Abstract:
Provided is a method for processing dump data packets in a low earth orbital (LEO) satellite. The method includes the steps of: a) extracting table identification (ID) information from a header of high-resolution camera (HRC) dump data transmitted from the LEO satellite; b) searching a HRC dump table from a HRC dump table list based on the extracted table ID information; c) extracting sequence information from the transmitted HRC dump data; d) completing and storing an complete table based on the sequence information searched in the HRC dump table and the extracted sequence information; and e) reading and displaying the HRC dump table upon request of an operator.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a method for processing dump data packets in a low earth orbital (LEO) satellite; and, more particularly, to a dump data packet processing method that can fast and exactly process high-resolution camera (HRC) dump data based on a table identification (ID) field for classifying a HRC dump table and a counter field indicating an order of packets in the LEO satellite.  
       DESCRIPTION OF RELATED ART  
       [0002]     In general, a low earth orbital (LEO) satellite circles round the earth in an orbit at an altitude of hundreds to thousands km and it includes an observation satellite such as an earth exploration satellite and a meteorological satellite, and a mobile communication satellite.  
         [0003]      FIG. 1  shows a general LEO satellite ground control system.  
         [0004]     The general LEO satellite ground control system includes a LEO satellite  101 , a telemetry, tracking and command (TTC) subsystem  104 , and an image receiving and processing system (IRPE)  106 .  
         [0005]     The LEO satellite  101  reads dump data of a high-resolution camera (HRC) from a memory according to a telecommand transmitted from the TTC subsystem  104 . The dump data are included in a data region allocated to a telemetry packet and transmitted to the TTC subsystem  104 . Actual image data are transmitted to the IRPE  106 .  
         [0006]     The TTC subsystem  104  transmits the telecommand to the LEO satellite  101  under the control of an operator. As a result, the TTC subsystem  104  receives a telemetry packet including the HRC dump data from the LEO satellite  101  and transmits it to a telemetry processing system  200 .  
         [0007]     Referring to  FIG. 2 , the telemetry processing system  200  includes a TM receiving unit  201 , a TM storing unit  202 , a TM displaying unit  203 , and a TM DB managing unit  204 .  
         [0008]     The TM receiving unit  201  processes the telemetry packets transmitted from the LEO satellite  101  based on the type of a telemetry packet and stores all telemetry packets in the TM storing unit  202 .  
         [0009]     The TM DB managing unit  204  stores and manages data required for extracting the HRC dump data.  
         [0010]     The TM displaying unit  203  reads data required for extracting the HRC dump data in the TM DB managing unit  204  upon the request of the operator, extracts the HRC dump data, composes and displays the dump data in the form of a HRC dump table which the operator can see. Herein, the HRC dump data are transmitted after divided into a plurality of telemetry frames based on the size. The TM displaying unit  203  extracts the HRC dump data from each telemetry frame, composes the HRC dump data as one completed table and displays the table in a terminal of the operator.  
         [0011]     Referring to  FIG. 3 , structures of a conventional HRC dump data packet and a HRC dump table will be described in detail.  
         [0012]     A HRC dump data  300  is inserted into a 64-byte region allocated to the telemetry frame and includes a packet identification (ID) field  301 , a start address field  302  and a data field  303 .  
         [0013]     The packet ID field  301  indicates the type of a telemetry packet and shows whether a telemetry frame is a normal packet having the HRC telemetry data or the HRC dump data packet having the HRC dump data.  
         [0014]     The start address field  302  indicates a start address of the HRC dump table.  
         [0015]     The data field  303  has the actual HRC dump data and it is the region excluding a header of the HRC dump data packet.  
         [0016]     When the size of the HRC dump data exceeds the allocated region, the HRC dump data are continuously transmitted in a next packet and the start address is re-established from the initial address of the previously packet to an address of a region obtained by adding the size of the pre-allocated data region to the initial address of the previous packet. Herein, when the size of the dump data is smaller than the size of the allocated region, ‘Null’ is inserted into the remaining data region.  
         [0017]     Meanwhile, a HRC dump table list  310  for processing the HRC dump data includes a table name field  311 , a start address field  312  and a size field  313 .  
         [0018]     The table name field  311  indicates a type of the HRC dump data table, i.e., a name. The start address field  312  indicates a start address of the table, and the size field  313  indicates a complete table size.  
         [0019]     The telemetry processing system  200  of the ground control system extracts a packet ID from a telemetry frame based on the HRC dump table list  310 . When it turns out that the extracted packet ID is the HRC dump data, the HRC dump data, which are transmitted after being divided into a plurality of data based on the start address included in the header, are composed as one HRC dump table and provided to the operator.  
         [0020]     When the HRC dump data are transmitted after divided into a plurality of telemetry frames, the HRC dump table is processed only based on the start address included in the header of the HRC dump data packet.  
         [0021]     Since the conventional HRC dump table list  310  has only information on the name, the start address and the entire size of the HRC dump table, it is not easy to identify in which HRC dump table the transmitted telemetry frame is included. When the HRC dump data are transmitted in the form of a plurality of packets, it is difficult to grasp where the packet comes in the order of the packets and it takes a long time to search the HRC dump table list and figure out the sequence of packets.  
         [0022]     Accordingly, a method for quickly and exactly processing HRC dump data packets is required.  
       SUMMARY OF THE INVENTION  
       [0023]     It is, therefore, an object of the present invention to provide a method for processing dump data packets in a low earth orbital (LEO) satellite to fast and exactly process high-resolution camera (HRC) dump data based on a table identification (ID) field for classifying a HRC dump table and a counter field indicating an order of packets.  
         [0024]     Other objects and advantages of the invention will be understood by the following description and become more apparent from the embodiments in accordance with the present invention, which are set forth hereinafter. It will be also apparent that objects and advantages of the invention can be embodied easily by the means defined in claims and combinations thereof.  
         [0025]     In accordance with an aspect of the present invention, there is provided a method for processing a dump data packet of a LEO satellite, the method including the steps of: a) extracting table identification (ID) information from a header of high-resolution camera (HRC) dump data transmitted from the LEO satellite; b) searching a HRC dump table from a HRC dump table list based on the extracted table ID information; c) extracting sequence information from the transmitted HRC dump data; d) completely composing and storing a complete table based on the sequence information searched in the HRC dump table and the extracted sequence information; and e) reading and displaying the HRC dump table upon request of an operator.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]     The above and other objects and features of the present invention will become apparent from the following description of the preferred embodiments given in conjunction with the accompanying drawings, in which:  
         [0027]      FIG. 1  is a diagram showing a general low earth orbital (LEO) satellite ground control system;  
         [0028]      FIG. 2  is a block diagram showing a conventional telemetry processing system;  
         [0029]      FIG. 3  is a diagram showing a conventional high-resolution camera (HRC) dump data packet and HRC dump table;  
         [0030]      FIG. 4  is a diagram showing a high-resolution camera (HRC) dump data packet and a HRC dump table list in accordance with an embodiment of the present invention; and  
         [0031]      FIG. 5  is a flowchart describing a method for processing a dump data packet of a LEO satellite in accordance with an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0032]     Other objects and advantages of the present invention will become apparent from the following description of the embodiments with reference to the accompanying drawings. Therefore, those skilled in the art that the present invention is included can embody the technological concept and scope of the invention easily. In addition, if it is considered that detailed description on a related art may obscure the points of the present invention, the detailed description will not be provided herein. The preferred embodiments of the present invention will be described in detail hereinafter with reference to the attached drawings.  
         [0033]      FIG. 4  is a diagram showing a high-resolution camera (HRC) dump data packet and a HRC dump table list in accordance with an embodiment of the present invention.  
         [0034]     A HRC dump data packet  400  used in the present invention includes a packet identification (ID) field  401 , a table ID field  402 , a counter field  403  and a data field  404 .  
         [0035]     The packet ID field  401  indicates a type of a telemetry packet and shows whether a telemetry frame is a normal packet having HRC telemetry data or a HRC dump data packet having the HRC dump data.  
         [0036]     The table ID field  402  indicates only table ID information which can identify a HRC dump table.  
         [0037]     When the HRC dump data are transmitted after being divided into a plurality of packets, the counter field  403  includes a serial number indicating an order of the packets.  
         [0038]     The data field  404  has actual HRC dump data and it is a remaining region excluding the header of the HRC dump data packet.  
         [0039]     The HRC dump table list  410  used in the present invention includes a table ID field  411 , a table name field  412 , a start address field  413 , a size field  414 , and a total count field  415 .  
         [0040]     The table ID field  411  indicates only the table ID which can identify the HRC dump table. The table name field  412  indicates a name of the HRC dump table. The start address field  413  indicates a table start address. The size field  414  indicates a complete table size. The total count field  415  indicates the number of total packets when the HRC dump data are transmitted after being divided into a plurality of packets.  
         [0041]     An entire operation process of the present invention will be described hereinafter referring to  FIG. 5 .  
         [0042]      FIG. 5  is a flowchart describing a method for processing a dump data packet of the LEO satellite in accordance with an embodiment of the present invention.  
         [0043]     When a ground control system receives a telemetry packet from the LEO satellite at step S 501 , the ground control system stores the telemetry packet in a storage based on a date at step S 502 . The ground control system checks a packet ID field of the telemetry packet at step S 503  and extracts a table ID field value from the HRC dump data packet at step S 505  in case that the packet ID is the HRC dump data at step S 504 .  
         [0044]     The ground control system reads a size of the HRC dump table and total counters from the HRC dump table list based on the extracted table ID at step S 506 .  
         [0045]     The ground control system checks the counter field extracted from the header of the HRC dump data and stores the counter field in a corresponding location at step S 507 . The ground control system compares the counter field included in the header of the HRC dump data with the total counters of the HRC dump table acquired in the step S 506 , and checks at step S 508  whether all HRC dump data packets corresponding to the table ID are normally transmitted.  
         [0046]     When it turns out that all HRC dump data packets corresponding to the table ID are not normally transmitted, the logic flow goes to the step S 501  and a reception process of a next packet is performed. When all HRC dump data packets corresponding to the table ID are normally transmitted, the entire table is completely composed and stored at step S 509 .  
         [0047]     When an operator requests the output of the HRC dump table, the ground control system reads and displays the HRC dump table at step S 510 .  
         [0048]     When it turns out in the step S 503  that the packet ID is not the HRC dump data, a telemetry display page is composed at step S 511  and displayed upon request of the operator at step S 512 .  
         [0049]     As described in the above, the present invention transmits the LEO satellite HRC dump data as an optimized format and quickly and exactly processes the transmitted HRC dump data in the ground control system to provide the HRC dump data the operator.  
         [0050]     That is, the HRC dump data includes diverse types of tables. The present invention gives ID for recognizing the HRC dump table to every HRC dump table and inserts the HRC dump table ID into the header of the HRC dump data transmitted from the satellite.  
         [0051]     Accordingly, the telemetry processing system of the ground control system can recognize in which table the packet is included based on the table ID included in the header of the HRC dump data.  
         [0052]     Also, when the HRC dump data are transmitted after being divided into a plurality of packets, the present invention inserts the serial number of the packet into the counter field of the packet header.  
         [0053]     Subsequently, the telemetry processing system of the ground control system checks whether the packets are transmitted in an order and the all packets are normally transmitted by using the field indicating the packet order in the inside of the table, i.e., the counter field included in the header of the HRC dump data. Therefore, the HRC dump table includes total counter fields showing how many packets the HRC dump data are divided into.  
         [0054]     As described above, the present invention can instantly recognize in which table the HRC dump data packet is included by using the table ID field and the counter field included in the header of the HRC dump data packet. Also, the present invention can instantly check whether the total packets included in the table are successfully transmitted.  
         [0055]     The present invention searches the HRC dump table by using the table ID field and the counter field included in the header of the HRC dump data packet, and can quickly and exactly process HRC (HRC) dump data of the LEO satellite transmitted after being divided into a plurality of packets by grasping the order of the HRC dump table.  
         [0056]     The technology of the present invention can be realized as a program and stored in a computer-readable recording medium, such as CD-ROM, RAM, ROM, a floppy disk, a hard disk and a magneto-optical disk. Since the process can be easily implemented by those skilled in the art of the present invention, further description will not be provided herein.  
         [0057]     The present application contains subject matter related to Korean patent application No. 2005-0102508, filed with the Korean Intellectual Property Office on Oct. 28, 2005, the entire contents of which are incorporated herein by reference.  
         [0058]     While the present invention has been described with respect to certain preferred embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims.