E stands for …

In its first launch since acquiring a number of suppliers Litton Marine Systems offers an improved version of a Decca radar Decca`s BridgeMaster radars have established their mark in the marine market and as Litton`s first launch were a suitable product. The new version is called the Decca BridgeMaster E and development of the radar was started some four years ago, long before Litton bought the company from Racal.

The BridgeMaster E radars include a number of features including an advanced form of clutter control. Notes Dr Clark Graham, Decca`s managing director: “These new systems build on the strong reputation for reliability and performance while advancing the state-of-the-art to new levels.”

Possibly the most innovative, and most apparent in operation, is the improved clutter control. Decca has developed its Vision automatic radar adaptive video processing (RVAP) system. The company says that this is the industry`s first true hands-free clutter suppression and gain control. According to Decca, Vision was developed by creating windows each of about 10 pulse bands width. Mapping of sea clutter under a wide range of conditions was undertaken with any general targets removed to give an accurate statistical analysis of the clutter within each band. The two video signals are then processed so that the actual radar conditions are effectively presented without any sea clutter, allowing even relatively weak targets to be successfully tracked.

While more traditional methods is still available in the BridgeMaster E series, Decca feels that the Vision option will have a major impact on radar navigation. “The operator will be free to concentrate on watch standing instead of making constant adjustments to the radar in order to optimise the display and detect weak targets in the presence of strong clutter return,” it comments. One area where Vision is expected to have most impact on operations is when approaching land, since it removes the need to switch to manual clutter suppression.

Vision is proprietary technology which Decca considers to be unique. It first started development with Racal Research some nine years ago but was bought by Litton along with Decca. The RCCL Project Eagle ships will be the first fitted with BridgeMaster E and Vision clutter control.

Decca has chosen to offer a number of variants for controlling the radars – the so called MMI (Man Machine Interface). Operators can choose to have either a trackball or joystick, allowing them to select highlighted options from the screen. These are either as pull-down menus or as directly variable control. Another MMI available is an optional keyboard, and Decca feels that this option will be more widely chosen by fast ferry operators. The MMIs can also be fitted as an optional remote control.

The BridgeMaster E series is aimed at meeting the needs of a wide range of users, either as a stand-alone unit or as part of an integrated bridge. To meet the needs of fast ferry operators the BridgeMaster E can track targets at up to 150 knots. They have been type approved to meet all new IMO regulations for both conventional and high-speed craft as well as DNV`s Watch 1 requirements. The company comments that they are designed to meet the requirements of all expected future IMO resolutions.

There are a number of operational capabilities including three motion modes, RM(R), RM(T) and TM. There are two VRMs and EBLs with off-centring permitted on one set, and recording and playback of selected target tracks and own ship is also available. The BridgeMaster E arpa and ATA (Automatic Tracking Aid) versions can track up to 40 targets at up to 40 naut miles and use both annular and polygonal auto acquisition zones. Polygonal zones are mainly intended for static, use since the user defines the shape. By contrast the basic EPA (Electronic Plotting Aid version complies with IEC 60872-3 and can track up to ten targets simultaneously. There are three different – 180, 250 and 340mm – full colour displays available and a wide range of X- and S-band configurations. Decca also stress the interswitching capability which is available in either two- or six-way options. The two-way option allows interswitching of up to two transceivers and four displays in various configurations, while the six-way option covers six transceivers and six displays.

BridgeMaster E uses multi-layer radar maps which can be stored in electronic folios for any voyage. These use standard ENC symbols, lines and colours and the system can accept navlines from electronic chart systems.

To facilitate installation, Decca has moved to a serial data link between the display and transceiver. This reduces cable requirements and installation costs. Installation is made easier, stresses Decca, by the use of full screen menus to reduce set up time and costs while internal performance monitors have been fitted to further reduce costs.

One aspect of this, notes Dr Graham, is that it will make the BridgeMaster E highly competitive for the large potential retrofit market for the products. Decca has introduced a Ready Radar programme where radars are deployed at selected locations world-wide. This enables the company to offer a 24-hour turnaround for replacement units at most locations. BridgeMaster E is backward compatible allowing customers to upgrade existing systems BridgeMaster systems progressively.

Reliability is a key factor in the design of the product, and Decca has subjected its BridgeMaster E to highly accelerated life testing. This is intended to continuously test all moving parts under full load conditions. Each radar undergoes temperature cycling, humidity, vibration and functional testing. Decca says that its tests exceed the limits set by regulatory bodies and that testing of the BridgeMaster E to date is equivalent to 23 years continuous operation at sea.

Litton Marine Systems will continue to develop its products in its three legacy companies: Decca, Sperry and C Plath. The company says that rationalisation allows each subordinate to retain its key strengths. Thus Decca will develop radars and its ISIS engine monitoring system – although its MIRANS system has ceased – while Sperry will develop integrated bridge systems (IBS) and C Plath will develop gyro compasses.

The primary reason for retaining, rather than renaming, the three companies is the recognised strengths of the brand names in a very conservative market. Initially radars will be branded with both Litton and Decca names except when a unit is included in a Sperry IBS in which case it will be a Litton Sperry IBS.