N151-055 TITLE: Multi-ship Sonar Bistatic Automatic Active Localization

TECHNOLOGY AREAS: Sensors, Electronics, Battlespace

ACQUISITION PROGRAM: PEO IWS 5, Undersea Warfare Systems

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 5.4.c.(8) of the solicitation. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.

OBJECTIVE: Develop Multi-ship Sonar Bistatic Automatic Active Processing and Localization Coordination that meets system requirements.

DESCRIPTION: The Navy needs improved performance when multiple surface ships are transmitting simultaneously in a strike group and when submarines utilize active sonar capability in coordinated operations. Bistatic reception and processing of active transmissions provides the capability for a single receiver to increase the amount of opportunities it has to exploit active acoustic transmissions, allows for stealthy receivers to process active transmissions without giving away its location, and decreases interference from many ships transmitting simultaneously. In order to achieve these bistatic reception benefits, each receiver needs some information about the remote source. A solution to the source information exchange problem within a communications implementation framework will allow for a cost-effective implementation approach to take advantage of the strike group and submarine active multi-ship coordination benefits.

Successful application of multi-ship bistatic active sonar processing requires information exchange or inference of certain source transmitter parameters to achieve optimal processing and localization accuracy [ref 1]. To utilize an active bistatic receiver successfully, the receiver requires information from or about the source platform including location, timing, and transmit types. The successful offeror will determine the optimal information to either transmit to or estimate on the bistatic receiver to minimize processing losses and to achieve weapons-quality localization solutions. The optimal information exchange will focus on acoustic warfare scenarios of interest for a source platform (surface ship mid- frequency sonar transmitters) and two receivers (surface ship and submarine mid-frequency active sonar receivers).

In order to process an active sonar transmission from a non-collocated source, a receiver must utilize or estimate the type of waveform transmitted; the source location, course, and speed; transmission time; and source and receiver time synchronization. A lack of knowledge in each of these areas can result in processing losses (lack of waveform information and matched filter), processing delays (to estimate waveform information), source location course and speed errors (localization errors), transmission time (localization error), and source and receiver time synchronization (localization error). The sensitivity of the localization error to these various parameters can be estimated [refs 1, 2]. The communications between source and receiver may be via high quality satellite communications; via limited-bandwidth satellite or acoustic communications; or via little or no communications. Limited bandwidth communications may impact the localization errors when parameters are transmitted with limited precision. No communications between source and receiver may increase the localization error due to errors in parameter estimation as well as an increase in non-recurring engineering costs to develop estimation algorithms. Utilizing example mid-frequency surface ship and submarine bistatic localization scenarios, a trade space study will indicate which parameters are most important to transmit or estimate, with what precision, and with what localization estimation approaches to achieve the minimum amount of transmitted information to achieve high levels of bistatic active processing and localization performance.

PHASE I: The company will develop a concept for a Multi-ship Bistatic Automatic capability that meets the requirements as stated in the topic description. This concept is based on an algorithm that will be added to the existing active monostatic processing capability. The company will demonstrate the feasibility of the concept in meeting Navy needs and will establish that the concept can be developed into a useful product for the Navy. Testing and analytical modeling will establish feasibility.

PHASE II: Based on the results of Phase I, the company will develop a prototype for evaluation. The software prototype will be evaluated to determine its capability in meeting performance goals and Navy requirements for the Multi-ship Bistatic Automatic capability. System performance will be demonstrated through prototype evaluation and modeling or analytical methods over the required range of parameters including numerous different operational scenarios. Evaluation results will be used to refine the prototype into an algorithm/software design that will meet Navy requirements. The company will prepare a Phase III development plan to transition the technology to Navy use.

PHASE III: The company will support the Navy in transitioning the technology for Navy use. The company will develop a Multi-ship Bistatic Automatic capability according to the Phase III development plan to determine its effectiveness in an operationally relevant environment. The company will support the Navy for test and validation to certify and qualify the system for Navy use.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Within the commercial sector, there is a need to detect and localize objects on the ocean bottom such as toxic waste containers or shipwrecks. This bistatic capability would support searches by surface vehicles.

REFERENCES:
1. H. Cox, "Fundamentals of Bistatic Active Sonar", NATO Advanced Study Institute Underwater Acoustic Data Processing, 18-29 July 1988.

2. D. Grimmett; S. Coraluppi; "Sensitivity Analysis for Multistatic LFAS Localization Accuracy," NURC-SR-386, January 2004.

KEYWORDS: Active bistatic sonar; non-collocated source; bistatic receiver; localization error for sonar transmission; limited bandwidth communications; estimation algorithms

** TOPIC AUTHOR (TPOC) **

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