RU75117U1 - HYDROPHYSICAL INFORMATION DATA TRANSMISSION EQUIPMENT USING A SATELLITE COMMUNICATION SYSTEM - Google Patents

Abstract

Equipment for transmitting hydrophysical information data using the Gonets-D1 satellite communication system, containing a subscriber terminal (AT), a pairing module (MS), an external information device (WU), characterized in that a data transmission module (MTD) is used, allowing the use of MS and WU in the AGS.

Description

The technical solution relates to the constructive implementation of means of hydrophysical research, in the implementation of autonomous systems for the collection and transmission of hydrophysical and environmental information.

To conduct long-term observations in the ocean, hydrophysical complexes (GFC) were used as part of autonomous stations, including buoy stations, the measurement results of which were transmitted to the coastal station using radio transmitting systems.

Known autonomous station for sensing the parameters of the aquatic environment adopted as a prototype [Wolfson L. M., Proshkin S. G., Yurchenko V. A. An autonomous positioning station for sensing the water environment in depth, способ MPK V63V 22/06, 1997], containing a container with a set of measuring modules, equipment for transmitting data of hydrophysical information, made with radio communication equipment, on-board control system and power supply system. The data transmission equipment includes: nodes, and blocks where various transformations of signals intended for further transmission by radio channel, a transmit-receive unit, an antenna-feeder device are performed.

The disadvantage of the conventional radio communication system used here is the limited range of the radio communication (up to hundreds of kilometers), determined by the power of the transmitter used, which is limited by the capacity of the power source of the autonomous station, as well as the sensitivity of the receiver. A qualitative increase in the radio communication range of autonomous hydrophysical stations (AGS) is currently associated with the introduction of a satellite communications system (CCC).

Mobile satellite communications systems appeared a little over 20 years ago, i.e. much later than conventional radio systems. The reason for this is a number of factors, primarily the low power-to-weight ratio of moving objects and more difficult operating conditions (the influence of the terrain, restrictions on the weight of transceivers and the size of antenna systems). Initially, mobile earth stations were developed for use in specialized systems (marine, air, automobile and railway) built on the basis of geostationary spacecraft (SC). To transmit information, analog modulation methods were used. Currently, there are more than 30 national and international (regional and global) projects in the world based on the use of low, medium and high (geostationary) orbits. The most famous are Globalstar, Iridium, Orbkomm, ICO, Odyssey, Ellipso, Messenger, Signal.

A qualitative leap in the development of satellite communications occurred after the appearance of the first projects of digital satellite systems based on spacecraft operating in medium and low orbits. This allowed the use of relatively cheap small-sized terminals and small antennas.

Given the possibility of using omnidirectional antennas and low-power transceivers, low-orbit systems are of most interest for mobile communications of autonomous hydrophysical stations.

It is known that the KURS space system [Selivanov A., Rogalsky V., Dedov N. The space system for collecting natural resource data from ground platforms and determining their location, KURS. "STA", 3/97], designed to collect meteorological and environmental data from platforms with simultaneous determination of their location.

The main disadvantage of the “KURS” system is the small size of the transmitted message (maximum size of 240 bits), the small number of spacecraft (up to 2) and in this regard, the algorithm for the prompt delivery of information to the subscriber, as well as the principle of constructing data transmission equipment, are not known. As can be seen from the content of the work, the main purpose of the KURS system is to determine the location, which is currently not relevant with the advent of the GLONASS space navigation system. Tests of the “KURS” system were carried out using various types of beacons, the amount of transmitted information was 144 bits during a separate session, which is clearly not enough to transmit hydrophysical information from autonomous stations.

Below is the domestic low-orbit system adopted as a prototype - the satellite system (SSS) “Gonets-D1” [Malashenko A.E., Pogoryansky A.G., Chuchelimov V.I. Multifunctional system of personal satellite communications “Gonets”., Marine research and technology for studying the nature of the World Ocean, issue 1, Yuzhno-Sakhalinsk, 2005], designed to transmit data and provide communication services to subscribers located anywhere in the world.

The main areas of application for CCC are: text messaging; monitoring the status and location of moving objects; environmental, industrial and scientific monitoring.

Services and areas of use of the “Gonets-D1” system, hereinafter the “Gonets” system, are mainly oriented towards regional (group) service, i.e. The bulk of the traffic is made up of messages between users located within a certain region. The region is about 4000 km long. Communications in the region are managed by a regional station. In one region may be one or more regional stations that serve their departmental networks (figure 1).

Here: 1 - group of satellites "Messenger"; 2 - regional station; 3 - subscriber terminals; 4 - public telephones.

The regional station organizes a group communication session at the time allotted for its work. At the same time, operational communication between subscribers in this region becomes possible. A regional station can organize service for certain groups of subscribers, for example, collecting information from measuring systems, collecting information about the location of vehicles. According to the principle of regional communication, communication between sea-going vessels can be organized, while the regional station of this network is located on the shore or on one of the vessels.

Along with the orientation of the system to regional services, even one satellite of the system provides global service, i.e. messaging from one subscriber to another when they are located in different regions of the globe

With low requirements for efficiency (up to several hours) delivery is carried out in the "e-mail" mode. The message transmitted to the satellite is stored and transmitted to the recipient when it appears in the radio visibility zone of this satellite.

Urgent delivery on interregional routes can be made using channels of other communication systems. In this case, a message delivered by a satellite to a regional station can be transmitted further over public telephone networks, dedicated data networks, through fixed satellite communications stations.

Subscriber terminal (AT) is a portable transceiver station with an antenna-feeder device. AT provides direct access to satellite channels, i.e. communicates directly with satellites in the radio visibility zone. Communication with the satellite is established automatically without operator intervention. The main component of the AT is the receiving-transmitting unit (BPP), which via an interface cable can be connected to an external information device (WU). Drop cables are used to connect the antennas to the ACU. The power supply of the power supply unit is provided using a power cable from a DC source with a voltage of 12 V. The interface module (MS) between the AT and the VU provides transmission and reception of messages between the AT and the VU.

The transmit-receive unit is a satellite radio modem and provides information exchange with VIS, information conversion into formats accepted in the Gonets-D1 system and vice versa, as well as support for the radio interface with the Gonets-D1 spacecraft relay complex.

Depending on the type of service provided in the Gonets-D1 system, the terminal works with the spacecraft in one of two modes: personal or group. In the personal service mode, the communication session with the spacecraft is organized by the terminal. The work performed in the session is determined by the session plan. A typical session plan defines the software (software) of the terminal and can change as the terminal enters the system. In one minute interval with the spacecraft, one terminal operates. In group mode

service session with the spacecraft is organized by the regional station. The terminals serviced in a group session operate according to a rigid program defined when the terminal was entered into the system. In one minute interval with the spacecraft, up to 46 terminals can operate on transmission with the volume of transmitted messages up to 1 kbit. One and the same terminal can operate in a personal and group mode depending on the service feature included by the regional station in the spacecraft marker signal.

In general, the AT procedure is as follows:

an informational message prepared for transmission is subjected to compression, error-correcting encoding, conversion to formats accepted in the “Gonets-D1” system and put in a queue for transmission;

when the “Gonets-D1” spacecraft appears in the AT radio visibility zone and the regional station (PC) conducts a communication session planned for it, this message is transmitted onboard the spacecraft with receipt of a receipt of reliable recording. In case of an invalid record, the transfer procedure is repeated until a positive receipt is received;

in the same communication session, the addressee, when he is with the sender in the service area of the same PC, should receive the message intended for him. The received information is decoded, restored from the formats of the “Gonets-D1” system, unzipped and transmitted to the control unit;

determination of the coordinates of the location of AT with a given frequency and their transmission is carried out automatically after its inclusion;

upon receipt of messages, a receipt message is generated and transmitted to the sender, confirming the reliable reception of information.

Thus, the Gonets-D1 CCC in the radio-visibility zone provides location AT, conducting communication sessions between the addressee and the sender, but special equipment is required for carrying out communication sessions between autonomous hydrophysical stations and the coastal stationary station - equipment for transmitting hydrophysical information.

Let us consider a method of transmitting hydrophysical information from autonomous hydrophysical stations operating on the sea surface using low-orbit satellite communications “Gonets”, which allows to increase the range of radio communications up to 4000 km.

To transmit information from autonomous hydrophysical stations (AGS) operating on the sea surface to a hospital and to control the AGS using the Gonets-D1 satellite communication system, special data transmission equipment (APD) is required.

The proposed utility model of data transmission equipment (APD) is designed to transfer information between the remote part (HF) (autonomous hydrophysical stations (AGS)) and the stationary (coastal / airborne) part of the hydrophysical complex (GFK). The ADF is part of the equipment that is installed on the gas station. Its structure (figure 2) includes a subscriber terminal (AT), a data transmission module (MTD)

interface module (MS) and an external information device (WU). Data transmission is carried out through the subscriber terminal (AT) of the low-orbit satellite communications system “Gonets”. AT, MS and VU as discussed above are part of the standard equipment of the Gonets-D1 SSS. To control the AGS and the removal of hydrophysical information from the AGS using the Gonets-D1 SSS, a data transmission module (MTD) is used, which allows the use of MS and VU in autonomous stations. This makes it possible to widely use the Gonets-D1 SSS in marine experimental studies using AGS.

The ADF is used as part of an autonomous hydrophysical station (AGS) and must ensure its operation in operating modes. The task of the ADF is to manage and control the operation of the AGS, as well as to bring and archive information transmitted via the satellite data channel. The task of the MS is to automatically convert the exchange protocols between AT and VU.

The block diagram of the data transfer between the control subscriber terminal (UAT) on the one hand and WU on the other hand is presented in figure 2.

Here: 1 - satellite communication channel; 2 - AT; 3 - a spacecraft (in this case, the low-orbit satellite of the Gonets-D1 system); 4 - AT; 5 - WU; 6 - MS; 7 - MTD; 8 - ADF.

The structural diagram of the MTD, i.e. block diagram of the interaction of MS and WU, implemented in hardware presented in figure 3.

Here: 5 - WU; 6 - MS; 7 - MTD; 9 - standby mode (RO); 10 - service request (AO); 11 - receipt at the daylight savings; 12 - information message (IP); 13 - receipt for IP; 14 - order (PR); 15 - receipt PR.

The algorithm for the operation of the MTD (i.e., the interaction of MS and VU) is presented in Fig.4.

Consider the MTD operation algorithm, which allows MS and WUs to be used in autonomous stations. The external device (WU) is in standby (RO) (9) service request (AO) (10) from the interface module (MS) (6). If VU (5) has generated an information message (IS) (12), which it needs to transmit to the interface module (MS) (6), then first VU (5) must check whether MS (6) issues a service request (ST) ) (10) to transmit an order (PR) (14). If MS (6) is silent then, VU (5) generates its request for service (AO) (10) to which MS (6), upon receipt of AO (10) from VU (5), must generate a receipt for a request for service ( KZO) (11) and send it to the VU (5) while it itself must go into standby mode for receiving IS (12). If VU (5) received a short-circuit protection (11), it starts transmitting IS (12), if not, VU (5) again sends an AO (10) MS (6) until it receives a short-circuit protection (11). When the MS (6) receives the IS (12) from the VU (5) and checks the IS (12) for integrity, it will generate and send the VU (5) a receipt for the information message (CIS) (13), if the SU (5) receives the CIS (13), then IS (12) is considered transferred and WU (5)

goes to PO (9), otherwise he will have to again, goes through all the stages, starting from ZO (10).

Now we consider the option if VU (5), checking if there is no DZ (10) from the MS (6), discovers that the DZ (10) from the MS (6) is. In this case, VU (5) will have to postpone the transfer of its IS (12) and, having generated a positive receipt for a service request (KZO) (11), send it to the MS (6), while it itself will have to go to standby (9) reception order (PR) (14). It should be noted that MS (6) will respond to AO (10) from AU (5) in the same way and upon receipt of AO (10) it will send a BOA (11) of AU (5) and will switch to the IS standby mode (12). If MS (6) received a short-circuit protection (11), it starts transmitting PR (14), if not, MS (6) again sends the AO (10) of the control unit (5) until it receives a short-circuit (11). When VU (5) receives PR (14) from MS (6) and checks PR (14) for integrity, it will generate and send MS (6) a receipt for order (CRC) (15) if MS (6) receives CRC ( 15), then PR (14) is considered to be transmitted and MS (6) goes to PO (9), otherwise it will again have to go through all the stages, starting from ZO (10).

It should also be noted that in the process of exchanging messages between VU (5) and MS (6) they will need some delay time (T _s ) necessary for the analysis of messages (AO (10), PR (14), IS (12)) when they receipt and formation of reciprocal receipt of receipt (KZO (11), CRC (15), CIS (13)). The reaction time will consist of the switching time (T _ol ) between receiving and sending data that takes several milliseconds and the system reaction time (T _rs ), which is still difficult to calculate, since it strongly depends on the chosen algorithmic implementation. However, it should be understood that the smaller the T _s and the faster will be the exchange of data with greater efficiency. The delay time (T _s = T _pr + T _pc ) is a very important parameter, since it characterizes the time after which the system decides that the message it sent did not reach the recipient.

Another important point that should be noted is the numbering of messages sent from the VU (5) to the MS (6) and from the MS (6) to the VU (5). It is proposed to introduce separate numbering of messages in VU (5) and in MS (6), since otherwise the systems will have to spend an extra resource on tracking the uniqueness of the next number, which is difficult in this exchange protocol. Since the system can and should clearly distinguish between received and sent messages, therefore, even matching messages by numbering will differ in the type and direction of transmission. Therefore, the messages ZO (10) and IS (12) formed by the VU (5) are numbered from 0 to 255 in increments of one (1 byte) have the direction of transmission to the MS (6) and never repeat, when the maximum value is reached, the count starts from zero, and messages ZO (10) and PR (14) formed by the MS (6) are numbered from 0 to 255 in increments of one (1 byte) have the direction of transmission in

WU (5) and never repeat, when the maximum value is reached, the count starts from zero. Since all receipts (KZO (11), CRC (15), CIS (13)) are issued for a specific message (DA (10), PR (14), IS (12)), then the number they have the same message, which they acknowledge. This means that all receipts are nominal. At the same time, the receipt always has a positive logical value, which indicates the correct understanding of the message (AO (10), PR (14), IS (12)), and if the message is understood incorrectly, then it is considered not accepted and the receipt will not be issued.

Thus, the MTD organizes the process of receiving and transmitting information via a satellite communication channel between an autonomous hydrophysical station (AGS) on the sea surface and a managing subscriber terminal (UAT) in a hospital or on a supply vessel.

Claims (1)

Equipment for transmitting hydrophysical information data using the Gonets-D1 satellite communication system, comprising a subscriber terminal (AT), a pairing module (MS), an external information device (WU), characterized in that a data transmission module (MTD) is used, allowing the use of MS and WU in the AGS.