ISO 20208:2015

INTERNATIONAL ISO
STANDARD 20208
First edition
2015-08-15
Space data and information transfer
systems — Delta-DOR Raw Data
Exchange Format
Systèmes de transfert des informations et données spatiales —
Format d’échange des données brutes Delta-DOR
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
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ii © ISO 2015 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 20208 was prepared by the Consultative Committee for Space Data Systems (CCSDS) (as
CCSDS 506.1-B-1, June 2013) and was adopted (without modifications except those stated in clause 2 of this
International Standard) by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee
SC 13, Space data and information transfer systems.

Recommendation for Space Data System Standards
DELTA-DOR RAW
DATA EXCHANGE
FORMAT
RECOMMENDED STANDARD
CCSDS 506.1-B-1
BLUE BOOK
June 2013
RECOMMENDED STANDARD FOR DELTA-DOR RAW DATA EXCHANGE FORMAT
AUTHORITY
Issue: Recommended Standard, Issue 1
Date: June 2013
Location: Washington, DC, USA
This document has been approved for publication by the Management Council of the
Consultative Committee for Space Data Systems (CCSDS) and represents the consensus
technical agreement of the participating CCSDS Member Agencies. The procedure for
review and authorization of CCSDS documents is detailed in Organization and Processes for
the Consultative Committee for Space Data Systems, and the record of Agency participation
in the authorization of this document can be obtained from the CCSDS Secretariat at the
address below.
This document is published and maintained by:

CCSDS Secretariat
Space Communications and Navigation Office, 7L70
Space Operations Mission Directorate
NASA Headquarters
Washington, DC 20546-0001, USA
CCSDS 506.1-B-1 Page i June 2013
RECOMMENDED STANDARD FOR DELTA-DOR RAW DATA EXCHANGE FORMAT
STATEMENT OF INTENT
The Consultative Committee for Space Data Systems (CCSDS) is an organization officially
established by the management of its members. The Committee meets periodically to address
data systems problems that are common to all participants, and to formulate sound technical
solutions to these problems. Inasmuch as participation in the CCSDS is completely
voluntary, the results of Committee actions are termed Recommended Standards and are
not considered binding on any Agency.
This Recommended Standard is issued by, and represents the consensus of, the CCSDS
members. Endorsement of this Recommendation is entirely voluntary. Endorsement,
however, indicates the following understandings:
o Whenever a member establishes a CCSDS-related standard, this standard will be in
accord with the relevant Recommended Standard. Establishing such a standard
does not preclude other provisions which a member may develop.
o Whenever a member establishes a CCSDS-related standard, that member will
provide other CCSDS members with the following information:
-- The standard itself.
-- The anticipated date of initial operational capability.
-- The anticipated duration of operational service.
o Specific service arrangements shall be made via memoranda of agreement. Neither
this Recommended Standard nor any ensuing standard is a substitute for a
memorandum of agreement.
No later than three years from its date of issuance, this Recommended Standard will be
reviewed by the CCSDS to determine whether it should: (1) remain in effect without change;
(2) be changed to reflect the impact of new technologies, new requirements, or new
directions; or (3) be retired or canceled.
In those instances when a new version of a Recommended Standard is issued, existing
CCSDS-related member standards and implementations are not negated or deemed to be non-
CCSDS compatible. It is the responsibility of each member to determine when such
standards or implementations are to be modified. Each member is, however, strongly
encouraged to direct planning for its new standards and implementations towards the later
version of the Recommended Standard.
CCSDS 506.1-B-1 Page ii June 2013
RECOMMENDED STANDARD FOR DELTA-DOR RAW DATA EXCHANGE FORMAT
FOREWORD
This document is a Recommended Standard for Delta-DOR Raw Data Exchange Format and
has been prepared by the Consultative Committee for Space Data Systems (CCSDS). It has
been developed via consensus of the Delta-DOR Working Group of the CCSDS Systems
Engineering (SEA) area.
The Delta-DOR Raw Data Exchange Format described in this Recommended Standard is the
baseline concept for Delta-DOR data interchange applications that are cross-supported
between Agencies of the CCSDS.
This Recommended Standard establishes a common framework and provides a common
basis for the format of Delta-DOR data exchange between space agencies. It allows
implementing organizations within each Agency to proceed coherently with the development
of compatible derived standards for ground systems that are within their cognizance.
Attention is drawn to the possibility that some of the elements of this document may be the
subject of patent rights. CCSDS shall not be held responsible for identifying any or all such
patent rights.
Through the process of normal evolution, it is expected that expansion, deletion, or
modification of this document may occur. This Recommended Standard is therefore subject
to CCSDS document management and change control procedures, which are defined in
Organization and Processes for the Consultative Committee for Space Data Systems
(CCSDS A02.1-Y-3). Current versions of CCSDS documents are maintained at the CCSDS
Web site:
http://www.ccsds.org/
Questions relating to the contents or status of this document should be addressed to the
CCSDS Secretariat at the address indicated on page i.
CCSDS 506.1-B-1 Page iii June 2013
RECOMMENDED STANDARD FOR DELTA-DOR RAW DATA EXCHANGE FORMAT
At time of publication, the active Member and Observer Agencies of the CCSDS were:
Member Agencies
– Agenzia Spaziale Italiana (ASI)/Italy.
– Canadian Space Agency (CSA)/Canada.
– Centre National d’Etudes Spatiales (CNES)/France.
– China National Space Administration (CNSA)/People’s Republic of China.
– Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)/Germany.
– European Space Agency (ESA)/Europe.
– Federal Space Agency (FSA)/Russian Federation.
– Instituto Nacional de Pesquisas Espaciais (INPE)/Brazil.
– Japan Aerospace Exploration Agency (JAXA)/Japan.
– National Aeronautics and Space Administration (NASA)/USA.
– UK Space Agency/United Kingdom.
Observer Agencies
– Austrian Space Agency (ASA)/Austria.
– Belgian Federal Science Policy Office (BFSPO)/Belgium.
– Central Research Institute of Machine Building (TsNIIMash)/Russian Federation.
– China Satellite Launch and Tracking Control General, Beijing Institute of Tracking
and Telecommunications Technology (CLTC/BITTT)/China.
– Chinese Academy of Sciences (CAS)/China.
– Chinese Academy of Space Technology (CAST)/China.
– Commonwealth Scientific and Industrial Research Organization (CSIRO)/Australia.
– CSIR Satellite Applications Centre (CSIR)/Republic of South Africa.
– Danish National Space Center (DNSC)/Denmark.
– Departamento de Ciência e Tecnologia Aeroespacial (DCTA)/Brazil.
– European Organization for the Exploitation of Meteorological Satellites
(EUMETSAT)/Europe.
– European Telecommunications Satellite Organization (EUTELSAT)/Europe.
– Geo-Informatics and Space Technology Development Agency (GISTDA)/Thailand.
– Hellenic National Space Committee (HNSC)/Greece.
– Indian Space Research Organization (ISRO)/India.
– Institute of Space Research (IKI)/Russian Federation.
– KFKI Research Institute for Particle & Nuclear Physics (KFKI)/Hungary.
– Korea Aerospace Research Institute (KARI)/Korea.
– Ministry of Communications (MOC)/Israel.
– National Institute of Information and Communications Technology (NICT)/Japan.
– National Oceanic and Atmospheric Administration (NOAA)/USA.
– National Space Agency of the Republic of Kazakhstan (NSARK)/Kazakhstan.
– National Space Organization (NSPO)/Chinese Taipei.
– Naval Center for Space Technology (NCST)/USA.
– Scientific and Technological Research Council of Turkey (TUBITAK)/Turkey.
– Space and Upper Atmosphere Research Commission (SUPARCO)/Pakistan.
– Swedish Space Corporation (SSC)/Sweden.
– United States Geological Survey (USGS)/USA.
CCSDS 506.1-B-1 Page iv June 2013
RECOMMENDED STANDARD FOR DELTA-DOR RAW DATA EXCHANGE FORMAT
DOCUMENT CONTROL
Document Title Date Status
CCSDS Delta-DOR Raw Data Exchange June 2013 Current issue
506.1-B-1 Format, Recommended Standard,
Issue 1
CCSDS 506.1-B-1 Page v June 2013
RECOMMENDED STANDARD FOR DELTA-DOR RAW DATA EXCHANGE FORMAT
CONTENTS
Section Page
1 INTRODUCTION. 1-1

1.1 PURPOSE . 1-1
1.2 SCOPE AND APPLICABILITY. 1-1
1.3 CONVENTIONS AND DEFINITIONS . 1-2
1.4 COMMON DELTA-DOR TERMINOLOGY . 1-3
1.5 STRUCTURE OF THE DOCUMENT . 1-3
1.6 REFERENCES . 1-4

2 OVERVIEW . 2-1

2.1 GENERAL . 2-1
2.2 THE DELTA-DOR TECHNIQUE . 2-1
2.3 THE NEED FOR RAW DATA INTERCHANGE . 2-4
2.4 CONVENTIONS FOR IDENTIFIERS . 2-4

3 RAW DATA EXCHANGE FORMAT BASIC STRUCTURE AND CONTENT . 3-1

3.1 OVERVIEW . 3-1
3.2 DELTA-DOR FILES . 3-1

4 OBSERVATION FILE STRUCTURE AND CONTENT . 4-1

4.1 GENERAL . 4-1
4.2 CONTENT OF THE OBSERVATION HEADER SECTION . 4-2
4.3 CONTENT OF SCAN SECTION . 4-3
4.4 CONTENT OF THE ENDING SECTION . 4-6

5 PRODUCT FILE STRUCTURE AND CONTENT . 5-1

5.1 GENERAL . 5-1
5.2 PRODUCT FILE RECORD HEADER DESCRIPTION . 5-3
5.3 PRODUCT FILE RECORD DATA DESCRIPTION . 5-15

6 FILE NAMING CONVENTIONS . 6-1

6.1 GENERAL . 6-1
6.2 FILE NAMES . 6-1

ANNEX A PARAMETERS THAT NEED CONVENTIONS TO BE
SPECIFIED (NORMATIVE) . A-1
CCSDS 506.1-B-1 Page vi June 2013
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CONTENTS (continued)
Section Page
ANNEX B SECURITY, SANA, AND PATENT CONSIDERATIONS
(INFORMATIVE) .B-1
ANNEX C ABBREVIATIONS AND ACRONYMS (INFORMATIVE) . C-1
ANNEX D INFORMATIVE REFERENCES (INFORMATIVE) . D-1
ANNEX E EXAMPLE OF RDEF OBSERVATION FILE (INFORMATIVE) .E-1
Figure
2-1 Delta-DOR Observation Geometry . 2-2
4-1 General Structure of the RDEF Observation File . 4-1
5-1 General Structure of one Product File Record . 5-1
5-2 Detailed Structure of the Product File Record . 5-2
5-3 General Structure of the Header . 5-4
5-4 General Structure of the Data Section of the Record . 5-17

Table
4-1 Description of the Scan Line . 4-4
4-2 Description of the Product File Line. 4-5
5-1 Product File Header . 5-8
5-2 Sample 32-Bit Word Packing . 5-15

CCSDS 506.1-B-1 Page vii June 2013
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1 INTRODUCTION
1.1 PURPOSE
Delta-DOR (Delta Differential One-Way Ranging) is a Very Long Baseline Interferometry
(VLBI) technique that can be used in conjunction with Doppler and ranging data to improve
spacecraft navigation by more efficiently determining spacecraft angular position in the plane
of sky. It involves the use of multiple ground stations, possibly belonging to different
agencies, for simultaneous acquisition of either spacecraft or quasar signals (see
reference [D2]).
This Delta-DOR Raw Data Exchange Format (RDEF) Recommended Standard specifies a
standard format for use in exchanging Delta-DOR raw data among space agencies. Delta-
DOR raw data exchange is required every time the data correlation involves at least one
participating station not belonging to the agency responsible for the correlation.This
document includes specifications on the parameter fields that the data format has been
designed to meet. For exchanges where these specifications do not capture the needs of the
participating agencies another mechanism may be selected.
1.2 SCOPE AND APPLICABILITY
This Recommended Standard contains the specification for a Delta-DOR RDEF designed for
applications involving Delta-DOR raw data interchange among space agencies.
The format here specified can be equally used for collecting and exchanging more general
open loop raw data.
This data format is suited to inter-agency exchanges that involve automated interaction. The
attributes of the RDEF make it primarily suitable for use in computer-to-computer
communication.
The characteristics of the data recording (sampling rate and quantization) are defined within
the RDEF. There is no definition of accuracy for raw Delta-DOR data, and hence no
assessment of accuracy is provided in the exchange format. An assessment of accuracy for
reduced Delta-DOR measurements is outside the scope of this Recommended Standard.
This Recommended Standard defines only the data format and content, but not the means for
its transmission. The method of transmitting the data among partners is beyond the scope of
this document. Data transmission could be based on a CCSDS data transfer protocol, file-
based transfer protocol such as SFTP, stream-oriented media, or other secure transmission
mechanism. In general, the transmission mechanism shall not place constraints on the
technical data content of an RDEF.
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1.3 CONVENTIONS AND DEFINITIONS
1.3.1 NOMENCLATURE
1.3.1.1 Normative Text
The following conventions apply for the normative specifications in this Recommended
Standard:
a) the words ‘shall’ and ‘must’ imply a binding and verifiable specification;
b) the word ‘should’ implies an optional, but desirable, specification;
c) the word ‘may’ implies an optional specification;
d) the words ‘is’, ‘are’, and ‘will’ imply statements of fact.
NOTE – These conventions do not imply constraints on diction in text that is clearly
informative in nature.
1.3.1.2 Informative Text
In the normative sections of this document, informative text is set off from the normative
specifications either in notes or under one of the following subsection headings:
– Overview;
– Background;
– Rationale;
– Discussion.
1.3.2 UNIT NOTATION
The following conventions for unit notations apply throughout this Recommended Standard.
Insofar as possible, an effort has been made to use units that are part of the International
System of Units (SI Units); units are either SI base units, SI derived units, or units outside the
SI that are accepted for use with the SI (see reference [2]), e.g.,
Hz: Hertz
s:  second
1.3.3 BIT AND BYTE ORDERING
In this document, the following convention is used to identify each bit in an 8-bit byte. The
first bit in the byte (i.e., the most right justified when drawing figures and tables) is defined
to be ‘Bit 1’, the following bit is defined to be ‘Bit 2’, and so on up to ‘Bit 8’.
CCSDS 506.1-B-1 Page 1-2 June 2013
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Byte ordering follows the convention of starting with Byte 1 (i.e., the most right justified
when drawing figures and tables) and increasing to the left.
1.4 COMMON DELTA-DOR TERMINOLOGY
Part of the standardization process involves the agreement on common interagency
terminology and definitions that apply to interagency Delta-DOR. The following
conventions apply throughout this Recommended Standard:
baseline: The vector joining two tracking stations.
channel: A slice of the frequency spectrum containing a spacecraft or quasar signal.
raw data: Time-ordered samples of received radio signal voltage.
sample: Instantaneous measurement of a radio frequency signal voltage.
scan: An observation of a radio source, with typical duration of a few minutes.
session: The time period of the Delta-DOR measurement including several scans.
meteo data: meteorological data (consisting of pressure, temperature, and relative humidity).
1.5 STRUCTURE OF THE DOCUMENT
Section 2 provides a general overview of the Delta-DOR technique and introduces the need
of the raw data exchange.
Section 3 describes the basic structure and contents of the CCSDS-recommended RDEF for
Delta-DOR.
Section 4 provides a description of the RDEF observation file.
Section 5 provides details on the RDEF product file.
Section 6 describes the RDEF file naming conventions.
Annex A lists the parameters for which conventions need to be specified.
Annex B discusses security aspects for the RDEF.
Annex C is a list of abbreviations and acronyms applicable to the document.
Annex D provides a list of informative references.
Annex E provides an example of a RDEF Observation File.
CCSDS 506.1-B-1 Page 1-3 June 2013
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1.6 REFERENCES
The following publications contain provisions which, through reference in this text,
constitute provisions of this document. At the time of publication, the editions indicated
were valid. All publications are subject to revision, and users of this document are
encouraged to investigate the possibility of applying the most recent editions of the
publications indicated below. The CCSDS Secretariat maintains a register of currently valid
CCSDS publications.
[1] Information Technology—8-Bit Single-Byte Coded Graphic Character Sets—Part 1:
Latin Alphabet No. 1. International Standard, ISO/IEC 8859-1:1998. Geneva: ISO,
1998.
[2] “The International System of Units (SI).” Bureau International des Poids et Mesures
(BIPM). 
[3] IEEE Standard for Floating-Point Arithmetic. 2nd ed. IEEE Std. 754-2008. New
York: IEEE, 2008.
[4] Time Code Formats. Recommendation for Space Data System Standards, CCSDS
301.0-B-4. Blue Book. Issue 4. Washington, D.C.: CCSDS, November 2010.
[5] Delta-Differential One Way Ranging (Delta-DOR) Operations. Recommendation for
Space Data System Practices, CCSDS 506.0-M-1. Magenta Book. Issue 1.
Washington, D.C.: CCSDS, April 2011.
NOTE – Informative references are provided in annex D.

CCSDS 506.1-B-1 Page 1-4 June 2013
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2 OVERVIEW
2.1 GENERAL
This section provides a high-level overview of the Delta-DOR technique. More details on
the technique can be found in references [5] and [D2]. In particular, reference [D2] provides
a detailed description of the Delta-DOR technique, including guidelines for DOR tone
spectra, guidelines for selecting reference sources, applicable foundation equations, and a
discussion of error sources and measurement accuracy that are not germane to the data
exchange recommendation presented in this document.
2.2 THE DELTA-DOR TECHNIQUE
Very Long Baseline Interferometry (VLBI) is a technique that allows determination of
angular position for distant radio sources by measuring the geometric time delay between
received radio signals at two geographically separated stations. The observed time delay is a
function of the known baseline vector joining the two radio antennas and the direction to the
radio source.
An application of VLBI is spacecraft navigation in space missions where delay
measurements of a spacecraft radio signal are compared against similar delay measurements
of angularly nearby quasar radio signals. In the case where the spacecraft measurements are
obtained from the phases of tones emitted from the spacecraft, first detected separately at
each station, and then differenced, this application of VLBI is known as Delta Differential
One-Way Ranging (‘Delta-DOR’ or ‘∆DOR’). (See figure 2-1.) Even though data
acquisition and processing are not identical for the spacecraft and quasar, both types of
measurements can be interpreted as time delay measurements, and they have similar
information content and similar sensitivity to sources of error (see reference [D2]). The data
produced in such a measurement session are complementary to Doppler and ranging data.
CCSDS 506.1-B-1 Page 2-1 June 2013
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Spacecraft
Quasar
θ
Correlator
Baseline B
c = speed of light
τ= B·cos(θ)/c τ
Figure 2-1 Delta-DOR Observation Geometry
To enable a Delta-DOR measurement, a spacecraft must emit several tones or other signal
components spanning at least a few MHz. The characteristics of the tones are selected based
on the requirements for phase ambiguity resolution, measurement accuracy, efficient use of
spacecraft signal power, efficient use of ground tracking resources, and the frequency
allocation for space research.
The Delta-DOR technique requires that the same quasar and spacecraft be tracked essentially
simultaneously during the same tracking pass, at two distinct radio antennas. Normally, a
Delta-DOR pass consists of three or more scans of data recording, each of a few minutes
duration. A scan consists of pointing the antennas to one radio source and recording the
signal. The antennas must slew to another radio source for the next scan, and so on. The
observing sequence is spacecraft-quasar-spacecraft, quasar-spacecraft-quasar, or a longer
sequence of alternating observations, depending on the characteristics of the radio sources
and the objectives of the measurement session. A minimum of three scans is required to
eliminate clock-epoch and clock-rate offsets and then measure spacecraft angular position.
Normally a three-scan sequence is repeated several times. Once collected, the received
signals are brought to a common site and correlated. A Delta-DOR observable is generated
from a differential one-way range measurement made between the spacecraft and the two
ground antennas, and by a measurement of the difference in time of arrival, at the same two
CCSDS 506.1-B-1 Page 2-2 June 2013
spacecraft delay τ
RECOMMENDED STANDARD FOR DELTA-DOR RAW DATA EXCHANGE FORMAT
stations, of the quasar signal. The observed quantity in a Delta-DOR observation is time
delay for each radio source.
For a spacecraft, the one-way range is determined for a single station by extracting the phases
of two or more signals emitted by the spacecraft. The DOR tones are generated by
modulating a sine wave or square wave onto the downlink carrier at S-band, X-band, or Ka-
band. Either a pure waveform may be used, producing a spectrum of pure tones, or a
modulated waveform may be used, producing a spectrum that more closely resembles the
spectrum of a natural radio source. DOR observables are formed by subtracting the one-way
range measurements generated at the two stations. The station differencing eliminates the
effect of the spacecraft clock offset, but DOR measurements are biased by ground station
clock offsets and instrumental delays.
For measuring the quasar, each station is configured to acquire data from it in frequency
channels centred on the spacecraft tone frequencies. This receiver configuration choice
ensures that the spacecraft-quasar differencing eliminates the effects of ground station clock
offsets and instrumental delays. By selecting a quasar that is close in an angular sense to the
spacecraft, and by observing the quasar at nearly the same time as the spacecraft, the effects
of errors in the modelled station locations, Earth orientation, and transmission media delays
are diminished.
In navigation processing, the delay or DOR observable is modelled for each scan of each
radio source. The measured observable depends on both geometric factors and on delays
introduced by transmission media. Meteo data are provided from each tracking site so that,
possibly in conjunction with other data such as GPS measurements, corrections can be
computed to account for tropospheric and ionospheric path delays. The modelled or
‘computed’ observable is based on geometric parameters and available calibrations for
tropospheric and ionospheric delays. Residuals are formed by subtracting the computed
observables from the measured time delay values. The ‘Delta’ between spacecraft and
quasar observations is generated internal to the navigation processing by subtracting residual
values of quasar observations from residual values of spacecraft observations.
Because each Delta-DOR measurement requires the use of two antennas, and navigation
accuracy is improved by baseline diversity, this technique is highly conducive to interagency
cooperation. Measurements from two baselines are required to determine both components
of angular position, with orthogonal baselines providing the best two-dimensional coverage.
While no agency has enough station complexes to provide orthogonal baselines by itself, the
existing assets of more than one agency today could provide two or more pairs of angularly
separated baselines and good geometric coverage for missions throughout the ecliptic plane.
Stations from different agencies can be used as Delta-DOR data collectors for navigation
purposes, assuming that the infrastructure has been laid to facilitate such cooperation. The
use of Delta-DOR has been very beneficial for numerous NASA, ESA, and JAXA missions,
beginning with Voyager in 1979. Current missions using Delta-DOR for navigation, as of
this writing, include Messenger, New Horizons, Dawn, EPOXI, Rosetta, and Hayabusa. The
technique is planned for future missions such as Mars Science Laboratory (NASA),
BepiColombo (ESA), and Ikaros (JAXA), and its use has become a standard part of many
CCSDS 506.1-B-1 Page 2-3 June 2013
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mission navigation plans. CCSDS standardization will help expand the use of the technique
by allowing interagency cross support.
2.3 THE NEED FOR RAW DATA INTERCHANGE
When performing a Delta-DOR measurement involving two (or more) agencies, raw Delta-
DOR data must be exchanged at least between one of the agencies that has acquired the data
and the agency that runs the correlation process and provides the results. The need of the raw
data exchange intrinsically comes with the characteristics of the measurement that, being an
interferometric technique, calls for the correlation of at least two data streams simultaneously
acquired.
Raw Delta-DOR data are not the only data being exchanged during an interagency Delta-
DOR session. Other data (such as tracking data messages, including meteo data, and orbit
ephemeris messages) must be exchanged among agencies. Such data are objects of other
CCSDS standards (see references [D9], [D10], [D11]) and are not discussed in the present
Recommended Standard. The transfer of information other than Delta-DOR raw data is
discussed in the Delta-DOR Operations Magenta Book (reference [5]) and will not be
included here.
2.4 CONVENTIONS FOR IDENTIFIERS
This Recommended Standard does not specify the conventions to be used for identifiers of
tracking stations, spacecraft, and radio sources. While these objects must be identified to
give meaning to the data, it is outside the scope of this Recommended Standard to specify the
names to be used. These parameters are described as they are introduced throughout the
Recommended Standard and are collected in annex A. Conventions to be used for such
parameters should be negotiated among the participating agencies and formalized as
specified in annex A of reference [5].
If accessible and agreed catalogues for identifiers of tracking stations, spacecraft, and radio
sources are available, they should be preferentially used.

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3 RAW DATA EXCHANGE FORMAT BASIC STRUCTURE AND
CONTENT
3.1 OVERVIEW
Delta-DOR RDEF is realized with two types of files: an Observation File made of a
sequence of ASCII text lines and a Product File made of a sequence of binary data records.
Both files are needed to properly perform the correlation.
The Observation File contains information about the Delta-DOR measurement session.
The Product File contains data collected during the Delta-DOR measurement session.
3.2 DELTA-DOR FILES
3.2.1 OBSERVATION FILE
There shall be one Observation File for each tracking station and for each measurement
session. The Observation File shall be made of a sequence of ASCII text lines (reference [1]).
3.2.2 PRODUCT FILE
3.2.2.1 The content of the Product File shall consist of time-ordered records each
containing two basic types of data structure:
– A Header part;
– A Data part.
3.2.2.2 A Product File shall contain data for a single tracking station.
3.2.2.3 A Product File shall contain data for a single Delta-DOR scan (therefore either
spacecraft or quasar data).
3.2.2.4 A Product File shall contain data for a single frequency channel.

CCSDS 506.1-B-1 Page 3-1 June 2013
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4 OBSERVATION FILE STRUCTURE AND CONTENT
4.1 GENERAL
NOTE – The Observation File contains parameters that are needed to describe the data
recording session and to support data correlation.
4.1.1 The Observation File shall contain:
a) a single Observation Header Section, followed by
b) one or more Scan Sections, followed by
c) an Ending Section.
NOTE – The organization of the Observation File is shown in figure 4-1.
Observation Header Section
Scan Section # 1
Scan Section # 2
•
•
Ending Section
Figure 4-1: General Structure of the RDEF Observation File
4.1.2 Each Section of the Observation File shall consist of data represented in ASCII text
lines.
4.1.3 Each line shall be as follows:
a) It may have variable length up to 180 characters (excluding the termination
character).
b) Only printable ASCII characters and blanks shall be used. Control characters such as
TAB, etc., shall not be used.
c) No blank lines can be used.
d) Each of the specified Sections may contain comment lines. Each comment line shall
start with the character ‘#’.
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e) The first character in each line of an Observation File shall identify the type of
information contained in that line.
NOTE – Details regarding each line type are provided in 4.1.4 and in the following
subsections, as appropriate.
f) One or more ‘blank’ characters shall be used to separate each of the various items
within each line.
g) Each line shall be terminated by a single Line Feed or a single Carriage Return or a
Carriage Return/Line Feed pair or a Line Feed/Carriage Return pair.
4.1.4 Each Section (except for the Ending Section) shall end with a line starting with
character ‘Z’.
4.2 CONTENT OF THE OBSERVATION HEADER SECTION
4.2.1 The Observation Header Section shall consist of as many lines as are needed.
4.2.2 The Observation Header Section shall contain a version line. This line shall start with
the character ‘V’.
4.2.3 The structure of the line shall be as follows:
V VERSION =
4.2.4 where is the version identifier, integer. The version number shall be
synchronised with the one given in the Product File
4.2.5 The Observation Header Section shall contain a single receive station line. This line
shall start with the character ‘R’.
4.2.6 The structure of the line shall be as follows:
R STATION =
4.2.7 where is the station identifier, four ASCII characters long. The Observation
Header Section may optionally contain a single transmitting station line. This line shall start
with the character ‘T’.
4.2.8 The structure of the line shall be as follows:
T STATION =
where is the station identifier, 4 ASCII characters long.
4.2.9 If the data are one-way, the transmitting station line shall be omitted.
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4.3 CONTENT OF SCAN SECTION
NOTE – The Scan Section describes the observation and provides the list of Product
File(s) associated with the scan.
4.3.1 A Scan Section shall contain a single scan line followed by one or more Product File
lines.
4.3.2 To improve readability, the scan Section should also contain comment lines providing
labels for the scan line and the Product File lines.
4.3.3 The scan line shall start with character ‘S’.
4.3.4 The structure of the scan line shall be as follows:
S
NOTE – The parameters are defined in table 4-1.
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Table 4-1: Description of the Scan Line
Item Name Item Description Format Units/ Precision/Range
SCAN_NUM Identifies the scan number, in a 3 digit No units, range 001-999
progressive order. integer
SRC_ID Specifies the source, SC ID or Up to 16 No units, up to 16 characters
Quasar ID. ASCII for quasar, 4 characters for
characters. spacecraft
Syntax is
referenced in
annex A.
START_TIM Specifies the nominal start time YYYY- UTC year, day of the year,
E for the scan. DDDThh:m hour/minute/second,
m:ss precision=1 s, range is unlimited
Time format as per reference [4],
ASCII time code B
STOP_TIME Specifies the nominal stop time YYYY- UTC year, day of the year,
for the scan. DDDThh:m hour/minute/second,
m:ss precision=1 s, range is unlimited
Time format as per reference [4],
ASCII time code B
RA Specifies the Right Ascension Decimal Degrees, range 0 to 360,
of the source. notation decimal notation with no more
Source position is referred to than 16 significant digits.
This field may be filled with
true equator and equinox of
number 999, meaning that no
date and it is corrected for
Right Ascension is provided.
aberration.
DEC Specifies the Declination of the Decimal Degrees, range -90 to +90,
source. notation decimal notation with no more
than 16 significant digits.
Source position is referred to
This field may be filled with
true equator and equinox of
number 999, meaning that no
date and it is corrected for
Declination is provided.
aberration.
TFREQ Specifies the Transmitted Decimal Hz, decimal notation with no
Frequency if the source is a notation more than 16 significant digits.
Spacecraft; if not, TFREQ= 0.
4.3.5 The Product File line shall start with character ‘D’.
4.3.6 There shall be a Product File line for each frequency channel.
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4.3.7 The structure of each Product File line shall be as follows:
D
NOTE – The parameters are defined in table 4-2.
Table 4-2: Description of the Product File Line
Item Name Item Description Format Units/
Precision/Range
DATAFILE Specifies the name of a 39 ASCII No units
Product File recording characters, as
specified in 6.2
COHERENCE_F Identifies whether or not the 1 ASCII No units, ‘T’ for True,
LAG signal is coherent with the character ‘F’ for False
carrier.
If True the fields DOR-MULT
and HARMONIC are used to
compute the tone frequency.
If False the fields FSUB and
HARMONIC are used to
compute the tone frequency.
DOR_MULT Specifies two integers used as A fraction of No units
the numerator and two integer
denominator of a number, numbers
which represents the
fundamental tone as a fraction
of the TFREQ, in case
COHERENCE-FLAG=‘T’;
example: 11/18440.
In case COHERENCE-
FLAG=‘F’, any number is
allowed.
FSUB Specifies the fundamental Decimal Hz, decimal notation
subcarrier frequency, in all notation with no more than 16
cases where such subcarrier is significant digits
not coherent with the carrier.
In case COHERENCE-
FLAG=‘T’, any value is
allowed.
HARMONIC Specifies the subcarrier or Integer No units
coherent tone harmonic
number.
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4.4 CONTENT OF THE ENDING SECTION
4.4.1 The Ending Section shall contain an end line, optionally preceded by one or more log
lines.
4.4.2 Each log line shall begin with the character ‘F’ and may contain information on how
to retrieve receiver messages, data, and log.
4.4.3 The end line shall begin with the ‘E’ character and have the following format:
E *=END=*
NOTE – A sample Observation File is shown in annex E.

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5 PRODUCT FILE STRUCTURE AND CONTENT
5.1 GENERAL
5.1.1 The Product File shall consist of several Records, each one containing exactly one
second of data and related information to correlate such second of data.
5.1.2 Each Record shall consist of data represented in binary format. It shall be made of
two Sections:
a) The Header Section (see 5.2)
b) The Data Section (see 5.3)
NOTE – Figure 5-1 shows the general structure of one Product File Record.
Header section
Record representing
one second of observation
Data section
Figure 5-1: General Structure of one Product File Record
5.1.3 Each Product File shall contain data for one scan, one channel, and one station (i.e.,
for a typical 2-station Delta-DOR sequence with 3 scans and 4 channels there will be 24
files).
5.1.4 The length of the Header Section is fixed as per figure 5-2; the length of the Data
Section is variable and shall be determined by the sample rate and sample size of the
recorded data. The total length of the Data Section sha
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