LAMOST will obtain up to ten-thousands of spectra per night and the data volume will be several gigabytes. It is planed to acquire ten-millions of spectra as a whole. In order to obtain the data high efficiently and gain more scientific results, LAMOST has an automatic software system for its observation and data processing. For this purpose, a set of software system for observation, process and storage, has been developed including Survey Strategy System (SSS), Observation Control System (OCS) and Data Processing System (DPS).
Survey Strategy System (SSS)
The scientific target of Survey Strategy System (SSS) of LAMOST is to make an effective observation project, determine the observation time and arrange the observation process. During spectroscopic survey of LAMOST, SSS analyzes all kinds of static and dynamic restrictions, finds a perfect observation position and allocates all fiber to objects under the guidance of gaining a high fiber use rate.
Where to point to the position and how to allocate the fibers is the primary problem that SSS solves. In order to achieve the goal, mean-shift method is developed, which is proved by simulation and preliminary practice to be a feasible and effective method.
Due to the process of making a valuable observation project for a survey observation with a large sky area, huge number of objects and long-term astronomical observation course, is more complicated and difficult. The transit restriction, focal surface and fiber location restriction should be considered carefully.
Observatory Control System (OCS)
Observatory Control System (OCS) is one of the main subsystems of LAMOST software. OCS operates the telescope in real-time during spectroscope observations and handle the observational schedule through SSS (Sky Survey System) and data processing through DHS. The goal of the OCS is to do the entire observing process automatically, and make the scientific gaining more efficiently.
The main mission of OCS is managing, coordinating and controlling the operations of telescope in a precise and orderly manner in according with the observation plan. OCS will be made of the software and LAMOST software system hardware components that interface between the telescope subsystems, and between the running modules. These interfaces will employ a multi-layers architecture that is centralized and distributed.
During the whole observation, every operation has its rules. Every operation command is send by OCS. When a command is received and accepted by subsystem, subsystem will execute the task and return the operational information to OCS at the same time. The basic execution sequence of those commands has two kinds: parallel and serial. The communication between OCS the subsystem is important. In order to guarantee that the command can be transported and executed safety, a command/status protocol, a command Acceptance/Rejection Protocol and a Command Execution Feedback Protocol between OCS and subsystems are defined. The command execution feedback protocol makes the OCS response more quickly. The Status Protocol includes errors, warnings and system information. For the change of status is random and unknown for OCS, there must be an approach to monitor and deal with the status. The subsystems have the responsibility to monitor the status and report the change to OCS. When OCS receives the change of status, it will generate an event and deal with the change of status. The OCS is designed and implemented as a set of cooperating, distributed objects components that consist of objects.
Data Processing System (DPS)
Goals of LAMOST spectra reduction and analysis software are to classify them and calculate parameters from those spectra. The whole structure of the software was described in a reference. The input data of the data reduction software is CCD raw images, which are fed to the 2-dimension (2D) Reduction Pipeline to be processed and extracted to 1-dimension (1D) spectra. The output of the 2D pipeline is extracted and calibrated 1D spectrum in the form of FITS file for each target. These 1D spectra is stored into hard disk array managed by a storage management server and indexed by a database system. The pre-processing procedure reads 1D spectrum through standard I/O, and fit continua absorption and/or emission lines. Then, the spectrum is classified and measured by the 1D Pipeline by temple matching and line recognition algorithm. The output of the software includes two parts: one is calibrated spectra with parameters and analysis results written to FITS files stored in hard disk array, the other is FITS formatted catalogs record all information of the processed targets. All the data products will be stored in a database of NAOC Data Center and released to public.