Unified Carrier Detecting Spread Spectrum Telemetry Signals And Identification Technology

As an important part of the space probe system, the telemetry tracking and command (TT&C) system plays an importance role in the telecontrol and telemetry of these special targets. So far in our country, the TT&C systems can be divided into two types:The United-Carrier TT&C (such as USB) and Spread Spectrum (SS) TT&C, the Spread Spectrum TT&C includes Direct Sequence Spread Spectrum(DS-SS) and hybrid Direct Sequence/Frequency-Hopped(DS/FH). In order to meet the needs of the unattended station to receive the two signals compatibility, the receiver must be able to detection the signal effectively. Due to the space electromagnetic and the diversity of signal modulation, leading to the traditional techniques on detection are often incapable. Under this background, this paper makes a deep research on the pivotal technology of the United-Carrier TT&C (such as USB) and Spread Spectrum (SS) signal detection and recognition the "TT&C,in order to realize a model which can detection and recognition the two signals for telemetry and telecontrol.Based on the study of the united-carrier TT&C communication system’s operating principle and characteristics, we obtain the detection and recognize approach which based on FFT, the simulation system in Matlab is also given. For the low SNR characteristics of the space electromagnetic environment, based on traditional signal detection techniques:delay and multiply, the Wigner-Ville transform of time-frequency analysis and Artificial Neural Networks (ANN) with Back-Propagation (BP) learning algorithm and cyclostationary theory on detection SS signal, We have intensive discussed on the principle and performance, and improved the algorithm. Finally the detector can not only detect SS signal, extract the carrier frequency, code rate parameters, it can also identify the signal DS-SS or DS/FH.For the need of ground unattended station can receive variety of TT&C signals in future, this paper use the united-carrier TT&C signal and SS signal detection and recognize algorithm design a signal detection and recognize model for multi-mode receiver. Combined with the system simulation and analysis, this model can detect the united-carrier TT&C signal and spread spectrum TT&C signal automatically.