Running an Ionospheric Ray Tracing Program on the PDP-11/40 Mini-Computer - Instruction Book.
Abstract
Locating the source of transmission is one of the tasks of military intelligence, In VHF frequencies and above, the technique is straight forward. In HF (2-30 MHz), the situation is different since the main mode of propagation is by reflection from the ionosphere. This enables the use of a different technique where the azimuth and elevation of the incoming wave are measured together with the state of the ionosphere at the time of reception. All this information is presented as an input to an ionospheric ray tracing program that calculates the ray's trajectory from the reception site to the transmitting point. The actual system needed is quite complicated and elaborate. Apart from the equipment to measure the direction of the arrival of the incoming wave, there is a requirement to measure in real-time the structure of the ionosphere at the area of interest. It is required, therefore, to measure the electron density profile and the tilts of the ionospheric layers. This can be accomplished by using a Digisonde together with a special 'Drift Attachment' equipment that can measure ionospheric tilts by Doppler techniques. This report is essentially an instruction book that shows how to run the ray tracing program on the PDP-11/40. The first part describes generally how to write into the machine, edit, debug, and run a FORTRAN program. The second part depicts the oepration of the ray tracing program itself.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1979
- Accession Number
- ADA068367
Entities
People
- Abraham Shuval
- Francis J. Gorman