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NERCS is an open VCS (Voice Communication System) for VTMS (Vessel Traffic Management Systems), Public Safety, Command & Control, and PMRS (Private Mobile Radio Systems). The system is to a large extent built and designed using COTS components, making NERCS a cost-efficient yet flexible, redundant and scalable solution.
The system may utilize almost any kind of existing radio transceiver, or the system can be deployed with integrated radios from the maritime VHF to UHF and air-band.
The system may be totally integrated with the communications network of a possible VTS in order to save deployment costs. The NERCS system may be completely integrated with the VTS workstation and the audio-logging is integrated with the VTS radar and tracking system effectively creating a multi-media logging and replay system.
The primary objective of the NERCS Voice Communication System is to provide the operator with a fast, reliable and flexible means to communicate with other parties.
The operational objectives are to:
- Provide users with high-quality radio based communications using low-bandwidth data links.
- Enable the user to utilize existing data links and radio equipment.
- Provide users with a fast and easy to use voice communications interface.
- Provide users with integrated voice logging and replay facilities.
- Provide a reliable and fail-safe system environment
NERCS accomplishes the given objectives by presenting the user with a easy to understand user interface.
The system typically consists of radio base stations, transceivers and a base station controller to which they units are connected. The base station controllers are being connected to a PCM type switched communications network via which they are connected to a voice bus/switch. The bus/switch handles the control and audio to and from the base station controllers and inserts it to TDMA based bus. Operator workstations may pick for reception the audio channels from the TDMA audio bus that they are entitled to. Control signalsand user commands between system components are being passed through a redundant switched Ethernet to ensure reliability.
The system meets hard availability requirements as it has no single point of failure when it comes to total system availability. Audio transmission and processing is entirely digital throughout the entire system. Most of the system functionality is implemented in software, which enables maximum configuration and operational flexibility. Key system equipment has been built using COTS components and portable software that ensures maximum system lifetime and low operation and maintenance costs. User interface components may be deployed using off-the shelf PC computers and displays, but integrated touch-screens and system consoles are available depending on user requirements.
The communication between the system components has been optimized to utilize as little bandwidth as possible. A radio base station or an operator working position may be connected to the system and set to utilize as little as 64kbit/s. Audio communication may be compressed using different algorithms depending on user requirements.
Information can be exchanged using any telecommunication infrastructure, such as fiber optic, spread spectrum, radio-link, ISDN, satellite or similar. Navielektro is if necessary able to construct the required telecommunication infrastructure for a specific delivery. The system offers a switched/bridged TCP/IP using the NERCS telecommunication system that may be used for control and integration of other sensors.
The VLS, Voice Logging System is responsible for receiving audio data that is streamed through the Ethernet. The VLS is able to log all audio channels that exist within a system to its internal storage subsystem. The storage subsystem is responsible for logging and indexing received audio data and organizing the information to a voice call structure. Voice data may be replayed using either NERCS operator workstation or optionally using the analyzer software within the JMAP framework. The VLS may be time synchronized using NTP (Network Time Protocol) for exact time keeping. Any combination of audio channels or audios may be chosen for replay and storage to external digital multimedia clips. In case the VLS is deployed as a component of the NLS (Navielektro Logging System) the audio may be synchronized with radar, track and data from other NLS modules.
The purpose of the NERCS DSC (Digital Selective Call) Service is to provide full or partial DSC to NERCS compliant systems enabling the NERCS to be operated as a full distributed GMDSS coastal radio system. The NERCS DSC may work in a completely distributed fashion enabling a NERCS or integrated NERCS-JMAP radio operator working position to conduct DSC operation, regardless of the physical location of the operator working position, control center or base station.
The NERCS DSC integration allows significant GMDSS (Global Maritime Distress Safety System) related DSC radio calls to be visualized as part of the i-VMS&C3S, RMP (Recognized Maritime Picture) or TaSP (Tactical Situation Picture). The system interconnects several DSC base stations VHF or HF with a number of control centers in such a manner that any base station (BS) may be controlled from any control center (CC) or any operator working position (OWS).The NERCS DSC also provides a concept of virtual MMSI numbers where each operator working position or a group of operator working positions may be assigned a virtual MMSI number. This essentially allows vessels to communicate directly with the shore based parties they desire.
The NERCS audio/switch system may be configured to provide an availability of at least 99.9% as recommended by e.g. IALA. In order to achieve better reliability the base system can be hardened by using dual TDMA audio buses etc. The required level of availability is provided by a combination of redundancy that is built-in to the system, where central equipment is duplicated and others may operate in degraded mode or be replaced by hot-standby units. According to statistics the most vulnerable parts are the telecommunications infrastructure and , so special care should be taken to harden the system infrastructure.
Navielektro is independent of 3rd party suppliers including radio transceivers, computer and telecommunication manufacturers. In addition the system software has been designed to be platform independent, which should ensure a maximum expected system life-time.
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Digital Selective Call Service