The Division of Radio Astronomy Science and Technology (DRAST) of the Shanghai Astronomical Observatory (SHAO) has been founded for more than 30 years. As one of the primary divisions of SHAO, DRAST is responsible for astronomy research and application using radio techniques. In addition to single-dish observations of radio spectral lines and pulsars with the Tianma 65-m Radio Telescope, the activities of DRAST encompass VLBI application on astrophysics, astrometry and space exploration.

DRAST is consisted of three groups:

1.Radio Astronomical Observation Base

2.Radio Astronomical Technique Laboratory

3.VLBI Data Processing Center

Director: ZHENG Weimin Deputy Director: LIU Qinghui, AN Tao

Introduction→ Research Direction

1. Single-dish observations

A public platform based on Tianma 65-m Radio Telescope is under construction for scientific research. It is scheduled to be open to Chinese scientists and international users. Areas of research interest include molecular line survey for star formation studies, and pulsar searching and timing to study the pulsar radiation mechanism, evolutionary process and interior structure, which is helpful to accumulate observational data for the establishment of pulsar time standard and deep-space automatic navigation.

2. Space radio astronomy

In order to promote the funding of the first space Low Frequency Radio Astronomical Observatory and the first space VLBI array project in the world, some efforts have been made on defining the scientific goals and key technologies in cooperation with some domestic and international partners.

3. Lunar exploration project

The division is responsible for establishing and operating the VLBI tracking system in Chinese Lunar Exploration Project (CLEP). In order to meet the requirements of engineering navigation, the 4 Chinese VLBI stations have been upgraded, the VLBI center in Shanghai was built, and the high speed data transfer from stations to the center was established. Some important software tools such as eVLBI data transfer, dynamic scheduling, correlator model calculation, and correlator software have been developed. So far the VLBI tracking system has been successfully applied for 4 Chinese lunar missions inclusive of Chang’E-1 in 2007, Chang’E-2 in 2010, Chang’E-3 in 2013 and Chang’E-5T1 in 2014.

4. Shanghai VLBI correlator

Shanghai VLBI correlator is dedicated to the data processing of the Chinese domestic VLBI observing programs, inclusive of the CMONOC project for monitoring the Chinese regional crustal movement and the Chinese deep space exploration project for spacecrafts tracking. It was accepted as an IVS correlator in 2012. In the near future, the center will also contribute to the data processing of the International VLBI Service for Geodesy and Astrometry (IVS) and the East Asia VLBI Network (EAVN).

5. Sheshan VGOS station

The next generation geodetic VLBI system is known as VLBI Global Observatory System (VGOS). The VGOS network continues to grow with many VGOS projects at various stages of accomplishment in the world. The steadily growing VGOS network will gradually enter into full operations and provide daily products. Collocated with SLR and GNSS techniques, Sheshan 25-m station is one of important stations in establishing the International Terrestrial Reference Frame (ITRF). The project is aimed to build a VGOS station at Sheshan, equipped with fast slewing antenna and broadband receiving systems.

6. New technologies and methods

The development of Chinese VLBI Data Acquisition System (CDAS) has been completed and will be upgraded in the future. The CDAS is a digital multi-channel Base-Band Converter. It had been widely used at 4 Chinese stations since April 2010. In October 2012, Tianma 65-m Radio Telescope, also installed the CDAS system.

It is also required to develop other technologies such as antenna control of large radio telescope, antenna measurements, and cryogenic receivers. Research of new technologies and methods in radio astronomy and deep space exploration are also encouraged.

DRAST→ Research Groups

Research Groups→ Radio Astronomical Observation Base

The group is responsible for the operation and maintenance of Sheshan 25-m Radio Telescope and Tianma 65-m Radio Telescope, and participation in the international VLBI sessions.

This group is involved in developing techniques related to antenna control system, antenna measurement, cryogenic receivers, spectral line receiver and pulsar timing terminal, as well as carrying out applied research in VLBI and single-dish observations.

Research Groups→ Radio Astronomical Technique Laboratory

Radio Astronomy Technique Laboratory, the former VLBI Technique Laboratory, is one of 3 research groups in the Division of Radio Astronomy Science and Technology (DRAST). It was founded in 1999.

The main objectives of the Radio Astronomy Technique Laboratory:

1.To play a leading role in developing VLBI techniques in China

2.To provide technique support for the VLBI stations of Chinese Academy of Sciences

3.To implement the regular operation of Chinese VLBI Network (CVN) for astronomy, space geodesy and spacecrafts tracking

To achieve these goals, we are engaged in:

1.Development of hardware VLBI correlator and software VLBI correlator

2.Development of Chinese VLBI Data Acquisition System (CDAS), a type of digital backends used in the VLBI community

3.Development of VLBI scheduling, modeling, correlation, antenna arraying and eVLBI technique

4.Deep space exploration and other applied research based on radio observations

Research Groups→ VLBI Data Processing Center

VLBI data processing center is located in Sheshan science and technology campus, about 40 kilometers from Xujiahui headquarter of Shanghai Astronomical Observatory. The data center was finished in June and was put into use in December 2013.

The VLBI data processing center consists of four parts:

1.Operation and control hall

2.Central computer room

3.Mark5 system room

4.Electric power supply room

The center is dedicated to the operation and data processing of the Chinese domestic VLBI observing programs, inclusive of the CMONOC project for monitoring the Chinese regional crustal movement and the Chinese deep space exploration project for spacecrafts tracking. It was accepted as an IVS correlator in 2012.

In the near future, the center will also contribute to the data processing of the International VLBI Service for Geodesy and Astrometry (IVS) and the East Asia VLBI Network (EAVN).