Nan, Y, Huang, X & Guo, YJ 2020, 'A Millimeter-Wave GCW-SAR Based on Deramp-on-Receive and Piecewise Constant Doppler Imaging', IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, vol. 58, no. 1, pp. 680-690.View/Download from: Publisher's site
Nan, Y, Huang, X & Guo, YJ 2020, 'Piecewise Constant Doppler Algorithm: Performance Analysis, Further Simplification and Motion Compensation', IEEE Transactions on Aerospace and Electronic Systems.View/Download from: Publisher's site
IEEE The piecewise constant Doppler (PCD) algorithm is a novel radar imaging process recently proposed for the generalized continuous wave synthetic aperture radar (GCW-SAR). This paper presents a detailed theoretical analysis on the PCD algorithm's performance and proposes a further complexityreduced PCD algorithm with motion compensation (MOCO) suitable for practical applications. Firstly, the difference between conventional SAR imaging and PCD imaging, i.e., the zeroth order versus the first order slant range approximation, is revealed. Exact ambiguity function expressions of the PCD imaging in range and azimuth directions respectively are then derived. An error function of the PCD imaging as compared with the ideal matched filtering method is further defined and shown to be a function of an image quality factor which can be used to quantify the PCD imaging performance. Finally, a faster and more flexible imaging process, called decimated PCD algorithm, is proposed, by which the image azimuth spacing can be easily extended and hence the computational complexity can be significantly reduced. The decimated PCD implementation incorporated with the MOCO is developed for practical GCWSAR applications and its imaging error lower-bounded by the PCD imaging error function is analyzed accordingly. Simulation and experimental results validate the theoretical analysis of the PCD imaging and show that the decimated PCD algorithm can achieve a high imaging quality at low cost.
Nan, Y, Huang, X & Guo, YJ 2018, 'Generalized Continuous Wave Synthetic Aperture Radar for High Resolution and Wide Swath Remote Sensing', IEEE Transactions on Geoscience and Remote Sensing, vol. 56, no. 12, pp. 7217-7229.View/Download from: Publisher's site
Nan, Y, Zhao, C & Li, B 2016, 'Joint detection scheme for cooperative spectrum sensing in cognitive radio network', Eurasip Journal on Wireless Communications and Networking, vol. 2016, no. 1.View/Download from: Publisher's site
© 2016, Nan et al. In this paper, a new architecture of cognitive radio network (CRN) is presented for future dynamic spectrum sharing in time-variant flat fading (TVFF) channels. We consider a practical scenario where secondary users (SUs) are able to access the idle spectrum by secondary user routers (SU_Rs). Managed by a fusion center (FC), SU_Rs can work together to capture the idle spectrum, and then assign to the SUs. Besides, it is imperative to guarantee the wireless communication quality between primary base station (P_BS) and SU_Rs. Therefore, a new cooperative spectrum sensing (CSS) algorithm is suggested to recursively estimate the channel state information (CSI) while capturing the idle licensed band. The united mathematics model relies on a dynamic state-space model (DSM) and a Bernoulli filters (BF) algorithm. TVFF channels are modeled as finite-state Markov channel (FSMC). In order to reduce complexity of CSS, the particles are manipulated and reconstructed. Experimental simulations demonstrate that, by exploiting dynamic CSI, sensing performance of the new CSS algorithm will surpass the traditional schemes and this new architecture can be used in a realistic spectrum sharing system.
Nan, Y, Huang, X & Guo, YJ 2019, 'A Fast Piecewise Constant Doppler Algorithm for Generalized Continuous Wave Synthetic Aperture Radar', 2019 International Radar Conference (RADAR), International Radar Conference, IEEE, Toulon, France.View/Download from: Publisher's site
The generalized continuous wave synthetic aperture radar (GCW-SAR) adopts one-dimensional data recording without the slow time dimension and hence offers many advantages compared with the conventional SAR system. In this paper, a fast piecewise constant Doppler algorithm is proposed based on further zero-th order approximation on top of the linear approximation of the slant range, leading to a flexible azimuth imaging spacing. Significant reduction of the complexity can be achieved by extending the azimuth imaging spacing and downsampling the received signal in digital domain. Simulation results validate the advantages of the proposed algorithm.
Le, AT, Nan, Y, Tran, LC, Huang, X, Guo, YJ & Vardaxoglou, JCY 2018, 'Analog Least Mean Square Loop for Self-Interference Cancellation in Generalized Continuous Wave SAR', In Proceedings of the IEEE 88th Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Chicago, US, pp. 1-5.View/Download from: Publisher's site
Generalized continuous wave synthetic aperture radar (GCW-SAR) is a promising new imaging radar system since it applies the full-duplex (FD) transmission technique to achieve continuous signaling in order to overcome several fundamental limitations of the conventional pulsed SARs. As in any FD wireless communication system, self-interference (SI) is also a key problem which can impact on the GCW-SAR system. In this paper, the analog least mean square (ALMS) loop in the radio frequency domain is adopted to cancel the SI for a GCW-SAR system with periodic chirp signaling. The average residual SI power after the ALMS loop is analyzed theoretically by a stationary analysis. It is found that the ALMS loop not only works with random signals in general FD communication systems, but also works well with the periodic signal in GCW-SAR systems. Simulation results show that over 45 dB SI cancellation can be achieved by the ALMS loop which ensures the proper operation of the GCW-SAR system.
Nan, Y, Huang, X & Guo, YJ 2017, 'A Generalized Continuous Wave Synthetic Aperture Radar', Proceedings of the 85th Vehicular Technology Conference, Vehicular Technology Conference, IEEE, Sydney, Australia, pp. 1-5.View/Download from: Publisher's site
Attention has been devoted to Synthetic Aperture
Radar (SAR) for half a century. Though it is a well-proven
remote sensing technique, conventional pulsed SAR has several
inherent limitations. In this paper, we present a new SAR concept,
called Generalized Continuous Wave SAR (GCW-SAR). By using
continuous wave signaling, the GCW-SAR system achieves better
performance and overcomes the limitations such as the minimum
antenna area in conventional SAR. Unlike the frequency modulated
continuous wave SAR (FMCW-SAR) system, the GCWSAR
image is reconstructed by correlation between the sampled
raw data and the location dependent reference signals. A fast
image reconstruction algorithm is also presented in the paper.
The principle of GCW-SAR and the effectiveness of the proposed
algorithm are validated by numerical simulation results.
Nan, Y, Huang, X & Guo, YJ 2017, 'Passive Synthetic Aperture Radar Imaging with Piecewise Constant Doppler Algorithm', 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications, IEEE, Veorna, Italy.View/Download from: Publisher's site
This paper presents a non-cooperative space-surface bistatic synthetic aperture radar (SS-BSAR) with a novel image reconstruction algorithm. Exploiting the continuous wave signal from the transmitters of opportunity, the new algorithm produces better imaging performance. Unlike the conventional passive SAR, the image reconstruction is achieved by correlation in time-domain without distinction between fast time and slow time. With the movement of the radar, the range curve can be linearized within multiple segments. In each segment, the Doppler frequency shift incurred in the reflected signal from a target can be assumed to be constant and thus the SAR image can be reconstructed recursively. The proposed piecewise constant Doppler (PCD) algorithm is validated by the simulation results.