Mitigating Range Ambiguity Method Based on DDMA for SAR Systems

Abstract

Range ambiguity can lead to deterioration of imagery quality for space-borne synthetic aperture radar (SAR). To solve this problem, we propose a mitigating range ambiguity method based on Doppler division multiple access (DDMA) in this paper. With the orthogonality of the DDMA waveform, transmit channels are separated at the receiver. Afterwards, a pre-processed operation for definition domains of different transmit channels is put forward to transform all definition domains into the same one. Thereafter, by multiplying measured data in a transmit channel by the complex conjugation of those in the other channel, a coupling phase term between the ambiguous range and the Doppler can be generated. So, utilizing the coupling phase, the echoes of different ambiguous regions can be distinguished in the slow-time domain, and they are extracted by designing time domain passband filters. Moreover, the images of different extracted ambiguous regions can be reconstructed to compose the whole unambiguous image. Finally, simulation results exhibit the effectiveness of the proposed method.

A Novel Multi-Beam SAR Two-Dimensional Ambiguity Suppression Method Based on Azimuth Phase Coding

“…In the application of synthetic aperture radar (SAR), a larger swath width favors lessening the number of flights and ameliorating the efficiency of information acquisition [1]. Constrained by the minimum antenna size, traditional single-input single-output (SISO) SAR cannot simultaneously solve the problems of range ambiguity and Doppler ambiguity [2][3][4][5]. Single-input multiple-output (SIMO) SAR utilizes multiple receiving channels to obtain additional degrees of freedom (DOF), and the methods such as multiple azimuth beams and multiple elevation beams have been proposed to address issues of range ambiguity and azimuth ambiguity [6][7][8][9][10][11].…”

Reduction of Doppler and Range Ambiguity Using AES-192 Encryption-Based Pulse Coding

“…The inherent Range and Doppler ambiguities in radar signal processing are significant issues that cause uncertainties in the location and relative velocity of targets. There are various methods available for mitigating these ambiguities, including using multiple subantennas [1], MIMO with pulse coding [2], beam pattern masking [3], dual phase term tracking [4], the use of multiple hypothesis tracking models and data association [5], mitigating range ambiguity using Doppler Division Multiple Access (DDMA) [6] and the use of phase codes to modulate the baseband signal [7].…”