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CEPT
ECC
Doc PTA(14)056
Electronic Communications Committee
CPG15 PT-A
Noordwijk, The Netherlands
7-10 April 2014
Date issued: 31 March 2014
Source: Russian Federation
Subject: WRC-15 Agenda Item 1.14
PROPOSALS FOR MODIFICATION
OF DRAFT CPM REPORT TEXT ON WRC-15 AGENDA ITEM 1.14
Summary:
The contribution proposes modification of section 2/1.14/5 Methods to satisfy the agenda
item of Draft CPM Report text on WRC-15 Agenda Item (AI) 1.14 by introducing a new
Method C which proposes to keep current definition of Coordinated Universal Time (UTC) as
contained in Recommendation ITU-R TF.460-6 and to keep current Radio Regulations No.
1.14.
Proposals:
PTA is invited to discuss the proposed modifications of Draft CPM Report text on WRC-15
AI 1.14 (see Appendix 1) and in case of approval to submit them for consideration at ITU-R
WP7A meeting as a document agreed by the CEPT.
Background:
Based on the results of the latest ITU-R WP 7A meeting (September, 2013) two Methods
were proposed to satisfy the agenda item (Annex 1 to Doc. 7A/42-E).
Method A proposes to suppress leap seconds mechanism from Recommendation ITU-R
TF.460-6 while keeping name of UTC time scale without changes.
The authors of Method A consider that the proposed approach would solve the difficulties for
systems relying on a continuous time scale. However Method A has two main disadvantages,
including:
- problem related to dissemination of differences to be added to UTC to obtain the solar time
(UT1) arises;
- necessity to update the software and/or hardware for radiocommunication systems using
UTC as approximation to solar time.
Method B was proposed as another option for satisfying the agenda item as one avoiding
disadvantages of Method A. In Method B it is proposed to keep the current definition of UTC
and introduce a continuous atomic time-scale based on TAI and simultaneous broadcasting
these two reference time-scales (current UTC and continuous atomic time scale) on equal
basis.
In that case the existing systems using UTC would become unaffected and the systems
requiring a continuous scale would use a continuous atomic time scale based on TAI.
However Method B would also have disadvantage associated with potential problems of
simultaneous dissemination and usage of two time scales.
Taking into account the above disadvantages of Methods A and B it is proposed to consider
an additional method. It implies keeping without changes both the current definition of the
Coordinated Universal Time (UTC) as contained in Recommendation ITU-R TF.460-6 and
the existing provisions of current Radio Regulations No. 1.14, suppression of Resolution 653
(WRC-12). This method does not exclude the possibility to introduce in Recommendation
ITU-R TF.460-6 additional definitions and modifications and/or materials in relation to
continuous time scales in order to apply them for radiocommunication systems where it is
required.
Appendix 1
Radiocommunication Study Groups
Received:
Source:
Subject: WRC-15 Agenda Item 1.14
Document 7A/
2014
English
-E
Russian Federation1
PROPOSALS FOR MODIFICATION OF
DRAFT CPM REPORT ON WRC-15 AGENDA ITEM 1.14
Introduction
The latest meeting of ITU-R Working Party 7A developed Draft CPM Report on WRC-15 Agenda
Item (AI) 1.14 (Annex 1 to Doc. 7A/42) containing currently two Methods to satisfy the agenda item.
They are:
- Method A implying to suppress leap seconds mechanism from Recommendation ITU-R TF.460-6
while keeping name of UTC time scale without changes;
- Method B proposing to keep the current UTC definition without changes and to introduce a
continuous atomic time scale based on TAI with simultaneous broadcasting these two reference timescales (current UTC and continuous atomic time scale) on equal basis.
However, practical implementation of Methods A and B seems difficult due to:
- in case of Method A the problems related to dissemination of differences to be added to UTC to
obtain solar time (UT1) as well as necessity to update the software and/or hardware for
radiocommunication systems using UTC for approximation to solar time arise;
- in case of Method B, potential problems of concurrent dissemination and usage of two time scales.
In this connection it is proposed to consider an additional method which implies keeping of the current
definition of Coordinated Universal Time (UTC) in Recommendation ITU-R TF.460-6 without
changes. This method does not exclude the possibility to introduce in Recommendation ITU-R
TF.460-6 additional definitions and modifications and/or materials in relation to continuous time
scales in order to apply them for radiocommunication systems where it is required.
Proposals
1
The document is agreed by CEPT
It is proposed to reflect the above new method as Method C in the Draft CPM Report text on WRC-15
AI 1.14 as shown in Annex 1.
Annex 1
PRELIMINARY DRAFT CPM REPORT TEXT
ON WRC-15 AGENDA ITEM 1.14
…
2/1.14/5 Methods to satisfy the agenda item
…
2/1.14/5.3 Method C
No change in definition of Coordinated Universal Time (UTC) specified in Recommendation ITU-R
TF.460-6, no change in provisions of Radio Regulations No. 1.14 and suppression of Resolution 653
(WRC-12).
Editorial note: This method does not exclude the possibility to introduce in Recommendation ITU-R
TF.460-6 additional definitions and modifications and/or materials in relation to continuous time
scales in order to apply them for radiocommunication systems where it is required.
2/1.14/5.3.1
Advantage
The proposed method does not affect radiocommunication systems and legal documentation using
existing definition of UTC specified in Recommendation ITU-R TF.460-6.
2/1.14/5.3.2
[TBD]
…
Disadvantage