You are here: ASAP > Discussion > ILS-OAS 3




Yes, looking for the mathematical algorithms is indeed what I am looking for. Would be nice to have the document, I guess one can reverse engineer the surface equations given that you have the constants but that can induce error. Will check with NLS on the mentioned document maybe I have some luck p.s. nothing against buying PHX seems a nice piece of software.

Antonio Locandro - COCESNA - GIS Specialist - Honduras


The 'green pages' OAS constants were derived from an NLR document entitled 'MEMORANDUM IN-81-007 U DESCRIPTION OF PROGRAM BOOKLET FOR THE CALCULATION OF ICAO-OAS DATA" It was dated 1981, and contained a Fortran implementation of the program [BOOKLET], which created the tables. It is quite simple, although the original was severely limited by computer memory and the programming style had some subtle tricks. I am happy to discuss the contents and the mathematics if you want to drop me a line at email: rayrr4-ali at

Ray Romano - Australia


Answer or Commentary:


I think that this information should be open source which would ensure standardisation of the OAS calculation routines used and avoid a situation where versions of the OAS constants are developed locally for internal use.


Do you want comment this article or ask something?
Fill the submission form »

« back to Discussion page