Satellite based Augmentation systems (SBAS)

SBAS are overlay systems, for the current GPS and GLONASS Global Navigation Satellite Systems (GNSS), using a suite of geostationary satellites, that will offer users more reliability through improved accuracy, availability, integrity and continuity. Though these improvements are being driven by aeronautical requirements, in practice all users, be they maritime, road, rail or surveying, will benefit.

The three major components of the SBAS are EGNOS (the European Geostationary Navigation Overlay Service), WAAS (the American Wide Area Augmentation System) and MSAS (the Japanese Multi-functional transport satellite (MTSAT) - based Satellite Augmentation System). The signals broadcast by SBAS will be totally compatible with the GPS/GLONASS signals, which means that the presence of the SBAS signal will not impair the reception of GPS/GLONASS signal in any way.

The implementation schedule for SBAS should culminate in the Advanced Operational Capability (AOC) during the period 2003 - 2005.

II. Answer the following questions

1. Why is the GLONASS similar to GPS?
2. When did the system become fully operational?
3. What does the system consist of?
4. How does each GLONASS satellite broadcast?
5. What form have the transmitted data got?
6. What is the SBAS?
7. What are the three major components of the SBAS?

III. Compare SBAS, GPS and GLONASS, discuss similar features, difference and benefits for users.

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

Global Navigation Satellite System; to be similar to; space-based navigation system; global all weather access; precise position; properly equipped; operational; orbital plane; altitude; orbital inclination; broadcast; constellation; to derive position; coarse acquisition; binary signal; modulo; pseudorandom sequence.

V. Read and translate the text. Find out the subordinate clauses and define their type.

STAREC (STA tus REC ording system)

STAREC is a maritime emergency reporting system to be used by ocean going vessels in order to immediately report emergency events when such situations occur. The STAREC float-free buoy contains a Data Recorder and an INMARSAT-C communications terminal that enables the buoy to report emergency events immediately from any ocean region within the coverage of the INMARSAT system. The high capacity Data Recorder can log data from a number of sensors around the ship, including position (e.g. GPS, LORAN, DECCA, etc.), course, speed, hull motion and hull integrity, etc.; these sensors could also include equipment to monitor the status of major hull openings such as bow and stern doors in roll on/roll off ferries. The buoy has been designed to send a short message to a pre-determined point on the shore, for instance, the ship owner and/or RCC, when, in the event of an accident, it floats free from the ship, or whilst ship-borne. The shore authority can then send a message instructing the buoy to transmit all recorded data in its memory, this arrangement has the positive advantage that recorded data is available on shore and it is not necessary to engage in an extensive search to find the buoy before the data can be recovered. The initiation of the system can be done by the vessel’s crew (e.g. bridge-located push button), or automatically when the buoy’s sensors register that the buoy has been released from its normal position. A further capability enables the shipping company or shore authority to check the status of any of the sensors at any one time, simply by interrogating and requesting the buoy to send a report.

STAREC continuously records important data about the vessel in order to relay ере data to on-shore authorities if an emergency situation occurs.

STAREC was developed because many vessels disappear without any trace while “en-route” Incidents like these often generate more questions than answers and STAREC can, within minutes after an incident, be able to relay stored data which can give these answers. In addition t total disappearances, other accidents like collisions, fire black outs and involuntary groundings have revealed the need for a “neutral” recording system which can tell the story about the vessels behaviour previous (minutes/hours) to the incident.

In many ways STAREC can be compared to the “black box system” used onboard airplanes. The major advantage of STAREC over the “black box system”, however, is that the critical data do not need to be physically retrieved from the buoy, but can simply be “polled” from it whilst it is still in the water, or shipborne.

VI. Translate the following sentences from Russian into English

1. Глобальная навигационная спутниковая система — советская и российская спутниковая система навигации, разработана по заказу Министерства обороны СССР.

2. Основой системы должны являться 24 спутника, движущихся над поверхностью Земли в трёх орбитальных плоскостях с наклоном орбитальных плоскостей 64,8° и высотой 19.100 км.

3. Принцип измерения аналогичен американской системе навигации NAVSTAR GPS.

4. ГЛОНАСС предназначена для оперативного навигационно-временного обеспечения неограниченного числа пользователей наземного, морского, воздушного и космического базирования.

5. Доступ к гражданским сигналам ГЛОНАСС в любой точке земного шара предоставляется российским и иностранным потребителям на безвозмездной основе и без ограничений.

6. Основное отличие от системы GPS в том, что спутники ГЛОНАСС в своем орбитальном движении не имеют резонанса (синхронности) с вращением Земли, что обеспечивает им большую стабильность.

7. Таким образом, группировка ГЛОНАСС не требует дополнительных корректировок в течение всего срока активного существования.

8. Тем не менее, срок службы спутников ГЛОНАСС заметно короче.