Study On The Broadcast Control Method Of The BPL Long Wave Time Service Signal

This paper studies rely on the CAS(Chinese Academy of Sciences)"the BPL long wave time service system modernization technical innovation project"and provide the research and the technical support for the project implementation, mainly carry on related research work in the BPL long wave time service signal broadcast control aspect base on the project implementation request. Although GPS has been widely used, BPL is still might not be substituted in the time service aspect's function for an important part of a national infrastructure. BPL used vacuum transmitter originally and the system will use the solid state transmitter after the transformation, with adding the function of the digit broadcast, the time code broadcast and the independent time service.Firstly,BPL time service signal broadcast control system is introduced briefly in this paper, Shaping method of vacuum transmitter broadcast pulse,producing method of broadcast control timer' trigger pulse and the pulse moment of the second control method of BPL time service broadcast are analyzed also.Producing method of timing trigger pulse and moment of the second control merhods of Loran-C pulse signal of solid state transmitter are analyzed and studied. On the basis of these achievements, we put forward pulse moment of the second control method of BPL time service signal:That is using the solid state transmitter timer's 1PPS second signal to trace broadcast control clock room benchmark standard 1PPS second signal, we can realize broadcast signal moment of the second accuracy control by the track survey data from precise calibration to the BPL broadcast signal to adjust the solid state transmitter timer's LPA correspondingly.Digital modulation technology is the foundation of BPL time code broadcast and independent time service. PPM (Pulse Position Modulation) digital modulation methods using in BPL time service system,"Eurofix"digital modulation technology and digital coding technology are introduced in the article. The methods of BPL time code and independent time service broadcast are discussed in detail. BPL time code broadcast and BPL time service broadcast pulse's moment of the second label data acquisition methods are given in the text.The precondition of accuracy control of time service signal is established on the foundation of time service signal's precise calibration. The calibration method of the original BPL time service broadcast control signal is analyzed and studied. We put forward the accurate measurement method of using XN-BPLT solid state transmitter as a platform for measuring the receiver delay,and this method can be further improve fine calibration precision of BPL time service broadcast signal and the timing precision of consumer receiver. In the article, broadcast control accuracy is estimated and analyzed. The results showed that broadcast control accuracy satisfied the BPL long wave technological transformation projects request.