Table 21 IALA Target Types References [1] IEEE Std 686-1997 IEEE Standard Radar Definitions [2] Merrill I Skolnik Introduction to Radar Systems, McGraw-Hill Higher Education, ISBN 0-07-290980-3 [3] P.D.L. Williams, H.D, Cramp and Kay Curtis Experimental study of the radar cross section of maritime targets, ELECTRONIC CIRCUITS AND SYSTEMS, July 1978. Vol. 2. No 4. [4] Ingo Harre RCS in Radar Range Calculations for Maritime Targets. [5] International Maritime Organisation (IMO) Performance Standards for radar reflectors (latest edition) [6] International Telecommunications Union (ITU) ITU-R SM.1541 Unwanted emissions in the domain [7] International Telecommunications Union (ITU) ITU-R SM.329-9 Spurious emissions [8] The International Organisation for Standardisation( ISO) ISO 8729 Ships and marine technology – Marine radar reflectors [9] International Commission for Air Navigation Definition of the Standard Atmosphere Software tools CARPET Computer Aided Radar Performance Tool TNO (Toegepast Natuurkundig Onderzoek) Physics and Electronics Laboratory, P.O. Box 96864, 2509 JG The Hague, Netherlands, AREPS Advanced Refractive Effects Prediction System Space and Naval Warfare Systems Center, San Diego, . Note that the use of off-the-shelf performance tools for assessment of the latest radar sensors, employing complex multiple pulse waveforms, may require specialist assistance to obtain appropriate and valid performance predictions. band
C Small open boat, fibreglass, wood or rubber with outboard motor and at least 2 persons onboard, small speedboat, small fishing vessels or small sailing boats. 0.5 – 5 m2 0.5 to 1 m ASL Rapidly fluctuating may be hidden behind waves up to 50 % of the time. Slow moving targets tend to lie lower in the water than fast moving ones and therefore RCS visible to the radar tends to increase with speed. Humans and non-metallic targets will give poor radar return in case of circular polarisation D Inshore fishing vessels, sailing boats and speedboats, equipped with radar reflector of good quality. 3 – 10 m2 1 to 2 m ASL Rapidly fluctuating. E Small metal ships, fishing vessels, patrol vessels and other similar vessels. 10 – 100 m2 2 to 4 m ASL Moderately fluctuating. F Coasters and other similar vessels. 100 – 1000 m2 6 to 10 m ASL RCS is highly dependent on aspect angle of the individual vessel. Rate of fluctuations is typically moderate. G Large coasters, Bulk carriers, cargo ships and other similar vessels. 1000 – 10,000 m2 10 to 25 m ASL H Container carriers, tankers and other similar vessels. 10,000 – 2,000,000 m2 15 to 40 m ASL I Buildings, cranes. Stacks of containers and other large structures. Up to 1,000,000 m2 on site Insignificant. J Floating items, oil drums and other similar items. Up to 1 m2 0 to 0.5 m ASL Rapidly fluctuating, highly dependent on sea characteristics and target movements. Birds, floating or flying. Sea level and up K Flocks of birds. Up to 3 m2 Sea level and up Rapidly fluctuating, flight paths tend to be characteristic of given species in given areas of interest. s
Table 27 Typical Range Performance Predictions for X-band Radar Antenna elevation IALA Target type Local Port Services Basic Standard Advanced Clear Clear 2 mm/h rain Clear 4 mm/h rain Clear 10 mm/h rain 20 m ASL 1 NIL NIL 5 NM NIL 2 7 NM 4NM 7 NM 6 NM 3 7 NM 4NM 8 NM 5NM 9 NM 7 NM 4 9 NM 8 NM 11 NM 9NM 12 NM 10 NM 5 12 NM 10 NM 13 NM 11 NM 14 NM 13 NM 50 m ASL 1 NIL NIL 10 NM NIL 2 10 NM 7 NM 12 NM 9 NM 3 10 NM 6 NM 12 NM 8 NM 14 NM 12 NM 4 13 NM 12 NM 15 NM 13 NM 17 NM 15 NM 5 16 NM 15 NM 18 NM 17 NM 20 NM 18 NM 100 m ASL 1 N/A NIL 12 NM NIL 2 13 NM 5 NM 16 NM 10 NM 3 17 NM 10 NM 18 NM 16 NM 4 20 NM 19 NM 22 NM 20 NM 5 23 NM 22 NM 25 NM 23 NM Sea states as defined per section 2.7.4.2 Table 28 Typical Range Performance Predictions for S-Band Radar Antenna Elevation IALA Target Type Standard S Advanced S [m ASL] Clear 10 mm/h 16 mm/h 25 mm/h Clear 10 mm/h 16 mm/h 25 mm/h [NM] [NM] [NM] [NM] [NM] [NM] [NM] [NM] 20 3 4.3 2.4 2.0 1.7 4.8 2.4 2.0 1.5 4 6.5 4.6 4.1 3.6 7.4 4.9 4.4 3.9 5 9.3 7.5 6.9 6.4 10.3 7.4 6.8 50 3 6.6 3.8 - - 6.8 - - - 4 9.9 7.7 6.8 5.9 11.1 8.3 7.4 6.5 5 13.5 12.0 11.2 10.4 14.7 12.7 11.9 11.0 100 3 8.9 - - - - - - - 4 13.7 11.0 9.1 4.0 15.3 12.1 10.3 0.9
customers and radar suppliers. The vagaries of the propagation paths can also introduce unpredictable positional measurement errors affecting both angle and range even when an object is clearly detected. HF radar installation requires some careful selection of suitable coastal terrain which may not suit all potential VTS locations. Similarly, suitable sites will rarely support the necessary infrastructure (power, communications, access for installation and maintenance) and these need to be factored into the installation and operational costs. Finally, optimising the nature of HF radar may impose high workload on specialised, highly trained operators. If the limitations are acceptable, this technology offers valuable passive detection in open waters, expensive to obtain by other means (airborne sensors and satellite). Realistically, however, HF radar systems are not used for VTS purposes. Synthetic Aperture Radar (SARSAT) Satellite-based Synthetic Aperture Radar (SARSAT) can provide vessel target information at ranges beyond that of shore-based sensors, including HF Radar. However, such services will probably only provide a single image of a specific area once per day through a few orbiting satellites. Images are stored on-board the satellite until they can be downloaded as the satellite passes over a ground station. The image is processed, following download from the satellite, to detect ships within the area and radar information (without identity) can be derived that can be used to recognise the type of vessel. This type of service is for analysis of vessel movement and not for any form of near real time monitoring. In addition to the latency between the required image capture and the download when passing over a ground station, there is also a further latency related to the processing of the received data. SARSAT may, for example, be useful for detecting illegal fishing activity in remote areas of a country’s Exclusive Economic Zone and for detecting oil spills and pollution. Specific Design, Configuration, Installation and Maintenance Considerations SARSAT is available from a variety of established service providers and does not require any special design, configuration or installation on the part of the VTS Authority. The VTS Authority will need to subscribe to a SARSAT image service and costs are involved on a per image basis. Once access to such a service has been established, the VTS Authority will be able to integrate the SARSAT target data as appropriate for his operational requirements.