This paper proposes a cyclic autocorrelation function (CAF) diversity combining technique for spectrum sensing using test statistics shared among multiple receive antennas with time-averaged weights. The proposed technique computes a weight factor by averaging CAF, and the weight factor is employed to improve the performance of signal detection. The proposed results are compared with some conventional techniques, and they show that the signal detection performance can be improved without the increasing computational complexities in comparison with the conventional techniques.
This paper reports prompt space-borne ALOS-2 SAR observation results of Hokkaido-Iburi-Tobu earthquake on 2018/09/06. Emphasis is placed on quick survey for disaster monitoring using fully polarimetric data. On 2018/09/08, ALOS-2 has acquired data over the disaster area. By comparison of the previous data (2017/08/26) before the earthquake, damaged areas by landslides are clearly detected. The analysis is based on the scattering power decomposition, which retrieves scattering mechanism change from bare soil surface caused by landslide and serves to identify the landslide location. The decomposition and anisotropy images are presented to show the effectiveness of fully polarimetric SAR sensing from space.
Space Time Adaptive processing (STAP) has been proposed to suppress the clutter in the airborne radar. In STAP covariance matrix of the received signal is employed to carry out the processing. This is often estimated by making use of returns from neighboring range bins of interest. In many simulation results, independent and identically distributed (IID) samples are assumed for the clutter. It is said that the more samples we consider in sample covariance matrix, the better signal-to-interference plus noise ratio (SINR) is achieved in STAP. However, we have found the optimum sample size to achieve maximum SINR in real circumstance. In this paper, we discuss the violation of IID assumption resulting in degradation of SINR using real sea clutter data observed by S-band side-looking airborne radar. The existence of the optimum samples is shown here.
Blau and Michaeli recently introduced a novel concept for inverse problems of signal processing, that is, the perception-distortion tradeoff. We introduce their tradeoff into the rate distortion theory of variable-length lossy source coding in information theory, and clarify the tradeoff among information rate, distortion and perception for general information sources. We also discuss the fixed-length coding with average distortion criterion that was missing in the previous letter.