Grammar for .scp files, which are the position list files for .scd files

1997/6/24 T.Handa
* Remarks : In Japanese character set \ (back slash) is replaced by \ (Yen mark). These two characters shared the same binary code and no difference for DOS system. In other word DOS system cannot recognize the difference of these two characters. You should read \ for \ if you find it on screen or writing. This manual is written based upon the onoff command version 2.60 and later and corresponding other commands. Older systems may not support some of the following functions. See a:\obs\readme.doc in your PC about the latest version.

Basics

The position list file gives a positions when the .scd file refers it by the "LIST" or "FILE" key as the second parameter of a line. The basic structure and restrictions are almost the same as the .scd file itself. For example, one line defines by 256 or less characters in ASCII code and the last two characters are CR and LF.
The position list file requires the criteria setup line instead of the frequency setup line. Other lines, those are the comment line, the region description line, the end line, and the integration instruction lines are the same as those in the .scd file, although the integration instruction lines cannot refer to other position list files and only select "ON", "OBJ", "ON2", and "OFF" options. Therefore, here we only instruct the criteria setup line and how to select the actual position for the listed ones.
Although the position list file has no fixed extension in its name, we recommend you to use .scp for the extension as an abbreviation of "scheduler position list".

A Criteria Setup Line

A criteria setup line must be the second line in a file if all comment lines are removed, and after the region description line. Only one criteria setup line is required in the position list file. It describes information about criteria setup which should not be changed in an position list file.
The criteria setup line requires four parameters which are separated by "," (comma) or " " (blank space) or tab.
The first parameter gives a time to calculate the Az-El positions advanced to the calculation epoch in seconds. During integration and calculation the objects move in the Az-El coordinate. The system selects one of the positions in the list according to the Az-El position just after the epoch of calculation as this parameter.
The second parameter is the weight for criteria in the difference along the azimuthal angle. The angle is evaluated in radian.
The third parameter is the weight for criteria in the difference along the elevation angle. The angle is evaluated in radian.
The fourth parameter is the weight for criteria in the difference along the azimuthal angle weighted with coy(El). The angle is evaluated in radian.
The fifth parameter is the weight for criteria in the difference of the air mass, sec(z).

example
10,0.1,0.0,0.0,1.0 mainly consider sec z but 10% Az difference at 10 sec later.

An Actual Selection Criteria

The system select one position in a position list file according to the following way. Just before reading the position list file the system has a position. Here after we call it as the reference point even if it is not the off position. The system calculates the positions of all listed points in Az-El coordinate at the time after the designed seconds. The system evaluated the "distance" according to the following formula. 

d=w1 |Az-Az0| + w2 |El-El0| + w3 |Az-Az0| cos{(El+El0)/2} + w4 | sec z - sec z0|,
where Az, El, z are azimuth, elevation, and zenith angle in radian, respectively, and suffix 0 means the values for the reference point. The system select the next point which gives the minimum d with the same integration mode (on or on2 or off) assigned in the corresponding integration instruction line in the .scd file. The selected point will be the reference point in the next step.
If the integration mode is on or on2, the selected point is removed from the candidates until another position list file will appear in the same .scd file. This removing procedure is just performed internal, so no effect on the position list file itself.
The tracking LSR velocity in the position list file is valid only when no tracking velocity is assigned in the corresponding integration instruction line in the .scd file.
Up to 20 positions are valid in a position listing line for the present system (onoff ver.2.60). This limit is for the total of on, on2, and off (onoff ver.2.60). The limit may be increased near future.
Positions below the horizon are automatically removed from the candidates. The system cashing the all (up to 20) positions in one position listing file at once. After first reading you can dismount the drive from the system before the system tries to read the new position list file or other files.