Date: Wed, 18 Jun 2003 23:11:24 +0100
From: Peter.Schmitz@esa.int
Subject: MEX TCXO Freq and HGA pattern
To: Dwight.P.Holmes@jpl.nasa.gov
Cc: Nigel.G.Angold@jpl.nasa.gov, Sami.W.Asmar@jpl.nasa.gov
X-Lotus-FromDomain: ESA

Dwight,

I was supposed to provide Dick Simpson with the Aux Oscillator Frequency
and the HGA pattern but I don't have his e-mail address. Can you please
forward this note to the people concerned.

According to the Trsp Design Report the on-board TCXO frequency is
       38274.7 KHz


Regarding the HGA pattern calibration performed on June 13th (disregard
the date on top of the plots) please find below the preliminary results
from ESOC flight dynamics:

Extract from e-mail Mathias Lauer dated 18/06/03, subject: "Analysis of
LEOP/Commissioning Activities" ....

3) Antenna Calibration:

A raster pointing was performed, such that the HGA pointed towards New Norcia
for 2 minutes with various offsets. The plots attached, show the received
signal strength along perpendicular axes in S- (S.pfd) and X-Band (X.pdf)
depending on the offpointing angle.

As you can see, the quality of the data is good for X-Band, but poor for
S-Band (even at 0 degree, the received signal strength is not the same for
the alpha and delta offpointing slew, although the nominal HGA boresight
is directly pointing towards NNO at 0 degree).

A fit of a Gaussian with the nominal 3dB half cone angles from the FDDB
through all data (not only the data which are shown in the plot) give an
offpointing of the direction with maximum signal strength w.r.t. the nominal
pointing direction of the antenna of 0.14 deg for both S-Band and X-Band,
but both directions differ by 0.16 deg. Compared with the AOCS Budget,
the S-Band offpointing is within the budgeted misalignment of the 0.213 deg,
but the X-Band offpointing violates the 0.077 deg in the budget.
....

(See attached file: X.pdf)(See attached file: S.pdf)

Kind regards
Peter