Satellite Constellation Measurement And Control Technology Research

Satellite plays more and more remarkable role in civilian fields and information warfare, along with the rapid development of aerospace technology. Many countries compete on R&D of various satellites to pursue their places for aerospace. As a key technology, satellite TT&C is necessary for monitoring satellite status. Since the 1990s, the concept of satellite group has been formed, which means multi small satellites of formation flying. These satellites keep specific geometrical shape when flying, carrying out signal processing, communication and effective payload mission etc. with close cooperation. This article presents the following research for technological issues about satellite group TT&C R&D.1. Research in channel fading specification in TT&C linkIt analyses TT&C channel model and generation mechanism and specification of non-frequency selective fading, frequency selective fading and time selective fading, by comprehensive consideration of both Doppler and multipath effects.2. Research in high power and high efficiency technology in TT&C transmissionDue to transmission efficiency decline caused by depth recession of power amplifier enough to meet the linearity specification when peak-to-average ratio of high-efficiency transmission wave form is oversized, this article introduces a predistortion high-efficiency transmission technology of baseband, which results in decreased recession of power amplifier, enhanced transmitter efficiency, lowered requirement for power supply and heat dissipation and enhanced reliability.3. High-precision synchronization technology between satellites and between satellite and groundSynchronization technology research is conducted by use of bidirectional comparison. It realizes satellite group TT&C synchronization by time information transmission on satellite links in the satellite group and then by comparison, processing and acquirement of synchronization error of two satellites. The bidirectional comparison method relies little on coordinate precision of satellite and ground station and can help to obtain relatively high synchronization precision through short-time data comparison and processing, with high resistance to environmental impact.Experimental system is developed, with which this technology is proved to be effective with high precision.4. Target search design for satellite group based on digital beam forming Satellite group TT&C requires TT&C and management for multi satellites simultaneously. Tracking and control of multi satellites simultaneously can be actualized by digital beam forming technology, which is based on to achieve target search in satellite group, in digital beam forming experimental system developed for satellite group TT&C. Tests have verified the effectiveness of target search technology in satellite group based on digital beam forming.