Yesterday I found what seems to be an acceptable form for the replica to use with RAFOS signals from the Webb sources in the Eastern Pacific. I will carry out some tests to show that the correlation process works like I think that it does.

I have set up software to calculate a "replica" for a RAFOS signal and correlate it with the signal received on the PSM VLA. The signal is exactly 80 seconds long, and consists of a sine wave starting at frequency f₁ and sweeping up by an amount W over the 80 seconds. [f₁ = 259.375 Hz and W =1.54 Hz are probably about right.] This signal is calculated for the series of time values which correspond to the recorded time series from the VLA. The calculated signal is set to zero outside of the 80-second period starting at time t₁, a parameter which can be varied from the console as the program runs. t₁ is also the starting time for the frequency sweep.

The phase of the signal at time t₁ is set to equal

To compare this replica with observation I have proceeded as follows:

• Select a strong RAFOS signal. A good one is the 4:30Z broadcast from SS1 on day 245 of 2001 (September 2). The data series is available as a series of times, in "Julian Day," and a long-integer signal array representing the averaging of the signals from the four hydrophones. (This represents a sort of beam forming.) The data is read into memory (from file s1245b.dat - see Nov. 25).
• Running the program p11125a.pro), choose a set of parameters (f₁, W, t₁, and f₁) and calculate the RAFOS signal.
• Multiply the signal and replica time series, point by point, to get a cross-correlated waveform.
• Average the cc waveform over naver points (naver = 100 for the moment).
• Plot the cc waveform, and print the sum of its values over the time series.