SOLVE BASE ; RESIDUAL BASE

The geometrical delay is computed through:

$\displaystyle \tau_g = \frac{\bf {b_{\cdot}s}}{c}$

(23)

where ${\bf b} = (X_{ij},Y_{ij},Z_{ij})$ and ${\bf s}=(\cos h \cos \delta, -\sin h\cos\delta,\sin\delta)$ are the baseline and source vectors respectively in a referential .

The resulting phase is:

$\displaystyle \phi_{ijk}$	$\displaystyle =$	$\displaystyle 2\pi \tau_g \nu_{RF}$
	$\displaystyle =$	$\displaystyle \frac{2\pi}{\lambda}{\bf b_{\cdot}s}$
	$\displaystyle =$	$\displaystyle \frac{2\pi}{\lambda_k}\left( X_{ij} \cos h\cos \delta - Y_{ij}\sin h\cos\delta + Z_{ij}\sin\delta\right)$	(24)

Using sources with known position distributed in hour angle and declination, a least square fit to the observed phases gives is used to derive the antenna position errors.

An additional term can be fitted corresponding to the offset between the azimuth and elevation axis of each antenna. It has a $\cos(El)$ dependance (in that case, data must be plotted as a function of elevation also in addition to the hour angle and declination of the "normal" baseline measurements).

Command RESIDUAL baseline will plot the residual phases resulting from the last SOLVE BASELINE command.