VTS & Coastal Surveillance
In general, both VTS and Coastal Surveillance Systems comprises Sensor sites and Control Centre facilities. There may be a greater need for VHF communication in VTS applications as it is essential that information is provided to the mariner, whereas coastal surveillance may have a greater need for VHF Direction Finding. In addition, a coastal surveillance application will need to have greater command & control of patrolling law enforcement assets whereas VTS will simply deploy a pilot to assist a vessel in difficult navigational circumstances.
V.128 Recommendations
Guidance on the Operational and Technical Performance Requirements of VTS Equipment may be found in the IALA Recommendation V.128. Edition 4 (the current version - published in May 2015) provides information about the key sensor components of a VTS System. It provides a useful overview of the technical characteristics of VTS equipment but whether it actually provides information that can help VTS Authorities in the specification of their VTS Requirement will be determined by the technical capability of the staff at the VTS Authority. If the staff are technically well qualified in their understanding of marine electronics, then V.128 Edition 4 and Guideline 1111 may help them to understand the key technical aspects of a VTS System. However, if the staff of the VTS Authority do not have such technical training then V.128 may not provide a suitable guide for specifying VTS Equipment. Unfortunately, V.128 does not provide guidance on the system requirements for the different types of VTS Service (Information Service, Traffic Organisational Service or Navigational Assistance Service). This is expected to be included in the next edition.
If specifying equipment, the buyer for a VTS Authority should be able to understand what equipment is available on the market and any new developments. However, if he uses a product specification from one particular system or sensor supplier, then he will probably receive quotations including that equipment even if it is not the best equipment for his requirement. So, where a buyer does not fully understand the market situation and latest developments, it would be more appropriate to specify the details of targets that must be detected and tracked, details about the environmental conditions and the identified risks that exist within the respective area. In such situation, each vendor could propose a solution to suit such requirements based upon his latest technology. It is often true that most Systems Integration and Technology Development companies know and understand the technology and are more “up to date” on the latest technical developments employed in Maritime Surveillance than the buyers of such systems. Therefore, it would seem illogical for the buyer of a Maritime Surveillance Solution to specify the precise equipment that should be supplied as this could lead buyers to unwittingly procure older “less up to date” technology. It would seem logical that Systems Integration companies could propose solutions based upon the latest technology if permitted to do so by a tender specification that does not simply specify a Bill of Materials. Where a Bill of Materials is specified, this prevents innovation as the buyer simply receives the equipment defined which may not be the most up to date or the most appropriate for the task it has to perform.
Basic, Standard or Advanced
These terms only apply to the Radar equipment, but they are frequently applied to a VTS System as a whole, which creates confusion. In fact, there is even confusion between IALA documents on this point as the VTS Manual 2012 refers to Basic, Standard and Advanced VTS Systems. It is not true to say that if you design a VTS system based on a radar with a 12ft Antenna (Basic Category) that it is "sub-Standard" in its performance due to the fact that an 18ft radar antenna would be considered as a Standard solution. A 12ft radar antenna may be ideally suited to some VTS situations and VTS systems could even be implemented with smaller radar antennas if this suits the operational needs of the VTS Authority. There are cost differences between the solutions that fall into the categories of Basic, Standard and Advanced. In some cases these are quite significant cost differences and therefore the value added through the higher specification systems must be able to demonstrate significant risk reduction benefits. However, it may also be worth considering whether additional Basic sensor sites could achieve the same performance as fewer Advanced sensor sites, but at lower cost.
In general, the term Basic refers to a radar sensor with a 12ft antenna, Standard refers to a radar sensor with an 18ft antenna and Advanced refers to a radar sensor with a radar antenna of 19ft or above. The main difference between these categories of radar sensor is the Azimuth resolution which determines the minimum target separation required for the radar sensor to resolve two separate targets that are in close proximity to each other.
Specifying a VTS System
IALA has defined the Types of Vessel Traffic Service in IALA guideline 1089. These are Information Service, Traffic Organisational Service and Navigational Assistance Service. An actual VTS System therefore needs to be able to support the appropriate differences in these types of service. The system specification should therefore be focussed on the necessary system functionality to support the type of service that is to be implemented.