tailieunhanh - Electronic Navigation Systems 3E Episode 14

Tham khảo tài liệu 'electronic navigation systems 3e episode 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Global Maritime Distress and Safety System 379 Inmarsat-B. This MES is a smaller and more compact digital version of Inmarsat-A and may eventually replace the older analogue system. Because of its use of digital technology an Inmarsat-B MES is able to communicate more efficiently and at much faster rates than an Inmarsat-A MES. Its services include two-way direct-dial high-quality phone Group 3 facsimile telex and 64 kbit s 1 and 56 kbit s-1 high sped data. Enhanced terminals are also able to offer multiple channel access and other high speed networks. Certified for use within the GMDSS. Inmarsat-C. A smaller and cheaper MES providing two-way data communications at 600 kbits-1. It does not handle voice but provides two-way communications via telex or computer data services. The electronics unit can be very small similar in size to a laptop computer and uses a small omnidirectional antenna. Inmarsat-C has been approved for use within the GMDSS and supports Enhanced Group Calling EGC the SafetyNET and FleetNET services. Other services include twoway messaging data reporting and polling position reporting safety emergency alerting and Internet email. Certified for use within the GMDSS. Inmarsat-D and D . Using equipment as small as a personal hi-fi system Inmarsat-D offers two-way data communications within the full coverage of Inmarsat satellites. It is a data-only system that is able to store and display up to 40 messages of up to 128 characters each and is used for personal paging and group calling as well as two-way communications. When a unit is integrated with a GPS receiver then labelled Inmarsat-D it is able to transmit position information for tracking and tracing services. Inmarsat-E. In the GMDSS system the Inmarsat-E system provides global alerting via Inmarsat satellites from Emergency Position Indicating Radio Beacons EPIRBs . A float-free EPIRB may also incorporate a GPS receiver that is interfaced with the transmitter to provide location data. Inmarsat