Measurement of the Frequency Stability of Responders in Aircraft

Xiaofan Liu

Abstract:	Measurement on an aircraft orbit, such as a satellite launching orbit, is made by the responder in the aircraft along with several remote track stations on the ground. During the launching, the system is required to have precise time synchronization and frequency accuracy. At the same time, accurate measurement of aircraft velocity requires high frequency stability of the system. However, atomic frequency standards in the ground stations supply time and frequency reference standard with excellent long term and short term frequency stability for the above-mentioned goals. The stability of responder is also an important factor affecting the performance of the system and there are more requirements for the corresponding time / frequency measurements. In the system, the responders do not use continuous wave (CW) but narrow pulse modulated wave, consequently, the characterization theory of their stability is more complicated and the measurement technique is more difficult for pulsed wave than that for CW. In this paper, a systematic characterization theory of the frequency stability for pulsed wave is demonstrated and the measuring methods are discussed. The paper describes the measurement systems, which have been set up in Beijing Institute of Radio Metrology & Measurement (BIRMM) and can be used to test the frequency stability of pulse coherent responders in time domain and frequency domain with high sensitivity and accuracy. Using these measurement systems, we have made successful measurements for the responders, with which the satellite launching orbits have been precisely obtained and tracked.
Published in:	Proceedings of the 25th Annual Precise Time and Time Interval Systems and Applications Meeting November 29 - 2, 1993 Ritz-Carlton Hotel Marina Del Rey, California
Pages:	445 - 456
Cite this article:	Liu, Xiaofan, "Measurement of the Frequency Stability of Responders in Aircraft," Proceedings of the 25th Annual Precise Time and Time Interval Systems and Applications Meeting, Marina Del Rey, California, November 1993, pp. 445-456.
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