(53) EISCAT Scientific Association System and Subsystem Design Description EISCAT3D_PfP

Transcription

1 Date Page (53) EISCAT Scientific Association System and Subsystem Design Description EISCAT3D_PfP

2 Table of Contents 1 SCOPE IDENTIFICATION SYSTEM OVERVIEW PURPOSE APPLICATION DEFINITIONS AND ABBREVIATIONS REFERENCES SYSTEM-WIDE DESIGN DECISIONS INTERACTIONS WITH SURROUNDING SYSTEMS PHYSICAL ENVIRONMENT BEHAVIORAL DESIGN Boot and re-boot Calibrate receive chain Transmit Receive Subsystem Shutdown Start an Experiment Calibrate transmit chain OVERALL DESIGN DECISIONS SYSTEM ARCHITECTURAL DESIGN SYSTEM COMPONENTS High level interfaces Pulse and Steering Control Network Components Antenna Time and Frequency Cables and Connectors Transmit unit container Climate monitoring equipment Subsystem Manager Transmit Support Structure Instrument Container First Stage Receiver CONCEPT OF EXECUTION INTERFACE DESIGN Data model EROS/Subsystem Manager Message Protocol REQUIREMENTS ALLOCATION NOTES DESCRIPTION OF DIAGRAMS Page 2 (53)

3 1 Scope 1.1 Identification This System and Subsystem Design Description (SSDD) applies to the EISCAT_3D Test Sub-array, also called Test Sub-array throughout this document. 1.2 System overview The Test Sub-array is a phased-array antenna radar system containing 91 crossed dipole antenna elements, a beamformer, a receiver, a transmitter and other subsystems for control, time-keeping et cetera. The purpose of the Test Sub-array is to serve as a proof of concept for the planned EISCAT_3D incoherent scatter radar system. EISCAT_3D Test Sub-array ss: Support Structure ic: Instrument Container au: Antenna tfu: Time and Frequency fsru: First Stage Receiver tuc: Transmit unit container cme: Climate monitoring equipment pscu: Pulse and Steering Control tu: Transmit ic sm: Subsystem Manager nc: Network Components cc: Cables and Connectors Diagram 1: The whole system This diagram displays the different subsystems of the Test Sub-array and also displays, where applicable, where the subsystems are located physically. Page 3 (53)

4 The support structure contains the three physical main parts Instrument Container, Transmit and Antenna. There are also Network Components, Cables and Connectors to connect everything to a complete system. The instrument container itself contains: Time and Frequency First Stage Receiver Climate monitoring Equipment Pulse and Steering Control Subsystem Manger (specific for the Instrument Container) The Transmit Container simply contains the Transmit and The Transmit Container simply contains the Transmit and the Antenna contains the antenna elements. Note that the diagram only displays the Test Sub-array subsystems. External systems (e.g. Computing System which is located inside of the Instrument Container) will not be displayed. 1.3 Purpose The purpose of this SSDD is to provide an overall description of the Test Sub-array system, including its logical design as well as its physical architecture down to subsystem level. 1.4 Application This document may be used as information to the developers and suppliers during the development, production, integration and verification processes for the Test Sub-array subsystems and components. The SSDD may also be used for educational purposes. To interpret the different types of diagrams displayed in this document, please see section Description of Diagrams for further information. Note that the SSDD is still under construction and its contents may change. Page 4 (53)

5 1.5 Definitions and Abbreviations Definition AAF ADC CPU dbm EROS LNA M&C PfP ps RC RF SFDR SNR SSDD SSPA VSWR WR Description Anti-Aliasing Filter Analog to Digital Converter Central Processing dbm (sometimes dbmw or decibel-milliwatts) is an abbreviation for the power ratio in decibels (db) of the measured power referenced to one milliwatt (mw). (wikipedia) EISCAT Realtime Operating System Low Noise Amplifier Monitoring and Control Preparation for Production picoseconds Radar Controller Radio Frequency Spurious Free Dynamic Range Signal to Noise Ratio System and Subsystem Design Description Solid State Power Amplifier Voltage Standing Wave Ratio White Rabbit Page 5 (53)

6 2 References The systems engineering work is based on the following documents: Reference [RCM] [NGTD] Title EISCAT_3D Radar Control and Monitoring Subsystem Report EISCAT_3D: The next generation international atmosphere and geospace research radar Technical Description [Impl] [MD] Implementation of EISCAT_3D Test Sub- Array Final Version June 2016 Milestone Document MC-1 Test sub-array sub-systems and interfaces. [SysML] SysML Distilled [WRS] White Rabbit Specification: version 2.0 [WRSw] White Rabbit Switch: User s Manual wrswitch-sw-v4.2 Page 6 (53)

7 3 System-wide design decisions This chapter describes the requested behavior of the Test Sub-array and the context it will operate in, including both the actual physical environment as well as the surrounding systems that the Test Sub-array needs to interact with in order to provide its assigned technical functions. 3.1 Interactions with surrounding systems The Test Sub-array will interact with a number of systems external to the Test Subarray. These interactions are displayed on the activity diagrams presented in chapter Behavioral design. The following diagram displays the surrounding systems the Test Sub-array will have interfaces to. ibd [block] Operational domain [Operational domain] : Antenna Calibration Tower p74 : EISCAT_3D Test Sub-array p73 : EROS Power switch Tromsö site p82 p75 1 Gb/s : EROS : Mains Power cs: Computing System Diagram 2: Operational domain The diagram above shows the operational domain, i.e. the EISCAT_3D Test Subarray and its surrounding systems. Page 7 (53)

8 Antenna Calibration Tower The Antenna Calibration Tower will be used during end-to-end calibration runs and will either transmit or receive the RF signals that are sent through the receive chain and transmit chain of the Test Sub-array. Any offsets (unexpected time delays) that are discovered through the calibration test will be used as input to the beamformer for example. The behavioral context of the Test Sub-array s interactions with the Antenna Calibration Tower is displayed on the calibrate diagrams in section "Subsystem interaction". The output of the beamformer is 20 (2x10) simultaneous beams which corresponds to a data rate of about 67 Gb/s. This data is sent off for storage at the EISCAT Tromsö site. The Tromsö site will be accessed through a wide area network (100 Mb/s communication link using fiber Ethernet) connecting the Test Sub-array site to the Tromsö University network. Computing System The computing system will, during the PfP phase, consist of a computer used to store and process the measurement data from the First Stage Beamformer. EISCAT_3D Test Sub-array The Test Sub-array is a phased-array antenna radar system containing 91 crossed dipole antenna elements, a beamformer, a receiver, a transmitter and other subsystems for control, time-keeping et cetera. EROS EROS (EISCAT real-time operating system) is an M&C software system that also serves as the user interface of the Test Sub-array. EROS monitors and controls the different subsystems through its communication with the Subsystem Managers that are included in the subsystems. The communication consists of the exchange of simple text messages. EROS sends status commands inquiring about the health of the subsystems and also sends non-time-critical control commands, for example commands related to system startup and shutdown. These commands then initiate some kind of predefined behavior, e.g. activities being carried out and/or information being returned. EROS can also receive unprompted notifications from the Subsystem Manager if it detects any anomalies. EROS will be located inside the main building at the Tromsö site and will be accessed through a wide area network (currently 100 Mb/s communication link using fiber Ethernet) connecting the Test Sub-array site to the Tromsö University network. The Slow Ethernet need will use a small part of this faster network. Page 8 (53)

9 EROS Power switch Remotely controlled independent networked power switch that allows EROS to reboot SubMan, the software running on the Subsystem Manager computer, see section Subsystem Manager for more information. Mains Power The power supply to the Test Sub-array site. 3.2 Physical environment The site for the Test Sub-array is located in Ramfjordmoen outside of Tromsö, Norway. Its climate has to be taken into consideration (risk of snow accumulation, et cetera) when designing the different subsystems, and the parts of the system that have direct interfaces with the environment also needs to be resilient to the kind of wildlife that can be expected at the site. 3.3 Behavioral design A smooth transition into the EISCAT_3D implementation phase as well as valuable insights regarding system design and performance are expected through the development and implementation of the Test Sub-array. One of the objectives is to gain knowledge regarding how the different subsystems work together as a single Test Sub-array, i.e. in terms of compatible interfaces, electromagnetic interference and functionality, et cetera. The main activity of the system is simply to operate the Test Sub-array. This activity can, in turn, be said to consist of a number of high-level sub activities that are displayed in the following diagram: Operate Test Sub-array Calibrate transmit chain Subsystem Shutdown Start an Experiment Transmit Calibrate receive chain Boot and re-boot Receive e Diagram 3: Function overview The overall behavior of these sub activities is displayed through activity diagrams in the following section. Page 9 (53)

10 3.3.1 Boot and re-boot The activity describes what, and which subsystems, is involved in the process of booting and re-booting the Test Sub-array. The activity consists of two different scenarios: one for a so called "cold start" following a mains power failure and one for a "warm start" where SubMan is still running and can respect an exit command from EROS. act [Function] Boot and re-boot [Warm Start Boot and re-boot] :EROS Computer SubMan Send exit command is SubMan responding to exit command? yes no Terminate process through kill command Computer restarts SubMan SubMan exits Shut down SubMan SubMan restarts Diagram 4: Warm Start Boot and re-boot Page 10 (53)

11 act [Function] Boot and re-boot [Cold Start Boot & re-boot after power has returned] :EROS Power switch :Subsystem Manager Subsystem :Close external power switch :Automatic computer boot-up :Run SubMan This may or may not occur. :Close power switch :Power up If the SubMan's default behavior is not to boot the hardware after power failure then the hardware needs to be booted explicitly by an EROS command Diagram 5: Cold Start Boot & re-boot after power has returned Page 11 (53)

12 3.3.2 Calibrate receive chain The activity describes what, and which subsystems, is involved in the process of calibrating the receive chain of the Test Sub-array. act [Function] Calibrate receiv e chain [Calibrate receiv e chain] :Antenna Calibration Tower :First Stage Receiv er :Computing System :User ActivityInitial :Prepare calibration tx :Receiv e calibration signals Note that this reflects the simplified flow and hence some tasks and/or flows have been omitted from this diagram :Amplify low signal :Perform antialiasing :Digitize RF signals :Process calibration signals :Calculate offsets etc :Insert new settings into the Beamformer :Implement new settings ActivityFinal Diagram 6: Calibrate receive chain Page 12 (53)

13 3.3.3 Transmit The activity describes what, and which subsystems, is involved in the Test Sub-array transmit process: from the start signal to the radio frequency waves being emitted from the Antenna Elements. The Transmit diagram displays sequences of system tasks or activities that will be carried out as well as the general flow between these activities over time as the Test Sub-array is in its transmit phase. Each vertical partition represents an actor (a subsystem, an external system or a user) that, during the transmit process, will carry out one or several activities or tasks. The arrows on the diagram represent token flows that simply indicate which activity is currently enabled during transmission. act [Function] Transmit [Transmit] :Pulse and Steering Control Transmit unit :Antenna Subsystems have been primed by EROS High Resolution Trigger: Send trigger signal :Perform internal system tasks :Generate & send RF signal :Send Control signals :Switch to transmit mode :Receiv e generated RF signals Note that looping occurs until all the scheduled transmission waveforms have been looped through. The behavior displayed on this diagram is simplified and does not explicitly describe for example transitions to the receive state and reception of transmission sample. :Amplify and send RF signals :Transmit RF signals Diagram 7: Transmit Page 13 (53)

14 3.3.4 Receive The activity describes what, and which subsystems, is involved in the receive process of the Test Sub-array: from the Antenna Elements receiving the echo signals to the First Stage Beamformer outputting measurement data for processing and storage. act [Function] Receiv e [Receiv e] :Pulse and Steering Control :Antenna :Transmit :First Stage Receiv er :Computing System ActivityInitial :Send Control signals :Switch to receiv e mode :Receiv e generated RF signals :Receiv e and transfer RF signals :Amplify low signal :Perform antialiasing :Digitize RF signals :Perform beamforming :Satellite echo remov al from data stream :Transfer beams :Process received beams ActivityFinal Diagram 8: Receive Page 14 (53)

15 3.3.5 Subsystem Shutdown The activity describes what, and which subsystems, is involved in the process of shutting down a subsystem of the Test Sub-array. act [Function] Subsystem Shutdown [Subsystem Shutdown] :EROS Power switch :EROS :Subsystem Manager Subsystem ActivityInitial :Send power off signal SubMan responding? No Yes :Open power switch :Recycle power :Execute shutdown process :Perform shutdown tasks :Close external power switch :Open power switch ActivityFinal Diagram 9: Subsystem Shutdown Page 15 (53)

16 3.3.6 Start an Experiment The activity describes what, and which subsystems, is involved in the process of starting a Test Sub-array experiment. act [Function] Start an Experiment [Start an Experiment] :EROS :Time and Frequency :Pulse and Steering Control :First Stage Receiv er :Transmit ActivityInitial Note that this reflects the simplified flow and hence some tasks and/or flows have been omitted from this diagram :Create and Send Test Sub-array start-up signal :Initialize streaming of priming commands :Receiv e priming commands :Receiv e priming commands :Receiv e priming commands :Receiv e priming commands :Perform system start-up tasks :Generate and distribute time :Receive time :Receive time Continuous flow :Perform system start-up tasks :Send subsystem prepared signal :Send subsystem prepared signal :Send subsystem prepared signal Activity final Diagram 10: Start an Experiment Page 16 (53)

17 3.3.7 Calibrate transmit chain The activity describes what, and which subsystems, is involved in the process of calibrating the transmit chain of the Test Sub-array. act [Function] Calibrate transmit chain [Calibrate transmit chain] :User :Pulse and Steering Control :Transmit :Antenna Calibration Tower Computing system? User :Load calibration pulse pattern :Send trigger signal :Perform internal system tasks :Send Control signals :Switch to transmit mode :Generate & send RF signal :Receiv e generated RF signals The settings are applied to the exciter, but how this is done is TBD. :Receiv e calibration signal :Sav e and process calibration data :Insert new settings :Apply new settings Diagram 11: Calibrate transmit chain Page 17 (53)

18 3.4 Overall design decisions Due to its nature, some of the subsystems of the Test Sub-array will have to be RF shielded in order to protect them from the radiated fields in the array, as well as the internally generated RF noise (e.g. clock signals). The following overall design decisions have been taken to address this: The Test Sub-array will contain two RF shielded instrument containers one for the Transmit System and one housing the First Stage Receiver, the Pulse and Steering Control, and the Time and Frequency. This solution will shield the sensitive subsystems by preventing direct electromagnetic interference to these from the Transmit. The design of the internal electronics will also include protection from internally generated electromagnetic noise within the Test Sub-array Page 18 (53)

19 4 System architectural design This chapter describes the technical system that enables the behavior described in section Behavioral design. The Test Sub-array consists of a number of subsystems and these components are defined and described in this chapter. This chapter displays a number of structural diagrams of the Test Sub-array and its subsystems. See section Description of Diagrams for more information. 4.1 System components The following diagram displays an overview of the technical subsystems of the Test Sub-array. The arrowed lines represent the categories of interactions that have been identified in between the subsystems. A category (e.g. status, time and RF) can comprise a number of different signals or information flows. The external systems that the Test Sub-array are interacting with are represented by the ports on the edge of the diagram. For a more comprehensive view this diagram can be read together with the "Operational Domain" diagram. Note that the diagram provides a simplified view, thus all parts and components of the subsystems may not be visualized. Page 19 (53)

20 The Test Sub-array is a phased-array antenna radar system containing 91 crossed dipole antenna elements, a beamformer, a receiver, a transmitter and other subsystems for control, time-keeping et cetera. ibd [block] EISCAT_3D Test Sub-array [Test Sub-array Technical systems High level Overview] au / a: Antenna taf / b: Time and Frequency Time & Sync. Status & EROS control Tx, Rx tu / c: Transmit Control, Rx Time & Sync. pasc / d: Pulse and Steering Control p09: Slow Ethernet Control Status & EROS control Rx, Tx signals Status & EROS control Status & EROS control fsr / e: First Stage Receiv er External flow Power p79: TBD Diagram 12: Test Sub-array Technical systems High level Overview This diagram displays a high level overview of the technical subsystems of the Test Sub-array High level interfaces This section and following subsctions describe the highlevel interfaces of the system.. Information flows - First Stage Receiver Name Information Producer Producer Consumer Consumer c_73e4 EROS control sac N/A fsr N/A c_73e4 Status fsr N/A sac N/A c_73e4 Status inquiry sac p14:slow Ethernet fsr p04:slow Ethernet Page 20 (53)

21 Name Information Producer Producer c_75e7 Measurement data fsr p07:fast Ethernet EISCAT_ 3D Test Sub-array c_89e79 TBD V EISCAT_ 3D Test Sub-array c_b47e4 Time, Synchronization p89:mechanical and Electrical Consumer Consumer fsr p75:fast Ethernet p79:tbd taf p47:slow Ethernet fsr p04:slow Ethernet c_c31e3 Rx, Tx signals tu N/A fsr N/A c_d11e76 Control pasc p11:tbd fsr p76:tbd Page 21 (53)

22 Information flows - Transmit Name Information Producer Producer Consumer Consumer c_73c28 EROS control sac N/A tu N/A c_73c28 Status tu N/A sac N/A c_a1c27 RF tu N/A au N/A c_a1c27 RF au N/A tu N/A c_c31e3 Rx, Tx signals tu N/A fsr N/A c_cd8 Control, Rx pasc N/A tu N/A Information flows - Time and Frequency Name Information Producer Producer Consumer Consumer c_73b47 EROS control sac N/A taf N/A c_73b47 Status taf N/A sac N/A c_b47e4 Time, Synchronization taf p47:slow Ethernet fsr p04:slow Ethernet Page 22 (53)

23 Information flows - Pulse and Steering Control Name Information Producer Producer Consumer Consumer c_73d9 EROS control sac N/A pasc N/A c_73d9 Status pasc N/A sac N/A c_cd8 Rx, Control pasc N/A tu N/A c_d11e76 Control pasc p11:tbd fsr p76:tbd Page 23 (53)

24 Information flows - EROS Name Information Producer Producer Consumer Consumer c_73b47 EROS control sac N/A taf N/A c_73b47 Status taf N/A sac N/A c_73c28 EROS control sac N/A tu N/A c_73c28 Status tu N/A sac N/A c_73d9 EROS control sac N/A pasc N/A c_73d9 Status pasc N/A sac N/A c_73e4 EROS control sac N/A fsr N/A c_73e4 Status inquiry sac p14:slow Ethernet fsr p04:slow Ethernet c_73e4 Status fsr N/A sac N/A Information flows - Antenna Name Information Producer Producer Consumer Consumer c_a1c27 RF tu N/A au N/A c_a1c27 RF au N/A tu N/A Pulse and Steering Control Page 24 (53)

25 The Test Sub-array subsystems are able to operate together as intended through different control pulses or triggers that determine when the different subsystems begin their different tasks. The Pulse and Steering Control contains the Radar Controller, the Exciter(s), a Subsystem Manager, Power supply and an Interlock Control. p13: Slow Ethernet ibd [block] Pulse and Steering Control [Pulse and Steering Control ] Time, Synchronization Time, Synchronization p08: TBD RF +2 dbm e: Exciter[1..*] Interlock rc: Radar Controller[1] control Prompting : High resolution trigger Control there will be 182 (91x2) exciter signals but the number of physical exciter units has not been decided sm: Subsystem Manager[1] ic: Interlock Control[1] Interlock control p12: TBD EROS control ps: Power supply Control Listens to {Control} Status 400 V Diagram 13: Pulse and Steering Control The Subsystem Manager provides slow control input, mainly during system start-up, and system status monitoring, see EROS in section Interactions with surrounding systems and section Subsystem Manager for more information Subsystem p09: Slow Ethernet Exciter The exciter generates RF signals that will be amplified and converted to analog before distributed to the antenna elements. The signals include all information about the frequency, phase and polarization. The exciter is also time synchronized through the WR system. Interlock Control The Interlock control is an autonomous system that supervises the timing of critical signals (e.g. the sequence in which the components are initiated and that everything is loaded correctly) that can severely damage the hardware if not in the correct sequence. If anything incorrect is detected the gating to the SSPA is turned off which in turn turns off the transmit mode. Input: all signals that control the radar. Power supply The power supply TBD. p10: Mechanical and Electrical p11: TBD Page 25 (53)

26 Radar Controller The radar controller (RC) will produce the control signals that run the radar operations. The most important trigger is the one equal to the start of the transmitted pulse. This trigger can be fitted with symmetric offsets for example that the SSPA (in the Transmit ) shall get its power feed before the RF begins and must hold a bit longer than the RF signal. Also of high importance is the pulse containing the length of the waveform. This pulse controls the Test Sub-array subsystems that are active during the transmitting phase, whereas its offsets (so called pre-triggers ) control the Test Sub-array subsystems that are not active during the transmitting phase. Radar control signals are not sent over Ethernet but via separate connectors or industrial bus through hubs. The RC is time synchronized through the WR system. Subsystem Manager The Subsystem Manager consists of a network server program, SubMan, and a Linux computer that SubMan runs on. The Subsystem Manager provides a network-accessible interface between its associated subsystem (a block of hardware with basic software and firmware that implements a set of specific radar functionality) and EROS. The Subsystem Manager implements SubMan that EROS communicates with in order to control and monitor the subsystem. This is enabled by the Subsystem Manager providing a TCP socket listener at a fixed (but configurable) network address. SubMan receives EROS control commands that specify what the subsystem is expected to do and SubMan also receives Status inquiry commands that specify specific information that EROS needs SubMan to return in the form of a Status message. SubMan also issues Notifications to EROS, without being explicitly prompted by EROS, if it detects an anomaly of some kind, e.g. if some predefined conditions are met (e.g. temperature exceeding a set maximum value). Page 26 (53)

27 Informationflows Name Information Producer Consumer c13 RF +2 dbm e N/A Pulse and Steering Control c15 Status sm N/A Pulse and Steering Control p08:tbd p09:slow Ethernet c15 EROS control Pulse and Steering Control p09:slow Ethernet sm N/A c V Pulse and Steering Control p10:mechanical and Electrical ps N/A c18 Control rc N/A Pulse and Steering Control p11:tbd c22 Time, Synchronization Pulse and Steering Control p13:slow Ethernet e N/A c23 Time, Synchronization Pulse and Steering Control p13:slow Ethernet rc N/A c24 Interlock control ic N/A Pulse and Steering Control p12:tbd Page 27 (53)

28 s Name Type Information p08 p09 p10 TBD Slow Ethernet Mechanical and Electrical p11 TBD to *Transmit unit *beamformer unit examples: *ack? p12 p13 TBD Slow Ethernet Network Components Network Components are TBD. Page 28 (53)

29 4.1.4 Antenna The Antenna includes the Antenna Elements, Cables and Connectors and the Mechanical Attachment to Support Structure. The purpose of the antenna array of the Test Sub-array is to transduce the RF signals to electromagnetic waves (or vice versa if in receive mode). The hexagonally shaped antenna array will consist of 91 crossed-dipole Antenna Elements, hence adding up to a total number of 182 dipoles to be sampled. The dipoles are tilted back towards the ground plane (inverted v-shape) to enable good steering without excessive changes in polarization ratio or antenna terminal impedance. The Antenna Elements are mounted on a meshed metallic support structure described in section Support Structure. ibd [block] Antenna [Antenna unit] ae / b: Antenna Element[91] MHz + 57 dbm fc: MHz 182 p01: TBD Diagram 14: Antenna unit The diagram above simply shows the Antenna containing the antenna Element Subsystem p02: Mechanical Attachment Antenna Element Dual polarized crossed inverted V-dipole. Proposed to meet IEC-norms used for outdoor antennas with an expected lifetime of more than 15 years before service. Page 29 (53)

30 Informationflows Name Information Producer Consumer c1 fc: MHz ae N/A Antenna p01:tbd c MHz + 57 dbm Antenna p01:tbd ae N/A s Name Type Information p01 p02 TBD Mechanical Attachment Time and Frequency White Rabbit (WR) is a protocol developed to synchronize nodes in a packet-based network with sub-nanosecond accuracy. The WR network consists of a set of different so called boundary and ordinary clocks in addition to a grand master clock. WR provides the link delay information and clock syntonization (frequency transfer) over the physical layer with Synchronous Ethernet (SyncE). In the SyncE scheme, the WR master (using the reference clock) encodes the outgoing data stream. The same clock is retrieved on the other side of the physical link, and the retrieved frequency can be further distributed. The recovered clock is also always looped back to the WR Master (via the WR Switch) for clock phase alignment with the master. The reference clock uses a GPS clock as the time and frequency standard (TBD). The WR Master functions as the grand master clock and is the source of time and frequency for the other WR clocks in the network. The WR Switch is a boundary clock that synchronizes and syntonizes to the master clock. The reference signals retrieved by the switch are redistributed to syntonize other slave clocks connected to its ports. The WR Slave is an ordinary clock which retrieves the reference signals sent over a link by the WR Master (via the WR Switch) and uses the recovered reference clock (after a phase adjustment) for all its operations. Page 30 (53)

31 ibd [block] Time and Frequency [Time and Frequency ] rc: Reference clock wrm: WR Master 230 V 230 V EROS control p17: Mechanical and Electrical : WR Switch Status Time, Synchronization Status and EROS control sent using SNMP protocol p47: Slow Ethernet Diagram 15: Time and Frequency In summary, the reference clock provides a reference phase for the transmitted and received signals. The WR Master uses a traceable clock to encode data over SyncE. The WR Switch then distributes the clock signal over a 1 Gbit/s Ethernet network (the same network will also be used for inputs and outputs of EROS). The clock is then recovered by the WR Slave which bases its timekeeping on it. The subsystems that are time dependent can retrieve the required time and synchronization to ensure that the system stays synchronized. The Subsystem Manager provides slow control input, mainly during system start-up, and system status monitoring, see section EROS for more information. Note that this subsystem may be subject to change Informationflows Page 31 (53)

32 Name Information Producer Consumer Status wrm p18:slow Ethernet Time and Frequenc y p47:slow Ethernet EROS control Time and Frequenc y p47:slow Ethernet wrm p18:slow Ethernet c V Time and Frequenc y p17:mechanical and Electrical rc p45:mechanical and Electrical c V Time and Frequenc y p17:mechanical and Electrical wrm p26:mechanical and Electrical c44 Time, Synchronization p21:slow Ethernet Time and Frequenc y p47:slow Ethernet s Name Type Information p17 Mechanical and Electrical p47 Slow Ethernet WR time Cables and Connectors The Test Sub-array also includes the Cables and Connectors necessary to connect the different subsystems. The system component includes: the technical solution to send the Radar control signals throughout the system the technical solution to send the Interlock control signals throughout the system Note that the cables and connectors for the Antenna Elements are included in the Antenna as described in section Antenna Transmit unit container The Transmit Container is container containing equipment for the transmit unit. Page 32 (53)

33 ibd [block] Transmit unit container [Transmit unit container] tu: Transmit p30 Control: TBD p32 RF (Tx and Rx): TBD p31 RF (Rx and Tx signals): TBD p29 p28 p27 RF from exciter (s): TBD p55: Mechanical Attachment 3-phase: Mechanical and Electrical 1 Gb: Slow Ethernet Diagram 16: Transmit unit container The diagram shows the Transmit Container and its external interfaces. The container contains the Trasmit. Page 33 (53)

34 s Name Type Information 1 Gb Slow Ethernet 3-phase Control p55 RF (Rx and Tx signals) RF (Tx and Rx) RF from exciter(s) Mechanical and Electrical TBD Mechanical Attachment TBD TBD TBD Climate monitoring equipment This unit will monitor the temperature and humidity inside the Instrument Container described in section Instrument Containers, and will send this information to the container Subsystem Manager s Name Type Information p49 p50 TBD Subsystem Manager The Subsystem Manager consists of a network server program, SubMan, and a Linux computer that SubMan runs on. The Subsystem Manager provides a network-accessible interface between its associated subsystem (a block of hardware with basic software and firmware that implements a set of specific radar functionality) and EROS. The Subsystem Manager implements SubMan that EROS communicates with in order to control and monitor the subsystem. This is enabled by the Subsystem Manager providing a TCP socket listener at a fixed (but configurable) network address. SubMan receives EROS control commands that specify what the subsystem is expected to do and SubMan also receives Status inquiry commands that specify Page 34 (53)

35 specific information that EROS needs SubMan to return in the form of a Status message. SubMan also issues Notifications to EROS, without being explicitly prompted by EROS, if it detects an anomaly of some kind, e.g. if some predefined conditions are met (e.g. temperature exceeding a set maximum value) s Name Type Information p65 TCP socket First Stage Receiver p66 Mechanical and Electrical First Stage Receiver. Subsystem Manager to the external power switch. p67 TBD First Stage Receiver p68 TBD First Stage Receiver p88 Listening TCP socket Transmit The main purpose of the Transmit is to produce high-power RF pulses that are radiated into space by the Antenna Elements. The subsystem consists of power amplifiers, T/R switches, power supply units and a Subsystem Manager (see EROS in section Interactions with surrounding systems and Subsystem Manager for more information). The power amplifiers are used to amplify the RF waveform for transmission and the SSPA is a power amplifier that supports long pulses and high duty cycle waveforms. The T/R Switch shifts the radar system from transmit mode (when the Transmit needs to be connected to the Antenna and disconnected from the receiver) to receive mode (when the T/R Switch will connect the incoming RF signals to the receiver) or vice versa. The following diagram displays the Transmit, its parts, and its external interfaces. Page 35 (53)

36 ibd [block] Transmit [Transmit ] p27: TBD RF +2 dbm su: SSPA s1: SSPA[182] trs: T/R switch[182] 182 fc: MHz MHz + 57 dbm 182 p32: TBD Interlock control interface 182 fc: MHz 182 p31: TBD Control p30: TBD sm: Subsystem Manager ps: Power supply EROS control Status 400 V p28: Slow Ethernet p29: Mechanical and Electrical Diagram 17: Transmit The diagram displays all external interfaces. When the subsystem is in transmitting mode, the RF signal from the Pulse and Steering Control is received by the SSPA unit. After amplification the RF signal is sent to the Antenna Elements via the T/R Switch and a, much attenuated, copy of the RF signal is also sent to the Front End of the First Stage Receiver. During receive mode the incoming RF signal is received by the First Stage Receiver via the T/R Switch Subsystem Power supply The power supply TBD. SSPA The SSPA contains the T/R Switch, and is installed and operated inside the container below the support structure for the antenna sub-array. The SSPA also contains supervisor functions for output power, excess reflected power, excess temperature, and other critical parameters. Subsystem Manager The Subsystem Manager consists of a network server program, SubMan, and a Linux computer that SubMan runs on. The Subsystem Manager provides a network-accessible interface between its associated subsystem (a block of hardware with basic software and firmware that implements a set of specific radar functionality) and EROS. The Subsystem Manager implements SubMan that EROS communicates with in order to control and monitor the subsystem. This is enabled by the Subsystem Manager providing a TCP socket listener at a fixed (but configurable) network address. Page 36 (53)

37 SubMan receives EROS control commands that specify what the subsystem is expected to do and SubMan also receives Status inquiry commands that specify specific information that EROS needs SubMan to return in the form of a Status message. SubMan also issues Notifications to EROS, without being explicitly prompted by EROS, if it detects an anomaly of some kind, e.g. if some predefined conditions are met (e.g. temperature exceeding a set maximum value) Informationflows Name Information Producer Consumer c37 EROS control Transmit p28:slow Ethernet sm N/A c41 Control Transmit p30:tbd su N/A c42 fc: MHz su N/A Transmit c43 fc: MHz su p34:tbd Transmit p31:tbd p32:tbd c MHz + 57 dbm su N/A Transmit p32:tbd Page 37 (53)

38 s Name Type Information Gating section in the Implementation of EISCAT_3 Sub-Array Interlock control interface p27 TBD p28 Slow Ethernet Status examples: *voltage *temperature p29 p30 Mechanical and Electrical TBD 400 V, 3 phase EISCAT_3D Test Sub-Array Tx sample A and Tx sa p31 TBD according to section in the Implementation o should be -30 db p32 TBD RxProtect milestone doc T/R value Page 38 (53)

39 Support Structure As previously described, the Antenna Elements are mounted on a meshed metallic support structure approximately two meters above the ground, thus protecting the elements from snow accumulation and interference caused by vegetation and wildlife. The solution will also enable better conditions for maintenance and will provide a support structure for the Instrument Containers described in the following section. ibd [block] Support Structure [Support Structure] ic: Instrument Container au: Antenna p52: Ground Attachment tuc: Transmit unit container p46: Mechanical Attachment [91] Diagram 18: Support Structure The support structure diagram contains the instrument container transmit unit container and antenna unit s Name Type Information p46 p52 Mechanical Attachment Ground Attachment Instrument Container Some of the sensitive systems and equipment are placed in an instrument container to aid with temperature and humidity control and RF shielding (to protect the internal electronics). Environmental and power monitoring equipment will also be placed in the container to enable remote monitoring and control. The electrical systems located inside the container will also include remote control capabilities to for example allow powering down failed or interfering units. Maintenance and cost are two major factors that will affect the design of the internal layout of the container. The Transmit is placed in its own container in order to meet the requirements described in section 3.7 Overall design decisions. To monitor the state of the Instrument Container, it will house its own Subsystem Manager. Page 39 (53)

40 ibd [block] Instrument Container [The Instrument Container including the systems and components it is housing] tfu: Time and Frequency pscu: Pulse and Steering Control p08 RF to Transmit unit: TBD p47 p11 Control: TBD p10 p09 p17 Time, Synch, EROS exchange: Slow Ethernet cme: Climate monitoring equipment p41 p66 arbeta bort ic sm: Subsystem Manager p05 p04 fsru: First Stage Receiv er : Computing System p53: Mechanical and Electrical p03 p07 Measurement data: Fast Ethernet p51: Mechanical Attachment RF (Rx and Tx signals): TBD Diagram 19: The Instrument Container including the systems and components it is housing The above diagram displays the instrument container and the subsystems located inside of it. The rectangles representing the technical subsystems are dashed to reflect that they are not parts of the instrument container Subsystems Climate monitoring equipment This unit will monitor the temperature and humidity inside the Instrument Container described in section Instrument Containers, and will send this information to the container Subsystem Manager. Subsystem Manager See section Subsystem Manager s Name Type Information Control TBD Page 40 (53)

41 Name Type Information Measure ment data p51 p53 RF (Rx and Tx signals) RF to Transmit unit Time, Synch, EROS exchange Fast Ethernet Mechanical Attachment Mechanical and Electrical TBD TBD Slow Ethernet Page 41 (53)

42 First Stage Receiver The First Stage Receiver consists of the following main subsystems: the receiver Front End, Analogue-to-Digital converter unit, and the First Stage Beamformer. The receiver Front End receives the wide-band, noisy signals from all the individual antenna elements and conditions them so that they are suitable for sampling and further digital processing. The conditioning includes frequency-band limitation by an Anti-aliasing Filter and amplification with a Low Noise Amplifier. The conditioned signals are then sampled with analogue-to-digital converters (ADC) and fed to the First Stage Beamformer. The First Stage Beamformer performs the first few stages of the digital signal processing that ultimately gives the antenna array its characteristic directional sensitivity ( forms the antenna beams ) ibd [block] First Stage Receiv er [First Stage Receiv er ] fc: MHz p03: p58 TBD lna: LNA fe / h: Front End LNA: Power supply aaf: Anti-aliasing filter p59 fc: MHz p80 adc / j: Multi channel ADC 14 or 16 bit WRS / m: WR Slav e p19 p91 p81 ADC / n: Power supply p85 TBD V 14 or 16 bit data TBD V p70 fsb / k: First Stage Beamformer p63 p61 ps: Power supply p64 p62 p77 Measurement data p07: Fast Ethernet p69 SubMan control Status p57 Power on/off TBD V Time, Synchronization SubMan control Control p67 p90 smfsr / p: Subsystem Manager First Stage Receiv er p88 p66 p65 p68 Status c99 Time, Synchronization Status inquiry, EROS control TBD V Notification, Status p79: TBD p04: Slow Ethernet p05: Mechanical and Electrical Diagram 20: First Stage Receiver p76: TBD As shown on the diagram, the First Stage Receiver consists of a Front End (containing filters and power supply), a First Stage Beamformer, a Multichannel ADC (and its power supply), a WR Slave, and a Subsystem Manager. The Subsystem Manager implements SubMan that EROS communicates with in order to control and monitor the subsystem. Note the ADC has been placed between the Front End and the First Stage Beamformer in the diagram but it is up to the designer of the First Stage Receiver if placed inside the Front End or inside of the First Stage Beamformer. Page 42 (53)

43 Subsystem First Stage Beamformer The First Stage Beamformer is used for signal processing and provides discrete spatial filtering across the aperture of the radar array. The system is responsible for sampling the signals from the Antenna Elements and filtering and forming multiple receive beams. Beamforming can, as previously mentioned, reduce the interference signals (external electromagnetic interference) but only if the receiver chain associated with each antenna element remains fairly linear. The First Stage Beamformer introduces carefully calculated, antenna element specific time delays to each of the digitized signals coming from the elements; sums the signals coherently, that is, adds them in the voltage domain rather than in the power domain; and performs the so called IQ-detection which converts a real-valued signal into a complex-valued signal that represent only one side of the original two-sided spectrum. In IQ-detection, the data flow rate, typically expressed in units of a million samples per second (MS/s), is converted from type NN MS/s real to NN/2 MS/s complex. Depending on the used IQ-detection method, the First Stage Beamformer may also shift the signal to near the zero frequency. In addition, the First Stage Beamformer may further reduce the bandwidth of the signal and the data flow rate in a process called decimation. The IQ-detection processing is required to produce a complex-valued sample stream that represents information coming from a particular direction in the sky, that is, the stream corresponds to a particular beam. It is required that up to 10 beams, in different pointing directions, are produced simultaneously. The Beamformer accomplishes this by using the same data samples from the Front End as above, but by using up-to nine other sets of the element-specific time delays and repeating the calculations. Taking into account the available two antenna polarization, a data stream corresponding to up to 20 full bandwidth beams (in 10 directions) will be produced out of the First Stage Beamformer. Front End The band-pass filtering done in the Front End has two main functions. First, it ensures that the signal bandwidth in front of the ADC is compatible with the sampling frequency in terms of the Nyquist criterion for bandpass sampling. The criterion states that the periodic spectral replicas of the analog band, by the sampling frequency, must not overlap. The other task is to prevent unwanted, often very strong, neighboring electromagnetic signals, the out-of-band interference, of entering the digital processing chain. This protection task of the filter can only succeed if the low noise amplifier in front of the filter can tolerate all the extra load caused by the out-of-band interference without losing its linearity, so that no spurious signals are generated directly into the measurement band. Multi channel ADC 14 or 16 bit The ADC digitizes the signals from the Front End and outputs them to the First Stage Beamformer. Power supply Page 43 (53)

44 The power supply TBD. Subsystem Manager First Stage Receiver The Subsystem Manager consists of a network server program, SubMan, and a Linux computer that SubMan runs on. The Subsystem Manager provides a network-accessible interface between its associated subsystem (a block of hardware with basic software and firmware that implements a set of specific radar functionality) and EROS. The Subsystem Manager implements SubMan that EROS communicates with in order to control and monitor the subsystem. This is enabled by the Subsystem Manager providing a TCP socket listener at a fixed (but configurable) network address. SubMan receives EROS control commands that specify what the subsystem is expected to do and SubMan also receives Status inquiry commands that specify specific information that EROS needs SubMan to return in the form of a Status message. SubMan also issues Notifications to EROS, without being explicitly prompted by EROS, if it detects an anomaly of some kind, e.g. if some predefined conditions are met (e.g. temperature exceeding a set maximum value). WR Slave The WR Slave extracts the time and synchronization from the 1 Gb Ethernet network and provides it to the subsystem. The WR Slave consists of specialized WR node cards. Page 44 (53)

45 Informationflows Name Information Producer Consumer c10 TBD V First Stage Receiver p05:mechanical and Electrical fsb N/A c12 Measurement data fsb N/A First Stage Receiver p07:fast Ethernet c2 fc: MHz First Stage Receiver p03:tbd fe p58:tbd c4 Time, Synchronization First Stage Receiver p04:slow Ethernet fe N/A c41 Notification, Status smfsr p65:tcp socket First Stage Receiver p04:slow Ethernet c42 Status inquiry, EROS control First Stage Receiver p04:slow Ethernet smfsr p88:listening TCP socket c46 TBD V First Stage Receiver c51 Control First Stage Receiver p79:tbd smfsr p66:mechanical and Electrical p76:tbd fsb p77:tbd c7 TBD V First Stage Receiver p05:mechanical and Electrical fe N/A c8 TBD V First Stage Receiver p05:mechanical and Electrical fe N/A Page 45 (53)

46 Name Information Producer Consumer c99 Time, Synchronization First Stage Receiver p04:slow Ethernet fsb p62:tbd s Name Type Information p03 TBD for receiving RF signals from the Transmit. p04 Slow Ethernet for exchanging information with EROS and receiving WR Time and Synchronization. p05 Mechanical and Electrical with the Mains Power. p07 Fast Ethernet Specification TBD. p76 TBD to the Radar Controller in the Pulse and Steering. p79 TBD External to Remotely Controlled Power Switch. Power to the Subsystem Manager. 4.2 Concept of execution TBD. This section will display any necessary state machines and/or sequence diagram when the information needed has been gained. Page 46 (53)

47 4.3 design This section will list the different information items that have been identified (see section System components) or proposed for each Information item category Data model The table below describes the information exchanged between the interfaces in the system. In the table symbols and are used to define generalisation respectively aggregation. Generalisation can be interpreted as "a sort of" and aggregation as "part of". Element IK Description Control Time critical control signals from the Radar Controller to the subsystems. The Control category could be comprised of information items such as: * Gating from Pulse and Steering Control to Transmit * T/R value (logical) from Pulse and Steering Control to First Stage Receiver and Transmit * Tx_on signal from Pulse and Steering Control to Transmit * Tx_ack signal from Transmit to Pulse and Steering Control * Rx_protect from Pulse and Steering Control to Transmit * Freq. ctrl signal internal to the Pulse and Steering Control * Delay ctrl signal internal to the Pulse and Steering Control * Ampl. ctrl signal internal to the Pulse and Steering Control * Phase ctrl signal internal to the Pulse and Steering Control Note that an exact specification of the signals is TBD and thus the information in this section may be subject to change. Page 47 (53)

48 EROS control Measurement data RF The EROS control category is comprised of the following information items(eros control command signals): * Test Sub-array start-up signal * Subsystem prime command * Subsystem start-up signal * Subsystem shut-down signal * TBD EROS control signals are sent from EROS to the Subsystem Managers and enable remote controlling of for example system start-up and shut-down. The EROS control signals use the Tcl wire protocol and are sent over the slow Ethernet network. After receiving an EROS control signal, the subsystem is expected to behave in some predefined manner. Note that an exact specification of the signals is TBD and thus the information in this section may be subject to change. 67 Gb/s stream of measurement data containing the resulting beams (2x10 beams) from the signal processing of the First Stage Beamformer. Radio Frequency signal Rx RF Status Status inquiry Received signal. The Status category is comprised of a number of status signals containing the status information requested by the Status inquiry commands. Status signals are sent from the Subsystem Managers to EROS and provides the information needed for EROS to determine the health of the subsystems. The Status signals use the Tcl wire protocol and are send over the slow Ethernet network. The Status inquiry command category is comprised of the following information items (status inquiry command signals): * Excess temperature from Transmit * Excess reflected power from Transmit * LNA_V_in * LNA_I_in * ADC_I_in Page 48 (53)

49 * ADC_V_in * Beamformer_I_in * Beamformer_V_in * Instrument Container Temperature * Instrument Container Humidity * Transmit Operating temperature, T_TU_op * Anti-aliasing operating temperature, T_AAF_op * LNA ambient temperature, T_LNA_amb * Response time, t_re, for subsystem * Component failure, F_comp * Transmit Storage Temperature, T_storage * TBD TBD V Status inquiry commands are sent from EROS to the Subsystem Managers and enable the overall monitoring of the health of the Test Sub-array subsystems. The Subsystem Manager receives the status inquiry command, retrieves the requested information and then returns it back to EROS through status signals. The Status inquiry command signals use the Tcl wire protocol and are sent over the slow Ethernet network. Electric power supply voltage. Time, Synchronization Tx signals RF Time signal containing frequency and synchronization (e.g. pulse-per-second) references used for timekeeping and time measurement. Samples of transmitted signal. Page 49 (53)

50 4.3.2 EROS/Subsystem Manager Message Protocol EROS communicates with SubMan via a single, configurable network address (IP address and port number) by using the Tcl wire protocol, see wire.html The general structure of a command from EROS to SubMan is a Unicode UFT-8 encoded string of space-separated words consisting of command name followed by flags, options, and command arguments: command = name parameter parameter The command structure is compatible with the standard C library routine getopt. The Tcl wire protocol embeds the command string into a communication frame, terminating in the line feed character (UNIX: \n ). The entire message string normally has the following structure: message = { instruction transaction_id { command } } LF The Tcl wire protocol supports three different instruction words, and SubMan supports at least two of them: send and async. instruction = send async Send means that SubMan performs the required task and then sends an explicit reply to the involved EROS client (which is blocked during the execution of the task). Note that everything described in this section must be carried out according to the Tcl wire protocol. Async means that SubMan performs the required task but it will not send a reply of any kind and the involved EROS client will not be blocked and is proceeding immediately after sending its command to SubMan. The async command may for example be used to launch a long-living action in the subsystem. Page 50 (53)

51 5 Requirements Allocation Requirements and requirement allocation are found in the Technical Specification for each subsystem. Page 51 (53)

52 6 Notes The diagrams in this document are created using SysML modeling language. The diagram presents a view of the system or subsystem and may not display all of the information that is available in the underlying system or subsystem model. 6.1 Description of Diagrams In this document both structural and behavioral diagrams are included. In structural diagrams, the different subsystems and components are represented by rectangles that each displays the type of system, the name of that instance, as well as any subsystems (parts) that are of contextual importance. A diagram can also display the interactions between the systems and these interactions are represented by lines. The lines can be arrowed which displays the direction of the flow (that composes the interaction, e.g. flows of information, matter, etc.) and the type of flow (for example control if control signals are sent between some systems) may also be displayed. The diagram below exemplifies a number of different items that can appear on a structural diagram, as described in the previous paragraph. External interfaces, if displayed, are represented by small squares on the diagram edges of the subsystems. Activity diagrams are used to specify behaviors, with a focus on the flow of control and the transformation of inputs into outputs through a sequence of actions. Activity partitions (visualized as the vertical swimlanes on the diagrams) enable you to allocate system behaviors to system structures (for example subsystems and users), i.e. displaying who will do what in which order. The arrows represent the flow between the different actions ( subactivities or tasks) of the activity. On the activity diagrams in this SSDD, the flows simply indicate which action is currently enabled during the execution of the activity. Activity diagrams express the order in which actions are performed as well as which structure performs each action, but they do not offer any mechanism to express which structure invokes each action. In summary, the activity diagram can be said to provide a dynamic view of the system that displays sequences of system tasks or activities that will be carried out, as well as the general flow between these activities over time. [SysML] Page 52 (53)

53 Diagram 21: Interpretation of structural diagrams Page 53 (53)