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Sensitivity 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 telescope time ( \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{tel}}}), the number of sources ( \ensuremath{n_\ensuremath{\mathrm{source}}}) and the elevation ( \ensuremath{\mathrm{el}}). For mapping, get the map sizes. There are two cases:
EKH restoration
The following checks and computations must be done.
$\displaystyle \ensuremath{\Delta^\ensuremath{\mathrm{\Vert}}_\ensuremath{\mathrm{sou}}}$ $\textstyle \le$ $\displaystyle 0.5^\circ,$ (29)
$\displaystyle \ensuremath{\Delta^\ensuremath{\mathrm{\bot}}_\ensuremath{\mathrm{tot}}}$ $\textstyle =$ $\displaystyle \ensuremath{\Delta^\ensuremath{\mathrm{\bot}}_\ensuremath{\mathrm{sou}}},$ (30)
$\displaystyle \ensuremath{\Delta^\ensuremath{\mathrm{\Vert}}_\ensuremath{\mathrm{tot}}}$ $\textstyle =$ $\displaystyle \ensuremath{\Delta^\ensuremath{\mathrm{\Vert}}_\ensuremath{\mathr...
...throw}}}+ \ensuremath{\Delta^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{base}}}$ (31)
$\displaystyle \ensuremath{\alpha}$ $\textstyle =$ $\displaystyle \mbox{an empirical increasing function of \ensuremath{\Delta^\ensuremath{\mathrm{\Vert}}_\ensuremath{\mathrm{sou}}}{}.}$ (32)

Shift-and-add restoration
The following checks and computations must be done.
  1. \ensuremath{\alpha} is set to the minimum of the empirical increasing function of \ensuremath{\Delta^\ensuremath{\mathrm{\Vert}}_\ensuremath{\mathrm{sou}}} because this restoration algorithm assumes that the restored sources are almost point-like.
  2. $\ensuremath{\Delta^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{submap}}}= 0.5\,\...
...\ensuremath{\Delta^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{edge}}} \right) }$ with $\ensuremath{\Delta^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{edge}}}= \ensurem...
...{throw}}}+\ensuremath{\Delta^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{base}}}$.
  3. If $\ensuremath{\Delta^\ensuremath{\mathrm{\Vert}}_\ensuremath{\mathrm{mos}}}\,\ens...
...}}}\le \ensuremath{\Delta^\ensuremath{\mathrm{2}}_\ensuremath{\mathrm{submap}}}$, then
    $\displaystyle \ensuremath{\Delta^\ensuremath{\mathrm{\bot}}_\ensuremath{\mathrm{tot}}}$ $\textstyle =$ $\displaystyle \ensuremath{\Delta^\ensuremath{\mathrm{\bot}}_\ensuremath{\mathrm{mos}}},$ (33)
    $\displaystyle \ensuremath{\Delta^\ensuremath{\mathrm{\Vert}}_\ensuremath{\mathrm{tot}}}$ $\textstyle =$ $\displaystyle \ensuremath{\Delta^\ensuremath{\mathrm{\Vert}}_\ensuremath{\mathr...
...hrow}}}+ \ensuremath{\Delta^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{base}}},$ (34)
    $\displaystyle \ensuremath{n_\ensuremath{\mathrm{source}}}$ $\textstyle =$ $\displaystyle 1.$ (35)

  4. Else
    $\displaystyle \ensuremath{\Delta^\ensuremath{\mathrm{\bot}}_\ensuremath{\mathrm{tot}}}$ $\textstyle =$ $\displaystyle \ensuremath{\Delta^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{submap}}},$ (36)
    $\displaystyle \ensuremath{\Delta^\ensuremath{\mathrm{\Vert}}_\ensuremath{\mathrm{tot}}}$ $\textstyle =$ $\displaystyle \ensuremath{\Delta^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{sub...
...hrow}}}+ \ensuremath{\Delta^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{base}}},$ (37)
    $\displaystyle \ensuremath{n_\ensuremath{\mathrm{source}}}$ $\textstyle =$ $\displaystyle \frac{\ensuremath{\Delta^\ensuremath{\mathrm{\Vert}}_\ensuremath{...
...}}}}{\ensuremath{\Delta^\ensuremath{\mathrm{2}}_\ensuremath{\mathrm{submap}}}}.$ (38)

    We note that in this case, \ensuremath{n_\ensuremath{\mathrm{source}}} is not here a real number of source but more a number of submap: It does not need to be an integer.
Step #3: Computation of \ensuremath{n_\ensuremath{\mathrm{cal}}} and \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{source}}}

$\displaystyle 1.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{cal}}}= \ensuremath{\mathrm{cei...
...}}}+\ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{cal}}}} \right) },$ (39)
$\displaystyle 2.$   $\displaystyle \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{source}}...
...rm{}}_\ensuremath{\mathrm{cal}}}}{\ensuremath{n_\ensuremath{\mathrm{source}}}}.$ (40)

If $\ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{source}}}< 0$, then return the following error message: ``The telescope time must at least be $\ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{cal}}}/\ensuremath{\epsilon_\ensuremath{\mathrm{tel}}}$.''
Step #4: 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}}}
OnOff

$\displaystyle 1.$   $\displaystyle \mbox{\ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{su...
...remath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{max}}}{} are fixed,}$ (41)
$\displaystyle 2.$   $\displaystyle \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{scan}}}=...
...}}) + \ensuremath{t^\ensuremath{\mathrm{overhead}}_\ensuremath{\mathrm{scan}}}.$ (42)

Mapping

$\displaystyle 1.$   $\displaystyle \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{subscan}...
...Vert}}_\ensuremath{\mathrm{tot}}}}{\ensuremath{v_\ensuremath{\mathrm{\Vert}}}},$ (43)
$\displaystyle 2.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{m...
...ath{t^\ensuremath{\mathrm{overhead}}_\ensuremath{\mathrm{subscan}}}} \right) },$ (44)
$\displaystyle 3.$   $\displaystyle \mbox{if} \quad \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensu...
... error message advising to increase \ensuremath{d_\ensuremath{\mathrm{scan}}},}$ (45)
$\displaystyle 4.$   $\displaystyle \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{scan}}}=...
...}}) + \ensuremath{t^\ensuremath{\mathrm{overhead}}_\ensuremath{\mathrm{scan}}}.$ (46)

Step #5: Computation of \ensuremath{n_\ensuremath{\mathrm{scan}}}, \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{res}}} and \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{tot}}}

$\displaystyle 1.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{scan}}}= \ensuremath{\mathrm{fl...
...}}{\ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{scan}}}} \right) },$ (47)
$\displaystyle 2.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{r...
...ath{t^\ensuremath{\mathrm{overhead}}_\ensuremath{\mathrm{subscan}}}} \right) },$ (48)
$\displaystyle 3.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{t...
...max}}}+ \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{res}}}.$ (49)

Step #6: Computation of \ensuremath{n_\ensuremath{\mathrm{cover}}} (Mapping only)

$\displaystyle 1.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{c...
...th{\mathrm{\bot}}_\ensuremath{\mathrm{tot}}}}{\ensuremath{\delta}}+1 \right) },$ (50)
$\displaystyle 2.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{cover}}}= \ensuremath{\mathrm{f...
...remath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{cover}}}} \right) },$ (51)
$\displaystyle 3.$   $\displaystyle \mbox{if} \quad \ensuremath{n_\ensuremath{\mathrm{cover}}}< 1, \q...
...to increase \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{tel}}}{}},$ (52)
$\displaystyle 4.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{t...
...}}}\, \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{cover}}}.$ (53)

Step #7: Computation of actual \ensuremath{n_\ensuremath{\mathrm{scan}}} and \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{res}}} (Mapping only)

$\displaystyle 1.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{scan}}}= \ensuremath{\mathrm{fl...
...suremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{max}}}} \right) },$ (54)
$\displaystyle 2.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{r...
...{scan}}}\ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{max}}}.$ (55)

Step #8: Computation of \ensuremath{\sigma_\ensuremath{\mathrm{}}}
OnOff

$\displaystyle 1.$   $\displaystyle \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{\ensurem...
...res}}}) \, \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{subscan}}},$ (56)
$\displaystyle 2.$   $\displaystyle \ensuremath{\sigma_\ensuremath{\mathrm{}}}= \frac{\ensuremath{\ma...
...\mathrm{}}_\ensuremath{\mathrm{\ensuremath{\sigma_\ensuremath{\mathrm{}}}}}}}}.$ (57)

Mapping

\begin{displaymath}
\ensuremath{\sigma_\ensuremath{\mathrm{}}}= \ensuremath{\al...
...athrm{\Vert}}}}{\ensuremath{n_\ensuremath{\mathrm{cover}}}}},
\end{displaymath} (58)

Step #9: Computation of the actual \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{source}}}, \ensuremath{n_\ensuremath{\mathrm{cal}}} and \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{tel}}}
We note that 1) the actual number of scan is $\ensuremath{n_\ensuremath{\mathrm{scan}}}+1$ when $\ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{res}}}\ge
1$ and \ensuremath{n_\ensuremath{\mathrm{scan}}} when $\ensuremath{n_\ensuremath{\mathrm{subscan}}^\ensuremath{\mathrm{res}}}= 0$ and 2) the true elapsed telescope time might be smaller than the user input.
$\displaystyle 1.$   $\displaystyle \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{source}}...
...uremath{t^\ensuremath{\mathrm{overhead}}_\ensuremath{\mathrm{scan}}} \right] },$ (59)
$\displaystyle 2.$   $\displaystyle \ensuremath{n_\ensuremath{\mathrm{cal}}}= \ensuremath{\mathrm{cei...
...uremath{\mathrm{source}}}}{\ensuremath{d_\ensuremath{\mathrm{cal}}}} \right) },$ (60)
$\displaystyle 3.$   $\displaystyle \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{tel}}}= ...
...}_\ensuremath{\mathrm{cal}}}}{\ensuremath{\epsilon_\ensuremath{\mathrm{tel}}}}.$ (61)

The noise computation is done for three different values of \ensuremath{\tau_\ensuremath{\mathrm{zen}}} (excellent, good and average conditions).


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