ScanEx Ground Stations Network: Network of ground stations receiving data from artificial Earth remote sensing satellites

Transcription

1 ScanEx Ground Stations Network: Network of ground stations receiving data from artificial Earth remote sensing satellites 1

2 Contents Network general characteristics: General information about ScanEx network Network structure and composition Network control system and its components SGS Operation Planner the application for planning the stations network operation SGS Service File Dispatcher service files dispatching system ScanReceiver the application for the receiving station control SGS Log Transmitter the application of reception log-files (reports) delivery SGS Operation Monitor the application of monitoring stations network operation quality Auxiliary applications SGS SatTrack Viewer Internet-service of visualization of orbital and ground tracks of satellites SGS Status Monitor the application for indication of current status of the receiving stations Network operation mode and performance APPENDIX 1. UniScan receiving station APPENDIX 2. Example of the network operation schedule per one day and its performance assessment

3 Network general characteristics: Composition 9 multimission multichannel receiving stations in 4 reception centers under general control Coverage All the territory of Russia and adjacent parts of the Arctic Ocean Supported missions Earth observation satellites used for regular data reception (2010 imaging season) Satellites, which data stations are technically ready to receive (testing completed, interfaces coordinated) TERRA (DB) AQUA (DB) ENVISAT RADARSAT-1 SPOT-4 SPOT-5 FORMOSAT-2 LANDSAT-5 EROS-A EROS-B CARTOSAT-1(IRS-P5) IRS-P6 CARTOSAT-2 RADARSAT-2 COSMO-SKYMED-1/2/3 THEOS TerraSAR-X Total performance Over 150 passes and over 600 GB of data per day 3

4 1. General information about ScanEx network Since 2001 ScanEx RDC has been manufacturing and installing compact multimission ground receiving stations UniScan for Earth observation satellites data reception. Fig. 1 illustrates the antenna system of the UniScan station, mounted on roof of an office building (town of Megion). Fig. 1. UniScan-24 station antenna in Megion As of today over 50 such stations have been operating in Russia and abroad. Most of them are stand-alone systems, receiving data within coverage zone according to the plans and programs of their owners. However, 9 of such stations, located in 4 reception centers, operate based on a common program and under common control from one center. These stations form a structure called a ScanEx Ground Stations Network". The map of locations and coverage of reception centers is shown in Fig. 2. The total longitudinal length of the network ensures the data reception from the majority of polar-orbiting satellites basically on any pass. Control is executed via Internet from the center, located in Moscow. The centralized network control enables to optimally plan the operations of all stations for solutions of both individual tasks of member-organizations, and the general task regular operational imagery of all Russian territory using all available satellites (availability restricted by technical specifications and license agreements only). 'Common control' does not just implicate the operation based on coordinated programs, but an actual direct operational control from one common center, without local operator intervention. A general timeline (pass schedule) is created daily at the control center for the network operations as a collection of several stations programs. Each individual program is automatically delivered to the respective ground station, automatically executed, and completion reports are automatically sent to the control center, where they are being analyzed and archived also automatically. 4

5 Of course, the network of ScanEx is not the only network in the world ensuring the reception of earth observation data. However, the total coverage area, the number of stations and the number of used satellites allow it to be qualified as a unique one. The fact that it has been created and is controlled by a private company makes it even more unique. 2. Network structure and composition The lower and the basic structural unit of the network is the receiver that ensures demodulation, decoding, formatting and recording of the telemetry flow from a satellite. One receiver provides satellite data reception via one channel, i.e. one carrier frequency in a time. Each receiver is connected to its own PC and operates based on its own schedule, and during each reception pass it records its own data file and reception report. Data can be transmitted from the same satellite via several channels simultaneously from one to four, depending on the satellite. To receive all the information it is required to have several receivers. The complex of the antenna system and several receivers connected to it form a receiving station. Several satellites may pass through the zone of each ground station at the same time, whereas one station can track only one satellite. The more satellites, the more is the probability of such a conflict. To minimize this probability several receiving stations are required to cover a common zone. A group of stations, located in one geography position and having the same coverage composes a reception center. As of today (2010 data) the network is comprised of 4 reception centers, consisting of 9 receiving stations having 22 receivers. Composition and location of reception centers is shown in table 1 and in Fig.2 below. Table 1. Location and composition of Reception Centers Location of Reception Centers Number of stations Number of receivers Moscow 3 8 Megion 1 2 Irkutsk 3 8 Magadan 2 4 5

6 Central Federal District (FD) North-Western FD Southern FD Privolzhsky FD Urals FD Siberian FD Far Eastern FD Moscow: 3 stations, 8 receivers Magadan: 2 stations, 4 receivers Moscow Magadan Control center Megion Irkutsk Megion: 1 station, 2 receivers Irkutsk: 3 stations, 8 receivers Fig. 2. Location of reception centers and their coverage. The heaviest load is on the reception centers in Moscow and Irkutsk, therefore each comprises three stations. There is considerably much less activity on the territory of the Magadan Center, than in Moscow and Irkutsk, so there are only two stations in this center. Finally, the easiest load is on the reception center in Megion, as the Moscow and Irkutsk zones almost interlock. Megion provides the reception along the junction of these zones and over the relatively small northern territory above them. Therefore there is only one station installed here. 3. Network control system and its components The network stations are distributed along the large territory, permanently working with satellites and in total handling from 100 to 200 passes per day. As several receivers, programmed independently, are used per each pass, then it implies several tens of separate pass schedules and several hundreds of reports per day. Certainly, such a workload requires automation that is organized in the system of centralized control of the stations network. All stations and the control center are interconnected via Internet in this system. Control process consists of operations represented in table 2. 6

7 The network is controlled by special software that is developed by ScanEx RDC. The software consists of several components, each of which is responsible for certain operations. Table 2 describes the operations and corresponding software components. Table 2. Description of operations and components of the special software for stations network control Operations description Software components Software components location Preparation of all network operations program (schedule). Entering schedules into the database. Automatic delivery of individual schedules to stations (receivers). Automatic reception by stations according to pass schedules. Automatic delivery of reports on execution of tasks (completed passes) to the server of the control center and entering them into the general database with schedules. Automatic analysis of received reports. Entering analysis results into the database and their visualization. Visualization of orbital motion of satellites and ground tracks Automatic collection of data about current status of receiving stations, data delivery to the server of the control center and their visualization. SGS Operation Planner Application for planning the stations network operations SGS Service File Dispatcher System of dispatching service files (schedule files and orbital elements) ScanReceiver Application for receiving station operations control SGS Log Transmitter Application for reception logfiles (reports) delivery SGS Operation Monitor Application for monitoring the stations network operations quality. SGS SatTrack Viewer Internet-service for visualization of orbital motion of satellites and ground tracks. SGS Status Monitor Application for indication of current status of receiving stations. - Control center s server (control via Web-browser from terminal of the operator). - Control center s server Receiving station PC - Receiving station PC - Control center s server - Receiving station PC - Control center s server - Operator s terminal - Operator s terminal - Control center s server - Receiving station PC - Operator s terminal The above components, except for SGS SatTrack Viewer and SGS Operation Monitor applications, form the basic network control loop from preparation of plan to its execution and assessment of reception quality. All software consists of MS Windows and Web-applications and runs on standard Internetprotocols. Control system components are briefly described below and Fig. 3 illustrates their locations and interactions. 7

8 Fig. 3. Flowchart of location and interaction of control system components 8

9 It is important to note that each of the components executes the function that is valuable in itself and therefore can be used outside the network. All server components of the system and the operator s terminal should be located within one LAN. Physically they can be placed even on one PC. Receiving stations can be within the same LAN or interact with the control center via Internet SGS Operation Planner the application for planning the stations network operation The application is intended for creation of a general network operation schedule by the operator. It is a distributed information system, consisting of the following elements: Database with the information about planned and previous reception passes; Special software, ensuring the replenishment of the database with the information from different sources (ballistic calculations, logs, pass schedules, etc.); Server part being a specialized extension of the HTTP server and intended for acting on requests and provision of information to users; Client part acted by the browser. This is the sole system element that is required directly for the user (operator) to work with the application. All these components, except for the client part, are installed in the control center servers with network access from the operators PCs. The application ensures the execution of the following functions: Computation of satellite passes over the stations zone; Display of the ground tracks for the selected pass of the selected satellite; Selecting a station to receive data from the selected pass of the selected satellite; Setting up reception formats; Export of individual schedules (i.e. schedules of operation of particular receivers) Planner application is the sole component in the system intended for interactive operations under the operator s control. The application interacts with the SGS Service File Dispatcher, which ships the schedules to the stations, and with SGS Operation Monitor that later analyzes the execution of these schedules SGS Service File Dispatcher service files dispatching system The system ensures automatic delivery to the receiving stations of files, required for their operation schedules of satellite passes over the ground stations, schedules of data downlink from satellites to the stations, files of orbital elements and loading these files into ScanReceiver station control application. The system is comprised of three modules a server, a client and a terminal. Each module consists of one or several programs. The system includes Web-server, using which the interaction on HTTP protocol is set up with the operator s terminal and receiving stations, and the mail server, intended for sending system operation error messages. A service ensuring the reception of service files from SGS Operations Planner, their archiving and keeping log-files is deployed on the control center server. A Web-server is also deployed over there ensuring files transmission to system clients components located on the PC of the receiving stations, upon requests. The server module executes the following functions: 9

10 Reception of service files (schedules, orbital elements) from the SGS Operation Planner server, their inventory and archiving; Delivery of service files to the receiving stations PCs upon their requests; Keeping delivery error logs. The client module is located on the PC of each receiving channel of each station, consisting of the applications performing the following functions: Generation of requests to get service files; Interaction with ScanReceiver application to load received service files into it. A browser is used as a terminal that can be launched on any PC in the local network of the control center to review the current status of the system a log that indicates times of the service files compilation and delivery to the receiving stations, as well as the delivery results ScanReceiver the application for the receiving station control ScanReceiver application first of all is intended for the autonomous receiving station control and executes all the functions required for that. However, at the same time, it is an important element of the network, as it ensures the operations as per the schedules, received from the control center, and creates reports about this. ScanReceiver application periodically requests the client module of the SGS Service File Dispatcher application, located on the same PC about the reception of new pass schedule and orbital elements files. In case of a positive answer the application loads newly received files and operates with them until the schedule is over or a new one is received. Data reception according to the current schedule, as well as all other operations in the network, is fully automatic and unattended. During each pass ScanReceiver application forms a report file and enters it name into the list of files to be delivered into the control center. The client part of the SGS Log Transmitter application operating on the same PC periodically checks the list and ensures the delivery of the files specified in it to the indicated addresses SGS Log Transmitter the application of reception log-files (reports) delivery SGS Log Transmitter application is intended for collection of log-files (reception reports), generated by ScanReceiver, and their further transfer to the control center. The application can operate either in transmitter mode, or in receiver mode. In the first case it sends files-reports of the receiving station and receives files-confirmations about their successful delivery, in the second case it receives reports and sends the confirmations. In both cases files delivery is executed via one the same protocols (SMTP). For the execution of its functions the application should have one copy operating in transmitter mode on the receiving station s PC (together with ScanReceiver application), and the second copy operating in receiver mode on one of the servers in the control center. The "transmitter", i.e. the SGS Log Transmitter application operating in transmitting mode, periodically scans the file where ScanReceiver application puts the names of files-reports to be transmitted to the center. Having a new record found, the transmitter sends the file indicated in it to the specific address. The "receiver", i.e. the SGS Log Transmitter application operating in reception mode, periodically scans the box, where log-files are sent to, for new messages. After finding such, the application gets them from the server and locates on the control center s server. Symmetrically, the receiver sends and the transmitter receives confirmations about the report 10

11 reception. A special algorithm of repeated delivery attempts in case of no confirmation is in place. Files, delivered by SGS Log Transmitter, later on are picked up and analyzed by SGS Operation Monitor SGS Operation Monitor the application of monitoring stations network operation quality SGS Operation Monitor carries out inventory and assessment of the network operation, including: keeping database of tasks (schedules) and reports about the fulfilment of these tasks by receiving stations, automatic analysis of the quality, visualization of results. The application consists of two modules: server an terminal. Only one copy of the server module is installed on the control center server. The terminal module provides the user s interface for operations with database and the catalog. It can be installed on any PC having access to the control center server via the local area network. The screenshot of the user s interface of the terminal module of SGS Operation Monitor application is shown in Fig. 4. The server module performs the following functions: Analysis of the contents of reports and comparison of them with tasks; Creation of tasks, reports and analysis results database; Creation of this database catalog. Analysis of reports is based upon their comparison with schedules. First of all, the program checks, if each time interval in the schedule has a report. Besides, it is required that the reception quality properties in this time interval (bit error rate and\or signal-to-noise ratio), indicated in the report, should meet certain criteria, individual for each satellite. If the time interval of data downlink from satellite is defined accurately, then the reliability of the conclusion made by SGS Operation Monitor about the execution or non-execution of the task by the receiver is basically 100 percent. However, in many cases the expected downlink time is determined approximately or is not known at all. In such cases the analysis of the reception results uses a combination of several additional empirical criteria, individual for each satellite. For example, it is assumed that if there is a signal at all, then the signal-to-noise ratio cannot be below a certain threshold; that the transmission duration cannot be shorter than a certain time interval; that switching the signal on and off can be only abrupt ad only once per a pass, etc. All these criteria are based on the long-term experience and finally enable to reach a conclusion about the success of the reception pass with the error probability of several percents. In cases when downlink times are not defined and indirect criteria are unreliable, the application checks only for presence of reports. The typical daily schedule of network operations and its view in SGS Operation Monitor, including reports analysis results, is shown in Fig.4 and Appendix 2. If SGS Operation Monitor makes a conclusion about an unsuccessful fulfilment of a task, it does not result in any action automatically, but it is supposed to draw the operator s attention or the attention of a specialist of the technical support service. The user interface of the application enables them to immediately open the respective reports for review and they (specialists) should make the final conclusion. 11

12 Fig. 4. Screenshot of the interface of the terminal module of SGS Operation Planner 3.6. Auxiliary applications SGS SatTrack Viewer Internet-service of visualization of orbital and ground tracks of satellites. SGS SatTrack Viewer operates based on Google Maps and Google Earth services and enables to visualize on the map the network stations, their coverage zones and ground tracks for each pass from the database of the SGS Operation Monitor application. Tracks visualization is performed in color coding, considering the reception results. Therefore, the service enables to see the network and to get the geographic representation of its operation. 12

13 Fig. 5. Screenshot of the SGS SatTrack Viewer application interface SGS Status Monitor the application for indication of current status of the receiving stations All other applications, except SGS Status Monitor, interact with stations and between themselves in terms of tasks and reports. Therefore, stations failures are detected only in reports about non-completed tasks. To shorten the time of failure detection, SGS Status Monitor application interacts with stations on a regular basis: at a specified interval that does not depend on the reception schedule the stations send files to the control center with basic parameters of current status. The files are transferred via TCP/IP protocol using the same lines as the schedule and reports transfers. The application ensures the reception of these files, their analysis and display in form, easy for visualization and anomaly detection. 13

14 Fig. 6. Screenshot of SGS Status Monitor application interface 4. Network operation mode and performance As it was mentioned before, all network stations are programmable, i.e. they can receive data from any satellite within certain limits of restrictions in data downlink rates. Which satellites are currently used to receive data is defined by the effective license agreement. In 2010 it is: TERRA, AQUA, ENVISAT, RADARSAT, SPOT 4, SPOT 5, FORMOSAT-2, LANDSAT-5, EROS A, EROS B. The total number of passes, redundancies included, is about per day. The data volume, acquired per each pass is from 1 to 10Gb. The total volume of data, received per day amounts to GB. As the network stations are connected to Internet via public lines, it is not possible to transmit such a volume of data through these lines of course. A great part of the received information is shipped on a regular basis to the central archive on hard disks. However, certain scenes, related to priority tasks, can be transferred via Internet. Usually, to transfer the results of one imaging session it takes from 30 minutes to two-three hours, depending on the volume of the scene and the communication line quality. Data processing tools are installed at receiving stations, if possible. This enables to do processing on-site from a remote terminal at the control center, to assess its results and thus minimize the volume of information to be transferred. 14

15 To give a better visual presentation of the network performance, Appendix 2 has a full schedule of the station operation for one typical day. APPENDIX 1. UniScan receiving station UniScan station is described here on the quality, functional level to give a general notion about it as a network unit. Detailed specs and description is provided in a separate document, available upon request. As any receiving station UniScan consists of two principal components the antenna system and the receiver (one or several). The antenna system of the UniScan stations is equipped with two- or three-axis rotators with 2.4 and 3.1 m reflectors in diameter. The 3.1-meter reflector can be installed only on a three-axis rotator. The rotators of both types ensure satellite tracking in any point of the upper hemi-sphere without zenith heyhole. Two-axis systems can have limitations while tracking the targets near the horizon (at elevations below 5 degrees). Control system ensures antenna motion along the pre-calculated trajectory and can automatically correct this trajectory by deviations at small angles and analysis of corresponding changes in input signal level (step tracking). This tracking mode is referred to as 'autotracking' hereinafter. The antenna is equipped with a low-noise amplifier and the signal frequency converter from 8200 ± 200 MHz downlink carrier to 1200 ± 200 MHz to feed receivers. Control cables and HFcables from antenna to the receiver can be up to 50 m in length. This is the maximum distance between the antenna and the control room where the antenna control system, receiver and operator s workstation are located. A UniScan station receiver is a single expansion board in the PC on the PCI bus. Only one receiver board can be installed in one PC. The input signal of the receiver is the telemetry signal on the intermediate frequency 1200 ± 300 MHz. The receiver demodulates the signal and transforms it into a digital sequence that is ingested via the PCI bus into the PC memory and recorded to the hard disk. The receiver can be programmed to receive signals at any carrier frequency within the indicated limits, and at any data rate up to a specific limit (170 or 320 Мbps depending on the device model), and at any modulation type used nowadays in the telemetry transmissions from EO satellites. Receiver control is managed via the same PCI bus. During the reception, besides demodulation, the receiver measures basic characteristics of the signal (carrier and clock frequency, level and signal-to-noise ratio). It also can execute a specific processing of the demodulated digital dataflow differentiated decoding, Viterbi decoding, frame synchronization. Station software enables to carry out reception in fully automatic and unattended mode. The source data for that are as follows: - pass schedule file, i.e. the list of time intervals for reception indicating the satellite s name and downlink format for each interval; - orbital elements files for all satellite indicated in the pass schedule. The following algorithm is implemented in the control program: - prior to the start of a pass, indicated in the schedule, the program calculates the satellite trajectory and sets up the parameters of the receiver according to the format specified in the schedule, 15

16 - from the moment of the pass start the program tracks the satellite, and analyzes the receiver status and of the demodulated data flow, - as soon as the receiver acquires the signal, the program switches the antenna system into the auto-tracking mode; when the signal is lost, auto-tracking is switched off, i.e. the satellite software tracking is still ongoing with due account for last introduced corrections, - as soon as the program detects iframe sync markers in the demodulated flow, it starts recording data to the disk and stops it if markers are missing for a certain period of time, - during the reception the program create several log-files (reports), where all current parameters of the antenna, receiver and data flow status are periodically recorded (including signal-to-noise ratio and bit error rate), - when the pass time, indicated in the schedule, is over, the program closes all data and reports files and waits for the start of the next pass. Nowadays all the ScanEx network stations are the UniScan ground stations with 2.4 m antennas. APPENDIX 2. Example of the network operation schedule per one day and its performance assessment Below is the complete schedule of the ScanEx ground stations network operation within one typical day ( ). The quality assessment table represents the summary of automatic assessment of the reception results made by SGS Operation Monitor. Quality assessment parameter can take on the following values: Not ready reception has been completed by the time of review, but the analysis is not ready yet. No info the time of the task completion is over, but not all log-files are received; Info lost same as in No info, but the allowed timeout is over. Over all log-files are received, but for this pass the time of downlink is not defined and no additional criteria are defined enabling to make a conclusion about the results. Ok the reception is successful. Error - the reception is not successful. The table below indicates the statistics of distribution of reception passes through the stations and results. Date Time Satellite Orbit Station Quality assessment :04:44-00:16:30 LANDSAT_ MGD1 Over :05:55-00:18:32 SPOT_ MGD2 Over :11:54-00:23:47 AQUA MARC3 Ok :11:54-00:23:47 AQUA MARC1 Ok :57:26-01:10:52 SPOT_ MGD2 Ok :57:26-01:10:52 SPOT_ MGD1 Ok :20:32-01:32:35 TERRA MGD1 Ok :34:30-01:43:00 AQUA MGD2 Ok :42:37-01:54:11 LANDSAT_ MGD1 Over :46:10-01:59:26 SPOT_ MGD2 Ok :47:50-01:55:18 LANDSAT_ IRK2 Over :47:50-01:55:18 LANDSAT_ IRK1 Over :50:26-01:58:59 AQUA MARC3 Ok :50:26-01:58:59 AQUA MARC1 Ok :52:21-01:58:51 SPOT_ IRK3 Ok :37:54-02:49:56 SPOT_ MGD2 Ok :37:54-02:49:56 SPOT_ MGD1 Ok :42:08-02:54:13 SPOT_ IRK3 Over :42:08-02:54:13 SPOT_ IRK2 Over :47:19-02:58:43 RADARSAT MARC3 Over :47:19-02:58:43 RADARSAT MARC2 Over :47:19-02:58:43 RADARSAT MARC1 Over :58:37-03:08:57 TERRA MGD2 Ok :58:37-03:08:57 TERRA MGD1 Ok :12:04-03:23:52 AQUA MGD2 Ok :20:50-03:29:22 LANDSAT_ MGD1 Over 16

17 :24:08-03:31:28 LANDSAT_ MEG Over :24:16-03:36:16 LANDSAT_ IRK2 Over :24:16-03:36:16 LANDSAT_ IRK1 Over :26:40-03:37:41 SPOT_ MGD2 Over :30:36-03:43:42 SPOT_ IRK3 Ok :46:36-03:56:48 ENVISAT MEG Over :18:19-04:26:54 SPOT_ MGD2 Ok :18:19-04:26:54 SPOT_ MGD1 Ok :21:15-04:32:56 SPOT_ MEG Ok :22:09-04:35:21 SPOT_ IRK3 Ok :22:09-04:35:21 SPOT_ IRK2 Ok :26:35-04:39:33 RADARSAT MARC2 Over :36:55-04:43:07 TERRA MGD2 Ok :36:55-04:43:07 TERRA MGD1 Ok :40:08-04:51:53 TERRA IRK1 Ok :50:33-05:01:34 AQUA IRK3 Error :53:08-05:00:44 AQUA MGD2 Ok :53:08-05:00:44 AQUA MGD1 Ok :01:01-05:12:43 LANDSAT_ MEG Over :02:28-05:12:49 LANDSAT_ IRK2 Over :02:28-05:12:49 LANDSAT_ IRK1 Over :06:53-05:14:14 SPOT_ MGD2 Over :06:53-05:14:14 SPOT_ MGD1 Over :11:00-05:23:27 SPOT_ IRK3 Ok :25:40-05:38:35 ENVISAT MEG Over :01:22-06:14:48 SPOT_ MEG Ok :03:12-06:12:40 SPOT_ IRK3 Over :03:12-06:12:40 SPOT_ IRK2 Over :06:35-06:13:50 SPOT_ MARC2 Over :06:43-06:16:51 RADARSAT MARC3 Over :16:49-06:28:53 TERRA MEG Error :18:59-06:26:31 TERRA IRK3 Ok :18:59-06:26:31 TERRA IRK1 Ok :27:50-06:39:33 AQUA IRK3 Ok :27:50-06:39:33 AQUA IRK1 Ok :38:53-06:50:35 LANDSAT_ MEG Over :42:44-06:52:37 LANDSAT_ MARC3 Over :42:44-06:52:37 LANDSAT_ MARC1 Over :52:30-06:59:24 SPOT_ IRK3 Ok :52:30-06:59:24 SPOT_ IRK2 Ok :54:18-07:04:48 SPOT_ MARC3 Ok :54:18-07:04:48 SPOT_ MARC2 Ok :54:18-07:04:48 SPOT_ MARC1 Ok :05:15-07:17:24 ENVISAT MEG Over :08:48-07:20:53 ENVISAT MARC2 Over :38:45-07:47:59 EROS-B IRK3 Ok :38:45-07:47:59 EROS-B IRK2 Ok :38:45-07:47:59 EROS-B IRK1 Ok :41:47-07:53:56 SPOT_ MEG Over :45:14-07:58:20 SPOT_ MARC2 Ok :54:50-08:05:31 TERRA MEG Error :58:05-08:09:45 TERRA MARC3 Ok :58:05-08:09:45 TERRA MARC1 Ok :11:47-08:20:07 AQUA MARC3 Ok :16:58-08:26:09 LANDSAT_ MEG Over :20:01-08:32:03 LANDSAT_ MARC2 Over :20:01-08:32:03 LANDSAT_ MARC1 Over :30:31-08:41:47 SPOT_ MEG Ok :33:53-08:47:19 SPOT_ MARC3 Ok :33:53-08:47:19 SPOT_ MARC2 Ok :33:53-08:47:19 SPOT_ MARC1 Ok :44:48-08:54:09 ENVISAT MEG Over :48:08-09:00:46 ENVISAT MARC2 Over :22:02-09:31:14 SPOT_ MEG Over :22:17-09:31:51 TERRA MGD2 Ok :22:17-09:31:51 TERRA MGD1 Ok :25:37-09:38:14 SPOT_ MARC2 Ok :32:52-09:40:12 TERRA MEG Error :35:59-09:46:00 TERRA MARC3 Ok :35:59-09:47:17 TERRA MARC1 Ok :46:52-09:58:41 AQUA MARC3 Ok :54:48-10:00:17 LANDSAT_ MEG Over :58:22-10:07:54 LANDSAT_ MARC2 Over :58:22-10:07:54 LANDSAT_ MARC1 Over 17

18 :10:30-10:18:46 SPOT_ MEG Over :14:31-10:26:03 SPOT_ MARC3 Over :14:31-10:26:03 SPOT_ MARC2 Over :14:31-10:26:03 SPOT_ MARC1 Over :23:36-10:30:11 ENVISAT MEG Over :28:17-10:37:17 ENVISAT MARC2 Over :58:05-11:10:00 TERRA MGD2 Ok :58:05-11:10:00 TERRA MGD1 Ok :01:09-11:08:21 SPOT_ MEG Over :06:42-11:14:50 SPOT_ MARC2 Over :14:54-11:21:21 TERRA MARC3 Ok :14:54-11:21:21 TERRA MARC1 Ok :25:24-11:36:16 AQUA MARC3 Ok :25:24-11:36:16 AQUA MARC1 Ok :22:39-12:31:38 EROS-B MARC3 Ok :22:39-12:31:38 EROS-B MARC2 Ok :22:39-12:31:38 EROS-B MARC1 Ok :35:09-12:45:01 RADARSAT MARC2 Over :36:34-12:47:44 TERRA MGD2 Ok :36:34-12:47:44 TERRA MGD1 Ok :39:18-12:46:52 TERRA IRK3 Ok :39:18-12:46:52 TERRA IRK1 Ok :12:17-14:25:12 RADARSAT MARC2 Over :13:57-14:25:43 TERRA IRK3 Ok :13:57-14:25:43 TERRA IRK1 Ok :01:42-15:12:33 AQUA MGD2 Ok :01:42-15:12:33 AQUA MGD1 Ok :52:27-16:03:16 TERRA IRK3 Ok :52:27-16:03:16 TERRA IRK1 Ok :52:53-16:04:32 RADARSAT MARC2 Over :39:22-16:51:21 AQUA MGD2 Ok :39:22-16:51:21 AQUA MGD1 Ok :55:11-17:05:50 ENVISAT MARC2 Over :34:31-17:44:26 TERRA MARC3 Ok :34:31-17:44:26 TERRA MARC1 Ok :17:29-18:27:25 AQUA MGD2 Ok :17:29-18:27:25 AQUA MGD1 Ok :21:16-18:32:33 AQUA IRK3 Ok :21:16-18:32:33 AQUA IRK1 Ok :32:47-18:45:44 ENVISAT MARC3 Over :32:47-18:45:44 ENVISAT MARC2 Over :32:47-18:45:44 ENVISAT MARC1 Over :10:39-19:22:42 TERRA MARC3 Ok :10:39-19:22:42 TERRA MARC1 Ok :55:48-20:01:20 AQUA MGD2 Error :55:48-20:01:20 AQUA MGD1 Ok :59:00-20:10:31 AQUA IRK3 Ok :59:00-20:10:31 AQUA IRK1 Ok :14:00-20:24:39 ENVISAT MARC2 Over :50:30-20:59:48 TERRA MARC3 Ok :50:30-20:59:48 TERRA MARC1 Ok :35:38-21:47:41 AQUA MEG Ok :38:06-21:44:35 AQUA IRK3 Ok :38:06-21:44:35 AQUA IRK2 Ok :38:06-21:44:35 AQUA IRK1 Ok :40:33-21:47:18 AQUA MARC3 Ok :40:33-21:47:18 AQUA MARC1 Ok :48:58-22:55:32 TERRA MGD2 Ok :48:58-22:55:32 TERRA MGD1 Ok :58:19-23:08:43 SPOT_ MGD2 Over :58:19-23:08:43 SPOT_ MGD1 Over :10:01-23:20:08 LANDSAT_ MGD2 Over :10:01-23:20:08 LANDSAT_ MGD1 Over :16:51-23:28:44 AQUA MARC3 Ok :16:51-23:28:44 AQUA MARC1 Ok :46:45-23:58:46 SPOT_ MGD2 Over :46:45-23:58:46 SPOT_ MGD1 Over Statistics of the reception results distribution through the stations (for the above schedule from ) 18

19 Station Received Over Ok No info Error Info lost ALL (всего) MGD MGD IRK IRK IRK MEG MARC MARC MARC