited skill of operational models at the meso-scale have so far limited the application of SE methods for acoustic Rapid Environmental Assessment purposes. In the framework of the BP07 experiment conducted South East of Elba, sound speed prediction skills of various SE techniques combining operational model outputs and in-situ measurements are assessed. Results suggest that SE-based prediction provide more robust 24hr forecasts. A detailed acoustic propagation sensitivity study at different frequencies and ranges also reviews the potential of these predictions for acoustic inversion and tomography efforts.
Improved ocean prediction skill and reduced uncertainty in the coastal region from multimodel super-ensembles. Rixen, M.; Book, J.; Carta, A.; Grandi, V.; Gualdesi, L.; Trees, C.; Grasso, R.; Merani, D.; Berni, A.; Leonard, M.; Martin, P.; Pinardi, N.; Oddo, P.; Guarneri, A.; Chiggiato, J.; Russo, A.; Vandenbulcke, L.; Lenartz, F. NURC-FR-2008-023. October 2008.
The use of Multi-model Super-Ensembles (SE) which optimally combine different models, has been shown to significantly improve atmospheric weather and climate predictions. In the highly dynamic coastal ocean, the presence of small-scales processes, the lack of real-time data, and the limited skill of operational models at the meso-scale have so far limited the application of SE methods. Here, we report results from state-of-the-art super-ensemble techniques in which SEPTR [a trawl-resistant bottom mounted instrument platform transmitting data in near real-time] temperature profile data are combined with output from a group of eight ocean models run in a coastal area during the Dynamics of the Adriatic in Real-Time (DART) experiment in 2006. Kalman filter and Particle filter based SE methods, which allow for dynamic evolution of weights and associated uncertainty, show increased skill (a minimum of 8%) as compared to the best single models. The latter method copes with non Gaussian error statistics and provides robust and reduced (by 40%) uncertainty estimates.
MCMG1 2008 - Percentage Clearance Trials and AB Measurement Experiment. Strode, C.;. NURC-FR-2008-022. October 2008.
During the Standing NATO Mine Countermeasures Group 1 (SNMCMG1) visit to La Spezia 5 minehunters conducted percentage clearance trials together with an A and Bd measurement experiment off the island of Palmaria. NURC was involved in the planning and subsequent analysis of these trials. This report presents the results of the analysis for distribution to the commanding officers of the participating units.
The effectiveness of a system-of-systems for countering asymmetric maritime threats in ports and harbours. Strode, C.; Cecchi, D.; Yip, H. NURC-FR-2008-021. September 2008.
The following study presents the results of a simulation of a proposed system-of-systems to counter terrorist threats to vessels and infrastructure in a port or harbour environment. The proposed system is comprised of a radar detection and tracking component and an unmanned surface vehicle (USV) equipped with non-lethal effector. The simulation shows that existing Radar and USV technology feasibly protects a high-value asset (HVA) from realistic contact inter-arrival rates. Furthermore, the determination of intent occurs at sufficient range to allow the HVA to defend itself if necessary.
Evaluation of the calculation for determining channel width using the Standard Deviation Navigational Error (SDNE). Bryan, K.; Davies, G. NURC-SWP-004. September 2008.
Currently, the channel width to be cleared by mine countermeasures (MCM) operations is determined by the largest Standard Deviation Navigational Error (SDNE) of the vessels which will transit the channel, together with the damage width of the key mine threat. This study reviews the use of the SDNE in the current MCM planning and evaluation algorithms and suggests more general models for the behaviour of transiting shipping and mine-ship interaction.
The impact of seabed characteristics on the modelling of minehunting effectiveness. Bryan, K.; Davies, G. NURC-SWP-003. September 2008.
Seabed characteristics play a critical role in the determination of minehunting effectiveness. In particular, high levels of operational clutter, or objects similar to or obscuring targets on the seafloor, have been shown to significantly reduce the effectiveness of minehunting operations. This report investigates the role of seabed characteristics in the evaluation of minehunting performance in current NATO doctrine and considers how current doctrine could be adapted for more accurate use by new generation sonar systems.
AIS emission anomaly detector in support of Maritime Surveillance. Baldacci, A. NURC-FR-2008-020. July 2008.
NURC is conducting a research activity supporting Maritime Surveillance applications. As part of this activity, intelligent agents for automatic anomaly detection are being investigated. At present time, Automated Identification System (AIS) is the main source of available information. The first kind of anomaly of interest is the termination of AIS emission, which occurs when the AIS transponder installed on a naval unit is turned off, possibly to hide the shipping activity. NURC has developed an AIS emission anomaly detector, which processes the continuous AIS data stream recorded by a network of land-based receivers (also known as the MSSIS network) and detects emission terminations. The detector has been tested with simulated and real datasets.
Volumetric distribution of oceanographic fields estimated from fusing remote sensing with in situ data collected by UUVs of opportunity. Alvarez, A. NURC-FR-2008-019. June 2008.
A main challenge of military oceanography (MILOC) is to assess the oceanographic conditions of denied/unsafe marine regions. Monitoring technologies are limited to those that can guarantee assured access to these regions. Remote sensing and unmanned underwater vehicles (UUVs) fulfils MILOC requirements. Unfortunately, the environmental information gathered by these technologies is not complete. Remote sensing provides information about some surface conditions and water column integrated variables. Potentially, UUVs could provide a fully environmental characterization of the region of interest but technological limitations and/or operational priorities have constrained their use during real crisis situations to missions with different purposes than environmental assessment. Under this scenario, data fusion techniques to maximize the information of the collected data are essential. This report proposes a technique to fuse data gathered by remote sensing platforms and UUVs performing missions not specifically designed for environmental data collection. The technique estimates the state that maximizes the a posterior probability. A variational methodology allows to include remote sensing information as boundary constraints. The approach uses three dimensional finite elements to solve the maximization problem. Unlike traditional geostatistical techniques, this allows to process data sets with a huge number of samples such as those obtained from UUVs. The proposed technique has been tested in a complex simulated environment. The approach produces realistic estimations of the volumetric distribution of the sampled oceanographic field. Results also highlight the relevance to incorporate into the estimation the surface information provided by remote sensors. Further research is suggested to validate the methodology using real data and to generalize it including other sources of information.
A Comprehensive Autonomy Architecture for MCM AUVs. Williams, P.D.; Evans, B.S.
NURC-FR-2008-018. June 2008.
A comprehensive autonomy framework for MCM AUV missions is presented. The approach is a flexible solution that allows information collected during the mission to be immediately exploited in the remainder of the mission. This adaptive nature of the resulting autonomous mission route can result in improvements over pre-planned routes. The proposed system is comprised of six behaviors, each of which deals with a fundamental component of the vehicle’s functionality. Thirteen performance measures that represent more specific objectives of the mission fall under the purview of the six behaviors. Operator-defined weights on these performance measures are used to compute the value of an objective function, which in turn determines the optimal vehicle settings to select. Example simulations that demonstrate the promise of the autonomy architecture, as well as the effects of different performance-measure weight settings, are shown. Quantitative comparisons of the autonomy approaches with standard pre-planned routes are also provided.
Automated Identification System anomaly simulator. Baldacci, A. NURC-MR-2008-002. June 2008.
Automated Identification System (AIS) is currently the main source of information available for maritime surveillance. The continuous AIS data stream, collected by and shared between an ever-increasing number of AIS receivers (land based, ship based and airborne) provides a real-time picture of the current maritime situation and of its evolution over time. Recently, the Nations have shown a growing interest in the exploitation of AIS information to automatically detect anomalous vessel behaviors, which constitute potential maritime threats to national security. NURC is currently developing intelligent agents, which can be used to process the AIS data and automatically detect anomalies. In order to develop and train the intelligent agents and to assess their performance, a ground truth is needed. For this reason, NURC has developed an AIS anomaly simulator. With this tool, it is possible to simulate AIS status, kinematic and positional anomalies. The anomalous AIS tracks can be used to feed another NURC product, which is a more general maritime data simulator, including AIS, RADAR and satellite imagery contacts. These comprehensive datasets can be used to develop multi-sensor data fusion and multi-sensor anomaly detection algorithms.
Preliminary Plan Battlespace Preparation Experiment. Varley, P.; Hammond, N.; Ranelli, P.; Schmidt, R.; Besiktepe, S.; Rixen, M.; Trees, C.; Grasso, R. NURC-SP-2008-002. June 2008.
This document is a Preliminary Trial Plan for a candidate Battlespace Preparation Experiment (BPE) to be conducted during 2009 during a to-bedetermined exercise. The Recognized Environmental Picture (REP) is a developing NATO Bi-SC concept that has a principal goal of providing integrated and timely geographic, meteorological and oceanographic (GEOMETOC) support to NATO operations. This is a necessary capability for providing Information Superiority in denied or unknown areas. The aim of the BPE is: “To demonstrate the ability, using organic assets of operational units, to produce and exploit at the tactical level, and in an operational context, a timely, highly resolved 4-D picture of geospatial, oceanographic and meteorological conditions in the Battlespace.” The proposed experiment addresses one of the two key elements in providing the REP; viz. the collection, assimilation and forecasting of GEOMETOC conditions. The other key element is the infrastructure to distribute the REP to the operational user. The BPE will address assimilation of locally recorded data in order to ‘improve’ the usefulness of the Local REP (LREP) to support tactical decisions in the period out to 24 hours ahead. It is proposed that the BPE should be a Hypothesis Testing Experiment. Three hypotheses have been proposed for testing within the context of an operation exercise. These hypotheses state: (*) If real-time in-theatre METOC data is assimilated into the delivered LREP then there will be a positive effect on the exercise 4-D METOC picture. (*) If the 4-D METOC picture is enhanced then TDA output will improve. (*) If the 4-D METOC picture is enhanced and the TDA output is improved then operational decision-making will improve.
Very shallow water and bottom modelling: final report. Conley, D.C.; Falchetti, S. NURC-FR-2008-011. May 2008.
This document comprises the final report of the Very Shallow Water Modelling Project, the overall goal of which was to work towards the development of a 3-D surf zone model capable of simulating not only circulation but also sediment transport and the subsequent bathymetric evolution arising from erosion and deposition. This topic is central not only to the prediction of bathymetric modifications in very shallow water and the surf-zone (shallower than 10 m) but also to such issues as mine burial by scour and even water column visibility.
ITMINEX08 – Percentage clearance trials. Strode, C. NURC-FR-2008-017. May 2008.
ITMINEX08 – Radar detection trials for port and harbour protection. Strode, C. NURC-FR-2008-016. May 2008.During exercise ITALIAN MINEX 2008 5 minehunters conducted percentage clearance trials off the island of Palmaria. NURC was involved in the planning and subsequent analysis of these trials. This report presents the results of the analysis for distribution to the commanding officers of the participating units.
During ITMINEX08 two trials were conducted in order to assess the ability of shipboard radar to detect and track a small surface craft in a harbour environment. This report details the results and observations made.
Deterrence as force multiplier in port protection and the defence against terrorism (DAT). Kessel, R.T. NURC-FR-2008-015. May 2008.
When military surveillance systems are brought into DAT and security operations, it is usually with a view to counter an attack in the moments that it is taking place. In effect, the developer assumes that a particular mode of attack is underway and it must be countered with a high probability of success. In security more generally, however, it is common to speak also of deterrence. One’s defensive stance pays off significantly, that is, by deterring would-be attackers through their prospect of failure. The effectiveness of many security systems can be explained in part by their deterrent effect. In this paper the effect of deterrence is introduced into a model of overall system effectiveness. The effect can be dramatic, featuring as a force multiplier on the order of magnitude or more, including systems whose effectiveness is compromised somewhat, of necessity, to keep the number of false alarms serviceably low. The model underscores the differences in technology perspective and efficacy when developers turn from combat to security applications.
NGAS engineering and technical report. Hughes, D.; Grandi, V. NURC-FR-2008-014. May 2008.
This report gives a quick look summary of the NGAS’07 experiment which took place in Norway between the 10th and the 25th of April 2007. The role of the report is twofold (a) to provide a written record of what occurred on the trial, detailing location, equipment employed, and giving an overview of the runs carried out; (b) to give a quick look at some of the unclassified and data collected during the trial and to give an indication of where future, more detailed research should focus. With reference to the second point it is shown that the data collected has the correct form and that the NURC NGAS platforms are working well. Future reports will discuss results of classified data and detail suggested algorithms.
Optimisation in the multistatic tactical planning aid (MSTPA). Wathelet, A.; Strode, C.; Vermeij, A.; Been, R. NURC-FR-2008-013. May 2008.
MSTPA is a tool that models all stages of the multistatic detection process from signal excess calculation to track formation and classification of a target track. MSTPA accounts for the complex dependencies between the environment, sensor performance and fusion of multistatic detections. This report documents the optimisation and target types in MSTPA. This document explains what has been modelled and how to use MSTPA to investigate ASW scenarios with multistatic systems. Example results obtained from the optimiser against the target types are presented. In addition a brief overview of MSTPA updated user interface, architecture, towed array model and input-output are described.
Utilization of satellite based inversion methods and fuzzy logic in decision support system (DSS). Pennucci, G.; Grasso, R.; Giannecchini, S.; Fabiani, A.; Trees, C. NURC-FR-2008-012. May 2008.
This report describes the study of techniques to provide decision support, using satellite remote sensing observations and fuzzy logic methodologies. The purpose is the development of analysis tools that fully exploit the information content in optical imagery data, particularly as it applies to remote sensing bathymetry for use in decision support. The concept was demonstrated by developing an end-to-end processing system for amphibious landing operation support at tactical scale. The prototype chains high resolution forecast models to predict environmental variables of interest, fuzzy logic expert systems for environmental impact assessment and automatic decision making, and Web-GIS client-server application for data management and distribution. Algorithms to estimate shallow water bathymetry from passive multi-spectral sensors are integrated into the decision support prototype as required by high resolution forecast models to predict wave conditions over the landing area. Results from the NATO Steadfast Jaguar 2006 exercise and the NURC Battlespace Preparation 2007 sea trial are provided and discussed.
Prototype framework for network-enabled, object oriented, geospatial decision support. Grasso, R.; Giannecchini, S.; Fabiani, A.; Pennucci, G.; Trees, C. NURC-FR-2008-010. May 2008.
A general net-centric architecture for supporting distributed data fusion and operational oceanography is proposed and discussed. The architecture allows the development of end-to-end processing systems, automating the data flow from data acquisition to data and products dissemination and visualisation. An integrated approach fusing remotely sensed data, forecast models and in situ observations is used for a precise characterisation of the littoral environment and to provide support to operations over the area of interest. Automatic decision aids is employed to assess the impact of environmental conditions on operations. Furthermore, data management and dissemination is provided through Web GIS services which are compliant with standards for interoperability. An example of system implementation in the context of landing operation support is described and discussed.
Applicability of open source geospatial software to the recognised environmental picture. Grasso, R.; Giannecchini, S.; Fabiani, A.; Pennucci, G.; Trees, C.; Le Gac, J.C. NURC-FR-2008-009. May 2008.
This report describes the main contributions of project 1D3 (Acquisition, Fusion and Delivery of Mission-Critical Geospatial Information in a Network-Enabled Environment) on assessing the applicability of open source Web-enabled GIS technology in support of recognised environmental picture (REP) and Tactical Decision Aid (TDA). Applicability is tested by means of the interoperable Web-GIS architecture developed at NURC under the same project 1D3, which has been deployed several times during the project span in support of NURC sea trails and NATO exercises. The system is compliant with standards provided by the Open Geospatial Consortium (OGC) for interoperability. The report is focused on activities conducted under NURC's Scientific Programme Of Work (SPOW) and in particular on the recent Battleplace Preparation 2007 (BP07) NURC sea trial. The potential applicability of this technology for supporting the REP and general operational tactical planning was demonstrated.
The variability of sonar detection range in port protection: theory, observations, and implications. Kessel, R.T.; Hollett, R.D. NURC-FR-2008-008. May 2008.
Observations of diver detection range and reflectivity are presented here for divers alternately wearing open circuit and closed circuit breathers, and wet suits and dry suits. The divers were swimming towards a commercially available diver detection and tracking sonar equipped with an option to access unprocessed stave data for the scientific post analysis. The sources of variability (random uncertainty) in detection range are treated at length with implications drawn for system analysts, operators, and security planners. Three sources of uncertainty are considered: uncertainty due to 1) the unknown or changing environment, 2) to the intrinsic probabilistic nature of detection, and 3) to the unknown or changing diver target strength. The intrinsic uncertainty in detection range is analyzed theoretically, apparently for the first time. A rule of thumb for the upper and lower bounds on detection range is derived. The analysis has application elsewhere in sonar and radar. The detection ranges observed here are considered in light of all three types of uncertainty. That intrinsic uncertainty was itself large relative to the sonar range setting, so no conclusions regarding greater or lesser diver target strength could be made from the observations of detection range. Analysts therefore extracted time series echo data (the beam-formed signal to reverberation ratio (SRR)) for divers approaching the sonar from a horizontal distance (range) of 200 to 150 m at midwater depth in roughly 10 m water. Comparisons were made in the SRR for the different diver equipment combinations, again with statistical uncertainties taken into account. The sonar detected and tracked all equipment combinations with virtually equal success. The implications for operators and security planners are expressly considered.
An approximate form of the Rayleigh reflection loss and its phase: application to reverberation calculation . Harrison, C. NURC-FR-2006-021/Ed.2. May 2008.
This report derives an extremely good approximation to the Rayleigh reflection loss for two half-spaces composed of water over sediment. This has some useful properties. Firstly it demonstrates that the usual linear approximation for the reflection loss (inside the critical angle) can be extended to the non-linear case. Secondly it shows that the non-linearity can be expressed as a separate function that multiplies the linear loss coefficient. Thirdly this non-linearity term depends only on sediment density and does not depend on sediment sound speed or volume absorption. Fourthly the non-linearity term tends to unity, i.e. the reflection loss becomes effectively linear, when the density ratio is about 1.27. There are similar findings for the reflection loss phase which lead to the well-known "lateral shift" or "effective depth". NOTE: This is the second edition of NURC-FR-2006-021, originally published in December 2006.
Modeling and analysis for harbour protection against underwater terrorist attacks. Yip, H.; Nguyen, B.; Grignan, P.; Vermeij, A. NURC-FR-2008-007. March 2008.
The paper describes a stochastic model of the effectiveness of a defence system to counter an underwater threat. This model is applied to a scenario with a surface vessel in a harbour environment. The Measures–Of–Effectiveness (moe) of the defence system is the probability that a defence system successfully defends a surface vessel from a terrorist attack. The following systems are considered in the analysis: an active sonar with a tracking system, an intercept platform with a non–lethal weapon system, and an underwater barrier with sensors to alert the defence of an intruder. The impact of the parameters of these systems on the moe are analysed. The analyses showed that the launch time of the interceptor is critical to the effectiveness of the defence system against the nominal uuv threat. The capabilities of the sonar are best utilised when the interceptor is launched shortly after the threat track–initiation. However, when the launch of the interceptor is delayed 180 seconds or more after track–initiation, the underwater barrier system is the only system that contributes to the effectiveness against the uuv. Increasing the length of the underwater barrier has the effect of increasing the stand–off distance against the nominal uuv threat, thus improving the effectiveness of the defense system. The defence system effectiveness against the diver is shown to be less sensitive to the interceptor’s launch time. A diver’s slower swim speed and assumed low explosive payload reduces the requirements for an underwater barrier. The contribution of the underwater barrier to the effectiveness against a diver is shown to be marginal.
Track Classification model for the Multistatic Tactical Planning Aid (MSTPA) Wathelet, A.; Vermeij, A.; Strode, C.; Justus, B. NURC-FR-2008-006. March 2008.
Multistatic ASW operations have the potential to improve the effectiveness of NATO ASW operations not only by the inherent systems performance but also by the way such systems are used tactically. This report documents the progress made in modelling a sonar operator in the task of classifying multistatic tracks in the Monte-Carlo simulation model of the multistatic tactical planning aid (MSTPA). The requirements for such a model are outlined together with a description of the sequential analysis framework and a set of classification algorithms. In addition the results of experiments conducted to select an appropriate algorithm are reported.
Contact-based AIS coverage estimation and distribution. Baldacci, A.: Fabiani, A.; Giannecchini, S. NURC-MR-2008-001. March 2008.
This document describes work performed in the framework of the Maritime Surveillance Program (MSP) focused on real-time automatic AIS coverage estimation based on recorded AIS contacts. This capability, requested to NURC by Component Command Maritime Headquarter Naples, Italy, (CCMar Naples) as a tool for maritime surveillance, has been promptly provided to the customer by leveraging NURC's expertise in the fields of AIS data processing and geospatial data fusion. AIS coverage maps are estimated over two different time periods: short-term coverage maps are estimated over 12-hour periods and give indication on short-term AIS coverage variability; medium-term coverage maps are estimated over longer periods (typically ranging from one week to one month) and give indication on medium-term and seasonal AIS coverage variability. AIS coverage maps are distributed via the OGC-compliant Web Map Server developed by the Geospatial Data Fusion Centre at NURC.
Modeling and analysis for harbour protection against underwater terrorist attacks. Yip, H.; Nguyen, B.; Grignan, P.; Vermeij, A. NURC-FR-2008-007. March 2008.
The paper describes a stochastic model of the effectiveness of a defence system to counter an underwater threat. This model is applied to a scenario with a surface vessel in a harbour environment. The Measures-Of-Effectiveness (moe) of the defence system is the probability that a defence system successfully defends a surface vessel from a terrorist attack. The following systems are considered in the analysis: an active sonar with a tracking system, an intercept platform with a non-lethal weapon system, and an underwater barrier with sensors to alert the defence of an intruder. The impact of the parameters of these systems on the moe are analysed. The analyses showed that the launch time of the interceptor is critical to the effectiveness of the defence system against the nominal uuv threat. The capabilities of the sonar are best utilised when the interceptor is launched shortly after the threat track-initiation. However, when the launch of the interceptor is delayed 180 seconds or more after track-initiation, the underwater barrier system is the only system that contributes to the effectiveness against the uuv. Increasing the length of the underwater barrier has the effect of increasing the stand-off distance against the nominal uuv threat, thus improving the effectiveness of the defense system. The defence system effectiveness against the diver is shown to be less sensitive to the interceptor's launch time. A diver's slower swim speed and assumed low explosive payload reduces the requirements for an underwater barrier. The contribution of the underwater barrier to the effectiveness against a diver is shown to be marginal.
Echo classification features and processing for mine-hunting with autonomous underwater vehicle. Groen, J.; Coiras, E.; Del Rio Vera, J.; Evans, B.S. NURC-FR-2008-005. February 2008.
The quality and effectiveness of sensor information provided by minehunting autonomous underwater vehicles (AUVs) equipped with high-resolution sonars has improved drastically in recent years. In parallel, data rates have significantly increased resulting in information overload. Automatic target recognition (ATR) is regarded as a solution for this problem. This report describes initial work to develop and assess ATR techniques for application to this higher resolution data. Four ATR approaches have been implemented and tested on simulated data, and the robustness and performance for each method was assessed. The work has provided an effective baseline for further ATR developments, encompassing four diverse techniques that have been shown to independently exploit information supplied by modern high resolution mine hunting sonar. Further work is required to confirm performance with real data and to examine different fusion techniques to maximise performance and environmental robustness.
FM and CW Fusion within the DEMUS system. Hughes, D.; Micheli, M. NURC-FR-2008-004. January 2008.
Multistatic sonar systems hold the promise of greatly increasing the performance of anti-submarine warfare (ASW) systems. The geometric distribution of transmitters and receivers can be set up to provide spatial diversity. This diversity, multiple looks at the same object from different directions, is expected to complicate the target’s tactics since it will be more difficult to avoid favourable aspects of insonification, consequently the target will be more liable to be detected. A further level of diversification is offered by the simultaneous use of FM and CW pulses. The FM pulses provide good range resolution as opposed to the CW pulses which have poor range resolution but provide information on the speed of the target. NURC’s DEMUS system is expected to provide an excellent platform for the investigation of the use of multiple receivers and multiple waveforms. In particular the absence of own Doppler due to the stationarity of the transmitter and receiver will give good performance for the CW contacts. In this report we have three objectives: (1) Detailing the modifications that have been made to NURC’s real-time signal processing chain to incorporate the production and analysis of CW contacts; (2) Investigate the performance of a simple fusion algorithm which associates FM and CW clusters to provide contacts with both good range resolution and Doppler information; (3) Detailing and analyzing three data sets, incorporating CW and FM, which are to be used for subsequent analysis of the Centre’s multi-hypothesis tracker, incorporating both pulse types. We show how good FM-CW association can be obtained for both noise-limited and low-reverberation levels. For situations in which a high level of reverberation is present we show that, as expected, the CW contacts are only observable outside of the reverberation ridge.
Airborne Forward Eyes Final Report. Pennucci, G.; Conley, D.C.; Holman, R. NURC-FR-2008-003. January 2008.
A feasibility study is presented which examined the application of COTS SUAV to perform quantitative image analysis for maritime REA. Data from two separate field exercises were collected and over 18 hours of airborne imagery were obtained using the AeroVironment Raven SUAV. Extensive testing was performed to characterize the SUAV geometry, meta-data reliability and video camera properties. The total system had been characterized with the images being georectified, mosaiced and time-averaged. Remotely sensed air based time-exposed surf-zone images were generated which were superior in quality to those produced from any land based camera systems. A methodology is proposed involving a satellite acquired georeferenced base image with feature recognition software to automatically correct and process these images.
Geospatial Data Fusion Server Architecture at NURC Fusion Centre. Giannecchini, S.; Fabiani, A.; Spina, F.; Grasso, R. NURC-FR-2008-002. January 2008.
This report describes the work done at NURC in 2004, 2005 and part of 2006 to provide a framework for Geospatial Data Management with special attention to the requirements imposed by large, multi-dimension, multi-band static and dynamic coverages. The aim is to support the application of these data within NURC for the ongoing research and in particular for research on Data Fusion. The report covers what was accomplished and how, and the reasons for selecting of the technical solutions. It presents the advantages and disadvantages of adopting of the OGC/ISO standards and the open source software based on these standards, and in particular the value of this approach for a multi-force/multinational user base.
NURC participation in the TIDE-REP Experiment at NATO exercise CWID 2005: a technical description. Ranelli, P.; Farid, A.; Spina, F.; Stenvoll, R.; Giannecchini, S.; Fabiani, A.; Pennucci, G.; Grasso, R.; McCarthy, E.; Baldasserini, G.; Turgutcan, F.; Robichaud, R.; Berni, A.; Merani, D. NURC-FR-2008-001. January 2008.
This report describes the NURC participation in CWID05 as part of the TIDE-REP demonstration. The exercitation was an opportunity to test NURC capabilities in multi-source data processing, in automatic decision making for environmental impact assessment and in geospatial data management through interoperable web-enabled GIS systems. Meteorological and oceanographic variables (METOCs) provided by forecast models and remotely sensed data as well were used in a fuzzy logic expert system to automatically assess the impact of the environment on operation execution at the tactical scale. Web-enabled GIS services compliant with the ISO and OGC standards were tested to distribute data and added value products through the web in an interoperable way. Moreover, a network link was set up to inject data from NURC into the so called “Purple-domain” in which classified communications during CWID were conducted. The link was successfully tested under special quality of service policies. The report gives an overview of the system architecture used to support the exercitation with data and added value products. Examples of METOCs and TDA products that were demonstrated and provided to C2IS (Command and Control Information Systems) users in near real time during CWID 2005 are included.
Legal principles guiding response in port protection. Arsenault, N.D. NURC-SP-2008-001. January 2008.
This report summarizes the legal principles that govern the use of force against underwater intruders in port protection. The scenario assumed is a ship, operating as part of the NATO Response Force (NRF), docked or at anchor in the inner harbour of a commercial port of an obliging country to refuel, restock, or make repairs. This report provides an introductory top-down awareness of legal principles that bound response when providing protection to ships in ports, which necessarily shapes the technology that supports response action. The cornerstone principle of the UN Charter is that force is prohibited except as self-defense under the principles of necessity and proportionality. The prohibition is reiterated in domestic law which governs ship and crew. The UN Convention on the Law of the Sea defines the legal responsibilities and limitations imposed on visiting ships in foreign ports regarding innocent passage, sovereignty of coastal state versus flag state, and the general duties imposed upon warships. A review of the Law of Armed Conflict is included since the technologies developed as a response to an attack must adhere to its guidelines. The report does not serve as Rules of Engagement or as a guide to personnel during operations. Neither does it consider particular technologies or responses.