1、QUESTION ITU-R 223/7*, *The role of differential GPS networks in timing applications (1997) The ITU Radiocommunication Assembly, considering a) the growing interest worldwide in the development of networks devoted to land navigation and vehicle localization with uncertainties at the 1 m level or bet
2、ter, based on the Differential GPS (DGPS) technique; b) that a relevant number of components and low cost instruments and devices, e.g. mobile telecommunication systems, are available that can use the correction data supplied in real time by a control centre; c) that GPS-disciplined oscillators are
3、used in increasing numbers in telecommunication applications; d) that the GPS signals are regularly measured in the timing centres for the international traceability of their local time scales; e) that the GPS antenna coordinates of most timing laboratories are known relative to each other with unce
4、rtainties within a few centimetres and that the local coordinated universal time (UTC) time scales are maintained in close agreement with the international time scale UTC, decides that the following Question should be studied 1 Which measurement protocol is suitable for determining differential timi
5、ng errors and which rate of update is adequate to the users needs? 2 What are the formats already in use for providing differential position information and to what extent can differential timing information be included? 3 What are the transmission media that could be used for transmitting the relev
6、ant information that allows a wide coverage area and a simple interface at the user side? 4 What uncertainty can be obtained using such systems for time scale dissemination and for syntonization of oscillators? 5 How could timing centres support the realization of the DGPS navigation networks? furth
7、er decides 1 that the results of the above studies should be included in (a) Recommendation(s); 2 that the above studies should be completed by 2011. _ *In the year 2009, Radiocommunication Study Group 7 extended the completion date of studies for this Question. *This Question should be brought to the attention of Radiocommunication Study Group 8.
