For satellite or aircraft networks, tracking, telemetry, and control (TT&C) and data transmission between different nodes are necessary. Traditional measurement mostly adopts the frequency division duplex (FDD) mode and uses a continuous measurement system to achieve high-precision measurement. However, as the number of network nodes increases, the mode suffers from complex frequency domain allocation, and high-cost measurement and data transmission equipment is required. This paper proposes the integrated signal in time division duplex (TDD) mode to improve frequency utilization to address these circumstances. The proposed signal can transmit the TT&C and data at the same frequency. In addition, the high-precision time-frequency synchronization and relative measurement technology in the TDD mode for distributed spacecraft or aircraft networks are studied. The simulation results show that the signal can work normally when the Doppler extrapolation error is less than a quarter of the integration frequency. The distance extrapolation error should be less than a quarter of the length of a chip. The integrated signal reduces the frequency band occupation and realizes the integration of TT&C and data transmission. In addition, the measurement performance is reduced by only 2~3 dB compared with that of the traditional pure TT&C signal.

Very long baseline interferometry (VLBI) is widely used for astronomical observations and navigation of deep space receivers. To solve the problems of the downlink signal being excessively weak to be received and the excessively large acquisition time, a new VLBI measurement method based on the uplink signal is proposed. Deep space ground stations can provide radio measurement signals for deep space spacecraft via the uplink. The range, Doppler and VLBI can be determined by the spacecraft through signals from multiple ground stations. In this manner, a higher signal to noise ratio (SNR) can be obtained. This study involves the development of a prompt acquisition algorithm for high dynamic deep space signals. Furthermore, the measurement and tracking of the phases of multiple VLBI stations by deep space receiver employing the uplink are analyzed. The use of the algorithms reduce the acquisition time for deep space receiver, and high precision results can be obtained for the VLBI measurement. Compared with the traditional VLBI method, the ranging error on the same distance is effectively improved, and the angle measurement accuracy is better than delta differential one way ranging (DOR). Because multiple spacecraft are not needed, there are fewer limitations than same beam interferometry (SBI). INDEX TERMS Navigation, very long baseline interferometry, acquisition and tracking, interferometry.

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In a multi-node spacecraft or unmanned aerial vehicle (UAV) group, a multifunctional signal containing measurement, navigation, and communication functions is required to simplify the receiver structure, and to increase spectrum utilization. The paper proposes a multifunctional signal based on a binary offset carrier (BOC) and binary phase shift keying (BPSK) modulation. The signals which carry different functions are orthogonal in the frequency domain, which causes the data transmission signal to not be affected by BOC signal. In addition, in the high carrier to noise ratio (C/N0), the spreading gain of the BOC signal ensures that the communication signal has a slight influence on navigation signals. Moreover, the multifunctional signal can achieve communication and measurement functions at the same frequency point and fast switching in multinodes. These advantages can simplify the receiver design and improve the frequency band utilization. Finally, in this study we completed the design and verification of the hardware system.

Abstract. Today's interference methods to the receiver include human jamming and non-human interference, and the human one can be divided into two typessuppressing jamming and spoofing jamming. In the spoofing jamming, the jamming source transmits or generates interference signal, trapping the receiver into a wrong location and time estimation of signals from receiving the real signal. Due to its strong similarity to the real one, the interference signal is difficult to be detected and suppressed by the receiver. Thanks to the similarity between spoofing jamming signal and multipath signal, the thesis aims to improve and optimize the WRELAX algorithm -by detecting and identifying signals after WRELAX algorithm according to the multipath fading, we can, finally, separate the spoofing jamming signal and real signal.