"Makes me wonder: what system was in place in the time of the Apollo missions for determining the exact location of a reentering spacecraft?"
The system was called the Apollo Unified S-Band System. For further reading, this document describes the various telemetry parameters, operating spectrums and transmission details:
This is a nice resource as well. Don't miss the articles at the bottom of the page from CQ that discuss the system. The Proceedings of the Apollo Unified S-Band Technical Conference document is definitely worth your time (it's also at the bottom of the page).
The system was called the Apollo Unified S-Band System. For further reading, this document describes the various telemetry parameters, operating spectrums and transmission details:
http://history.nasa.gov/alsj/TM-X55492.pdf
This is a nice resource as well. Don't miss the articles at the bottom of the page from CQ that discuss the system. The Proceedings of the Apollo Unified S-Band Technical Conference document is definitely worth your time (it's also at the bottom of the page).
http://www.ab9il.net/aviation/apollo-s-band.html