Abstract

1. RADIO TELESCOPE . Space Systems and Control Laboratory (Ongo-02c) Abstract Design Approach and Considerations New funding and research has increased the popularity of radio astronomy among scientists around the world. Although radio telescopes are quite useful for fundamental research on the nature of the universe, Iowa State University does not have a working facility. For the past several years, the Iowa Space Grant Consortium has been sponsoring the development of a radio telescope system. The 8.5-meter parabolic dish antenna is located at the Fick Observatory near Boone, IA. The project consists of transforming the dish into a functional radio telescope which will be used by Astronomy/Physics students and faculty. Testing Specifications • Individual electrical circuitry testing • Software motor control systems tests on-site using actual dish systems • Cable loss test to measure the loss from the dish to receiver • Intensity test with integrated hardware to measure intensity of a source • Accuracy tests of the entire radio telescope Planning • Problem Statement • ISU’s lack of a working radio telescope limits the research that can be conducted by faculty, staff, and students of the Department of Physics and Astronomy. • Approach • The proposed solution is to develop a functional radio telescope that can be used for research and educational purposes. To do this, electrical, mechanical, and software systems must be developed. • System Status at Start of Semester • Motor controller and receiver unable to be activated by the computer • Software did not allow tracking of a moving source over time • No efficient raster scan implementation • Remote operation of telescope not feasible due to hardware issues with interface box • System Block Diagram Green = Task Complete Yellow = Task In Progress Red = Task Abandoned Deliverables • Interface box that has functioning motor control circuitry, coaxial switch relay circuitry, and receiver relay circuitry • Tracking software that will track a celestial source over time • Raster scan software that efficiently performs a raster scan of a segment of sky • Technical documentation of design considerations and decisions for future teams • Documentation and instructions for operators of the radio telescope Implementation Project Requirements • Functional Requirements • System receives and captures the intensity of incoming radio signals at 1420 MHz • Software provides useful user interface that allows dish to be controlled and positioned • Self-protection strategies protect the dish and its operators from control system failure • Non-functional Requirements • The user interface shall be easy for non-team members to use • The software and hardware shall be fully documented • Design Constraints • Design must accommodate existing parts whenever possible • Hardware must be protected from the elements as well as operator error • Design must utilize high-quality, permanent parts A spectrum analyzer was used to test the remote toggle function of the noise source and system continuity. This testing showed the noise source increased the signal strength by 10 dB. The cannon plug connector on the front end of the dish had become damaged from use and needed to be replaced. The new cable will prevent wires from shorting together. Basic Operation of the Radio Telescope • Astronomer enters the celestial coordinates of the source to be studied • Tracking software positions the dish to track the source • Limit circuitry prevents over-rotation and damage to the system • Telescope receives radio signals • Data acquisition software processes and records signals Software capable of tracking a celestial object over time was implemented in LabVIEW. The software updates the position of the telescope periodically, in order to track an object as it moves across the sky. This schematic will be used to generate a PCB layout to replace the limit switch relay board. The limit switch relay board acts as hardware protecting against damage to the motors and also handles positioning data. Conclusion The radio telescope at Fick Observatory is not fully operational at this time. The motor control circuitry works, the telescope can be positioned remotely, and the receiver can receive the incoming radio signals, but the accuracy is not yet within specifications. Work this semester focused on debugging the interface box, testing and replacing cabling at the observatory, writing the tracking and raster scan software, investigating aC++ API, and laying out a new limit switch PCB, as well as creating schematics for the various circuitry used in the system and furthering documentation of the project. In the future, numerous tests must be performed to determine the accuracy of the telescope. After these objectives are completed, the radio telescope will be able to track celestial objects and provide useful data to radio astronomers. Coaxial cable (carries radio signal) SystemDiagram Acknowledgement The team members thank the Iowa Space Grant Consortium at Iowa State University for its support and generous donations. They also thank their advisor, Dr. John P. Basart, who has contributed to the project with his vast knowledge of dish systems and radio astronomy. First Semester Members Ali Abdelsalam (EE) Greg Bonett (EE) Osman Abdelsalam (EE) Laura Janvrin (EE) Faculty Advisor Dr. John P. Basart Client Dr. John P. Basart Second Semester Members Niclo Hitchcock (EE) Nick Jensen (CprE) Sulianet Ortiz (EE) Fall 2007