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| Investigation of Synchronization for Software Receivers on Unmanned Aerial Vehicles(UAVs) |
| Xiong Hai-liang①; Xiao Zhu①; Yang Hong①②; Tian Hong-xin①; Yi Ke-chu① |
| ①State Key Lab of Integrated Service Networks, Xidian University, Xi'an 710071, China; ②China Academy of Space Technology, Beijing 100094, China |
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Abstract To ensure the reliability of the data transmitting for the Unmanned Aerial Vehicles (UAVs) in dynamic environment, a novel class of fast acquisition algorithm based on Partial Matched Filters and Two-Leveled FFT(PMF-TLFFT) is proposed, which is capable of searching for the code synchronization point as well as estimating the carrier-frequency offset for correction. However, in dynamic environment, as the UAVs usually possesses a larger axial acceleration compared with that of the satellite repeater, the Doppler frequency shifts dramatically, making the tracking loop of a general receiver out of balance. Therefore, An FPLL based on Look-Up Tables (LUT-FPLL) is presented, which employs a list of experiential values in FLL and the bandwidth of the loop filter in FLL is adaptively adjusted, this ensures the high precision tracking performance. Simulation results demonstrate that with the input SNR higher than -35 dB, initial carrier-frequency offset ranging from -12.8 kHz to +12.8 kHz and axial acceleration 5 m/s2 the receiver on the UAVs can efficiently and reliably work.
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Received: 11 November 2008
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2009, Vol. 31 
