A technical problem is pointed out to meet the requirements to the true-bearing-signal users (RADAR, AIS).
And three kind of techniques of detecting ship's bearing have been considered at NAV 44 (namely as 1] utilization of geomagnetism, 2] independent system (Gyro, Fiber optic gyro, etc.) and 3] utilization of radio wave (GPS, etc.) and though type-approved merchandise of TMHD is required to be marketed by July 2002 when SOLAS new Chapter V comes into effect, it is seemed difficult for TMHD.
The NAV Sub-Committee discussed the draft performance standards of THD proposed by Japan this time and finalized the standard at the TWG (Technical Working Group).
With regard to the magnetic sensor system (magnetic sensor being included in THD), dynamic error test is followed to the performance standard of magnetic compass at footnote as "If the sensing part is a magnetic one it should meet resolution A.382(X) and should be tested separately in accordance with the relevant standard".
The plenary session approved the draft THD performance standards and decided to forward it to MSC73 for adoption. The date of entry into force is expected to be 1 July 2002.
The details of test standards are entrusted to ISO standards. Therefore, the report of the Technical Working group of NAV/46 recorded specially the request for the cooperation between IMO and ISO for the purpose of the development of technical standards.
(Note) ISO/TC 8/SC 6 is going to start a WG to discuss the THD standards.
3. Performance standards for bride watch alarms
In order to prevent an unmanned situation from happening a loss of capability of lookout owing to dozing, suffering a heart or bodily accident, etc. with respect to the navigator in charge of the watch on the bridge, the subject devices give alarm to the navigator in charge of the watch and to the master.
The completion target date of the subject item is 2001, and the discussion about it will be continued to NAV 47 next time. The name was decided as Bridge Navigational Watch Alarm System and the abbreviation BNWAS.
4. World-wide radionavigation system
In TWG'S consideration of the draft amendment to IMO resolution A.860 (20), a part of the definitions of the "service of GNSS" and "GNSS system" in Appendix 1 (terms used in GNSS) and a part of titles and requirements of "system level parameter", "absolute accuracy", and "integrity risk" in Appendix 2 (list of minimum requirements) were amended.
Following the result of consideration at the TWG, the draft amendment to resolution A.860 (20) on maritime policy for the future GNSS was produced. It was decided that this draft amendment should be sent to MSC73 for its approval and also adoption at the 22nd Assembly.
The Sub-Committee agreed unanimously with the action items, under which the draft amendment to resolution A.815 (19) concerning world-wide radionavigation system was included as a new work item among the agenda items of NAV47's work programme.
