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Journal of the Australian Naval Institute

Knowledge Edge - Maritime Battlespace

Roger P. Creaser

miners have over the centuries won renown and recognition for their inventiveness in seeking to gain and maintain the knowledge edge in the maritime environment. Advances in navigation and charting have given navies significant tactical advantage in numerous engagements. In this century we have seen the introduction of sonar, radar and naval aviation to extend the tactical horizons of major combatants and thereby increase the knowledge available to commanders. More recently the proliferation of space based systems has added a new dimension to the kind and quality of knowledge that can be accessed.

We are. however, talking here about the knowledge edge and not just knowledge. This distinction needs to be made, particularly with the increased access worldwide to the technologies that can be used to gather and process information. The distinguishing feature is how this information is presented and interpreted, and we will find that this aspect will have an increasing impact on the way in which we design and operate maritime platforms.

Data Integration

Much of the data that we gather either through on board or off board sensors is presented as track level data. One or more skilled system operators often do the integration of this data into the overall tactical picture. This is not only slow, but it can also mean than useful information is overlooked or lost.

The development of integrated combat systems as pioneered by the Collins class submarines represents a means of overcoming the problem in that any operator can. in principle, have access to the full sensor and weapon information. This is certainly a major improvement and one that is increasingly being used. Even here, however, trade-offs must be made due to the constraints of bandwidth limiting the extent that full sensor data can he accessed by high level information processing functions.

The synergism amongst the various sources of data can. however, be significantly improved by use of data integration or data fusion techniques. In this approach one source of data is related to another in a formal means that can yield a significant improvement in the overall effectiveness. In its simplest form, one sensor might cue another. For example a highly directional missile approach warning receiver might cue a fire control radar of the approaching direction of an anti ship missile and thereby increase the time available to

effect a countermeasure.

In more advanced forms of data integration mathematical relationships are derived that relate the type of data and the rate at which it is delivered. The result is that tracks are developed much more quickly and with reduced ambiguity. This can be of particular value where multipart! conditions exist, which result in a target return arriving at the receiver by more than one path. Multipath can make it not only difficult to establish the track, but very difficult to determine target range. By integrating the data from different sources in a way that correlates such parameters as position and Doppler. accurate tracks can be established quickly with high confidence.

Data integration when combined with such advanced tracking techniques as Hidden Markov Modelling can result in a very high degree of automation in the detection and tracking of targets. Such advanced technology gives a distinct knowledge edge in those tactical situations where response times must he kept as short as possible. Advances in data integration are moving us rapidly towards the concept of the integrated battle space in the maritime environment.

Cooperative Engagement Capability

A prime example of this is the USN developed cooperative engagement capability (CEC), which is a single distributed anti air warfare system that uses the sensors and weapons of different platforms and units. CEC describes the set of hardware and software that allows weapons and tactical systems, distributed over many platforms, to share unprocessed data in almost real time. The system creates an identical picture at each unit, and the quality of the picture is required to be at least as good as that produced from the most accurate sensor on any of the platforms. As well as sharing sensor data, decision and engagement data are also shared, and this is the driving factor in CEC and represents the knowledge edge available to individual units within a task force.

The anti air warfare environment can place very high demands upon surface combatants both in terms of self defence and the defence of the platforms under escort. High speed aircraft capable of launching long range sea skimming anti ship missiles can pose a very real threat and one that is difficult to counter unless adequate warning is provided. CEC offers the capability of significantly extending the information horizon of a surface combatant to the extent that the


July/September 1998

Journal of the Australian Naval Institute


missile launch platform is threatened. However, should a missile he launched the early warning provided should provide a very high probably of success in defeating the attack.

CEC is dependent upon a number of advances in technology, such as the introduction of phased array radar for air search combined with lire control. It is this technology that allows the near real time tracking and cooperative engagement to be achieved across the CEC net. Also of significance is the data link and picture compilation facility, being a technology leap from the combined tracking of tactical data links to true sensor data integration at the eonlaet-to-contact level.

Target Classification

So far we have concentrated on the gains that can be achieved by bringing a high degree of automation to the maritime battle space by using advanced mathematical and signal processing techniques. This is. however, only one part of the know ledge edge. The responsibility of command remains and the further we extend the information horizon, the more difficult it can be to classify the target as friend or foe.

Where the target operates a communications link or radar, it is possible to use electronic support measures to classify the target. Capturing a communications link or a radar pulse and carrying out in near real lime the required processing is not a trivial exercise. The receivers have to cover a wide bandwidth, typically 0.5-18GHz where radar signals are concerned, and have the dynamic range and sensitivity required to intercept and process a single pulse.

To meet these demanding requirements DSTO has been developing multi-channel receivers that provide high sensitivity across a wide instantaneous bandwidth. The high sensitivity receiver uses an acousto-optic device, a Bragg cell, in which the angular deflection of a laser beam shone through the cell varies with the frequency of the radar signal coupled acoustically to the cell. A closely spaced set of photo-diodes detects the deflection of the laser beam and very accurately determines the frequency of the received radar signal. The output of each photo-diode is processed in parallel to form a multi-channel receiver.

Once the signal is captured, its characteristics can be determined, the source identified and in many circumstances the radar and the platform that carries this particular type of radar classified. Where radar is concerned, it is possible using modern high speed sampling devices to digitise and store the signal in digital radio frequency memories. Subsequent advanced signal processing enables the extraction and recognition of features that "linger print" individual radars, which allows specific or individual ships or

aircraft to be identified on the basis of their radar transmission.

Digital radio frequency memories can be used to manipulate and re-radiate the stored signal so confusing the radar. This is an example of where the knowledge edge has been used for knowledge warfare.

Similar techniques are used for the classification of aircraft, surface ships and submarines by capturing the sound or sonar signals emitted by these platforms The RAN and RAAF are recognised for their expertise in classifying targets using passive sonar techniques, and this applies in particular to the submariners. DSTO has remained at the forefront of sonar classification technology and developed a numher of techniques particularly suited to the RAN's operational environment. This applies in particular to narrowband signatures, hut DSTO is also working lo detect and classify automatically transient acoustic signals emitted, often inadvertently, by submarines. These signals can be processed to classify the emitter as a submarine as opposed to a surface ship, the class of submarine or ship can often be determined and its track and speed calculated. Multipalh interference effects can be exploited to obtain the target's depth.

These and related classification techniques represent both leading edge technology and very advanced signal processing techniques. Such expertise is of paramount importance if tactical decisions are to he made with confidence.

Closing the Loop

The knowledge edge as ii exists today is very much dependent upon making best use of the sensors anil sources of information available and using techniques and technology that allows effective data integration and interpretation. However, there is relatively little scope for the skilled operator to modify the process to meet specific requirements and achieve significant further improvements.

The next advance is likely to be the closing of this loop in that the sensors can be reconfigured dynamically to suit a particular tactical situation. For example, we might obtain higher quality information by only using part of the acoustic aperture of a sonar array, or we might choose only to process a certain number of sonobuoys in a field. In a phased array radar the pulse rale and the effective radiated power might be dynamically modified based upon the Strength of the received signal.

To achieve this dynamic feedback between operate! and the sensor and processing chain and thereby make the overall process more effective will require very careful sampling of the operating environment and the development of very advanced algorithms thai control

Jufy/September 1998


Journal of the Australian Naval Institute

(be sequence of events that constitute the detection process. The result will be the development of operator aids, which allow the operator to control the overall process from target detection through to classification, localisation and the subsequent tactical decision in an optimum way. The complex control theory required for operator aids is beginning to be developed and its introduction into the processing chain for radars and sonars is likely to herald the next advance in the knowledge edge.

Australia's Contribution

DSTO and industry, supported by the ADR have maintained a continuing commitment to Australia keeping its knowledge edge in the maritime hattlespace. The JORN over-the-hori/on radar network is a prime example, providing large area near real lime surveillance of the northern maritime approaches. The integration of JORN data with that obtained from microwave radars whether on ships, in an airborne early warning aircraft or on land will provide a very significant knowledge edge for the maritime baltlespace across our north.

DSTO assisted by Navy and industry is about to trial seabed acoustic arrays that might be used either tactically or strategically. These large aperture sonar systems should provide long range acoustic surveillance of selected areas. The information obtained when integrated with data obtained from JORN will increase our ability to detect, classify and localise air and sea movements across the northern approaches.

In electronic warfare, DSTO has an active research program in the use of optical fibres and associated optical processing devices to store, carry and process radar signals. Optical fibre based equipment has considerable potential to both improve performance and lower cost, and make it much easier to install electronic warfare systems on ships and aircraft. A complementary program in gallium-arsenide technology enables microwave devices to he constructed on a single chip. The DSTO and CSIRO joint program in this technology will mean that monolithic microwave integrated circuits (MMIC) are designed and built in Australia. Optical fibre and MMIC technology is allowing Australia to implement advanced electronic warfare processing techniques that are the basis for the next generation of systems needed to maintain this aspect of the knowledge edge,

DSTO is also pursuing some quite radical technologies that promise to make quite remarkable contributions where sonar technology is concerned. One such example is •'acoustic daylight" whereby the ambient sound energy in the sea is focused through an acoustic lens, in the same manner that a optical lens focuses ambient light. This allows images of objects

to be formed adding a new dimension to covert underwater surveillance.

Another technique that has significant potential promise is stochastic resonance. This technique injects noise into a sonar signal in such a way that it causes weak signals to resonate, the resultant increased response allows the signal to be delected against the background noise. Stochastic resonance could double the detection range of conventional passive sonar systems.

Next Steps

In the future, it is likely to be increasingly difficult to maintain the knowledge edge due both to the proliferation of technology and because of increasing diversity of the types of threats that might need to be countered. It will, therefore, be increasingly important to develop very robust systems that are inherently structured to make the best use of technology and the various sources of information and intelligence.

The move to joint operations is an example of this trend and the RAN together with the ADF is placing increased emphasis on joint operations and highly integrated C3J systems. Such systems will become increasing reliant on satellites to provide high bandwidth links that can transmit encrypted video providing the joint commander and the tactical commander very high levels of information. Satellites will also increasingly gather information that contribute directly to the knowledge edge. DSTO's Project Takari has is a long-term research program to address C3I requirements.

Satellite technology and its attendant systems carry with them a very large capital investment. One means of reducing this cost is to enter into joint programs with other major navies and share the cost and gain a high degree of leverage from the associated research programs. A further benefit of such an approach is that it facilitates interoperability, which in itself can provide a significant knowledge edge.

We must, however, always be mindful that it is our strategic and tactical commanders that are directly supported by the knowledge edge. As technology delivers more information, it must be interpreted and presented in ways that are explicit, unambiguous and meaningful. Human factors and human computer interface research are increasingly becoming an important aspect of the maritime baltlespace. Three-dimensional displays are beginning to appear and a greater degree of user interactivity is becoming embedded to allow the command team to use their combined skills and expertise to converge rapidly to the most appropriate representation of the tactical situation.


July/September 1988

Journal of the Australian Naval Institute


An example of an advanced concept of this approach is the command system being built by the US Defense Advanced Research Projects Agency (DARPA) which represents the command picture as holograms. Tiny cameras will interpret gestures as instructions and microphones convert speech into computer commands. A working system should be available in two years and a fully operational version by 2002.

The knowledge edge in the maritime battlespace represents the synergism between the continuing evolution of tactical doctrine and advances in science and technology. As a consequence it will continue to shape the form and structure of maritime forces, their contribution to joint operations and provide Australia with the strategic and tactical advantage needed to safeguard our security.

Roger P Creaser

The Author

Dr Roger Creaser is Chiel. Maritime Operations Division in ihc Defence Science and Technology Organisation (DSTO). Dr Creaser has held a number of senior positions within DSTO including Chief, F.lecironic Warfare Division. Counsellor Defence Science Washington, and Scientillc Adviser Army. In February 1998. Dr Creaser was the co-chairman of I 'ndersea Defence Technology-Pacific, lie Id in Sydney Dr Creaser has a long associalion with lhe RAN and his particular interests are combai sysiem lechnology. sonur systems and maritime operations research.

July/Septemher 1998


Journal of the Australian Naval Institute


An article submitted by Coastwatch

The Role

Coastwatch. a brunch of the Australian Customs Service I ACS I. has as its role the provision of a surveillance and response service to detect potential or actual.unlawful activity in Australian coastal and offshore waters and the coordination of a response, as required, to such detections.

The ACS is tasked by the Australian government to provide a civil nati- coastal and offshore surveillance and response service to a range of government agencies. This service is prov ided by Coastwatch.

The Organisation

The area of operations confronting Coastwatch is vast. It covers 37 (MX) kilometres of coastline and an offshore maritime /one of nine million square kilometres.

To meet the this challenge, Coastwatch uses a fleet of fourteen specially equipped aircraft under contract. Augmenting these resources are the Fremantle Class Patrol Boats and P3 Orion aircraft of the Australian Defence Force (ADF), made available by Cabine to Coastwatch as part of the ADF's contribution. The surface assets are supported by vessels of the Customs marine fleet. Coastwatch is also able to charter other aircaft and vessels on an ad hoc basis should the need arise.

The civil surveillance and response program is managed by the National Manager. Coastwatch. who controls and coordinates the program through a structure comprising a central office located in Canberra and regional offices in Darwin. Broome. Cairns and Thursday Island.

The hub of this national organisation is the Canberra Operations Centre, which coordinates and manages all surveillance and response operations 24 hours a day. It also provides a 24-hour free phone point of contact for members of the public to provide information on any unusual or suspicious activities.

AKo situated in Canberra are the Planning and Liaison and the Surveillance Resources groups. Planning and Liaison has responsibility for collating clients" surveillance needs and incorporating these into a forward Hying and sailing programs. Surveillance Resources handles all matters relating to contract management and monitoring, including training for contract aircrew and Coastwatch staff.

The ACS National Marine Unit, also headquartered in

the Coastwatch branch in Canberra, is responsible to the National Manager Coastwatch for all aspects of the day-to-day operation of the ACS licet of ocean­going vessels. These vessels provide

ACS and other government agencies with strategic maritime patrol services as well as tactical operational support.

How Coastwatch Works

Coastwatch activities are determined by the surveillance needs ol client agencies, which include, but are not limited to:

  • Customs

  • Australian Fisheries Management Authority

  • Australian Quarantine and Inspection Service

  • Department of Immigration and Multicultural Affairs

Great Barrier Reef Marine Park Authority

  • Environment Australia

  • Australian Federal Police

Every flight and marine patrol is multi-tasked to meet the needs of client agencies.

Strategic surveillance forms the majority of the Hying program. It involves the translation of planned, risk-assessed "askings submitted by client agencies into ongoing Hying programs. The Hying programs are developed in Canberra two to three months in advance as "broad picture plans", to allow Coastwatch regional of rices and the contractor to determine the general resource requirement. The program is aufficiently flexible that it can be varied to suit changing circumstances at any time.

Strategic surveillance "askings are submitted by the client agencies through a formal committee system -the Operations and Program Advisory Committee (OPAC). This group, which comprises all Coastwatch clients, meets in Canberra each month and overviews the outcome of the surveillance program and the development and planning of the future program. A network of regional sub-committees provide regional feedback for consideration by OPAC and the central


Tactical surveillance Hying is the result of sightings from the strategic program or from specific operational intelligence, usually received without warning and which present a more demanding


July/September 1998

Journal of the Australian Naval Institute

scenario than routine, strategic surveillance. The success of the tactical operations is paramount and they are given absolute priority .

When a Coastvvalch aircraft detects an incident which the crew considers to be a potential or actual breach oi Australia's laws it reports direct lo t'oastwalch's Operations Centre which immediately consults the appropriate clients as to their requirements. If a surface interception is considered necessary then Coastwatch arranges for the most appropriate vessel, most often a Naval Patrol Boat or a ACS vessel, to provide the response. Often Coastwatch aircraft continue to provide air support to the response vessel until the interception has been achieved. Coastvvalch maintains a role until the situation is placed under the control of the appropriate agency.

Coastwatch. like any other operator of aircraft in Australia, also provides operational support lo the search and rescue authorities.


The principal components of Australia's current civil surveillance effort are:

  • in excess of 145(H) hours of visual and electronic aerial surveillance provided by civilian contract fixed-wing aircraft;

  • 1000 hours of civilian contract helicopter surveillance in the Torres Strait:

  • 250 hours per year of dedicated RAAF P3C Orion offshore patrol of the Australian Fishing Zone:

1800 patrol boat days per year provided by RAN patrol boats primarily for civil response purposes:

  • complementary effort by Customs ocean-going vessels, particularly to provide an operational response capacity for any inshore sightings or incursions detected by Coastwatch assets: and

  • capacity to charter or hire additional air or surface resources, if required.

Following a steady increase in demand for Coastwatch services, a new contract commenced in 1995 that, with a 30 per cent budget increase compared with the previous arrangement, which provided a 190 per cent increase in surveillance capacity - to in excess of SO million square nautical miles per year. This involved the introduction of new aircraft with greater ranges and improved performances, fitted with state of the art equipment including digital surface surveillance radar, high definition television and video recording, infra-red cameras and night search capabilities.

The result is a mix of visual and electronic operations providing a surveillance matrix which increases the probability of detection as vessels approach the coastline. As well, different types of aircraft move

ftom one location to another to ensure maximum productivity for each type and its optimum contribution to overall surveillance.

The Aircraft

Coastwatch uses the following aircraft:

Pilatus Britten-Norman Islander PBN2B

Six aircraft - deployed at Broome (one). Darwin (one). Cairns (two), and Horn Island in the Torres Strait (two).

Search capacity: visual - 651) nautical miles track

Operating heights: l(K) to 50(H) feet. Surveillance air speed: 110 to 120 knots.

Crew: 1 pilot. 2 observers.

Equipped with: cameras, gyro-stabilised binoculars, and a comprehensive communications suite.

Aero Commander AC500 Shrike One aircraft - deployed at Broome.

Search capacity: visual - 750 nautical miles track.

Operating heights: 100 to 5000 feet. Surveillance air

speed: 130 to 150 knots.

Crew: I pilot. 2 observers.

Equipped with: cameras, gyro-stabilised binoculars, and a comprehensive communications suite.

Bombadier (De Havilland) Dash 8 Series 2 Three aircraft are deployed - one each at Broome. Darwin and Cairns. Search capacity: electronic - 80 0(H) square nautical miles at 300 nautical mile radius. Operating heights: 200 lo 25 000 feet. Electronic surveillance speed: 185 knots. Crew: 2 pilots. 2 observers. Equipped with: cameras, gyro-stabilised binoculars, digital surface surveillance radar, infra-red camera and high definition television camera mounted in a stabilised turret.

Reims F406

Three aircraft are deployed - one each at Broome. Darwin and Cairns.

Search capacity: electronic - about 60 000 square nautical miles at a 150 nautical mile radius: visual -650 nautical mile range. Operating heights: 100 to 10 (H)0 feel.

Operating speeds: electronic surveillance- 170 knots, visual surveillance- 145 knots.

Crew: I pilot. 2 observers.

Equipped with: cameras, gyro-stabilised binoculars. vligital surface surveillance radar and night vision


July/September IWN


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