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System Design Note 1.03 Created: 14 May 2002 Last modified: 18 November 2003 |
FUNCTIONAL AND PERFORMANCE REQUIREMENTS DOCUMENT
Peter J. McGregor
Institute of Advanced
Studies
Revision
History
|
Revision
No. |
Author & Date |
Approval & Date |
Description |
|
Revision 1 |
Peter J. McGregor |
John Hart |
Draft initial document. |
|
Revision 2 |
Peter J. McGregor |
Jan van Harmelen |
Revised initial document. |
|
Revision 3 |
Peter J. McGregor |
Jan van Harmelen |
Revised for CoDR |
|
Revision 4 |
Jan van Harmelen 2 May 2003 |
Peter J. McGregor 8 May 2003 |
Revised after CoDR |
|
Revision 5 |
Peter J. McGregor |
Mark Jarnyk |
Version presented at CDR |
Contents
5.1
System Functional Requirements
5.2
System Performance Requirements
5.3
Imager Functional Requirements
5.3.1
Imager Wavelength Coverage
5.3.6
Imager Non-Common Path Phase Errors
5.3.10
Imager Pupil Viewer Resolution
5.4
Imager Performance Requirements
5.4.4
Imager System Throughput
5.4.5
Imager Instrumental Background
5.4.8
Imager On-Detector Guide Window Performance
5.4.9
ODGW Tracking Performance
5.4.10
Imager Pupil Viewer Sensitivity
6.1
System Functional Requirements
6.1.2
Instrument Alignment Provision
6.1.3
Mechanical and Thermal Tolerances
6.1.15
Metric Dimensions on Drawings
6.2
System Performance Requirements
6.2.1
Instrument Alignment Maintenance
6.2.2
Cryogenic Cooling System
6.3
Imager Functional Requirements
6.4
Imager Performance Requirements
7.1
Imager Detector Functional Requirements
7.1.2
Imager On-Detector Guide Window
7.1.3
Imager Detector Electrical Interface
7.1.4
Imager Detector Controller
7.2
Imager Detector Performance Requirements
7.2.1
Imager Detector Read Noise
7.2.2
Imager Detector Dark Current
7.2.3
Imager Detector Stability
7.2.4
Imager Detector Maximum Continuous Frame Rate
7.2.5
Imager On-Detector Guide Window Maximum Continuous Frame Rate
8.1
Mechanism Control System Functional Requirements
8.1.1
Mechanism Control System Duplication
8.1.2
Mechanism Control System Operability
8.2
Mechanism Control System Performance Requirements
8.2.2
Impact on Mechanism Accuracy
8.2.3
Impact on Scientific Performance
8.3
Temperature Control System Functional Requirements
8.3.1
Temperature Control System Duplication.
8.3.3
Imager Detector Temperature Control
8.3.4
Limiting Rate of Temperature Change
8.3.6
Safety of Accelerated Warm-Up
8.4
Temperature Control System Performance Requirements
8.4.1
CWS Plate Temperature Stability
8.4.2
Imager Detector Temperature Stability.
9
Electrical and Electronic Requirements.
9.1
Electrical and Electronic Functional Requirements
9.1.4
Cassegrain Cable Wrap Interfaces
10.1
Software Functional Requirements
10.2
Software Performance Requirements
11.1
Cassegrain Rotator Interfaces
11.1.1
Instrument Support Structure Interface.
11.1.3
Electric Power Interface
11.1.4
Cooling Water Interface
11.1.5
Signal, Control, and Data Interfaces
11.2
Control Systems Interfaces
11.2.1
Observatory Control System to
GSAOI Instrument Sequencer
11.2.2 Observatory Control System
to GSAOI Components Controller.
11.2.3 Observatory Control System
to GSAOI Detector Controller
11.2.4 Acquisition and Guidance
Unit to GSAOI Detector Controller
11.2.5
Data Handling System Interface
11.2.6
Interlock System Interface
12.1.1
Transportation Altitudes
12.2.1
Operational Environment
13.1.2
Service and Calibration Manual
13.1.3
Software Maintenance Manual
13.1.6
Drawing Numbering System
13.4
Maintainability and Serviceability
13.4.5
Relative Equipment Arrangements
13.6.1
Toxic Products and Formulations
13.7
Electromagnetic Radiation
13.7.1
Electromagnetic Radiation Generation
13.7.2
Susceptibility to Electromagnetic Radiation
1 Purpose
The Gemini South Adaptive Optics Imager (GSAOI) Operational Concept Definition Document (OCDD) defines the scientific requirements of the GSAOI instrument and describes operational scenarios. These are translated into technical requirements in the GSAOI Functional and Performance Requirements Document (FPRD). Other technical requirements for Gemini facility instruments derive from the GSAOI Design and Fabrication Contract Statement of Work (GEM00334A). The scientific and technical requirements are summarized in this FPRD, and their relationships are identified so that all functional and performance requirements can be traced from top-level science requirements.
The two purposes of the GSAOI FPRD are to provide the Gemini scientific community with an understanding of what GSAOI will do and how quickly or how well it will do it, and to provide engineers with the requirements on which to base the GSAOI design. The design is derived from this document. This document takes precedence over other design and fabrication documents. The design must serve the requirements in this document completely. Every feature of GSAOI should be traceable to a requirement in this document, and there should be no features of GSAOI that are not required by this document.
GSAOI will be designed in stages, with a review after each stage is complete. Comments from the review committee will be folded into the design, so the requirements will change as the design changes. Therefore, this document will be updated as needed after each major design review to maintain the correspondence between requirements and design. This current version reflects the status at the Conceptual Design Review.
2 Applicable Documents
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Document ID |
Source |
Title |
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GEM00334A |
IGPO |
GSAOI Design and Fabrication Contract Statement of Work |
|
RSAA |
GSAOI Operational Concept Definition Document |
|
|
IGPO |
Telescope Structure, Drives, and Brakes to Science Instruments ICD |
|
|
IGPO |
Telescope Control to Science Instruments ICD |
|
|
IGPO |
Interlock System to Science Instruments ICD |
|
|
IGPO |
Instrument Support Structure ICD |
|
|
IGPO |
Instrument Support Structure to Science Instruments ICD |
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|
IGPO |
A&G System to On-Instrument WFS ICD |
|
|
IGPO |
Science Instruments to Observatory Control ICD |
|
|
IGPO |
Science Instruments to Data Handling ICD |
|
|
IGPO |
Science Instruments to System Services ICD |
|
|
IGPO |
On-Instrument Wave Front Sensor ICD |
|
|
IGPO |
OIWFS Feed Optics System ICD |
|
|
IGPO |
OIWFS Camera/Controller ICD |
|
|
IGPO |
The Parameter Definition Format |
|
|
IGPO |
Gemini Electronic Design Specification |
|
|
IGPO |
Gemini Software Design Description |
|
|
IGPO |
Gemini System Error Budget Plan |
|
|
|
AT&T Bell Laboratories, 1988 |
Ott, H. W., Noise Reduction Techniques in Electronic Systems, Second Edition |
3 List of Acronyms
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A&G |
Acquisition and Guidance |
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CAD |
Command Action Directive |
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CAR |
Command Action Response |
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CDROM |
Compact Disc Read Only Memory |
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CICS |
Core Instrument Controller Software |
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CPU |
Central Processing Unit |
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DC |
Detector Controller |
|
DHS |
Data Handling System |
|
EPICS |
Experimental Physics and Industrial Control System |
|
FITS |
Flexible Image Transport System |
|
FPRD |
Functional and Performance Requirements Document |
|
GIS |
Gemini Interlock System |
|
GSAOI |
Gemini South Adaptive Optics Imager |
|
|
HgCdTe Astronomical Wide Area Infrared Imager |
|
ICD |
Instrument Control Document |
|
ICS |
Instrument Control System |
|
IGPO |
International Gemini Project Office ("Gemini" or "the Project") |
|
IOC |
Input-Output Controller |
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ISS |
Instrument Support Structure (the "cube") |
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LAN |
Local Area Network |
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MCAO |
Multi-Conjugate Adaptive Optics |
|
NDR |
Non-Destructive Read |
|
NGS |
Natural Guide Star |
|
NIFS |
Near-infrared Integral Field Spectrograph |
|
NIRI |
Near Infra-Red Imager |
|
OCDD |
Operational Concept Definition Document |
|
OCS |
Observatory Control System |
|
ODGW |
On Detector Guide Window |
|
PPC |
Power PC |
|
RAM |
Random Access Memory |
|
RMS |
Root Mean Square |
|
RSAA |
|
|
SDSU |
|
|
SIR |
Status Information Record |
|
TBD |
To Be Decided |
|
TCS |
Telescope Control System |
|
UPS |
Uninterruptible Power Supply |
|
VME |
Versa
Module |
|
WCS |
World Coordinate System |
4 Introduction
This document represents the current understanding of the
capabilities and performance of the Gemini South Adaptive Optics Imager (GSAOI)
to be designed, fabricated, tested, delivered, and commissioned by the
GSAOI will be the workhorse instrument used with Gemini's Multi-Conjugate Adaptive Optics (MCAO) system. GSAOI is a diffraction-limited imaging instrument. It will use a single imaging scale of 0.02"/pixel and have a square field of view 85" on a side. GSAOI will be equipped with broad band Z, J, H, K′, Ks and K filters and narrow band zero-redshift emission line filters. High sensitivity is essential to achieve the demanding science goals that have been set for the instrument. A pupil viewing system that will allow the internal cold stop to be accurately aligned with the telescope exit pupil will aid in realizing this sensitivity. An On Detector Guide Window (ODGW) will track flexure variations between MCAO and GSAOI at the same wavelength as the science observation, and act as a tip-tilt reference for MCAO when required.
5 Optical Requirements
5.1 System Functional Requirements
5.1.1 MCAO Compatibility
REQ-OCD-0001: GSAOI will accept the MCAO f/34 input beam with a pupil near the telescope secondary mirror.
5.1.2 Imager
REQ-OCD-0002: GSAOI will have an imager channel for science observations.
5.2 System Performance Requirements
5.2.1 Vacuum Environment
REQ-FPR-0001: All optical components and coatings will meet
all performance requirements when operated in a vacuum of less than 10‑5
Torr at operational temperatures down to 65 K.
5.2.2 Thermal Cycling
REQ-FPR-0002: The performance of all optical components and coatings will not be degraded by repeated thermal cycling at a maximum rate of temperature change of 0.25 K/minute over the operating, storage, and transportation temperature ranges.
5.3 Imager Functional Requirements
5.3.1 Imager Wavelength Coverage
REQ-OCD-0004: The imager will operate in the wavelength range from 0.9-2.4 mm.
5.3.2 Imager Spatial Sampling
REQ-OCD-0005: The imager will have a scale of ~ 0.02²/pixel.
5.3.3 Imager Field-of-View
REQ-OCD-0006: The imager will have a field-of-view of > 80²´80².
5.3.4 Imager Cold Stop
REQ-OCD-0007: The imager will include a fixed cold stop at an image of the MCAO exit pupil. The cold stop will be sized so as not to vignette the imager beam while reducing background radiation to the greatest extent possible.
5.3.5 Imager Pupil Viewer
REQ-OCD-0008: The imager will have a facility for viewing an image of the MCAO exit pupil.
5.3.6 Imager Non-Common Path Phase Errors
REQ-OCD-0009: The imager will be capable of measuring low-order wave front errors through the entire optical path to the imager detector with a spatial resolution of ~ 200 mm referenced to the telescope primary mirror.
Notes and Comments:
- Measurement of the wave front error at the imager detector will permit the removal of static aberrations due to the imager optics.
- It is envisaged that this requirement will be met by recording pupil images on either side of focus, analyzing the images with the Roddier program, and inputting the result to the MCAO system as coefficients of low order Zernike polynomials. The ICD is TBD.
5.3.7 Imager Filters
5.3.7.1 Imager Filter Suite
REQ-OCD-0010: The imager will be able to interchange between any of the following filters and will have provision for at least 5 more filters:
|
Item |
Filter |