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Session 107 - Radio Astronomy and VLBI Instruments.
Display session, Thursday, January 16
Radio astronomy observations with the DSN are being automated to simplify operations for DSN personnel, enable remote directing and monitoring by investigators, allow the use of short blocks of antenna time, and use of unanticipated antenna availability on very short notice. The key elements of the system are the Equipment Activity Controller (EAC), which performs the same functions as a DSN operator's console but with additional capabilities, the Radio Astronomy Controller (RAC), which controls radio astronomy and other Ramp;D equipment, and the PC Field System (PCFS), which controls the VLBI recorders. Normally, the EAC is client to both the RAC and the PCFS. The EAC graphical user interface (GUI) normally runs on the EAC, but need not, allowing for remote operation. Messages between the client and servers are Extended Tcl (TclX) commands and are passed using a simple TCP/IP protocol called Net Services. The Tcl command set has been augmented with Net Services commands. The EAC will accept commands from both the PCFS and RAC, enabling either of those to be the focus of the experiment, with the EAC acting effectively as a client providing access to DSN antennas and receivers. The design also allows a user developed program (e.g. a Tk script) on a remote computer (e.g. at JPL) to be the focus of the experiment. All communications and the DSN's operational network are secured through the use of hardware encryption units. This poster describes primarily the RAC and the design of its server software. Each connection to the server is assigned its own Tcl interpreter. All have access to specific commonly shared data. While only certain tasks can control resources, a large number of monitoring connections can be accepted. In addition, the server executes specific Tcl scripts at predefined intervals. These timed scripts can be edited in real-time for greater experiment flexibility.
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Program listing for Thursday