An Advanced Phase Synchronization Scheme for LT-1

The Synchronization Transceiver Design and Experimental Verification for the LuTan-1 SAR Satellite

“…Its main mission is to acquire high accurate DEM and support some civil applications, such as biomass inversion, disaster forecasting, and climate and environmental monitoring [22]. The GNSS disciplining module in LuTan-1 mission employs a disciplined rubidium clock to provide a time-frequency signal for the SAR systems with high accuracy [24,[27][28][29][30]. However, the oscillator noise between the two satellites will severely degrade the performance of the LuTan-1 imaging and interference processing [13].…”

“…In order to achieve phase synchronization, a common phase reference needs to be established between the primary and slave satellite [24]. For this purpose, it is considered to establish a phase synchronization link between the two satellites.…”

“…Slave Satellite The demodulated phase ϕ 12 (t) is available at the primary satellite for a synchronization signal transmitted by the slave satellite. Correspondingly, the demodulated phase ϕ 21 (t) is available at a slave satellite for a synchronization signal transmitted by a primary satellite [24]. In essence, the synchronization signal can be regarded as the special radar signal.…”

“…As shown in Figure 2, the first free duration is the free duration between the time of the end of the radar signal transmission and the starting time of the echo receiving windows, and, correspondingly, the second free duration is the free duration between the time of the end of echo receiving window and the starting time of the next PRI [23]. In the LuTan-1 system, the phase synchronization signal is exchanged in the second free duration [24]. Thus, the normal operation of SAR can be prevented from being interrupted, avoiding the data missing effect [18].…”

“…In LuTan-1 systems, an innovative non-interrupted synchronization scheme is used which will not interrupt the normal SAR operation [23]. LuTan-1 exchanges the synchronization signals immediately after the ending time of the radar echo-receiving windows and before the starting time of the next pulse-repetition internal (PRI) [18,24]. Therefore, it cannot interrupt the normal SAR data acquisition, further improving the synchronization accuracy and avoiding the data missing effect.…”