Craig

 

Many thanks for your helpful response to Brian.  Wearing both my hats – as intergovernmental overseer of Inmarsat’s safety communication services and as the Co-ordinator I would like to enter a plea for simplicity here: meaning from my perspective I would very much prefer to see consistency with existing norms in the standards we adopt for LRIT, unless there is a compelling reason to go another way.  We have unwittingly generated a number of inconsistencies in the past in IMO, we need to be sure of what we’re doing here.  I suspect we are seeing a clash of cultures in this, in that computer data practice may very well differ significantly from that used at the operational level in other maritime applications.  I do not at present see the reasoning behind the date/time format you are adopting – given that  have not participated in the deliberations of your Comms group up to now.  I don’t want to ask you go over old ground again just for my benefit, but I do ask that you review the logic behind what you propose so as to be sure there are sound and valid reasons for the decision you are taking in this respect.

 

Best wishes

 

 

 

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@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@lists.ncf.ca
Subject: Re: [Ccglrit-gcclrit] June 12-14 meeting of the Ad hoc Working Group onEngineering Aspects of LRIT, Hamburg Germany

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