N093-168 TITLE: Target Localization Using Multi-Static Sonar with Drifting Sonobuoys

TECHNOLOGY AREAS: Air Platform, Sensors

ACQUISITION PROGRAM: Advanced Extended Echo Ranging ACAT IV-T and Improved Extended Echo Ranging

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation.

OBJECTIVE: Develop an algorithm capable of accurately locating a target using only acoustic signals collected on a passive and active multi-static sonar system consisting of drifting buoys without the use of other data to locate the buoys.

DESCRIPTION: Algorithms are currently used to locate targets in the ocean using active and passive multistatic sonobuoy systems. These systems currently require a means to accurately locate drifting buoys in order to accurately locate the targets. A need exists to accurately locate targets from acoustic data alone without using other navigational data such as aircraft sightings, radar, or global positioning systems (GPS). Using acoustic signals by themselves to accurately locate targets and produce reliable confidence limits for target locations would increase the reliability and simplicity of the system while reducing cost. Past approaches, such as those concentrated on using a particle filter or Kalman filter algorithm (see references), have been unsuccessful. The algorithm for locating targets should take into consideration all relevant sources of error and produce accurate confidence limits that contain the correct target location. The algorithm should be able to overcome any uncertainties in buoy locations yet still converge to the correct answer for the target and its confidence limits.

PHASE I: Develop and define an algorithm that yields accurate locations and accurate confidence limits on location for targets using only acoustic data from drifting active and passive sonobuoys in the ocean.

PHASE II: Apply the algorithm to several sets of field data collected during actual sea tests. Demonstrate the algorithm with simulated data using realistic scenarios.

PHASE III: Integrate the algorithm into aircraft (e.g. P-3, H-60, or surrogate). Transition the system into aircraft used for surveillance.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Developed technology would potentially benefit existing systems where locations of transmitters or receivers are not accurately known.

REFERENCES:
1. "Sequential Monte Carlo Methods in Practice:" Doucet, Freitas, and Gordon (editors), ISBN 0-387-95146-6

2. "Applied Optimal Estimation:" Arthur Gelb (editor), ISBN 0-262-57048-3

3. Stan E. Dosso and Nicole E. B. Collison, "Acoustic tracking of a freely drifting sonobuoy field," J. Acoust. Soc. Am. 111 (5), May 2002, page 2166. [There are also several pertinent references contained therein.]

4. John L. Spiesberger, "Geometry of locating sounds from differences in travel time: Isodiachrons", J. Acoust. Soc. Am. 116 (5), Nov 2004, page 3168.

5. John L. Spiesberger, "Probability distributions for locations of calling animals, receivers, sound speeds, winds, and data from travel time differences," J. Acoust. Soc. Am 118 (3), Sept 2005, page 1790.

6. John L. Spiesberger, "Hyperbolic location errors due to insufficient numbers of receivers," J. Acoust. Soc. Am. 109 (6), June 2001, page 3076.

7. Nathan Marchand, "Error Distributions of Best Estimate of Position from Multiple Time Difference Hyperbolic Networks," IEEE Transactions on Aerospace and Navigational Electronics, June 2009, page 96.

8. Ralph O. Schmidt, "A New Approach to Geometry of Range Difference Location," IEEE Transactions on Aerospace and Electronic Systems, Vol. 8, No. 6, Nov 1972, page 821.

KEYWORDS: Sonobuoy; Position; Confidence Limits, Sequential Estimation; Target Location; Algorithm

** TOPIC AUTHOR (TPOC) **

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