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Multistatic Transmission Loss (TL) Estimation



TECHNOLOGY AREA(S): Electronics, Sensors

ACQUISITION PROGRAM: PMA-264 Anti-Submarine Warfare Systems

OBJECTIVE: Develop a robust Transmission Loss (TL) estimation capability for multistatic Anti-Submarine Warfare (ASW) sonars that can be used to reduce the operator workload by eliminating clutter.

DESCRIPTION: New functionalities in ASW for active multistatics, such as operating multiple sources simultaneously, and the resulting higher transmission rates provide enhanced detection capabilities. However, there is an increase in false detections, leading to an increased operator workload. One approach to reducing operator workload is to use TL estimation to help discriminate clutter from possible target echoes.

The challenge exists in that TLs can vary significantly depending on the environmental state, bathymetry of the ocean at the time, and location of a given sonar transmission(s). Therefore, it is not possible to empirically measure either the TLs themselves or even to fully measure the environmental state of an operational area prior to an ASW mission. In order to achieve an implementable solution that operates robustly in a wide range of locations and environmental conditions, it is necessary to develop statistical models that adequately estimate the TLs for a given location, sensor geometry, and set of environmental conditions.

Emphasis should be placed on the development of algorithms and software that utilize historical data with in-situ measured TL data (provided in Phase II), to evaluate existing real world data collection sets and measure the resulting improvement on TL estimation to operator performance. The two-way transmission loss of active sonar detections (dependent on environmental state, bathymetry of ocean at the time and location of a given sonar transmission(s)) should be estimated to improve search mission planning. The detection TL estimates can then be used to reject clutter contacts that originated from areas of high TL.

Candidate algorithms will be assessed using datasets with known clutter to test the ability to reduce or remove clutter. Assessment will be based on known data sets with known “false alarms.” Dummy data sets will be provided to selected Phase I companies for use during development.

Work produced in Phase II may become classified. Note: The prospective contractor(s) must be U.S. owned and operated with no foreign influence as defined by DoD 5220.22-M, National Industrial Security Program Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Security Service (DSS). The selected contractor and/or subcontractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances, in order to perform on advanced phases of this project as set forth by DSS and NAVAIR in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material IAW DoD 5220.22-M during the advanced phases of this contract.

PHASE I: Research and investigate the suitability and feasibility of proposed TL estimation algorithm / software, enabling clutter reduction on simulated and unclassified data sets. Identify technological and reliability challenges of the design approach, and propose viable risk mitigation strategies.

PHASE II: Design and develop an engineering level (beta) robust TL estimation algorithm / software prototype based on the design from Phase I. Demonstrate the technique(s) by processing existing real world data collection sets and measure the resulting improvement in TL estimation to operator performance in accordance with the parameters in the Description.

PHASE III DUAL USE APPLICATIONS: Develop a production level version of the final robust TL estimation algorithm / software. Based on research, develop a timeline / plan / process for implementation of the algorithm / software and assist in transitioning the product to the Airborne ASW community through the Advanced Product Build (APB) process. Private Sector Commercial Potential: The developed technology has the potential to be useful for any system that can benefit from more accurate receiver and transmitter localization; benefitting industries may include seismic and oil exploration.


  • Pittenger, RDM R. & Wiseman, C., (2015). Measured Transmission Loss—A Key to Improved Sonar Performance Prediction, Maximizing Sonar Effectiveness by Measuring Acoustic Transmission Loss. Sea Technology Magazine,
  • Urick, R. J. (1967). Principles of Underwater Sound for Engineers (1st ed.). New York: McGraw-Hill Book Company

KEYWORDS: Airborne ASW; Mission Planning Tools; ASW Operator Workload Reduction; Tactical Decision Aids; Transmission Loss; Estimation

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