Development of Precision Time and Frequency Comparison System Using a Broadcasting Satellite

通过在电视信号中使用同步脉冲和彩色副载波，我们可以在远距离上精确地比较时间和频率。本研究的目的是利用卫星广播电视信号实现时间和频率的精确比对。我们得到了以下结果：1.北海道大学(札幌)和邮电部无线电研究实验室(东京)利用广播卫星BS-2a进行了时间比较。我们对两个测量系统的延迟时间差进行了修正。此外，我们还利用预测的轨道数据修正了与广播卫星的传播延迟时间之差。结果表明，广播卫星的测量精度约为0.1&lt；微秒。实验还表明，如果在两个接收点使用相同的测量系统，则可实现约10毫微秒的精度。使用广播卫星BS-2a对北海道大学和鹿儿岛大学(鹿儿岛)进行了频率比较。多普勒频移的产生是因为广播卫星围绕地球静止轨道漂移。札幌和鹿儿岛的多普勒位移值不同。然后，由于残留的多普勒频移，频率比较误差(df/f)在&lt；10^(10)&gt；中只有几个部分。然而，结果表明，如果用广播卫星的预测轨道数据对测量结果进行修正，误差在&lt；10^(-11)&gt；量级。这种比较方法是通过廉价的卫星广播接收设备和简单的脉冲和副载波提取装置来实现的。可以说，从经济性和普及性的角度来看，该方法是有优势的。

We may compare time and frequency precisely over long distance by using a synchronization pulse and color subcarrier in a television signal. The purpose of this research was to realize precision time and frequency comparison by means of a satellite broadcasting television signal. We obtained the following results.1. Time comparison was carried out between Hokkaido University ( Sapporo ) and the Radio Research Laboratories, Ministry of Posts and Telecommunications ( Tokyo ) using the broadcasting satellite BS-2a. We corrected the delay time difference of both measurement systems. Furthermore, we corrected the difference of propagation delay time from the broadcasting satellite using predicted orbital data. Then, it was shown that the accuracy of about 0.1 <micro> sec is achieved by the broadcasting satellite. It was also shown that if we use the same measurement system in both of the receiving points, the precision of about 10nsec is realized.2. Frequency comparison was carried out between Hokkaido University and Kagoshima University ( Kagoshima ) using the broadcasting satellite BS-2a. The Doppler shift arises because the broadcasting satellite drifts around the geostationary orbit. The Doppler shift values are different in Sapporo and Kagoshima. Then, the frequency comparison error ( df/f ) amounts to a few parts in <10^(10)> due to the residual Doppler shift. However, it was shown that if we correct the measured results using the predicted orbital data of the broadcasting satellite, the error is in the order of <10^(-11)> .3. This comparison method is realized by inexpensive satellite broadcasting receiving sets and simple pulse and subcarrier extractors. Then, it may be said that the method is advantageous from the view point of economy and widespread availability.