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Formal Reports

Report of results of completed projects or major milestones either in scientific terms or in terms acceptable to a wider audience. Note: Unless linked to the full text, reports are only available to NATO member nations from designated distribution centres. 

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A report on the proof-of-concept experiment (LLOMEx13) to use conventional 532nm LiDARs to measure vertical oceanographic properties A report on the proof-of-concept experiment (LLOMEx13) to use conventional 532nm LiDARs to measure vertical oceanographic properties

Date added: 10/30/2014
Date modified: 10/30/2014
Filesize: Unknown

A report on the proof-of-concept experiment (LLOMEx13) to use conventional 532nm LiDARs to measure vertical oceanographic properties. Trees, Charles. CMRE-FR-2014-016. October 2014.

During the Ligurian Sea LiDAR and Optical Measurement Experiment (LLOMEx'13) Sea Trial in March 2013, two conventional 532nm LiDAR systems were deployed making measurements of LiDAR waveforms concurrently with in situ profiling and towed platforms equipped with optical instrumentation. A significant portion of the LLOMEx'13 Sea Trial was devoted to a "Proof-of-Concept" for using LiDARs to vertical sample the water column for estimating oceanographic properties, specifically the Inherent Optical Properties (IOPs). The above-water LiDAR (MiniLiDAR) was a converted atmospheric LiDAR that was modified to withstand the maritime environmental conditions, as well as to operate close to the air-sea interface and still record the time gated returned laser signals. Because of weather conditions (rain, high seas and surface bulb formation), the MiniLiDAR had difficulty retrieving waveforms that were not contaminated by the surface interface or water drops that formed on both the laser and detector lens. The in situ profiling LiDAR system (Fine Structure Underwater Imaging LiDAR, FSUIL) performed superbly collecting vertical profiles of the LiDAR waveforms throughout most of the sea trial. During the FSUIL profiling, an IOP instrumented profiling platform (Multi-Angle SCattering Optical Tool, MASCOT) was simultaneously lower. The MASCOT measured spectral attenuation, absorption and scattering, thus providing the optical data necessary for the development of LiDAR algorithms to retrieve these properties from the reflected laser signals. A simplistic "single scattering" Radiative Transfer Equation (RTE) model was developed and tuned to the FSUIL data. The retrieved IOP data from the LiDAR waveform agreed well with that measured in situ by the MASCOT. Some fine tuning of the LiDAR RTE model is needed so that "multiple scattering" can be included in the solution. This inclusion should improve the accuracy of the optical retrievals as well as provide uncertainty budgets for these algorithms. A follow-on Sea Trial (LLOMEx) is proposed for late 2015 or early 2016 that would sample the Alboran Sea, which is a highly dynamical physical and optical region that also has persistent internal waves generated by the Straits of Gibraltar.

Real-time continuous active sonar processing Real-time continuous active sonar processing

Date added: 10/16/2014
Date modified: 10/16/2014
Filesize: Unknown

Real-time continuous active sonar processing. Canepa, Gaetano; Munafó, Andrea; Murphy, Stefan M. CMRE-FR-2014-015. September 2014.

This report describes the development of continuous active sonar (CAS) processing at CMRE. The software uses sub-band processing to achieve a faster update rate than is possible with pulsed active sonar (PAS). The software development was based on CMRE's PAS processing software, CAINPro, which has been thoroughly tested during previous sea trials and in post-processing data analysis. Computational efficiency was carefully considered and many optimizations were made so that the software can run in real-time using the constrained computing resources on board CMRE's Ocean Explorer autonomous underwater vehicles. The software was successfully tested during the REP14 Atlantic sea trial in July 2014, and was able to demonstrate real-time detection of an echo repeater on all nine sub-bands that were processed. The algorithm runs in real-time with a speed approximately six times faster than the original PAS software running equivalent processing.

Propagation and bistatic reverberation with convergence in a range-dependent environment: implementation in Artemis Propagation and bistatic reverberation with convergence in a range-dependent environment: implementation in Artemis

Date added: 09/11/2014
Date modified: 09/11/2014
Filesize: Unknown

Propagation and bistatic reverberation with convergence in a range-dependent environment: implementation in Artemis. Harrison, Chris H. CMRE-FR-2014-014. September 2014.

The flux formulation for propagation has already been modified to include ray convergence effects in a range-independent environment. This work is extended to include range-dependent propagation and bistatic reverberation suitable for direct insertion in the sonar performance model Artemis. The examples are run with a new implementation of Artemis that includes range-dependent convergence.

Autonomous frameworks for implementation of REMUS autonomy at CMRE Autonomous frameworks for implementation of REMUS autonomy at CMRE

Date added: 09/10/2014
Date modified: 09/10/2014
Filesize: Unknown

Autonomous frameworks for implementation of REMUS autonomy at CMRE. Connors, Warren ; Couillard, Michel. CMRE-FR-2014-013. September 2014.

Increases in the reliability and capability of underwater robotics has made them attractive for both research and operational use. The development and deployment of autonomous algorithms on robotic platforms is an active area of research at CMRE. Autonomous capability results in highly complex systems, however the implementation of autonomous frameworks attempts to manage this complexity through providing software and services to the developer. Various frameworks have been developed each with differing capabilities and constraints. CMRE has primarily been using the MOOS IvP framework exclusively to provide autonomous control for anti-submarine warfare (ASW) and mine countermeasures (MCM) tasks. For MCM, the MUSCLE vehicle has been the primary underwater system, demonstrating advanced sensing and control capabilities. Although a highly capable vehicle, the MUSCLE cannot be used frequently for ad-hoc prototyping and experimentation, due to size and support requirements. CMRE does possess an idealvehicle for this task, the REMUS 100. This work examines four autonomous frameworks for use in autonomy research at CMRE with respect to the capabilities, reuse of existing autonomy software, licensing, complexity, deployment requirements and performance. The goal of this work is to provide guidance on the capabilities and differences of these frameworks, with a focus on deployment on the REMUS 100. Although any of the examined frameworks can be successfully used for autonomy development, this work recommends a joint deployment of the ROS and MOOS framework on the REMUS 100, and provides an initial conceptual design for the development of autonomous capabilities using the REMUS RECON interface. This will provide CMRE a broader view of implementation technologies for providing both advice and developed technologies to NATO nations, with a focus on interoperability.

Addition of localisation services to acoustic communication for enhanced navigation of AUVs in multi-static anti-submarine scenarios Addition of localisation services to acoustic communication for enhanced navigation of AUVs in multi-static anti-submarine scenarios

Date added: 09/10/2014
Date modified: 09/10/2014
Filesize: Unknown

Addition of localisation services to acoustic communication for enhanced navigation of AUVs in multi-static anti-submarine scenarios. Munafò, Andrea. CMRE-FR-2014-012. July 2014.

This work proposes a novel approach to enhance Autonomous Underwater Vehicles (AUVs) navigation through the addition of localisation services to networked acoustic communication. The proposed approach is based on the inclusion of timing information within acoustic messages through which it is possible to know the exact time of an acoustic transmission in relation to its reception. The exploitation of such information at network level makes it possible to create an interrogation scheme similar to that of a longbaseline (LBL). The advantage of the proposed approach is that the AUVs themselves are the transponders of the baseline, and hence there is no need for dedicated instrumentation. In the Collaborative Anti-Submarine Warfare (CASW) scenario, the AUVs are both mobile nodes of an underwater acoustic network and receivers of a multi-static sonar system. In this respect, it is possible to use the vehicles? on-board processing to calculate range and bearing to the active source. This information is fused together with the LBL-like interrogation to further limit the navigation error. Details on the implementation of the proposed approach within the anti-submarine underwater sensor network are provided in this paper, together with a description of the software structure of the overall navigation system. Results are provided based on the data collected during the COLLAB13 experimental campaign, where a three nodes network was deployed off the coast of La Spezia, Italy. Two scenarios are reported: one in which the LBL-like approach is used as the only means to support the AUV navigation, and one in which the LBL-like measurements are fused together with those provided by the multi-static processing. In both scenarios the AUVs can only rely on a limited set of data from its odometry, namely water flow speed and compass heading. This is the information that is typically available for vehicles operating in deep waters or that cannot rely on expensive navigation systems. Results show how the usage of multi-static processing data and more importantly, the inclusion of localisation data to the normal network traffic can be instrumental in enhancing the AUVs navigation, even at long ranges and with sporadic communication.

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