Designing for TARA

Abstract

The TARA scans through a column of atmosphere in order to observe and study cloud system behavior. After 10 years of operation new knowledge of processing has been acquired which allows for an update that will improve measurement quality and processing speed. The main question of this thesis is: How to implement data processing, visualization and storage for TARA? The system, from the radar control to the visualization and storage, needs to be built from scratch. In order to most effectively achieve this, the entire system has been split up into two parts that will be designed separately. To be able to combine the parts, the groups will work together to build an overarching structure in which the separate blocks can be easily implemented (chapter 2). In chapter 3 the program of requirements is given, in which all the requirements for the system are mentioned. Different topics have been researched, in order to be able to do this project, this can be read in chapter 4. Over the years a variety of radar types have been developed, each having its own advantages and disadvantages. Four of the different properties are important in TARA. That are: monostatic vs. bistatic, FM-CW radar vs. pulsed radar, Doppler radar and polarimetric radar. Frequency modulation is used to be able to determine the range of the measured objects. By comparing the received frequency with the current transmitted frequency the time that was needed for the signal to travel can be determined, also the Doppler speed of the particles can be calculated. For the implementation of this project we will work with LabVIEW and Matlab. An overall block diagram has been made, after which the more detailed block diagrams and state diagrams of the three blocks that group 2 has to design, could be made. The overall block diagram shows the signals that every block in the systems sends out or receives (chapter 5). The final block diagrams are shown in Appendix A and the state diagrams in Appendix B. The state diagrams are used to describe how the sub-systems accomplish their tasks. Incoming data is processed by Matlab code which is provided. This is one of the main reasons for the choice of LabVIEW, because Matlab code can be implemented in the program via Matlab nodes. Variables that should not be changed during measurement and should be used by multiple different systems are put into global functional variables. Variables that can be changed are sent via notifiers. After everything was designed and some choices for implementation were made, the implementation could begin (chapter 6). First an overarching system was made, but during the development it became apparent that the actions of this system could be interpreted as those of the Radar Control block, a block that was originally designed by group 1. After the choices were made on how the Radar Control operates, the design process of the GUI started and the data processing and visualization block were implemented. Implementation of the storage block has however not been realized, because of time constraints and task re-allocation between the two sub-groups. Finally the system has been implemented in the actual TARA.First real-time measurements have been succesfully performed. An evaluation about what has been achieved compared to the requirements discussed in chapter 3, can be read in chapter 7. As already stated before, the storage has not been implemented, so requirements considering storage have not been met. Besides that, most requirements are met, although improvements can still be made. In chapter 8 a discussion is given about the points on which the project could be improved. In chapter 9 the conclusion is drawn that most of the requirements are met and recommendations are given on how to improve the system further.