Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 1 Concepts for remote control of VLBI-telescopes: on the way to the first public software release Alexander Neidhardt (FESG) Martin Ettl (FESG), Reinhard Zeitlhöfler (FESG), Reiner Dassing (BKG), Hayo Hase (BKG), Matthias Mühlbauer (BKG), Christian Plötz (BKG), Sergio Sobarzo (UdeC), Cristian Herrera (UdeC), Walter Alef (MPIfR), Helge Rottmann (MPIfR), Ed Himwich (NASA/GSFC/NVI)
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 2 Wettzell and the idea of controlling VLBI telescopes by remote
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 3 The idea: remote attendance and control of VLBI telescopes Wettzell, O’Higgins/Antarctica and TIGO/Concepción TIGO Concepción/Chile GARS O’Higgins/Antarctica RT Wettzell/ Germany TTW Wettzell/ Germany Remote Control on Site Communication Teleworking
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 4 The idea: remote attendance and control of VLBI telescopes Wettzell, O’Higgins/Antarctica and TIGO/Concepción Idea of a strict design-separation of these parts Device control code Communication code Presentation & user interface code
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 5 The idea: remote attendance and control of VLBI telescopes Wettzell, O’Higgins/Antarctica and TIGO/Concepción FS Monitor Client GUI Network FS Monitor Client Communication FS Monitor Server Communication FS Monitor Server Functionality FS Monitor Device … Server functionality Communication Graphical User Interface (GUI) Client FS e-control
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 6 The communication – with a remote procedure call middleware and ssh FS Monitor Client GUI Network FS Monitor Client Communication FS Monitor Server Communication FS Monitor Server Functionality FS Monitor Device … FS
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 7 [SAX07]: Saxonia Systems: Remote Procedure Call, Download [PUD01]: Puder, Arno; R ö mer, Kay: Middleware für vereteilte Systeme, 1.Auflage, dpunkt.verlag GmbH Heidelberg 2001 The communication – with a remote procedure call middleware Application 1Application 2Application n Distribution platform Operating System 1 Architecture 1 Operating System 2 Architecture 2 Operating System n Architecture n Transportation Client runs Client waits Client runs Server waits Server runs 1. RPC- Call 4. RPC- Return 2. Procedure- Call 3. Procedure- Return
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 8 The communication – using a middleware generator fsmc.idl idl2rpc.pl fsmc.idl FS GUI (wxWidgets) Automatically generated communication code FS- connection code g++ fsmc Client fsmc Server Step 1: Write interface definition for fsmc Step 2: Call idl2rpc.pl to generate communication code Step 3: Write code to connect to fieldsystem Step 4: Write code for data presentation Step 5: Compile Internet Command line shell Web Interface Graphical User Interface (GUI)
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 9 A fieldsystem extension – remote accessible, autonomous process cells FS Monitor Client GUI Network FS Monitor Client Communication FS Monitor Server Communication FS Monitor Server Functionality FS Monitor Device … FS
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 10 A fieldsystem extension – autonomous process cells Watchdog- (Father-) Process Automatic Safety Device Request Activation Memory Must be written by user Own code Autonomous process cell offers remote fieldsystem monitoring (at the moment Linux based) SNAP System Call Simple Log Access Fieldsystem Device … FS Shared Memory Remote User Interface Command line, wxWidgets, Browser, … Internet Strict design-separation of - Device control code - Generated communication code - Presentation & user interface code
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 11 A fieldsystem client – remote (graphical) user interface FS Monitor Client GUI Network FS Monitor Client Communication FS Monitor Server Communication FS Monitor Server Functionality FS Monitor Device … FS
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 12 Separation of control and presentation logic Interchangeability of presentation layer (console shell (ncurses), graphical user interface (wxWidgets), web access via Browser, web service, …) Remote controllable via client-server-architecture on idl2rpc-middle- ware Modularity in window units and additionaly possible, separately created administration user interfaces for each device Basis for graphical user interface: wxWidgets (C++ based Open- Source-Framework for plattform indefendent developement of graphical user interfaces) Webcam A fieldsystem client – graphical, textual or browser based
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 13 Paths to go remote FS Monitor Client GUI Network FS Monitor Client Communication FS Monitor Server Communication FS Monitor Server Functionality FS Monitor Device … FS
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 14 Possibility 1: Direct access Possible paths to the field system on behalf of security reasons Possibility 4: Access via direct SSH-Tunnel over SSH-Tunnel to firewall Possibility 3: Access via SSH-Tunnel to firewall Possibility 2: Access via direct SSH-Tunnel RPC-Connection Direct SSH-Tunnel SSH-Tunnel to firewall SSH-Tunnel to firewall RPC-Connection Direct SSH-Tunnel RPC-Connection Firewall Autonomous process cell Autonomous process cell Autonomous process cell Autonomous process cell Client controlled connections
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 15 Successfull tests and usage TIGO Concepción/Chile GARS O’Higgins/Antarctica RT Wettzell/ Germany Communication Teleworking A few successful remote attendance tests Regular usage of remote attendance and control especially on weekends Several successful remote attendance and control observations
Technische Universität München Alexander Neidhardt Forschungseinrichtung Satellitengeodäsie 16 Thank you!