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54   COT Division, 1st Session-Final Report
use of responder systems for identification is agreed, but no recommendations are made regarding the detailed requirements of responders or the technical merits of alternative design proposals.
The necessity of knowing at the ground station the accurate height of all aircraft is agreed and it is recognized that direct measurement of height from the ground with the required accuracy is impracticable. There is a necessity, therefore, for automatic transmission of height information from the aircraft.
The Committee envisages that the transmission of information from the aircraft regarding position, height and identity will be made on a responder system. The Committee agrees that, in addition to ground radar surveillance in the approach zone, precision monitoring during final approach, and also during take-off is essential.
4.4.-CONSIDERATION OF MOVEMENT AREA CONTROL
In considering the traffic control requirements for the movement area, Appendix A to Section VII of the Final Report was used as a basis for discussion.
The Committee adopted the recommendation that primary radar should be used in the movement area.
Discussing the methods of identification, the Committee further suggests that communication is necessary to all vehicles normally using the movement area. It is suggested, as an interim measure, that VHF direction-finders might be used for identification of vehicles and aircraft.
The Committee agrees with the recommendation regarding proposals for instruction and guidance. It further recommends that whenever possible the equipment used in area and approach traffic control zones should be used in the movement area as well.
It is regarded as necessary that aircraft and vehicles in the movement area must be able not only to determine their position, but to receive, and act on, instructions from the control agency.
Mechanisms actuated by the passage of vehicles or aircraft appear worth consideration for aerodrome ground traffic guidance.
5.-Discussion on Functional Requirements for Long-Range Aids to Air Navigation
5.1.-METHOD OF POSITION FIXING
Position lines are unlikely to coincide with parallels of latitude and meridians of longitude and are unlikely to have their origin within the chart being used; therefore, the precise shape of position lines is unimportant since charts will have to be overprinted.
The relative merits of short-based (angular) and wide-based (hyperbolic) systems have been discussed. The short-based system demands extreme accuracy of instrumentation, whereas the wide-based system, using different parts of the ether, may suffer inaccuracies from this cause which have not been fully investigated. The Committee recommends that both lines of attack be pursued.
5.2.-ABILITY TO FOLLOW ANY OPERATIONALLY DESIRABLE TRACK
The Committee notes the requirement of Section I, Paragraph 8.1.2, and the implication that radio via a computer should provide the sole means of navigation on long-distance routes. The importance and value of such a step is appreciated. A possible solution, it is considered, may be found in a dead reckoning computer periodically corrected by radio information.
5.3.-ALTIMETRY
The Committee notes that there are really three requirements: moderate accuracy for pressure pattern flying, high accuracy for reporting meteorological data and low level altimetry for monsoon flying. It is hoped that all three requirements can be met in a single instrument. The Committee recognizes that the greater the accuracy of the altimeter, the lower the latitude to which pressure pattern flying can be used. 
6.-Discussion on Operational Requirements for Radio Aids to Collision Warning
GENERAL CONSIDERATIONS
The Committee endorses the statement in Section I, Paragraph 9, that the fundamental means