An integrative synchronization and imaging approach for bistatic spaceborne/stratospheric SAR with a fixed receiver

Abstract

Bistatic spaceborne/stratospheric synthetic aperture radar (SAR) with a fixed receiver is a novel hybrid bistatic SAR system, in which a spaceborne SAR serves as the transmitter of opportunity, while a fixed receiver is mounted on a stratospheric platform. This paper presents an integrative synchronization and imaging approach for this particular system. Firstly, a novel synchronization method using the direct-path signal, which can be collected by a dedicated antenna, is proposed and applied. The synchronization error can be completely removed using the proposed method. However, as the cost of synchronization, the characteristic of synchronized echo's range history becomes quite different from that of general bistatic SAR data. To focus this particular synchronized data, its 2-D spectrum is derived under linear approximations and then a frequency-domain imaging algorithm using two-dimensional inverse scaled Fourier transform (2-DISFT) is proposed. At last, the proposed integrative synchronization and imaging algorithm is verified by simulations.

An integrative synchronization and imaging algorithm for GNSS-based BSAR

“…As presented in Subsection 3.2, after the elimination of navigation messages, the Doppler phase can be used to estimate the accurate value of the instantaneous Doppler frequency. Firstly, the Doppler frequency can be extracted using (19). However, due to the phase synchronization error φ e (t n ), the extracted Doppler frequency fluctuates from point to point.…”

“…However, these algorithms were derived without considering the signal synchronization issue. In fact, there is an intrinsic connection between the signal synchronization and the imaging formation [19][20][21][22]. Therefore, to accomplish the imaging process of real GNSS-based BSAR data, these image formation algorithms have to be reconstructed.…”

Focusing of Spotlight Tandem-Configuration Bistatic Data with Frequency Scaling Algorithm

“…Bistatic synthetic aperture radar (SAR) imaging has been widely discussed in recent years [1][2][3][4]. Besides the synchronization problems [5,6], fast imaging algorithms are still in search.…”