kSIST FprEN 17350:2020

SLOVENSKI STANDARD
oSIST prEN 17350:2019
01-julij-2019
SCM - Obrazec za časovno razporejanje in vodenje - Standardizirani format
SCM - Scheduling and Commanding Message - Standard
Raumfahrt - Überwachung der Weltraumlageerfassung - Planungs- und Kommando-
Nachricht
SCM - Message de planification et de commande - Norme
Ta slovenski standard je istoveten z: prEN 17350
ICS:
49.140 Vesoljski sistemi in operacije Space systems and
operations
oSIST prEN 17350:2019 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

SCM - Message de planification et de commande - Raumfahrt - Überwachung der Weltraumlageerfassung

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

If this draft becomes a European Standard, CEN and CENELEC members are bound to comply with the CEN/CENELEC Internal

Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any

This draft European Standard was established by CEN and CENELEC in three official versions (English, French, German). A

version in any other language made by translation under the responsibility of a CEN and CENELEC member into its own

language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.

CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium,

Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,

Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,

Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.Recipients of this draft are invited to submit, with their comments, notification

of any relevant patent rights of which they are aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

© 2019 CEN/CENELEC All rights of exploitation in any form and by any means Ref. No. prEN 17350:2019 E

European foreword ....................................................................................................................................................... 4

0 Introduction ...................................................................................................................................................... 5

1 Scope .................................................................................................................................................................... 6

2 Normative references .................................................................................................................................... 6

3 Terms, definitions, symbols and abbreviations ................................................................................... 6

3.1 Terms and definitions ................................................................................................................................... 6

3.2 Symbols and abbreviations ......................................................................................................................... 7

4 Overview — Context of the document ..................................................................................................... 9

5 General nature of the standard — Documentation within the format ..................................... 10

6 SCM structure and content ........................................................................................................................ 10

6.1 General structure ......................................................................................................................................... 10

6.1.1 General ............................................................................................................................................................. 10

6.1.2 XML document header................................................................................................................................ 12

6.1.3 Segment ........................................................................................................................................................... 13

6.1.4 Observation Block ........................................................................................................................................ 13

6.1.5 Command ........................................................................................................................................................ 13

6.1.6 Schedule Request ......................................................................................................................................... 14

6.2 Nested logical segments in the format.................................................................................................. 14

6.3 Auxiliary messages ...................................................................................................................................... 14

6.4 General rules .................................................................................................................................................. 14

6.4.1 Delay times ..................................................................................................................................................... 14

6.4.2 Unforeseen/unknown delays in direct commanding (“command” segments)...................... 15

6.4.3 Check of validity ........................................................................................................................................... 15

6.4.4 Default behaviour in case of erroneous input ................................................................................... 15

6.4.5 Significance of element order .................................................................................................................. 16

6.4.6 Exchange of SCM files .................................................................................................................................. 16

6.4.7 Time specification ........................................................................................................................................ 16

6.4.8 Leading and trailing empty spaces in XML elements ...................................................................... 16

6.4.9 Case Sensitivity ............................................................................................................................................. 16

6.4.10 Commenting ................................................................................................................................................... 16

6.5 OS Control Computer and OS Scheduler Inputs ................................................................................. 16

6.6 Quantization of Commands/Requests .................................................................................................. 17

6.7 Parameter Types .......................................................................................................................................... 17

7 Detailed SCM Syntax .................................................................................................................................... 18

7.1 Introduction: First-Level Structure ....................................................................................................... 18

7.2 Definition of the segment 'header' ......................................................................................................... 19

7.3 Definition of the segment 'metaData' ................................................................................................... 20

7.4 Definition of the segment 'commonData' ............................................................................................ 22

7.5 Definition of the segment 'command' ................................................................................................... 22

7.5.1 General ............................................................................................................................................................. 22

7.5.2 metaData segment ....................................................................................................................................... 23

7.5.3 Camera segment ........................................................................................................................................... 23

7.5.4 Device segment ............................................................................................................................................. 24

7.5.5 Spectrograph segment ............................................................................................................................... 25

7.5.6 ImageData segment ..................................................................................................................................... 26

7.5.7 Target segment .............................................................................................................................................. 26

7.5.8 CalibrationObservation segment ............................................................................................................ 30

7.5.9 Exposure segment ........................................................................................................................................ 31

7.5.10 Shutter Segment ............................................................................................................................................ 32

7.5.11 Observation segment .................................................................................................................................. 32

7.6 Definition of the segment 'scheduleRequest' ..................................................................................... 33

7.6.1 SCM scheduleRequest segment ................................................................................................................ 33

7.6.2 MetaData segment ........................................................................................................................................ 34

7.6.3 Camera segment ............................................................................................................................................ 35

7.6.4 Device segment .............................................................................................................................................. 35

7.6.5 Spectrograph segment ................................................................................................................................ 35

7.6.6 ImageData segment ..................................................................................................................................... 35

7.6.7 Target segment .............................................................................................................................................. 35

7.6.8 SurveyStrategy segment ............................................................................................................................. 35

7.6.9 Constraints segment .................................................................................................................................... 38

7.6.10 CalibrationObservation segment ............................................................................................................ 46

7.6.11 Exposure segment ........................................................................................................................................ 46

7.6.12 Observation segment .................................................................................................................................. 46

7.7 Macros ............................................................................................................................................................... 46

8 Sequence higher level structures ............................................................................................................ 47

8.1 Higher Level logical structures (“sequence” segments) ................................................................. 47

writing to FITS headers .............................................................................................................................. 49

Annex A (informative) Commanding and Scheduling Message background .......................................... 51

Annex B (informative) Examples ........................................................................................................................... 52

B.1 Commanding a Series of Observations ................................................................................................. 52

B.2 Requesting Follow-up observations two hours apart ..................................................................... 54

Annex C (informative) Survey Strategy Types and Related Parameter Requirements —

Description of Survey Strategies ............................................................................................................. 59

C.1 General ............................................................................................................................................................. 59

C.2 Parameter Requirements for Survey Strategy Type 1 (vertical strip) ...................................... 61

C.3 Parameter Requirements for Survey Strategy Type 2 (horizontal strip) ................................ 61

C.4 Parameter Requirements for Survey Strategy Type 3 (free mosaic) ......................................... 61

Annex D (informative) Handling of Filter Requests ........................................................................................ 62

D.1 Filter specification........................................................................................................................................ 62

D.2 Specifying narrowband filter types (wavelength value) ................................................................ 62

Bibliography ................................................................................................................................................................. 64

This document (prEN 17350:2019) has been prepared by Technical Committee CEN/CLC/JTC 5 “Space”,

This document has been prepared under a mandate given to CEN by the European Commission and the

Annex C (informative) describes the survey strategy types and related parameter requirements.

The “Scheduling and Commanding Messages” (SCM) specifies a standard format for observing system

commanding and scheduling. This document aims to ease the planning and operation processes and to

reduce the effors from researchers that use several different observing systems and/or simulation

The SCM establishes a common language for exchanging information on planning, scheduling, and

a) Facilitate interoperability and enable consistent warning between data originators who supply

The SCM is applicable to ground-based activities related to the planning, scheduling, and execution of

the observations of celestial objects. It is used by planning software, scheduling software, telescope

data file which is used to control an observing system (OS), which contains absolute information on

actions the OS is due to perform, e.g. absolute times and sky coordinates for observations, and which is

read by an OS control computer that still processes part of their content (e.g. conversion of equatorial

coordinates to telescope hardware coordinates, execution of pre-defined standard routines for

calibration processes that are called by a single entry in the command file, etc.) and sends commands to

Note 1 to entry: Opposed to Observing system command files, these files usually do not contain absolute

information on when an OS is due to perform a certain action, but rather constraints that allow a scheduler to

flexibly allocate the requested actions. The scheduler, on the other hand, can write command files which are

commands that are produced by an OS control computer and are selectively sent to the according

Solar System objects whose orbit brings them into close proximity with the Earth, which all have a

perihelion distance < 1.3 astronomical units (the distance Sun - Earth, ~149.6x10^6 km), and which

include near-Earth asteroids (NEAs), near-Earth comets, a number of solar-orbiting spacecraft, and

specific effort to obtain observations of an

interesting object at times subsequent its discovery, with the goal of improving the knowledge of its

Note 1 to entry: Follow-up telescopes are generally distinct from survey telescopes, and operate with a more

close supervision of an observer, which selects the targets in need of follow-up. Survey telescopes may also

observe known objects, thus providing follow-up observations, although these observations are often not the goal

Note 2 to entry: 'Tracking' is used in the SST field and identical to 'follow-up' in the NEO field.

radial distance between an observer and an object at a given instant of time, which is one of the direct

observable that can be derived from a radar observation, by measuring the travelling time of a radio

wave reflected from the object's surface, and which, since ground-based optical astrometry does not

allow to directly determine radial distances, range measurements from radar are extremely powerful

project operating telescopes designed to detect unknown moving objects in the sky, some of which will

Note 1 to entry: Surveys typically operate in a mostly automated way, and can detect and report measurements

complete observation system, i.e. an optical telescope together with its camera, or a radar

The SCM generally uses units that are part of the International System of Units (SI), either base, derived,

or non-SI units that are accepted for use within the SI. The following units are used in the SCM:

In order to simplify the standard and the interface to an observing system control computer or

This document gathers the requirements described in the Proposal for a Telescope Commanding and

The basic application scenarios of the standard are illustrated in Figures 1 and 2, once for the

application as a scheduler input file and once for the application as an OS command file.

In the first case, the SCM file is created by a human operator or an automated planning tool and either

directly submitted to an observation scheduler or retrieved by it from a database. The scheduler creates

an observation schedule based on the targets and constraints provided in the SCM and sends

corresponding commands to the OS control computer. In case of an OS network it is also possible that a

central scheduler sends commands to several OSs. The scheduler can be located at the OS or work

remotely. The scheduler needs to be reasonably “smart” to interpret the constraints in the SCM and to

preferably calculate pointing coordinates from provided object ephemerides or retrieve information on

It is well possible that the observation scheduler passes on the command to the OS control computer via

another SCM, as illustrated in Figure 2. The OS control computer in this case is likely to be allocated

somewhere close to the OS. It needs to be much less “smart” than the scheduler, assuming that in the

typical case it will already be provided by a simple coordinates and timing information.

For individual images, the FITS (Flexible Image Transport System) standard allows the inclusion of a

considerable amount of information in the machine- and human-readable image header. There is thus

no need to duplicate this information in a separate file for observations of several images. The same

applies to information on used hardware in robotic OS networks where observation requests are not

submitted to individual OSs. The information on the OS used can also be written to the images' FITS

headers, as done in the Las Cumbres Observatory Global Telescope Network, for example. In case of

larger campaigns, however, it might be useful to have access to concise observation history in one file

(i.e. which observations have really been carried out, actual observation conditions, …). For the sake of

clearness, it is preferable to have this information in a single file, not interrupted by command or other

To guarantee traceability from an image to the underlying command, the command message format

foresees the option to request the command message ID (and potentially also its location) to be written

An SCM file consists of at least one “observation block” which can be either a “command” or a “schedule

request”. The “header” element contains basic parameters of the message itself. All actual commanding

parameters for the OS are, in the basic case, included in a “command” element. In this element, the

camera to be used is specified, the path and filename where the resulting image file shall be saved are

detailed, information to be written into the image file’s FITS header can be passed on, and the physical

observation parameters are transferred. Hereby, coordinates are defined in decimal degrees, exposure

time in seconds. If more than one observation is desired, another “command” segment can be added at

the end of the file. Overlapping information can be defined for all “commands” in a “commonData”

The standard is described in an XML-based language. The logical layout of an XML document always

follows a tree structure. The higher-level structure of an SCM is shown in Table 4.