The Real-Time Framework of the Push-to-Talk (PTT) Synchronization Scheme for Distributed SAR

Distributed synthetic aperture radar (SAR) has various applications, including multiangle imaging, SAR tomography, and interferometric SAR. However, these applications are affected by several factors, especially clock synchronization. Recently, an innovative push-to-talk (PTT) scheme was proposed to tackle the clock synchronization problem. As the PTT scheme can directly obtain the time and frequency deviations of the ultrastable oscillators (USOs), it gives the possibility to achieve the clock synchronization of distributed SAR in real time. Therefore, this letter builds a real-time framework of the PTT scheme. Compared with the previous clock synchronization module (CSM), an estimation module and a control module are added in this framework to fabricate an improved CSM (ICSM). The time and frequency deviations obtained by the ICSM are used to directly correct the GPS disciplined rubidium clocks. Based on the ICSM, some simulations are performed. The results indicate that the established real-time framework can achieve high-precision time and frequency synchronization. In addition, we discuss the system implementation.