4.2.2 Ground Segment Data Management Architecture

    The ground segment is just as important as the other  component of whole MMVS project. In the ground segment, data management system  must be designed is such a way it is able to handle large amount of data  received through the communication system, and that the data delivered to and  from the ground segment must be processed and utilized efficiently, that is,  data management system must handle large volume of data, and must distribute  these data at high rates for all use with high level of security.

    The basis of the hardware will consist of an efficient network of workstations  operating in conjunction with all components of ground segment system. For emergency purposes, the main data management system will be backed-up  by a secondary system that is also running simultaneously with the main system.

Below is a list of sequence of specific functions the data management system  must perform to manage the data efficiently with a high level of security.

Encoder/Decoder  - Used to minimize the error or inaccuracy in data being transferred due to  noise and interruption in the background. The data are encoded or decoded at the  ground control, ISS and MMVS.

Quality  Monitoring - Used to monitor the quality of data link between MMVS and ground  control or ISS, and to make sure the link is properly working during data  transfer.

Encryption/Decryption  software program  - Used to ascertain that the data transmitted to and from ground control  unit has not been tampered with. The encryption software is activated upon data  transmission so that in the event the data is intercepted the data is opened in  a form of encrypted file. However, upon arrival of the data to appropriate  destination, decryption software may or may not be activated depending on the  security level required for that particular data information. Without proper  copy of decryption software, the data received is useless since the encrypted  file recognizes only proper decryption software.

De-multiplexing  - Allows to distribute the received data to several users.

Time  Tagging - Data is time tagged on the MMVS, ground control unit and ISS. With each data information, there exists an additional piece of timing  data used to estimate the real time that received data was produced.

Data  Storage - Allows the received data to be kept in storage or memory system in case some or  all of the information being received or sent are to be kept for record. The  data storage system is enabled simultaneously with the data receiver to ensure  all information is recorded. In addition, data storage function will enable to  review or assess received data.

Data  Compression -Used  to increase the capacity of a data stream. This will allow the transfer of data  through a narrower band communications channel.  In addition, one allows to transmit more information over a  given bandwidth medium when data is compressed.

Ground  Control Data Management Architecture Diagram