Typical Iris Port System
The Iris PC-based radar system offers enhanced performance at a cost that is considerably lower than other systems. The use of standard Windows software means that users will already be familiar with the interface and allows for ease of maintenance and support. Many potential problems can either be solved by local IT support staff or rectified via the internet.
Scanners from a range of manufacturers are compatible with the Iris system and range from the Raymarine Pathfinder and Simrad, Koden, Anritsu ranges to Kelvin Hughes and Bridgemaster ranges. Data from the radar scanner is fed into the computer through an IRIS radar interface card located in one of the computer's PCI expansion slots. If AIS data available, it is fed from the receiver into one of the computer's serial ports in standard NMEA format. The computer will generally be fitted with a RAID5 array of hard drives to ensure data integrity in the event of a disc failure.
Operator Display
Generally, the main display computer is located in Port Control. Access to the computer itself is normally only required at switch on, when loading software or extracting recorded data and therefore it can be stowed away for normal operation. The IRIS software is based on a "client/server" structure where user access to data is controlled by certificates and passwords which prevent unauthorised access to the system, or limit the functionality available to a particular user.
The display software performs the following functions:
- Display of radar data and AIS data over a S-57 based chart background with user selectable chart layers.
- Moving target enhancement
- Selectable radar range from 0.125 to 36 Nautical Miles
- 8 bit (256 level) video processing
- Range Rings and compass ring
- Picture offset, zoom and pan
- Measurement tools: Electronic Bearing Lines/Variable Range Markers
- User definable markers
- Display of custom graphics as required
- Automatic tracking of targets within specified zones
- Auto-acquire, auto drop and manual track acquire/drop
- Alarm zones
- Automatic recording of raw radar, track, CCTV, AIS (and shortly VHF voice data)
- Choice of screen palettes
- Selectable measurement units
- Replaying of recordings
- Radar controls including:
- On/Off/Standby
- Tune
- Range and Pulse Length/PRF
- Variable persistence (afterglow)
- Radar Interference filter
- Sector Blanking (Blind sectors)
- Moving Target Enhancement
- Sea and Rain Clutter Control
- Selectable scan correlation
- Gain
- Screen palettes
- Selection of units
The moving target enhancement feature allows the operator to readily distinguish moving targets from fixed targets such as land masses or buoys. Moving targets are displayed at higher intensities without the spreading of the target image as is often the case with other systems. Therefore radar resolution is not compromised and close targets can be distinguished. In addition, the IRIS tracking algorithm prevents moving target tracks from diverging on to fixed targets such as buoys and jetties even if the fixed target has a stronger radar return.
Networkable
The system is fully networkable and expandable so that additional displays and scanners in other locations can easily be incorporated, either at the time of installation or at a later date if necessary, without disruption to the existing system simply by adding extra computers and software connected by a wired or wireless network. Any of the displays can then view any of the radars and any number of displays can view the same radar simultaneously.
Operating System
IRIS runs under either Windows 2000 or Windows XP but the software has been designed to use the minimum number of Windows system calls for easy transfer to Linux/Unix.
Recording/Replay
In the event that an incident requires further investigation, the appropriate section of the file can be archived securely onto a CD for further analysis and to provide a permanent record of the event. If required, additional playback only software can be supplied to allow recordings to be viewed on a separate computer. The IRIS system records radar video, alarms, target information and system information. Recording time is a function of storage space: currently a 6-8 week radar recording requires approximately 40 GB of disc space.
Radar video
The radar video is time stamped raw 8-bit video which means that the actual radar data is recorded rather than the display itself allowing for better incident analysis.
Target information
- Target Name
- Position
- Course and speed
- Alarms and status
- Quality of track
System information
- Time
- Software version, status, ID, location, name
- Important settings
- System alarms
Specifications
- Horizontal beamwidth at the 3dB point: 1.15°
- Vertical beamwidth at the 3dB point: 25°
- Range resolution on short pulse (up to 1NM): 7.5 metres
- Range resolution on medium pulse (1 - 6NM) 30 metres
- Range resolution on long pulse (12 - 72NM) 90 metres
- Bearing resolution: ± 0.35 °
- Screen measurement accuracy: 7.5metres/ ± 0.35 °or 1 screen pixel, whichever is greater
- Track dynamic position error: < 20 metres
- Track speed error after 3 min steady state: < 1 knot
- Track course error after 3 min steady state: <1 °
- Radar Extractor & Tracker
- Track course error after 3 min steady state: <1 °
- Speed Accuracy Max +/- 0.2 knots
- Range Accuracy: Better than 2 metres after 1 minute
- Bearing accuracy: Better than 0.3º
- Position accuracy: Better than 2 metres after 1 minute