Thanks, Craig
Good clarification on the data format from the ships. However, you now
infer that CSPs will perhaps be asked to format messages from ships -
but not all CSPs have signed up to do this (I know of only one). It is
the understanding of many CSPs that the manipulation of the "raw" data
from ships starts at the ASP level. Also, the LRIT coordinator has said
in the past that coordination ("oversight") starts at the ASP level. The
CSP has largely been seen (until now) as purely the comms pipe that
provides the LRIT data from ships to the ASP and to start involving CSPs
in manipulating LRIT data would extend the oversight role.
Writing in specifications for all CSPs would therefore appear to be
premature!
Kind regards
Brian
Brian Mullan
Head, Maritime Safety Services
Inmarsat, 99 City Road, London EC1Y 1AX, UK
Tel: +44 (0)20 7728 1464
Fax: +44 (0)20 7728 1689
Mob: +44 (0)7711 495836
www.inmarsat.com
________________________________
From: Hayley, Craig [mailto:HayleyCR@DFO-MPO.GC.CA]
Sent: 01 June 2007 13:52
To: Brian Mullan
Cc: ccglrit-gcclrit(a)lists.ncf.ca
Subject: RE: [Ccglrit-gcclrit] June 12-14 meeting of the Ad hoc Working
Group onEngineering Aspects of LRIT, Hamburg Germany
Hi All,
I'm please to see a good discussion has developed around this topic.
Hopefully, more discussion on other topics in the documents will be
initiated over the coming week before we meet in Hamburg.
Given the e-mails on this topic, the text (including wording in the
table) should be altered to eliminate any confusion.
I agree that the specific data elements (latititude, longitude, year,
month, day, hour, minute, unique equipment identifier) that the
shipborne equipment transmits is the important information. The "format"
of how those elements are displayed is accomplished by land based
software (not shipborne equipment software). Essentially, an application
piece of software will take those data elements, process them and
display them in a given "format". It has been decided that SOAP messages
(using XML format) will be the back bone of the LRIT communication
system. Thus, the various data elements contained in a given LRIT
message will have to be "formatted" as such. The question of whether
application software residing at the CSP or ASP (not software on the
shipborne equipment) begins to format the data elements into an LRIT
message (SOAP using XML) as defined in the communications document is
another issue. Currently, the document is written such that the CSP (for
the International Data Centre case) begins to build SOAP messages and
pass them to the ASP. We have to define an interface between the ASP and
the CSP for the International Data Centre case. If we allowed CSPs to
transmit information to the ASP using different formats, protocols, etc
than it wouldn't be fair to the ASP. This would add an extra cost burden
on the ASPs given that they would have to support multiple formats,
protocols, etc. Please note that national data centers and regional data
centers are free to define and allow different formats, protocols, etc
from the CSP to the ASP.
The intention of the LRIT communications document shall be to specify
the data elements transmitted by the shipborne equipment as stated in
Brian's previous e-mail:
Shipborne Data Elements:
Latitude -> degrees, minutes and decimal minutes to two decimal places
N / S
Longitude ->degrees, minutes and decimal minutes to two decimal places
E / W
Unique equipment ID -> number
Year -> 4 digit year number
Month -> 2 digit month number
Day -> 2 digit day number
Hour -> 2 digit hour number
Minute -> 2 digit minute number
Regards,
Craig Hayley
________________________________
From: Brian Mullan [mailto:Brian_Mullan@inmarsat.com]
Sent: Friday, June 01, 2007 6:18 AM
To: Hayley, Craig
Cc: ccglrit-gcclrit(a)lists.ncf.ca
Subject: RE: [Ccglrit-gcclrit] June 12-14 meeting of the Ad hoc Working
Group onEngineering Aspects of LRIT, Hamburg Germany
Hi, Hayley
Many thanks for your email. I can agree that the text of the document is
clear; but that the wording in the table is not consistent and appears
even to contradict the text you quote. My copy of the document shows
wording for 1.1.1.1 that is different:
"The intent of this document is to outline the technical specifications
for communication within the international Long-Range Identification and
Tracking (LRIT) system as stated in the terms of reference of resolution
MSC.211(81)."
Your reference is new text in 2.2.2.4 in the copy that I received
(15-02-2007 LRIT ad hoc WG)
In Table 2, the heading indicates "Parameter provided by LRIT Shipborne
Equipment" and then describes the various elements, including specifying
the format. It is clear to me and others that this method of presenting
the information in the table means that the information transmitted by
the shipborne equipment *must* follow the format written in the table.
This is where the difficulty lies - the wording is over-prescriptive and
does not accord with the wording in 2.2.2.4. My original email showed
how, in Inmarsat C position reporting at least, the way the information
is transmitted. Other shipborne systems probably will have their own
format for presenting data to the ASP.
May I suggest, please, that we stick to requiring that the specific data
elements (unique identifier, latitude/longitude and date/time of the
position) are transmitted from the ship and then only start to prescribe
the format for onward transmission from the ASP? In other words, as long
as the shipborne equipment transmits, as a minimum, the required
elements, any format is acceptable. This allows for all approved
shipborne LRIT systems to be offered, no matter in which order or format
the data is presented. This approach will also allow the table to be in
accord with the new wording in 2.2.2.4
I hope that this is clear. Your hard work is very much appreciated and
it is clearly understood that the document remains a "work in progress".
Please don't take my input as criticism - it is not! All I seek is
clarity of the wording for all.
With best wishes
Brian
Brian Mullan
Head, Maritime Safety Services
Inmarsat, 99 City Road, London EC1Y 1AX, UK
Tel: +44 (0)20 7728 1464
Fax: +44 (0)20 7728 1689
Mob: +44 (0)7711 495836
www.inmarsat.com
________________________________
From: Hayley, Craig [mailto:HayleyCR@DFO-MPO.GC.CA]
Sent: 31 May 2007 19:05
To: ccglrit-gcclrit(a)lists.ncf.ca
Cc: Brian Mullan
Subject: RE: [Ccglrit-gcclrit] June 12-14 meeting of the Ad hoc Working
Group onEngineering Aspects of LRIT, Hamburg Germany
Hi Brian,
Thanks for the e-mail. I hope more people will take the time to read the
documents and provide comments. I assume you are referring to the LRIT
communication document.
Please note the following text in the LRIT communications document:
1.1.1.1 The parameters added by the LRIT shipborne equipment
include the latitude, longitude, Time Stamp when the position was
generated, and the shipborne equipment identifier. The "Format" of these
parameters as outlined in table 2 indicates how the parameters shall be
formatted while the information is contained within the LRIT message and
does not specify the format of how the shipborne equipment transmits the
information.
Regarding your concerns with the format of the date/time... The only
difference that I can detect between the date/time you state and what is
in Table 2 of the LRIT communications document is the separators ("-"
versus ":") for the year, month, day, hour and minute. The separator
used to separate the year, month, etc in the date stated in table 2 is
not important and in no way linked to the format coming out of the
shipborne equipment. The format is with respect to SOAP messages
communicated along the various LRIT communication segments. CSPs for the
IDC shall have to "build" SOAP messages complying with table 2 in the
communications document using the format from the ship borne equipment.
The important thing with the time stamp is that seconds are not
transmitted.
Regarding your concerns with the format for latitude... We had a
discussion on your e-mail and the intention was to implement your
recommendation. I can't recall why the "seconds" component of the
latitude didn't change to decimal minutes with a precision of 2 decimal
places. The most likely reason is that I forgot to incorporate this
change in the document due to the numerous requests. My apologies on
this topic. I will make the change for latitude to decimal minutes
unless someone raises a compelling reason not to change. Any body from
the Communications group recall if there was a specific reason why we
didn't make the change (Jilian, Guy, etc.)???
I would like to high light to everyone that these documents are in
constant flux as a result of many requests from different inputs at the
Ad Hoc meeting. Thus, it is important to fully read the documents that
come out of each meeting to ensure that any particular topic of interest
is addressed in a satisfactory manner.
Thanks,
Craig Hayley
System Engineer
Canadian Coast Guard
709-772-7740
________________________________
From: ccglrit-gcclrit-bounces(a)lists.ncf.ca
[mailto:ccglrit-gcclrit-bounces@lists.ncf.ca] On Behalf Of Brian Mullan
Sent: Thursday, May 31, 2007 12:35 PM
To: ccglrit-gcclrit(a)lists.ncf.ca
Subject: Re: [Ccglrit-gcclrit] June 12-14 meeting of the Ad hoc Working
Group onEngineering Aspects of LRIT, Hamburg Germany
Thanks, Tracy
In table 2 I note that the format of date/time is still shown as
YYYY-MM-DD-HH-MM. My earlier email (attached) made comment on this. Also
in Table 2, note appears to have been taken of my comments regarding
latitude/longitude position for Longitude only, but ignores Latitude.
We must not start requiring reformatting for transmitted data that is
already designed into existing shipboard equipment - PLEASE!
Many thanks
Brian
Brian Mullan
Head, Maritime Safety Services
Inmarsat, 99 City Road, London EC1Y 1AX, UK
Tel: +44 (0)20 7728 1464
Fax: +44 (0)20 7728 1689
Mob: +44 (0)7711 495836
www.inmarsat.com
________________________________
From: ccglrit-gcclrit-bounces(a)lists.ncf.ca
[mailto:ccglrit-gcclrit-bounces@lists.ncf.ca] On Behalf Of Peverett,
Tracy
Sent: 29 May 2007 22:27
To: ccglrit-gcclrit(a)lists.ncf.ca
Subject: [Ccglrit-gcclrit] June 12-14 meeting of the Ad hoc Working
Group onEngineering Aspects of LRIT, Hamburg Germany
Second of two e-mails
As promised, attached please find the updated LRIT Communications
specification.
Best regards
Tracy
Tracy Peverett
Senior Policy Analyst
Canadian Coast Guard
Tel: 1-613-990-4046
Fax: 1-613-998-3255
e-mail: peverettT(a)dfo-mpo.gc.ca
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