next up previous contents
Next: Parameter values Up: Algorithms Previous: Sensitivity estimation   Contents

Time estimation

Step #1: Initialization
Initialize the values of \ensuremath{\epsilon_\ensuremath{\mathrm{tel}}}, \ensuremath{d_\ensuremath{\mathrm{submap}}}, \ensuremath{d_\ensuremath{\mathrm{scan}}}, \ensuremath{d_\ensuremath{\mathrm{cal}}}, \ensuremath{\eta_\ensuremath{\mathrm{cal}}}, \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{pointing}}}, \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{focus}}}, \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{skydips}}}, \ensuremath{t^\ensuremath{\mathrm{overhead}}_\ensuremath{\mathrm{scan}}}, \ensuremath{t^\ensuremath{\mathrm{overhead}}_\ensuremath{\mathrm{subscan}}}, \ensuremath{\Delta^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{array}}}, \ensuremath{\Delta^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{throw}}}, \ensuremath{\Delta^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{base}}}, etc...
Step #2: User input
Get the rms noise ( \ensuremath{\sigma_\ensuremath{\mathrm{}}}), the number of sources ( \ensuremath{n_\ensuremath{\mathrm{source}}}) and the elevation ( \ensuremath{\mathrm{el}}). For mapping, get the map sizes and transform them using the same formula as Step #2 in the sensitivity estimation.
Step #3: Computation of \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{subscan}}}, \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{max}}} and \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{scan}}}
Same as Step #4 in the sensitivity estimation.
Step #4: Computation of \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{tot}}} from \ensuremath{\sigma_\ensuremath{\mathrm{}}}
OnOff

$\displaystyle 1.$   $\displaystyle \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{\ensurem...
...thrm{zen}}} \right) }}{\ensuremath{\sigma_\ensuremath{\mathrm{}}}} \right] }^2,$ (62)
$\displaystyle 2.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{t...
...\ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{subscan}}}} \right) }.$ (63)

Mapping

$\displaystyle 1.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{cover}}}= \ensuremath{\mathrm{f...
...hrm{zen}}})}{\ensuremath{\sigma_\ensuremath{\mathrm{}}}} \right] }^2 \right\}},$ (64)
$\displaystyle 2.$   $\displaystyle \mbox{if} \quad \ensuremath{n_\ensuremath{\mathrm{cover}}}< 1, \q...
...ror message advising to decrease \ensuremath{\sigma_\ensuremath{\mathrm{}}}{}},$ (65)
$\displaystyle 3.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{c...
...th{\mathrm{\bot}}_\ensuremath{\mathrm{tot}}}}{\ensuremath{\delta}}+1 \right) },$ (66)
$\displaystyle 4.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{t...
...}}}\, \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{cover}}}.$ (67)

Step #5: Computation of \ensuremath{n_\ensuremath{\mathrm{scan}}} and \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{res}}}
Same as Step #7 in the sensitivity estimation.
Step #6: Computation of \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{source}}}, \ensuremath{n_\ensuremath{\mathrm{cal}}} and \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{tel}}}
Same as Step #9 in the sensitivity estimation.
Step #7: Computation of the actual noise
We note that the reached sensitivity will be slightly larger than requested by the user because of the ceil function in the computation of \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{res}}}. We thus recompute the sensitivity as in the Step #8 of the sensitivity estimation.
All these computations are done for three different values of \ensuremath{\tau_\ensuremath{\mathrm{zen}}} (excellent, good and average conditions).


next up previous contents
Next: Parameter values Up: Algorithms Previous: Sensitivity estimation   Contents
Gildas manager 2014-07-01