Experimental Log: Roger Bland, January 10, 2002
Finalize RAFOS Matched-Filter Detection
( logbook |2001 data | ifremer on RAFOS |Garfield at NPS |raftimes )

6:28 Thursday January 10, 2002. Yesterday I almost completed a calculation concerning detection by cross-correlation; I will finish it today. The gist of it is that the correct way to detect the RAFOS signal is with quadrature detection using two replicas 90 degrrees out of phase, and that this can be done even with the signals which have been frequency-shifted down to D.C. However, the frequency-shifting must be donw with two sine waves, 90 degrees apart, in order not to lose part of the signal.

Rather than wait to finish the calculation, I will make the changes necessary in my programs and start them running, since the calculations take quite a bit of time.

I will do a little scan for something near 17.14 hours, using my old, incorrect detection scheme, which however still saw the signal near 4:12 .
Day 291 - nothing
Day 292 - huge blob at 17:13
Day 293 - AM - nothing (good signal); PM, nice signal at 61718.728+3.9 sec
Day 294: PM, nice signal at 61718.426+3.9 sec
Day 296: PM, no signal over bkgd of 4.5
Day 297: AM, no signal over bkgd of 5; PM, no signal over bkgd of 4.5
Day 298: AM, no signal over bkdg of 5; PM, weak signal at 61718.838+4.0 sec
Day 299:
Day 301: AM, possible weak signal; PM, weak signal at 61718.522+3.9 sec
Day 302: AM, possible weak signal;
Day 303: PM, nice signal at 61718.501+4.0 sec; NOTE - all for RAFOS signals present and clear.
Day 304: AM, weak or absent; PM, nice signal at 61718.676+3.9 sec
Day 305: AM, absent;
Day 306: PM, obscured by noise
Day 307: AM, signal absent; scale of the signal seems wrong; PM, problems with the data.
Day 308: AM, nice signal at 18518.705+3.9 - but signal level is much higher than usual; PM, ??????
Day 309:
Day 310: AM, good signal at 18518.662+3.8 sec, signal level high; PM, signal weak or absent
Day 311: AM, signal weak or absent; PM, signal at 61718.566+3.8 sec
Day 312: AM, nice signal at 18518.767+4.0 sec, signal level back to normal (background about 3)
Day 313: PM, signal weak or absent; MPS tests going on.

I will go back to working on the programs; but it certainly seems as if there is a source at a little past 5H and 17H.