Date Page
2016-06-30 1(53)
EISCAT Scientific Association
System and Subsystem Design Description
EISCAT3D_PfP
System and Subsystem Design Description 2016-06-30
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Table of Contents
1 SCOPE ........................................................................................................................................... 3
1.1 IDENTIFICATION .......................................................................................................................... 3 1.2 SYSTEM OVERVIEW ..................................................................................................................... 3 1.3 PURPOSE ..................................................................................................................................... 4 1.4 APPLICATION .............................................................................................................................. 4 1.5 DEFINITIONS AND ABBREVIATIONS ............................................................................................. 5
2 REFERENCES .............................................................................................................................. 6
3 SYSTEM-WIDE DESIGN DECISIONS ..................................................................................... 7
3.1 INTERACTIONS WITH SURROUNDING SYSTEMS ............................................................................ 7 3.2 PHYSICAL ENVIRONMENT ........................................................................................................... 9 3.3 BEHAVIORAL DESIGN .................................................................................................................. 9
3.3.1 Boot and re-boot ............................................................................................................. 10 3.3.2 Calibrate receive chain................................................................................................... 12 3.3.3 Transmit .......................................................................................................................... 13 3.3.4 Receive ............................................................................................................................ 14 3.3.5 Subsystem Shutdown ....................................................................................................... 15 3.3.6 Start an Experiment ........................................................................................................ 16 3.3.7 Calibrate transmit chain ................................................................................................. 17
3.4 OVERALL DESIGN DECISIONS .................................................................................................... 18
4 SYSTEM ARCHITECTURAL DESIGN ................................................................................. 19
4.1 SYSTEM COMPONENTS .............................................................................................................. 19 4.1.1 High level interfaces ....................................................................................................... 20 4.1.2 Pulse and Steering Control Unit ..................................................................................... 24 4.1.3 Network Components ...................................................................................................... 28 4.1.4 Antenna Unit ................................................................................................................... 29 4.1.5 Time and Frequency Unit ............................................................................................... 30 4.1.6 Cables and Connectors ................................................................................................... 32 4.1.7 Transmit unit container .................................................................................................. 32 4.1.8 Climate monitoring equipment ....................................................................................... 34 4.1.9 Subsystem Manager ........................................................................................................ 34 4.1.10 Transmit Unit ............................................................................................................. 35 4.1.11 Support Structure ....................................................................................................... 39 4.1.12 Instrument Container ................................................................................................. 39 4.1.13 First Stage Receiver Unit ........................................................................................... 42
4.2 CONCEPT OF EXECUTION ........................................................................................................... 46 4.3 INTERFACE DESIGN ................................................................................................................... 47
4.3.1 Data model ..................................................................................................................... 47 4.3.2 EROS/Subsystem Manager Message Protocol ............................................................... 50
5 REQUIREMENTS ALLOCATION.......................................................................................... 51
6 NOTES ......................................................................................................................................... 52
6.1 DESCRIPTION OF DIAGRAMS ..................................................................................................... 52
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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.
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.
EISCAT_3D Test Sub-array
nc: Network Components cc: Cables and Connectors
ss: Support Structure
au: Antenna Unitic: Instrument Container
fsru: First
Stage
Receiv er Unit
pscu: Pulse
and Steering
Control Unit
tfu: Time and
Frequency
Unit
ic sm: Subsystem Manager
cme: Climate
monitoring
equipment
tuc: Transmit unit container
tu: Transmit Unit
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The support structure contains the three physical main parts Instrument Container,
Transmit Unit and Antenna Unit. There are also Network Components, Cables and
Connectors to connect everything to a complete system.
The instrument container itself contains:
Time and Frequency Unit
First Stage Receiver Unit
Climate monitoring Equipment
Pulse and Steering Control Unit
Subsystem Manger (specific for the Instrument Container)
The Transmit Unit Container simply contains the Transmit Unit and The Transmit
Unit Container simply contains the Transmit Unit and the Antenna Unit 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.
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1.5 Definitions and Abbreviations
Definition Description
AAF Anti-Aliasing Filter
ADC Analog to Digital Converter
CPU Central Processing Unit
dBm 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)
EROS EISCAT Realtime Operating System
LNA Low Noise Amplifier
M&C Monitoring and Control
PfP Preparation for Production
ps picoseconds
RC Radar Controller
RF Radio Frequency
SFDR Spurious Free Dynamic Range
SNR Signal to Noise Ratio
SSDD System and Subsystem Design Description
SSPA Solid State Power Amplifier
VSWR Voltage Standing Wave Ratio
WR White Rabbit
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2 References
The systems engineering work is based on the following documents:
Reference Title
[RCM] EISCAT_3D Radar Control and Monitoring
Subsystem Report
[NGTD] EISCAT_3D: The next generation
international atmosphere and geospace
research radar Technical Description
[Impl] Implementation of EISCAT_3D Test Sub-
Array Final Version June 2016
[MD] 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 wr-
switch-sw-v4.2
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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 Sub-
array. 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.
Diagram 2: Operational domain
The diagram above shows the operational domain, i.e. the EISCAT_3D Test Sub-
array and its surrounding systems.
ibd [block] Operational domain [Operational domain]
Tromsö sitep74
p75
p73
p82
: EISCAT_3D
Test Sub-arrayp74
p75
p73
p82
: Antenna
Calibration
Tower
cs: Computing
System
: EROS
: EROS Power
switch
: Mains Power
1
Gb/s
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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.
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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:
Diagram 3: Function overview
The overall behavior of these sub activities is displayed through activity diagrams in
the following section.
Operate Test Sub-array
TransmitTransmit
Calibrate receiv e chainCalibrate receiv e chain Receiv eReceiv e
Start an ExperimentStart an ExperimentCalibrate transmit chainCalibrate transmit chain
Boot and re-bootBoot and re-boot
Subsystem ShutdownSubsystem Shutdown
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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.
Diagram 4: Warm Start Boot and re-boot
act [Function] Boot and re-boot [Warm Start Boot and re-boot]
Computer SubMan:EROS
Send exit
command
SubMan exitsComputer
restarts SubMan
is SubMan responding to exit command?
Terminate
process through
kill command
Shut down
SubMan
SubMan
restarts
yes
no
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Diagram 5: Cold Start Boot & re-boot after power has returned
act [Function] Boot and re-boot [Cold Start Boot & re-boot after power has returned]
:EROS Power switch Subsystem:Subsystem Manager
:Close external
power switch
:Automatic
computer boot-up
:Run SubMan
:Power up
This may or may not
occur.
:Close power
switch
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
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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.
Diagram 6: Calibrate receive chain
act [Function] Calibrate receiv e chain [Calibrate receiv e chain]
:User:Computing System:First Stage Receiv er
Unit
:Antenna Calibration Tower
:Prepare
calibration tx
:Amplify low
signal
:Perform anti-
aliasing
:Digitize RF
signals
:Calculate offsets
etc
:Process
calibration
signals
Note that this reflects the
simplified flow and hence some
tasks and/or flows have been
omitted from this diagram
:Insert new
settings into the
Beamformer
:Receiv e
calibration
signals
:Implement new
settings
ActivityInitial
ActivityFinal
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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.
Diagram 7: Transmit
act [Function] Transmit [Transmit]
:Antenna Unit:Pulse and Steering Control Unit Transmit unit
High Resolution
Trigger: Send
trigger signal
:Generate & send
RF signal
:Perform internal
system tasks
:Send Control
signals
:Switch to
transmit mode
:Receiv e
generated RF
signals
:Amplify and send
RF signals:Transmit RF
signals
Subsystems have
been primed by
EROS
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.
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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.
Diagram 8: Receive
act [Function] Receiv e [Receiv e]
:Pulse and Steering
Control Unit
:Computing System:First Stage Receiv er Unit:Transmit Unit:Antenna Unit
:Receiv e and
transfer RF
signals
:Receiv e
generated RF
signals
:Amplify low
signal
:Switch to receiv e
mode
:Perform anti-
aliasing
:Perform
beamforming
:Transfer beams
:Digitize RF
signals
:Send Control
signals
:Process
receiv ed beams
:Satellite echo
remov al from data
stream
ActivityInitial
ActivityFinal
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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.
Diagram 9: Subsystem Shutdown
act [Function] Subsystem Shutdown [Subsystem Shutdown]
:EROS Power switch Subsystem:Subsystem Manager:EROS
:Send power off
signal
:Execute
shutdown
process
:Open power
switch
:Perform
shutdown tasks
:Recycle power:Open power
switch
:Close external
power switch
ActivityFinal
ActivityInitial
SubMan responding?
YesNo
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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.
Diagram 10: Start an Experiment
act [Function] Start an Experiment [Start an Experiment]
:Transmit Unit:First Stage Receiv er Unit:Pulse and Steering Control Unit:Time and Frequency Unit:EROS
:Create and Send
Test Sub-array
start-up signal
:Initialize
streaming of
priming
commands
:Receiv e priming
commands
:Perform system
start-up tasks
:Receiv e priming
commands
:Perform system
start-up tasks
:Receiv e time
:Generate and
distribute time
Note that this reflects the simplified flow
and hence some tasks and/or flows have
been omitted from this diagram
:Receiv e priming
commands
:Receiv e time
:Receiv e priming
commands
Continuous flow
:Send subsystem
prepared signal
:Send subsystem
prepared signal
:Send subsystem
prepared signal
Activity final
ActivityInitial
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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.
Diagram 11: Calibrate transmit chain
act [Function] Calibrate transmit chain [Calibrate transmit chain]
UserComputing system?:Antenna Calibration Tower:Pulse and Steering Control Unit :Transmit Unit:User
:Send trigger
signal
:Perform internal
system tasks
:Send Control
signals
:Generate & send
RF signal
:Receiv e
calibration signal
:Receiv e
generated RF
signals
:Insert new
settings
:Sav e and
process
calibration data
:Load calibration
pulse pattern
:Switch to
transmit mode
:Apply new
settings
The settings are applied
to the exciter, but how
this is done is TBD.
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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 Unit, the Pulse and
Steering Control Unit, and the Time and Frequency Unit. This solution will shield
the sensitive subsystems by preventing direct electromagnetic interference to these
from the Transmit Unit.
The design of the internal electronics will also include protection from internally
generated electromagnetic noise within the Test Sub-array
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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.
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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.
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.
4.1.1 High level interfaces
This section and following subsctions describe the highlevel interfaces of the system..
Information flows - First Stage Receiver Unit
Name Information Producer Interface
Producer
Consumer Interface
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
ibd [block] EISCAT_3D Test Sub-array [Test Sub-array Technical systems High lev el Ov erv iew]
p09: Slow Ethernet
pasc / d: Pulse and Steering Control Unit
p09: Slow Ethernet
tu / c: Transmit Unit
p79:
TBD
fsr / e: First Stage Receiv er Unit
p79:
TBD
taf / b: Time and Frequency Unitau / a: Antenna Unit
Control
Time & Sync.
Status & EROS control
Time & Sync.
Status & EROS control
Rx, Tx signals
Status & EROS control
Control, Rx
Status & EROS control
Power
Tx, Rx
External flow
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Name Information Producer Interface
Producer
Consumer Interface
Consumer
c_75e7 Measurement data
fsr p07:Fast Ethernet EISCAT_
3D Test
Sub-array
p75:Fast Ethernet
c_89e79 TBD V
EISCAT_
3D Test
Sub-array
p89:Mechanical
and Electrical
Interface
fsr p79:TBD
c_b47e4 Time,
Synchronization
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
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Information flows - Transmit Unit
Name Information Producer Interface
Producer
Consumer Interface
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 Unit
Name Information Producer Interface
Producer
Consumer Interface
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
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Information flows - Pulse and Steering Control Unit
Name Information Producer Interface
Producer
Consumer Interface
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
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Information flows - EROS
Name Information Producer Interface
Producer
Consumer Interface
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 Unit
Name Information Producer Interface
Producer
Consumer Interface
Consumer
c_a1c27 RF
tu N/A au N/A
c_a1c27 RF
au N/A tu N/A
4.1.2 Pulse and Steering Control Unit
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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 Unit contains the Radar Controller, the Exciter(s), a
Subsystem Manager, Power supply and an Interlock Control.
Diagram 13: Pulse and Steering Control Unit
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.
4.1.2.1 Subsystem
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.
p11:
TBD
p08: TBD
p09:
Slow
Ethernet
p13: Slow
Ethernet
p12:
TBD
p10:
Mechanical
and
Electrical
Interface
ibd [block] Pulse and Steering Control Unit [Pulse and Steering Control Unit]
p11:
TBD
p08: TBD
p09:
Slow
Ethernet
p13: Slow
Ethernet
p12:
TBD
p10:
Mechanical
and
Electrical
Interface
e: Exciter[1..*] rc: Radar Controller[1]
sm: Subsystem Manager[1]
ic: Interlock Control[1]
: High resolution
trigger
ps: Power supply
there will be 182 (91x2)
exciter signals but the
number of physical
exciter units has not
been decided
400 V
Time,
SynchronizationTime,
Synchronization
Status
EROS
control
Interlock
control
Interlock
control Prompting
Control
RF +2
dBm Control
182182
Listens
to
{Control}
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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 Unit) 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).
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4.1.2.2 Informationflows
Name Information Producer Interface Consumer Interface
c13 RF +2 dBm
e N/A Pulse and
Steering
Control
Unit
p08:TBD
c15 Status
sm N/A Pulse and
Steering
Control
Unit
p09:Slow Ethernet
c15 EROS control
Pulse and
Steering
Control
Unit
p09:Slow Ethernet sm N/A
c16 400 V
Pulse and
Steering
Control
Unit
p10:Mechanical
and Electrical
Interface
ps N/A
c18 Control
rc N/A Pulse and
Steering
Control
Unit
p11:TBD
c22 Time,
Synchronization
Pulse and
Steering
Control
Unit
p13:Slow Ethernet e N/A
c23 Time,
Synchronization
Pulse and
Steering
Control
Unit
p13:Slow Ethernet rc N/A
c24 Interlock control
ic N/A Pulse and
Steering
Control
Unit
p12:TBD
System and Subsystem Design Description 2016-06-30
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4.1.2.3 Interfaces
Name Type Information
p08 TBD
p09 Slow Ethernet
p10 Mechanical and
Electrical
Interface
p11 TBD to
*Transmit unit
*beamformer unit
examples:
*ack?
p12 TBD
p13 Slow Ethernet
4.1.3 Network Components
Network Components are TBD.
System and Subsystem Design Description 2016-06-30
Page 29 (53)
4.1.4 Antenna Unit
The Antenna Unit includes the Antenna Elements, Cables and Connectors and the
Mechanical Attachment Interface 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.
Diagram 14: Antenna unit
The diagram above simply shows the Antenna Unit containing the antenna Element.
4.1.4.1 Subsystem
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.
p02: Mechanical
Attachment Interface
p01:
TBD
ibd [block] Antenna Unit [Antenna unit]
p02: Mechanical
Attachment Interface
p01:
TBD
ae / b: Antenna Element[91]
fc:
233.3
MHz
233.3 MHz
+ 57 dBm
182182
System and Subsystem Design Description 2016-06-30
Page 30 (53)
4.1.4.2 Informationflows
Name Information Producer Interface Consumer Interface
c1 fc: 233.3 MHz
ae N/A Antenna
Unit
p01:TBD
c1 233.3 MHz + 57
dBm
Antenna
Unit
p01:TBD ae N/A
4.1.4.3 Interfaces
Name Type Information
p01 TBD
p02 Mechanical
Attachment
Interface
4.1.5 Time and Frequency Unit
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.
System and Subsystem Design Description 2016-06-30
Page 31 (53)
Diagram 15: Time and Frequency Unit
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.
4.1.5.1 Informationflows
p17:
Mechanical
and
Electrical
Interface p47: Slow Ethernet
ibd [block] Time and Frequency Unit [Time and Frequency Unit]
p17:
Mechanical
and
Electrical
Interface p47: Slow Ethernet
wrm: WR Masterrc: Reference
clock
: WR Switch
Status and EROS
control sent using
SNMP protocol
230 V
230
V
EROS
control
Status
Time,
Synchronization
System and Subsystem Design Description 2016-06-30
Page 32 (53)
Name Information Producer Interface Consumer Interface
Status
wrm p18:Slow Ethernet Time and
Frequenc
y Unit
p47:Slow Ethernet
EROS control
Time and
Frequenc
y Unit
p47:Slow Ethernet wrm p18:Slow Ethernet
c28 230 V
Time and
Frequenc
y Unit
p17:Mechanical
and Electrical
Interface
rc p45:Mechanical
and Electrical
Interface
c32 230 V
Time and
Frequenc
y Unit
p17:Mechanical
and Electrical
Interface
wrm p26:Mechanical
and Electrical
Interface
c44 Time,
Synchronization
p21:Slow Ethernet Time and
Frequenc
y Unit
p47:Slow Ethernet
4.1.5.2 Interfaces
Name Type Information
p17 Mechanical and
Electrical
Interface
p47 Slow Ethernet WR time
4.1.6 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 Unit as described in section Antenna Unit.
4.1.7 Transmit unit container
The Transmit Unit Container is container containing equipment for the transmit unit.
System and Subsystem Design Description 2016-06-30
Page 33 (53)
Diagram 16: Transmit unit container
The diagram shows the Transmit Unit Container and its external interfaces. The
container contains the Trasmit Unit.
RF from exciter
(s): TBD
Control:
TBD
1 Gb: Slow
Ethernet
RF (Rx and
Tx signals):
TBD
3-phase:
Mechanical
and
Electrical
Interface
RF (Tx and Rx): TBD
p55: Mechanical Attachment
Interface
ibd [block] Transmit unit container [Transmit unit container]
RF from exciter
(s): TBD
Control:
TBD
1 Gb: Slow
Ethernet
RF (Rx and
Tx signals):
TBD
3-phase:
Mechanical
and
Electrical
Interface
RF (Tx and Rx): TBD
p55: Mechanical Attachment
Interface
p30
p31
p27p28p29
p32
tu: Transmit Unit
p30
p31
p27p28p29
p32
System and Subsystem Design Description 2016-06-30
Page 34 (53)
4.1.7.1 Interfaces
Name Type Information
1 Gb Slow Ethernet
3-phase Mechanical and
Electrical
Interface
Control TBD
p55 Mechanical
Attachment
Interface
RF (Rx
and Tx
signals)
TBD
RF (Tx
and Rx)
TBD
RF from
exciter(s)
TBD
4.1.8 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.
4.1.8.1 Interfaces
Name Type Information
p49
p50 TBD
4.1.9 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
System and Subsystem Design Description 2016-06-30
Page 35 (53)
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).
4.1.9.1 Interfaces
Name Type Information
p65 TCP socket First Stage Receiver Unit
p66 Mechanical and
Electrical
Interface
First Stage Receiver Unit. Subsystem Manager to the external
power switch.
p67 TBD First Stage Receiver Unit
p68 TBD First Stage Receiver Unit
p88 Listening TCP
socket
4.1.10 Transmit Unit
The main purpose of the Transmit Unit 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 Unit
needs to be connected to the Antenna Unit 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 Unit, its parts, and its external
interfaces.
System and Subsystem Design Description 2016-06-30
Page 36 (53)
Diagram 17: Transmit Unit
The diagram displays all external interfaces. When the subsystem is in transmitting
mode, the RF signal from the Pulse and Steering Control Unit 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 Unit. During receive mode the incoming RF signal is
received by the First Stage Receiver Unit via the T/R Switch.
4.1.10.1 Subsystem
Power supply
The power supply TBD.
SSPA Unit
The SSPA Unit 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.
p32:
TBD
p28: Slow Ethernetp29: Mechanical and Electrical
Interface
p31:
TBD
p30:
TBD
p27:
TBD
Interlock control
interface
ibd [block] Transmit Unit [Transmit Unit]
p32:
TBD
p28: Slow Ethernetp29: Mechanical and Electrical
Interface
p31:
TBD
p30:
TBD
p27:
TBD
Interlock control
interface
sm: Subsystem Manager ps: Power supply
su: SSPA Unit
s1: SSPA[182] trs: T/R switch[182]
RF +2 dBm
Control
400 VStatus
EROS
control
fc: 233.3
MHz
233.3 MHz + 57 dBm
fc: 233.3 MHz
182 182
182 182
182
182
System and Subsystem Design Description 2016-06-30
Page 37 (53)
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).
4.1.10.2 Informationflows
Name Information Producer Interface Consumer Interface
c37 EROS control
Transmit
Unit
p28:Slow Ethernet sm N/A
c41 Control
Transmit
Unit
p30:TBD su N/A
c42 fc: 233.3 MHz
su N/A Transmit
Unit
p31:TBD
c43 fc: 233.3 MHz
su p34:TBD Transmit
Unit
p32:TBD
c43 233.3 MHz + 57
dBm
su N/A Transmit
Unit
p32:TBD
System and Subsystem Design Description 2016-06-30
Page 38 (53)
4.1.10.3 Interfaces
Name Type Information
Gating section 3.11.12 in the Implementation of EISCAT_3D Test
Sub-Array
Interlock
control
interface
p27 TBD
p28 Slow Ethernet Status examples:
*voltage
*temperature
p29 Mechanical and
Electrical
Interface
400 V, 3 phase
p30 TBD
p31 TBD according to section 3.11.12 in the Implementation of
EISCAT_3D Test Sub-Array Tx sample A and Tx sample B
should be -30 dB
p32 TBD
RxProtect milestone doc
T/R value
System and Subsystem Design Description 2016-06-30
Page 39 (53)
4.1.11 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.
Diagram 18: Support Structure
The support structure diagram contains the instrument container transmit unit
container and antenna unit.
4.1.11.1 Interfaces
Name Type Information
p46 Mechanical
Attachment
Interface
p52 Ground
Attachment
Interface
4.1.12 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 Unit 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.
p46: Mechanical
Attachment Interface[91]
p52: Ground
Attachment Interface
ibd [block] Support Structure [Support Structure]
p46: Mechanical
Attachment Interface[91]
p52: Ground
Attachment Interfaceau: Antenna Unitic: Instrument Container
tuc: Transmit unit container
System and Subsystem Design Description 2016-06-30
Page 40 (53)
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.
4.1.12.1 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.
4.1.12.2 Interfaces
Name Type Information
Control TBD
Measurement
data: Fast
Ethernet
RF to Transmit
unit: TBD
Time, Synch, EROS
exchange: Slow
Ethernet
RF (Rx and
Tx signals):
TBD
Control: TBD
p51: Mechanical
Attachment Interface
p53: Mechanical and
Electrical Interface
ibd [block] Instrument Container [The Instrument Container including the systems and components it is housing]
Measurement
data: Fast
Ethernet
RF to Transmit
unit: TBD
Time, Synch, EROS
exchange: Slow
Ethernet
RF (Rx and
Tx signals):
TBD
Control: TBD
p51: Mechanical
Attachment Interface
p53: Mechanical and
Electrical Interface
p07p03
p04p05
fsru: First Stage Receiv er Unit
p07p03
p04p05
p08
p11
p09p10
pscu: Pulse and Steering Control Unitp08
p11
p09p10
p47
p17
tfu: Time and Frequency Unit
p47
p17
p41
arbeta
bort
p66
ic sm: Subsystem Manager
p41
arbeta
bort
p66
cme: Climate monitoring
equipment: Computing System
System and Subsystem Design Description 2016-06-30
Page 41 (53)
Name Type Information
Measure
ment data
Fast Ethernet
p51 Mechanical
Attachment
Interface
p53 Mechanical and
Electrical
Interface
RF (Rx
and Tx
signals)
TBD
RF to
Transmit
unit
TBD
Time,
Synch,
EROS
exchange
Slow Ethernet
System and Subsystem Design Description 2016-06-30
Page 42 (53)
4.1.13 First Stage Receiver Unit
The First Stage Receiver Unit 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”)
Diagram 20: First Stage Receiver Unit
As shown on the diagram, the First Stage Receiver Unit 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 Unit if placed inside the Front End or inside of the First Stage Beamformer.
p79: TBD
p07: Fast
Ethernet
p05:
Mechanical
and
Electrical
Interface
p04:
Slow
Ethernet
p03:
TBD
p76: TBD
ibd [block] First Stage Receiv er Unit [First Stage Receiv er Unit ]
p79: TBD
p07: Fast
Ethernet
p05:
Mechanical
and
Electrical
Interface
p04:
Slow
Ethernet
p03:
TBD
p76: TBD
p61
p63
p64 p62
p70
p77
fsb / k: First Stage Beamformer
p61
p63
p64 p62
p70
p77
p57
p59
p58
p69
fe / h: Front End
p57
p59
p58
p69
aaf: Anti-aliasing
filter
lna: LNA
ps: Power supply
LNA: Power
supply
p80
p81
adc / j : Multi channel
ADC 14 or 16 bit
p80
p81
p85
p91
ADC / n: Power supply
p85
p91
p19
WRS / m: WR Slav e
p19
p65
p68
p67
p66p88
p90
smfsr / p: Subsystem
Manager First Stage
Receiv erp65
p68
p67
p66p88
p90
TBD V
TBD
V
TBD V
TBD V
Time,
Synchronization
Status inquiry,
EROS control
Time,
Synchronization
fc: 233.3 MHz
fc: 233.3
MHzMeasurement
data
Control
14 or 16 bit data
Status
SubMan controlPower on/off
Notification, Status
Status
SubMan
control
c99
System and Subsystem Design Description 2016-06-30
Page 43 (53)
4.1.13.1 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
System and Subsystem Design Description 2016-06-30
Page 44 (53)
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.
System and Subsystem Design Description 2016-06-30
Page 45 (53)
4.1.13.2 Informationflows
Name Information Producer Interface Consumer Interface
c10 TBD V
First
Stage
Receiver
Unit
p05:Mechanical
and Electrical
Interface
fsb N/A
c12 Measurement data
fsb N/A First
Stage
Receiver
Unit
p07:Fast Ethernet
c2 fc: 233.3 MHz
First
Stage
Receiver
Unit
p03:TBD fe p58:TBD
c4 Time,
Synchronization
First
Stage
Receiver
Unit
p04:Slow Ethernet fe N/A
c41 Notification,
Status
smfsr p65:TCP socket First
Stage
Receiver
Unit
p04:Slow Ethernet
c42 Status inquiry,
EROS control
First
Stage
Receiver
Unit
p04:Slow Ethernet smfsr p88:Listening
TCP socket
c46 TBD V
First
Stage
Receiver
Unit
p79:TBD smfsr p66:Mechanical
and Electrical
Interface
c51 Control
First
Stage
Receiver
Unit
p76:TBD fsb p77:TBD
c7 TBD V
First
Stage
Receiver
Unit
p05:Mechanical
and Electrical
Interface
fe N/A
c8 TBD V
First
Stage
Receiver
Unit
p05:Mechanical
and Electrical
Interface
fe N/A
System and Subsystem Design Description 2016-06-30
Page 46 (53)
Name Information Producer Interface Consumer Interface
c99 Time,
Synchronization
First
Stage
Receiver
Unit
p04:Slow Ethernet fsb p62:TBD
4.1.13.3 Interfaces
Name Type Information
p03 TBD Interface for receiving RF signals from the Transmit Unit.
p04 Slow Ethernet Interface for exchanging information with EROS and
receiving WR Time and Synchronization.
p05 Mechanical and
Electrical
Interface
Interface with the Mains Power.
p07 Fast Ethernet Specification TBD.
p76 TBD Interface to the Radar Controller in the Pulse and Steering
Unit.
p79 TBD External Interface 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.
System and Subsystem Design Description 2016-06-30
Page 47 (53)
4.3 Interface design
This section will list the different information items that have been identified (see
section System components) or proposed for each Information item category.
4.3.1 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 Unit to Transmit Unit
* T/R value (logical) from Pulse and Steering Control Unit to
First Stage Receiver Unit and Transmit Unit
* Tx_on signal from Pulse and Steering Control Unit to Transmit
Unit
* Tx_ack signal from Transmit Unit to Pulse and Steering
Control Unit
* Rx_protect from Pulse and Steering Control Unit to Transmit
Unit
* Freq. ctrl signal internal to the Pulse and Steering Control Unit
* Delay ctrl signal internal to the Pulse and Steering Control Unit
* Ampl. ctrl signal internal to the Pulse and Steering Control
Unit
* Phase ctrl signal internal to the Pulse and Steering Control Unit
Note that an exact specification of the signals is TBD and thus
the information in this section may be subject to change.
System and Subsystem Design Description 2016-06-30
Page 48 (53)
EROS control
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.
Measurement data
67 Gb/s stream of measurement data containing the resulting
beams (2x10 beams) from the signal processing of the First Stage
Beamformer.
RF
Radio Frequency signal
Rx
△RF
Received signal.
Status
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.
Status inquiry
The Status inquiry command category is comprised of the
following information items (status inquiry command signals):
* Excess temperature from Transmit Unit
* Excess reflected power from Transmit Unit
* LNA_V_in
* LNA_I_in
* ADC_I_in
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* ADC_V_in
* Beamformer_I_in
* Beamformer_V_in
* Instrument Container Temperature
* Instrument Container Humidity
* Transmit Unit 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 Unit Storage Temperature, T_storage
* TBD…
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.
TBD V
Electric power supply voltage.
Time,
Synchronization
Time signal containing frequency and synchronization (e.g.
pulse-per-second) references used for timekeeping and time
measurement.
Tx signals
△RF
Samples of transmitted signal.
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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
https://core.tcl.tk/tcllib/doc/trunk/embedded/www/tcllib/files/modules/comm/comm_
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.
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5 Requirements Allocation
Requirements and requirement allocation are found in the Technical Specification for
each subsystem.
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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]
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Diagram 21: Interpretation of structural diagrams
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