Ships’ Weather Reports

Reports from vessels which form part of the voluntary observing fleet under auspices of the WMO. Ships’ Weather Reports can be sent through Inmarsat-A or Inmarsat-C.

 

II. Make 15 special questions for this text.

III. Be ready to discuss the types of the navigations warnings in English.

IV. Translate the following words and word combinations from English into Russian

The Worldwide Navigational Warning Service; promulgation; navigational warnings; danger to navigation; to be of temporary nature; Notices to Mariners (NM); NAVAREA warnings; coastal warnings; local warnings; to collate; long-range; failure; major navigational aids; newly discovered wrecks; natural hazards; anti-pollution operations, cable-laying activities; shipping routes; long-range electronic position fixing system; underwater activities; mobile drilling rig; derelict; congested waters.

 

V. Translate the following sentences from Russian into English

  1. Информация по безопасности на море включает навигационную информацию на определенные районы морей и океанов.
  2. Задача навигационных предупреждений – срочно сообщить мореплавателям об обнаруженных опасностях.
  3. Такая информация является обязательной для приема на всех судах вне зависимости от района плавання.
  4. Для передачи навигационных предупреждений существует Всемирная Служба навигационных предупреждений, которая является координированной службой.
  5. В ВСНП весь Мировой океан разделен на 16 морских районов, называемых НАВАРЕА, и обозначаемых римскими цифрами.
  6. В каждом из районов имеется страна-координатор, ответственная за сбор, анализ и передачу навигационной информации.
  7. Имеются три вида навигационных предупреждений: предупреждения НАВАРЕА; прибрежные предупреждения; местные предупреждения.
  8. В об щем случае предупреждения НАВАРЕА содержат информацию, которая необходима мореплавателям для опеспечения безопасного плавання на океанских переходах.
  9. В прибрежных предупреждениях распространяется информация, которая необходима для безопасного плавания в границах определенного региона.
  10. Местные предупреждения дополняют прибрежные предупреждения, предоставляя подробную информацию в приделах прибрежных вод.
  11. Навигационные предупреждения каждого вида имеют свою сквозную информацию в течение всего календарного года, начиная с номера 0001 в 00.00 часов Всемирного координированного времени 01 января и до 24.00 31 декабря текущего года.
  12. Предупреждения НАВАРЕА, а также прибрежные предупреждения передаются на английском языке.
  13. Дополнительно предупреждения НАВАРЕА могут передаваться на одно мили более официальных языках ООН.
  14. Прибрежные предупреждения могут передаваться также на национальном языке, а местные – только на национальном языке как объект национальной службы.

 


 

UNIT 9

I. Read and translate the text.

COSPAS-SARSAT SYSTEM

The COSPAS-SARSAT (Cospas – Space System for Search of Distress Vessels, SARSAT – Search and Rescue Satellite-Aided Tracking)) system is a satellite-aided search and rescue (SAR) system designed to locate distress beacons transmitting on the frequencies 121.5 MHz and 406 MHz.

COSPAS-SARSAT is a joint international satellite-aided search and rescue system, established by organizations in Canada, France, the United Sates and Russia.

The COSPAS-SARSAT system has demonstrated that the detection and location in distress signals can be facilitated by global monitoring based on low-altitude satellites in near-polar orbits. It has been used successfully in a large number of SAR operations worldwide.

Unless, as an alternative, a ship is provided with a L-band satellite EPIRB operating in sea areas A1, A2 and A3 only, the carriage of a float-free satellite EPIRB operating on the 406 MHz in the COSPAS-SARSAT system is required on all SOLAS ships.

There are at present three types of beacons, namely Emergency Locator Transmitters (ELTs) (airborne), EPIRBs (maritime) and Personal Locator Beacons (PLBs) (land). These beacons transmit signals that are detected by COSPAS-SARSAT polar orbiting satellites equipped with suitable receivers/processors. The signals are then relayed to a ground receiving station, termed a Local User Terminal (LUT), which processes the signals to determine the beacon location. An alert is then relayed, together with location data and other information, through a Mission Control Centre (MCC), either to a national RCC, another MCC or to the appropriate SAR authority to initiate SAR activities.

Doppler shift (using the relative motion between the satellite and the beacon) is used to locate the beacons. The carrier frequency transmitted by the beacon is reasonably stable during the period of mutual beacon-satellite visibility. The frequencies currently in use are 121.5 MHz (international aeronautical emergency frequency) and the 406.0 – 406.1 MHz band. The 406 MHz beacons are more sophisticated than the 121.5 MHz beacons because of the inclusion of identification codes in the messages, but complexity is kept to a minimum. To optimize Doppler location, a low-altitude near-polar orbit is used. The altitude of the COSPAS satellites’ orbit is approximately 1,000 km while that of SARSAT satellites is about 850 km. These low-latitudes result in a low uplink power requirement, a pronounced Doppler shift, and short intervals between successive passes. The near-polar orbit results in complete world-coverage over a period of time. The nominal satellite system configuration comprises four satellites, two supplied by COSPAS and two by SARSAT.

The COSPAS-SARSAT system implements two coverage modes for the detection and location of beacons, namely the real-time mode and the global coverage mode. Both the 121/5 and 406 MHz systems operate in the real-time mode, while only the 406 MHz system operates in the global coverage mode.

Real-time 121.5 MHz repeater data system: If an LUT and beacons are in view of the satellite, a repeater onboard the satellite relays the 121.5 MHz EPIRB signals directly to the ground where it is received and processed. For this reason, worldwide real-time mode coverage is unlikely to be achieved.

Real-time 406 MHz processed data system: Once the satellite receives the 406 MHz EPIRB signals, the Doppler shift is measured and the beacon digital data is recovered from the beacon signal. This information is time-tagged, formatted as digital data, and transferred to the downlink repeater for real-time transmission to any LUT in the satellite view. The data is simultaneously stored on the satellite for later transmission in the global coverage mode.

Global 406 MHz coverage mode: The 406 MHz system provides global coverage by storing data onboard for later dumping and reception by LUTs. Each satellite EPIRB can therefore be located by all operating LUTs.

Satellite EPIRBs – 121.5 MHz EPIRB: EPIRBs operating on 121.5 MHz are already in widespread use. They are used onboard light aircraft and ships and must meet national specifications based on International Civil Aviation Organization (ICAO) standards.

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Satellite EPIRBs – 406 MHz EPIRB: The development of 406 MHz satellite EPIRBs has been undertaken to overcome certain shortcomings of the 121.5 MHz system. The new EPIRBs were specifically designed for satellite detection and Doppler location and include the following features: improved location accuracy and ambiguity resolution; increased system capacity, i.e. a greater number of beacons transmitting simultaneously in the field of view of a satellite can be processed; global coverage; unique identification of each beacon; inclusion of distress information.

The 406 MHz satellite EPIRBs transmit a 5 W radio frequency (RF) burst of approximately 0.5 second duration every 50 seconds. Improved cycle provides good multiple-access capability, with a system capacity of 90 activated beacons simultaneously in view of the satellite, and low mean power consumption.

An important feature of the new EPIRBs is the inclusion of a digitally encoded message, which may provide such information as the country of origin of the unit in distress, identification of the vessel or aircraft, nature of distress and, in addition, for EPIRBs coded in accordance with the maritime location protocol, the ship’s position as determined by its navigational equipment.

Most satellite EPIRBs are dual-frequency 121.5/406 MHz beacons, though the inclusion of the frequency 121.5 MHz is not mandatory. This enables suitably equipped SAR units to home in on the 121.5 MHz transmission and permits overflight monitoring by aircraft. This type of homing facility is indicated to the rescue authorities by the message.

Depending on the type of beacon (maritime, airborne or land) beacons can be activated either manually or automatically.

 

II. Make 15 special questions for the text.

III. Make a summary of the text above.

IV. Translate the following words and word combination from English into Russian

Space system; distress vessel; satellite-aided tracking system; satellite-aided search and rescue; to locate distress beacons; detection; low-altitude satellite; near-polar orbit; float-free satellite EPIRB; Emergency Locator Transmitter; Personal Locator Beacons; ground receiving station; Local User Terminal; Mission Control Centre; Doppler shift; coverage mode; real-time mode; the global coverage mode; time-tagged; to store the data; shortcoming; ambiguity; power consumption; digitally encoded message; the maritime location protocol.

 

V. Translate the following sentences from Russian into English

1. Система КОСПАС-САРСАТ Состоит из шести низкоорбитальных спутников, расположенных на околополярной орбите, пяти геостационарных спутников, локальной земной станции связи, центра управления и координационно-спасательных центров.является спутниковой системой, основанной на использовании низкоорбитальных спутников на околополярной орбите.

2. Абонентами системы являются спутниковые аварийные радиобуи.

3. Система КОСПАС-САРСАТ работает в диапазоне частот 406.0-406.1 МГц.

4. Система обеспечивает оповещение о бедствии и определение местоположения спутниковых АРБ по доплеровскому сдвигу частоты.

5. Система КОСПАС-САРСАТ использует два режима охвата для обнаружения буев.

6. Обе системы работают в режиме реального времени.

7. В разработке и вводе в эксплуатацию спасательной системы принимали участие СССР (в дальнейшем Россия), США, Канада и Франция.

8. Международная спутниковая система КОСПАС-SARSAT является одной из основных частей ГМССБ и предназначена для обнаружения и определения местоположения судов, самолетов, других объектов, потерпевших аварию.

9. Система КОСПАС-SARSAT одобрена Международной морской организацией (ИМО) и Международной организацией гражданской авиации (ИКАО).


 

UNIT 10

1. Read and translate the following text

THE NAVSTAR GLOBAL POSITIONING SYSTEM (GPS)

General Information

GPS is a military satellite navigation system that is owned and operated by the United States Department of Defense. The space segment of this system, consists of at least 24 operational satellites evenly distributed between 6 orbital planes with an inclination to the horizon of 55° to the Equator and altitudes of 20200 km (10900 n miles). This configuration ensures that a minimum of four satellites with suitable elevations is visible to a receiver anywhere on the Earth's surface at any time. GPS will therefore provide continuous, worldwide position fixing. The complete constellation is in place and the US authorities have declared initial operational capability. Subject to a number of constraints, the current constellation of satellites provides useful position information. However, GPS users are cautioned that signal availability and accuracy are subject to change without warning. System integrity is also unreliable because of the current lack of real-time warning to users when satellites malfunction. The United States Department of Defense policy is that GPS satellites transmit signals, which are intended primarily for military purposes and are subject to change without prior notice. The use of GPS signals for positioning, navigation, time transfer, or any other purpose will be at the user's risk. However, whenever possible, advance notice of periods when the GPS satellites should not be used will be provided by the Department of Defense and distributed by the US Coast Guard.

A recent (1998) announcement by the Office of the Assistant Secretary for Public Affairs in Washington DC, USA, stated that two new civilian signals will be provided by the US Global Positioning System (GPS). The second signal, to be made available from the year 2003, will have public safety applications, particularly in international aviation, land transportation and maritime uses. A lead-time of several years is needed because the new signal capability will have to be built into the next generation of GPS replacement satellites. The addition of a second signal will greatly enhance the accuracy, reliability and robustness of civilian GPS receivers by enabling them to make more effective corrections for the distorting effects of the Earth's atmosphere on the signals from space. The addition of a third frequency from the year 2005 will be of particular benefit to scientific users and surveyors, adding to the speed with which users can obtain GPS positions and timing, and improving the overall accuracy and reliability of the system. One of the new signals will be located in the frequency of the current GPS L2 signal, which previously has been used only for military purposes. Separate civilian and military signals can coexist on this frequency, as they already do at the GPS L1 frequency. The frequency for the third civil signal is now known as L5 and will receive the international frequency allocation and protection needed to enable it to meet safety of life requirements.

A GPS position fix is obtained by measuring the ranges from a series of selected satellites to a receiver. Ranges are determined by measuring the propagation time of the satellite data transmissions. However, it is not possible to precisely synchronise the satellite and receiver clocks, the ranges measured are not true ranges, but are termed "pseudoranges" since they contain a receiver clock offset error. In order to achieve a two-dimensional (2-D) fix on the Earth's surface at least three "pseudoranges" must be obtained; the receiver microprocessor can then resolve the three range equations to remove the effects of receiver clock offset error. Similarly four "pseudoranges" would be required to obtain a 3-D fix.

Each satellite transmits data on two frequencies in the L-band: L1 = 1575-42 MHz and L2 = 1227-60 MHz. Both frequencies are integer multiples of the basic 10-23 MHz clock frequency. Dual-channel receivers will be able to use two frequencies to correct for the effects of ionospheric refraction. Data transmitted on the L1 and L2frequencies is encoded by a Pseudo Random Noise (PRN) modulation. The L5 frequency will be 117645 MHz.

GPS provides two levels of positioning capability: the Precise Positioning Service (PPS) and the Standard Positioning Service (SPS). The PPS is derived from the Precise (P) code whilst the SPS is derived from the Coarse and Acquisition (C/A) code. The P code, which is primarily for military use, is transmitted on the L1 and L2 frequencies. The C/A code is transmitted on the L1 frequency only at present but in the future will also be transmitted on the L2 frequency to provide the second civil signal. In order to protect the military use of the L1 and L2 signals, the M code has been developed to be spectrally separate from the C/A code. The M code is an improvement on the P code and will be broadcastable on a regional basis. Investigations into methods to improve fix accuracy have led to the development of Differential GPS (DGPS).

 

II. Answer the following questions

  1. What is the GPS?
  2. What does the space segment of this system consist of?
  3. What does this configuration ensure?
  4. How is a GPS position fix obtained?
  5. In what way are ranges determined?
  6. What levels of positioning capability does GPS provide?

 

III. Decipher the abbreviations:

GPS, DGPS, 3-D, L-band, PRN, MHz, SPS, PPS, C/A code, P code

 

IV. Translate the following words and word combinations from English into Russian

Global Positioning System, Department of Defense, operational satellite, orbital plane, inclination, altitude, the Earth's surface, position fixing, constraint, signal availability, accuracy, malfunction, civilian signal, lead-time, distorting effect, allocation, range, the propagation time, satellite data transmission, "pseudorange", offset, dual-channel receiver, Pseudo Random Noise.

 

V. Translate from Russian into English

1. Глобальная система позиционирования — спутниковая система навигации, обеспечивающая измерение расстояния, времени и определяющая местоположениe.

2. GPS позволяет в любом месте Земли (не включая приполярные области), почти при любой погоде, а также в космическом пространстве вблизи планеты определить местоположение и скорость объектов. Система разработана, реализована и эксплуатируется Министерством обороны США.

3. Основной принцип использования системы — определение местоположения путём измерения моментов времени приема синхронизированного сигнала от навигационных спутников до потребителя.

4. Расстояние вычисляется по времени задержки распространения сигнала от посылки его спутником до приёма антенной GPS-приёмника.

5. Несмотря на то, что изначально проект GPS был направлен на военные цели, сегодня GPS широко используются в гражданских целях.

6. GPS-приёмники продают во многих магазинах, торгующих электроникой, их встраивают в мобильные телефоны и смартфоны.

7. Потребителям также предлагаются различные устройства и программные продукты, позволяющие видеть своё местонахождение на электронной карте; имеющие возможность прокладывать маршруты с учётом дорожных знаков, разрешённых поворотов и даже пробок; искать на карте конкретные дома и улицы, достопримечательности, кафе, больницы, автозаправки и прочие объекты инфраструктуры.

8. С помощью GPS определяются точные координаты точек и границы земельных участков