Defense Acquisitions: Testing Needed to Prove SURTASS/LFA	 
Effectiveness in Littoral Waters (10-JUN-02, GAO-02-692).	 
For decades, the Navy has been striving to improve its ability to
detect potential enemy submarines before they can get within	 
effective weapons range of U.S. forces. In 1985, the Navy	 
established the Surveillance Towed Array Sensor System (SURTASS) 
Low Frequency Active (LFA) sonar program to develop a long-range 
capability for detecting a new generation of quieter Soviet	 
nuclear and diesel submarines operating principally in the open  
ocean. However, as the Navy conducted testing of the system in	 
the mid-1990s, some public interest groups and scientists raised 
concerns that SURTASS/LFA may cause harm to marine mammals. The  
Navy discontinued operational testing of the system and initiated
an environmental impact statement process. The Navy will not	 
begin testing or operating the system until it recieves a Letter 
of Authorization from the National Marine Fisheries Service. A	 
decision on the authorization is expected later in 2002.	 
SURTASS/LFA will increase the Navy's capability to detect	 
submarines in the open ocean, where the system was originally	 
intended to operate. The Navy has considered a number of existing
alternatives to SURTASS/LFA and found that the system provides	 
long-range detection capabilities not available with other	 
-------------------------Indexing Terms------------------------- 
REPORTNUM:   GAO-02-692 					        
    ACCNO:   A03515						        
  TITLE:     Defense Acquisitions: Testing Needed to Prove SURTASS/LFA
Effectiveness in Littoral Waters				 
     DATE:   06/10/2002 
  SUBJECT:   Operational testing				 
	     Marine policies					 
	     Antisubmarine warfare				 
	     Defense capabilities				 
	     Navy Low Frequency Active Sonar Program		 
	     Navy Surveillance Towed Array Sensor		 
	     Navy Submarine Surveillance Program		 

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Report to the Honorable Patsy Mink, House of Representatives

United States General Accounting Office



Testing Needed to Prove SURTASS/ LFA Effectiveness in Littoral Waters

GAO- 02- 692

Page 1 GAO- 02- 692 SURTASS Sonar

June 10, 2002 The Honorable Patsy Mink House of Representatives

Dear Ms. Mink: For decades, the Navy has been striving to improve its
ability to detect potential enemy submarines before they can get within
effective weapons range of U. S. forces. In 1985, the Navy established the
Surveillance Towed Array Sensor System (SURTASS) Low Frequency Active (LFA)
sonar program to develop a long- range capability for detecting a new
generation of quieter Soviet nuclear and diesel submarines operating
principally in the open ocean. Since the end of the Cold War, the Navy has
shifted its focus to include regional conflicts and the threat posed by
diesel- electric submarines operating in littoral waters. 1 The Navy
continued to develop SURTASS/ LFA because it showed technological potential
to detect objects at great distances. Sound produced at low frequencies can
travel further underwater than sound produced at higher frequencies. 2
However, as the Navy conducted testing of the system in the mid- 1990s, some
public interest groups and scientists raised concerns that SURTASS/ LFA may
cause harm to marine mammals. The Navy discontinued operational testing of
the system and initiated an environmental impact statement process.
Currently, the Navy will not begin testing or operating the system until it
receives a Letter of Authorization from the National Marine Fisheries
Service. According to Navy officials, a decision on the authorization is
expected later in 2002.

In addition, some of the same groups that have raised environmental concerns
have questioned whether SURTASS/ LFA will increase the Navy?s undersea
detection capabilities and whether the Navy has an alternative for the
system. In response to your request, we examined (1) the extent SURTASS/ LFA
will enhance the Navy?s antisubmarine warfare capabilities to detect
submarines and (2) whether there are other existing or planned

1 Littoral waters refer to the coastal, near shore regions of the world.
These waters may vary in depth from shallow (600 feet or less) to over
several thousand feet deep. 2 At low frequencies, the absorption loss for
sound in water is much less, thus increasing the distance it can travel.

United States General Accounting Office Washington, DC 20548

Page 2 GAO- 02- 692 SURTASS Sonar

systems that can provide the same long- range detection capabilities as

Based on available evidence, SURTASS/ LFA will increase the Navy?s
capability to detect submarines in the open ocean, where the system was
originally intended to operate. While the Navy has indicated SURTASS/ LFA is
also intended to help meet the threat posed by submarines in littoral
waters, there has been limited demonstration of the system?s capability in
these areas. The effectiveness of the system in littoral waters generally
tends to diminish because of geographic and system design characteristics.
In addition, the system has operational limitations regarding the amount of
coverage it can provide. The overall operational evaluation that
demonstrates the suitability and effectiveness of SURTASS/ LFA in open
oceans is planned for fiscal year 2004. The Navy has not yet defined what
testing will be conducted in littoral waters.

The Navy has considered a number of existing alternatives to SURTASS/ LFA
and found that the system provides long- range detection capabilities not
available with other systems. Other available systems offer different
capabilities and practical limitations. For example, while passive sonar
systems are effective at short distances, they have less range and ability
to detect quiet submarines than SURTASS/ LFA. In addition, while fixed
systems were used effectively to address the Cold War threat, there are
practical constraints on where these systems can be located to meet the
broader submarine threat that exists today. Although SURTASS/ LFA also has
certain operational limitations, the Navy has concluded that these are
outweighed by the benefit of long- range detection. However, the Navy
acknowledges that no single technology or system will meet its overall
submarine detection requirements and that a ?tool box? approach involving
multiple methods must be used to address the existing threat. The Navy also
acknowledges that it needs to improve its antisubmarine warfare
capabilities, and it continues to explore a variety of new detection

This report includes a recommendation that before the Navy uses SURTASS/ LFA
in littoral waters it needs to test the system in these areas to determine
the system?s effectiveness. In commenting on a draft of this report, the
Department of Defense (DOD) concurred with our findings and recommendation.
Results in Brief

Page 3 GAO- 02- 692 SURTASS Sonar

The primary goal of antisubmarine warfare is to protect U. S. ships and
assets from enemy submarines. Undersea surveillance and detection of
submarines are a critical part of this mission. During the Cold War, the
Navy relied on a combination of fixed, mobile, passive, and active sonar
systems to detect enemy nuclear and diesel submarines, particularly those
from the Soviet Union. Passive sonar systems ?listen? or receive signals,
whereas active systems send out signals to search for targets and receive an
echo or response. The systems are used on mobile platforms, such as Navy
surface ships, submarines, and aircraft, and in fixed arrays that are laid
or buried across the ocean floor in various strategic locations. However,
because of technology advancements, the Soviet Union and other countries
developed quieter submarines. As a result, submarines became harder to
detect, and the Navy grew concerned that enemy submarines could get within
effective weapons range of U. S. ships and assets. The Navy determined it
needed a system that could detect quiet submarines at great distances. In
response to this need, the Navy launched the SURTASS/ LFA program in 1985,
which was originally designed for use in open oceans.

The SURTASS/ LFA system operates in conjunction with the Navy?s existing
passive SURTASS sonar system. The two components, as illustrated in figure
1, make up a mobile acoustic undersea surveillance system that is intended
to provide detection, cueing, 3 localization, and tracking information on
modern quiet nuclear and diesel submarines for the battle group or other
tactical commanders. The passive component detects sounds or echoes from
undersea objects through the use of hydrophones on a receiving array that is
towed behind the ship. The active or transmitting component of the system
sends high- intensity, low frequency sonar from transducers suspended by a
cable under the ship. The active signal will produce a return echo that,
when received, provides location and range data on submerged objects. The
system uses 18 pairs of undersea transducers and 18 shipboard high- power
amplifiers. The SURTASS/ LFA system is heavy, weighing 327,000 pounds, and
requires a specially designed ship to carry and operate it.

3 Cueing is sending location information to a platform to attack the target.
If the first platform is unable to attack the target, the location
information is sent to another platform to conduct the attack. Background

Page 4 GAO- 02- 692 SURTASS Sonar

Figure: Diagram of SURTASS/ LFA System

Source: Navy.

The Navy plans to use two SURTASS/ LFA systems. The first was installed in
1992 on the research vessel Cory Chouest. The other system, completed in
1993, will be installed on the twin- hull auxiliary general- purpose ocean
surveillance ship, T- AGOS- 23, which the Navy designed to carry the SURTASS
system. The ship was originally scheduled for delivery in 1994, but
construction was delayed due to the bankruptcy of the contractor and it will
not be completed until late 2002. The Navy estimates that it has cost
approximately $375 million to develop and produce the two systems and that
it will spend an additional $40 million to field and operate the systems
through fiscal year 2009. These estimates do not include the cost of the

During the course of developing and testing the SURTASS/ LFA system,
environmental interest groups, including the Natural Resources Defense
Council, began to raise concerns that the system may cause harm to marine
mammals. Environmentalists were concerned that the highintensity sound
emitted by the system could cause physical damage to marine mammals and
adversely affect their behavior. In August 1995, in a letter to the
Secretary of the Navy, the Natural Resources Defense Council questioned
whether the Navy had complied with all applicable environmental laws and
regulations. In response to growing public concerns and recognition that
further assessment of the system was needed, the Navy decided to initiate an
environmental impact statement

Page 5 GAO- 02- 692 SURTASS Sonar

process. 4 As part of this process, the Navy conducted a scientific research
program from 1997 to 1998 to test the effects of low frequency sonar on a
limited number of whale species off the coasts of California and Hawaii. The
Navy distributed a draft environmental impact statement for public comment
in 1999 and issued a final environmental impact statement in 2001. The Navy
concluded in the environmental impact statement that the potential impact or
injury to marine mammals from SURTASS/ LFA is negligible. As reflected in
the environmental impact statement, this is based on using the system with
certain proposed geographic restrictions and monitoring to prevent harm to
marine mammals.

Because there is some potential for incidental harm to marine mammals, the
Navy must obtain a Letter of Authorization from the National Marine
Fisheries Service before SURTASS/ LFA can be used. 5 The National Marine
Fisheries Service issued a draft authorization for public comment in 2001,
which concurred with the findings of the Navy?s environmental impact
statement. If approved, the authorization would allow the Navy to use the
SURTASS/ LFA system with certain specified mitigation measures and
restrictions. These measures include limiting (1) sonar sound levels to 180
decibels within 12 nautical miles of any coastline or in any designated
biologically important offshore area and (2) sound levels to 145 decibels in
known recreational or commercial dive sites. In addition, the authorization
would require the Navy to monitor marine mammals from the ship visually and
with passive and high frequency active sonar. If marine mammals were
detected, the Navy would be required to shut down LFA operations to prevent,
to the greatest extent possible, marine mammals? exposure to potentially
harmful sound levels. The decision on the authorization is expected later in

4 The Navy prepared the environmental impact statement to meet the
requirements of the National Environmental Policy Act, which requires
agencies to prepare a detailed environmental impact statement for every
major federal action that may significantly affect the quality of the
environment. The purpose of this requirement is to ensure that decision
makers evaluate environmental consequences. The environmental impact
statement was also used to respond to Executive Order 12114, which requires
agencies to consider environmental effects abroad (including the oceans) of
major federal actions, in this case the Navy?s planned use of SURTASS/ LFA
outside the United States.

5 The authorization from the National Marine Fisheries Service is required
under regulations implementing a provision of the Marine Mammal Protection
Act governing small ?takes? of marine mammals incidental to specified
activities, in this case any disturbance, injury, and/ or death to marine
mammals incident to the operation of SURTASS/ LFA.

Page 6 GAO- 02- 692 SURTASS Sonar

Notwithstanding the mitigation measures outlined by the Letter of
Authorization, environmental organizations are still expected to oppose the
use of the SURTASS/ LFA. They have indicated that although conclusive
evidence has not been established regarding the harmful effects of the
SURTASS/ LFA on marine mammals, 6 enough is known about the potential
adverse effects of sound on marine mammals to warrant no further use of the
system. 7 They have also questioned the usefulness of the system to the
Navy. The Navy has also recognized gaps exist in scientific knowledge about
the impact of the system on marine mammals, but it considers that the risk
is minimal and not enough to warrant ceasing its use. In addition, the Navy
has stated that it has done an extensive amount of testing, research, and
analysis regarding the use of SURTASS/ LFA and marine mammals and that
current information combined with the planned mitigation and monitoring
procedures and ongoing research, support resuming SURTASS/ LFA operations.
Furthermore, the Navy has emphasized that the need for a long- range
detection capability still exists.

Based on initial testing conducted to date, SURTASS/ LFA appears to provide
long- range undersea detection capabilities in the deep, open ocean that
surpass any system planned or in existence. However, the system may not be
as effective in littoral waters. A final operational evaluation must still
be conducted to determine the overall effectiveness and suitability of the
system, and while Navy officials are developing a plan to evaluate the
system, they have not yet defined what testing will be conducted in littoral

6 In 1994, the National Research Council found that almost no quantitative
information existed to assess the impact of low- frequency noise on marine
mammals. In 2000, the National Research Council reported that while much had
been learned since 1994, there were still substantial uncertainties
concerning the possible effects of the LFA program and other low- frequency
sounds on marine mammals.

7 Environmental groups have become increasingly concerned about the use of
SURTASS/ LFA, in part, because of recent incidents involving the stranding
of whales. In March 2000, for example, the mass stranding of 17 whales
occurred on a beach in the Bahamas. Although SURTASS/ LFA was not in use at
the time, the Navy has acknowledged that tactical mid- range frequency sonar
aboard Navy ships on an exercise in the area was most likely responsible for
the incident. SURTASS/ LFA

Increases Antisubmarine Capabilities in Open Ocean, but Its Capabilities Are
Unproven in Littoral Waters

Page 7 GAO- 02- 692 SURTASS Sonar

The primary benefit of SURTASS/ LFA is that it will provide a significant
increase in long- range undersea detection capability in the open ocean.
Active sonar at low frequencies is more effective and transmits further
undersea because its absorption rate in water is relatively low. Because of
this, a low frequency active signal can travel several hundreds of miles if
unimpeded. In contrast, mid frequency and high frequency sonar transmits on
the order of tens of miles. Therefore, low frequency active sonar can
potentially cover an area of the ocean vastly greater than sonar at higher
frequencies. In addition, a benefit of active sonar is its ability to seek
out targets rather than wait passively for a target to approach. As a
result, a system such as SURTASS/ LFA can provide the means to detect enemy
submarines before they can get within the effective weapons range of U. S.
ships. Also, because it is mobile, the system provides greater deployment
flexibility and can detect target information in areas beyond the reach of
fixed sonar systems according to Navy officials. Moreover, the SURTASS/ LFA
technology can provide long- range detection with less assets and operators
than other technologies.

SURTASS/ LFA also has several operational limitations, including the amount
of coverage it can provide and its vulnerabilities. The Navy plans to use a
total of only two systems, with one deployed to the Pacific Fleet and the
other to the Atlantic Fleet to support antisubmarine missions. Therefore,
the amount of area the system can cover will be limited. The Navy recognizes
that two systems are not sufficient to meet operational requirements and
prefers to have more. In addition, SURTASS/ LFA may be vulnerable to attack
because the ships carrying the systems will not have onboard defense
systems. The ships are also relatively slow and therefore incapable of
remaining close enough to the transiting battlegroup to be protected.
Furthermore, because SURTASS/ LFA transmits an active, high volume signal,
it can readily reveal its location, which further increases its
vulnerability. However, the Navy concluded that the operational limitations
are outweighed by the benefit of long- range detection.

Results of SURTASS/ LFA testing to date show that the system will increase
the Navy?s capability to detect modern submarines at long range in deep,
open ocean areas. Starting in 1989 through 1992, the Navy conducted a series
of developmental tests on SURTASS/ LFA that were focused on validating the
performance of a demonstration system in these areas. The objectives of
these tests were to obtain an increased understanding of technical
performance issues such as the long- range transmission of signals and
signal processing techniques. Based on the successful results of these
tests, the Navy concluded the system Operational Benefits and

Limitations Demonstration of Capabilities

Page 8 GAO- 02- 692 SURTASS Sonar

performance requirements were achievable and decided to proceed with full-
scale engineering development.

In 1992, the Navy began conducting operational tests using an engineering
development model that more closely represented the operational SURTASS/ LFA
system. The purpose of these tests was to determine the performance of the
system under more realistic at- sea conditions and against more realistic
threat scenarios, including quiet submarines. Numerous tests were performed
to assess the system?s capabilities in deep waters, such as in the middle of
the Atlantic Ocean. These tests concluded that SURTASS/ LFA could detect
targets at long range and resulted in recommendations that the program
continue with its development. In addition, a test in 1994 determined that
the engineering development model performed well enough that the system
could be introduced to the fleet as an interim capability. However,
operational testing revealed some reliability and maintainability problems
with critical software. Navy officials told us that they intend to resolve
these issues before the overall operational evaluation is complete.

While testing has demonstrated that SURTASS/ LFA can increase detection in
the open ocean, the system has shown limited capability in littoral waters.
Tests indicate the system provides some detection capability in littoral
waters but at a range that is significantly less than that achieved in the
open ocean. Moreover, the effectiveness of SURTASS/ LFA generally decreases
closer to shore as the water becomes more shallow. Navy officials told us
that these results were expected and can be attributed to system design and
geographic characteristics. The characteristics of low absorption rate and
low frequency signal that make SURTASS/ LFA effective for extended ranges in
the deep, open ocean are the same characteristics that limit its
effectiveness in littoral waters. For example, littoral waters, particularly
along coastlines, typically have more complex and prominent floor features
than those in the open ocean. In littoral areas, sonar signals may
reverberate or rebound off the ocean floor making target detection
difficult. The littoral environment is also more acoustically harsh because
it has shifting currents, variable water densities, and shallow water depth.
As a result, active sonar signals- particularly those at low frequency-
reverberate and degrade more than they do in the open ocean. In addition,
the littoral environment has more magnetic anomalies, which can severely
degrade bearing accuracy. Littoral waters also have more shipping traffic
and greater ambient noise, making it much more difficult for the system to
distinguish and detect threat submarines from other noise- generating
vessels. In addition, the presence of more shipwrecks and near shore debris
in these locations

Page 9 GAO- 02- 692 SURTASS Sonar

increases the number of false targets and, therefore, increases the
challenges to detect, locate, and distinguish threat submarines.

Although the Navy has largely completed developmental testing and conducted
a series of initial operational tests of the SURTASS/ LFA system, it must
still complete a final operational test and evaluation to establish the
operational effectiveness 8 and suitability 9 of the system. Currently, this
evaluation is planned for fiscal year 2004, providing the program receives
authorization from the National Marine Fisheries Service. The Navy planned
for the evaluation to primarily focus on demonstrating the system?s
capabilities in the open ocean. Although the test evaluation master plan was
updated in 1996, the concept of operations and the original operational
requirements have not been updated to reflect the Navy?s shift in focus to
littoral threats. In accordance with Department of Defense guidelines, a
system should be tested under realistic conditions and in environments where
it is intended to be used. In addition, any testing and operations will have
to be in compliance with applicable operating restrictions such as the
National Marine Fisheries Service Letter of Authorization. Currently, Navy
working groups are in the process of updating a concept of operations for
the SURTASS/ LFA system and developing the test evaluation master plan that
will be used to conduct the operational evaluation. However, they have not
decided on the extent to which the system will be tested in littoral areas.

Since the beginning of the program, the Navy has considered a number of
existing and potential alternatives to SURTASS/ LFA, and each time it found
that the system provides long- range detection capabilities other systems
could not provide. Available technologies offer different capabilities and
practical limitations. Although SURTASS/ LFA provides increased detection
ranges, the Navy advocates a ?tool box? approach that uses a mix of
complementary technologies to detect enemy submarines.

8 DOD defines operational effectiveness as a system?s overall degree of
mission accomplishment when representative personnel use the system in its
planned or expected operational environment considering organization,
doctrine, tactics, survivability, vulnerability, and threat.

9 DOD defines operational suitability as the degree to which a system can be
satisfactorily placed in field use considering such factors as availability,
compatibility, transportability, interoperability, reliability, wartime
usage rates, maintainability, safety, and supportability. Other

Warfare Technologies Complement but Are Not Substitutes for SURTASS/ LFA

Page 10 GAO- 02- 692 SURTASS Sonar

Existing passive, active, and nonacoustic technologies have a limited
capability to detect submarines at long range. Passive sensors, for example,
are effective at short range but have become more limited in their
capability since the development of quieter submarines. Even though recent
improvements to passive systems have extended their range, submarine
quieting measures have lowered submarine noise levels to nearly the level of
the ambient noise of natural sounds in the ocean. As a result, the Navy is
concerned that an enemy submarine could get within effective weapons? range
of U. S. forces before passive systems could make contact with an enemy
submarine. Passive systems by the nature of how they operate are
environmentally benign because they do not transmit sound.

Active sensors systems that can be used from aircraft provide extended
ranges and large area coverage, but large area coverage requires a high
number of assets of both aircraft and sensors to be deployed. Antisubmarine
warfare aircraft are expensive to operate, and they require shore- based
facilities, which are limited because of continued decreases to the number
of these installations. A shipboard system, such as SURTASS/ LFA, provides
the advantage of extended range and duration of searches, but when it is
used in a continuous search mode, it has the drawback of revealing the
ship?s position.

The Navy determined that nonacoustic technologies, such as radar, laser,
magnetic, infrared, electronic, optical, hydrodynamic, and biological
sensors, have demonstrated some utility in detecting submarines. Their
usefulness, however, is limited by range of detection, unique operating
requirements, meteorological/ oceanographic disturbances, and/ or a
requirement that the submarine be at or near the surface for detection.
Today, nuclear submarines can remain submerged at considerable depths
indefinitely, and new battery technology and air- independent propulsion 10
have increased the time that diesel submarines can remain at depth.

The capabilities of passive, active, and nonacoustic technologies vary
depending on whether they are used on fixed, mobile, and deployable
platforms. During the Cold War, the Navy relied on a comprehensive system of
fixed undersea acoustic sensors as its primary means of initial detection of
enemy submarines. In recent years, the Navy?s Submarine

10 Air- independent propulsion (AIP) is technology that significantly
extends a conventional diesel- electric submarine?s submerged time.

Page 11 GAO- 02- 692 SURTASS Sonar

Surveillance Program has undergone a major transition from emphasis on
maintaining a large, dispersed surveillance force to detect and track Soviet
submarines to a much smaller force. As a result, a number of fixed acoustic
arrays have been turned off, placed in stand- by status, or damaged and not
repaired. Fixed systems have a number of practical constraints such as
requiring long lead times to install. They are also expensive, require
extensive maintenance, and run the risk of being discovered, avoided, or
tapped into. On the other hand, mobile systems are not limited to a specific
location and can be deployed to areas of interest to the fleet at any time.
Mobile systems also have the benefit of providing coverage in locations
beyond the range of fixed systems or augmenting the capabilities of fixed

In the late- 1990s, the Navy prepared an evaluation of alternatives on the
requirements for long- range active undersea surveillance in a white paper.
The evaluation examined expanding current technologies, developing new
technologies, and improving the LFA system. The paper concluded that

 increasing the numbers of antisubmarine warfare search, detection, and
attack platforms in an attempt to flood the target area with search systems
requires a high number of assets and a large number of operators and results
in high costs due to the continued use of multiple systems;  increasing the
number of assets also does not solve the problems of

high false contact rates, short detection ranges, and danger to the sensor
platform itself because an active signal discloses the ship?s position; 
developing new passive systems will have a marginal potential to

improve sensor detection ranges unless a new technology, yet to be
identified, emerges; and  improving the performance levels of active sonar
systems like LFA

addresses the critical issue of the range at which the threat submarine is

More recently, in 2001, the Navy conducted a comprehensive evaluation of
existing and emerging antisubmarine warfare technologies that involved
several expert panels consisting of Navy officials and representatives from
the scientific, academic, and intelligence communities. The objective of
this evaluation was to assess current and planned detection technologies to
determine where the Navy has shortfalls in capability and where to invest
future resources. A total of 125 technologies and concepts were initially
evaluated and 16 were selected for additional analysis. The 16 technologies
and concepts were analyzed against criteria that included

Page 12 GAO- 02- 692 SURTASS Sonar

robustness, operational suitability, survivability, technical maturity,
potential operational effectiveness, deployment flexibility and
responsiveness, and potential overall impact and military utility. The
SURTASS/ LFA program received high ratings for all criteria except for

As a result of the panels? analyses, the Navy determined that SURTASS/ LFA
provides the needed extended range coverage and deployment flexibility and
reduces the need for multiple assets, all at a comparatively low operational
and per unit cost. With fewer assets devoted to submarine detection, naval
commanders can use the additional assets to manage and control the undersea
battle space. Because of these benefits, the Navy plans to rely on the
SURTASS/ LFA to detect and locate enemy submarines at greater distances
before they get within effective weapons range. While SURTASS/ LFA is
effective at long range detection, Navy officials still conclude that there
is no single system capable of providing all Navy submarine detection
capabilities and advocate the use of multiple, complementary systems or a
?tool box? approach to meet this need. The most effective approach to
conducting antisubmarine warfare operations is a ?layered defense? beginning
with a long detection range, early warning sensor, followed by short- range
tactical active and passive sonars designed to coordinate the engagement of
targets detected by the long- range system.

The Navy continues to identify and develop new antisubmarine warfare
technologies as well as explore new applications of existing technologies.
Because no single antisubmarine technology or system meets all of the Navy?s
undersea surveillance and detection requirements, the Navy continues
acquisition and development efforts to increase detection efficiency and to
respond to new threat challenges. A key focus of these efforts has been in
developing antisubmarine warfare capabilities for littoral areas. The Navy
is in the process of refining and developing a variety of alternatives to
take advantage of LFA technology, but without its current limitations. For
example, the Navy is exploring a higher frequency, lighter, and compact LFA
system design, which incorporates several advantages to enhance performance
in shallow water. However, it is too soon to assess whether these new
developments will improve submarine detection capabilities.

Currently, the Navy is preparing for the overall operational evaluation of
the SURTASS/ LFA but has not developed a test plan or decided on the extent
to which the system will be tested in littoral waters. Without testing

Page 13 GAO- 02- 692 SURTASS Sonar

in littoral areas, the Navy will not know whether the system is suitable and
effective where the enemy threat is of increasing concern and detection is
more challenging. In addition, testing results would provide users with a
better understanding of the system?s capabilities and help the Navy make
more informed decisions about investments in future submarine detection
efforts. During our review, we noted to Navy officials that if they intend
on operating the system in littoral areas, then they should conduct testing
to gain a better understanding of the system?s advantages and limitations
and how to use it most effectively in the Navy?s ?tool box? approach to
antisubmarine warfare. In response, Navy officials indicated they would
reconsider what testing to include in the operational evaluation.

Before the Navy operates SURTASS/ LFA in littoral areas, we recommend that
the Secretary of the Navy direct program officials to establish a test plan
and conduct testing of the system to demonstrate its capabilities in those

In written comments to a draft of our report, DOD agreed with our
recommendation. In addition, DOD also provided technical comments that we
incorporated into the report as appropriate. DOD?s comments appear in
appendix I.

To acquire information about the SURTASS/ LFA program, including
requirements, alternatives, acquisition, development, operations, threat
assessments, history, and current status, we interviewed officials and
obtained documentation from the SURTASS program office (PMW- 182); the Space
and Naval Warfare Command?s Intelligence, Surveillance, and Reconnaissance
Directorate (PD- 18); Office of the Principal Deputy Assistant Secretary of
the Navy (Research, Development, and Acquisition); Office of the Deputy
Assistant Secretary of the Navy for Mine and Undersea Warfare; Office of the
Chief of Naval Operations Antisubmarine Warfare Requirements Division;
Office of the Chief of Naval Operations Undersea Surveillance Branch; Office
of the Commander Submarines Atlantic; Office of the Commander Undersea
Surveillance Operations; Integrated Undersea Surveillance System Command
Center; TAGOS project office, Military Sealift Command; USNS Impeccable (T-
AGOS- 23); Office of Naval Research; Office of Naval Intelligence; Defense
Intelligence Agency; and the Naval Undersea Warfare Center. Recommendation

Executive Action Agency Comments

Scope and Methodology

Page 14 GAO- 02- 692 SURTASS Sonar

To obtain information about SURTASS/ LFA operational testing, effectiveness,
suitability, and performance, we interviewed officials and obtained
documentation from the Office of the Director of Operational Testing and
Evaluation, Office of the Assistant Secretary of Defense; the Office of the
Navy Commander Operational Test and Evaluation; and many of the above
identified organizations.

To obtain information about environmental issues, requirements, assessments,
and monitoring and mitigation plans, we interviewed officials and obtained
documentation from the Office of the Assistant Secretary of the Navy for
Installations and Environment; Office of the Chief of Naval Operations,
Environmental Planning and National Environmental Policy Act Compliance
Branch; the State of California Coastal Commission; the State of Hawaii
Department of Land and Natural Resources; Marine Acoustics Inc; the National
Marine Fisheries Service; the Marine Mammal Commission; the Natural
Resources Defense Council; Rainbow Friends Animal Sanctuary; and the
Keystone Center.

We performed our work from July 2001 through March 2002 in accordance with
generally accepted government auditing standards.

As agreed with your office, unless you publicly announce the contents of
this report earlier, we plan no further distribution until 30 days from the
report date. At that time, we will send copies of this report to interested
congressional committees; the Secretary of Defense; the Secretary of the
Navy; and the Director, Office of Management and Budget. We also will make
copies available to others upon request. In addition, the report will be
available at no charge on the GAO Web site at http:// www. gao. gov.

Page 15 GAO- 02- 692 SURTASS Sonar

Please contact me at (202) 512- 4530 or John Oppenheim at (202) 512- 3111 if
you or your staff have any questions concerning this report. Other major
contributors to this report were Dorian Dunbar, Gary Middleton, Adam
Vodraska, and Allen Westheimer.

Sincerely yours, James F. Wiggins Director, Acquisition and Sourcing

Appendix I: Comments from the Department of Defense

Page 16 GAO- 02- 692 SURTASS Sonar

Appendix I: Comments from the Department of Defense


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