The accurate Synthetic Aperture Radar (SAR) image registration is important for exact analyses of mine deformation and ecological environment change. Currently, many image registration algorithms have been proposed, but these registration algorithms cannot be directly applied to SAR image, so an integrated registration approach is presented in this paper. Firstly, it is the coarse matching with Canny edge dividing regions; secondly, it is the fine matching by SIFT algorithm with improved Canny edge features; finally, obtain accurate registration SAR image. This approach has fewer computations than that simply using SIFT feature matching. Experimental analyses with SAR images of Yanzhou Mine demonstrate the efficiency and the accuracy of this approach for mine SAR image registration, which provides a simple and effective tool in SAR monitoring of mining deformation and ecological changes.

Automatic Registration of SAR Images with the Integrated Complementary Invariant Feature

Recently APA has become one of most popular algorithms in application of Acoustic Echo Cancellation. Because of the contradictory factors of convergence rate and steady-state misalignment, a new algorithm by the behavior of associating variable regularization and evolving order has been proposed in this paper. Despite of the conventional assumption that the a posteriori error is zero, we take the statistical characteristic of the noise into consideration during the adaptation process. Exact and approximate formulations for the optimal regularization factor are derived. Numerical simulation results show that the proposed algorithm improves the performance of the APA in terms of its faster convergence rate and lower steady-state misalignment compared to existing variable regularization APA and evolving order APA, respectively. Meanwhile it can be seen that near-end speech signal has been restored more effectively

APA with Evolving Order and Variable Regularization for Echo Cancellation

Satellite-based positioning field of research is growing rapidly as there is an increase in demand for precise position requirements in various civil and commercial applications. There are many errors that affect the GNSS signals while propagation from satellite to receiver, which eventually induces errors in pseudo-range measurements. In order to assess the receiver characteristics for a specific error condition, the real-time signals may not be appropriate, and it is challenging to perform repeated experiments with the same error condition. The advantage of the GNSS simulator is that users can model the different scenarios for any given location on the globe, which are repeatable at any point of time. The conventional hardware simulators are expensive and have few limitations. In this paper, a reconfigurable hybrid simulator is proposed with some advantages over traditional hardware simulators, such as low cost, reconfigurability, and controllability over fundamental parameters. It can be able to record intermediate stage data, which makes it more suitable for the GNSS research field. The proposed multi-GNSS simulator considered implementing IRNSS-L5, IRNSS-S1, and GPS-L1 band signals. A general-purpose computer can perform the necessary calculations for signal generation. The hybrid simulator can be able to generate the digital I/Q data, which can be stored as I/Q data or can be connected to a general-purpose SDR (Software Defined Radio) for RF signal generation (bladeRF in this case). The I/Q data can be used with the software receiver to analyse the receiver performance concerning the specific error. The generated GNSS signals are validated with software and hardware receivers, and the obtained position is observed as expected. 

Multi GNSS IRNSS L5 IRNSS S1 and GPS L1 Hybrid Simulator A Reconfigurable Low cost Solution for Research and Defence Applications

In order to optimize the baseband signal processing algorithm of BeiDou Navigation Satellite System (BDS) software receiver and improve the accuracy of pseudorange measurement and positioning, the baseband signal processing algorithm is analyzed. In this paper, the delay lock loop (DLL) is adapted for C/A code tracking, and the frequency locked loop (FLL) assisted Costas phase locking loop (PLL) is used for carrier tracking. Moreover, the different PLL discriminators are analyzed in detail. According to the simulation results of the discriminators, the two-quadrant arctangent discriminator is selected as the phase discriminator in the Costas PLL for BDS receiver. The simulation results showed that the improved baseband processing algorithm can perform reliable tracking for BDS receiver baseband signal. Our work will be helpful to better understand and design of BDS software receiver.

http://ieeexplore.ieee.org/iel7/7569773/7578222/07578508.pdf

BDS receiver baseband signal tracking processing algorithm

The invention discloses a synthetic control feedback correcting system and method for satellite signal simulation. The method comprises the steps of acquiring navigation parameter state values of a plurality of sets of satellite simulation signals at intervals in a set period; calculating a synthetic control parameter through a synthetic control parameter mathematical simulation calculation methodaccording to the navigation parameter state value of the current period; using the synthetic control parameter as the phase control quantities of each order of a high-order signal synthesizer to control the high-order signal synthesizer to output digital intermediate frequency signals; inputting the digital intermediate frequency signals to a navigation parameter estimation module to obtain a navigation parameter state estimation value; subtracting the navigation parameter state value of the current period from the navigation parameter state estimation value to obtain a navigation parameter state deviation value, and using the navigation parameter state deviation value to correct the navigation parameter state value of the next period. The deviation between the digital signals subjected to signal synthesis and the signal result obtained by mathematical simulation calculation can be reduced, and the precision of mathematical simulation calculation is improved.

Synthetic control feedback correcting system and method for satellite signal simulation

Navigation signal simulator can generate signals consistent with real GNSS (Global Navigation Satellite System) signals, which can be processed by GNSS receivers in the same manner as it processes satellite signals in a real testing environment. The simulator can offer a high-fidelity means of testing GNSS receivers and other related systems. Such tests can be carried out in laboratories due to control of the GNSS constellation and global atmospheric environment by a single device. The navigation signal simulator, which can provide a real-like environment for the research and testing of navigation receivers, has been the key instrument for developing navigation systems and receiving devices, particularly for high-dynamic receivers. Therefore it has increasingly received widespread attentions in military and industrial sectors. With the development of a variety of new navigation systems and signal standards, there is a higher demand for the compatibility and renewal speed of the navigation signal simulators; specifically, it should be multi-mode and reconfigurable in order to realize the flexible design of navigation systems. Although a lot of GNSS simulators have been developed and used, the reconfigurable technologies have not yet appeared in the literature and applied to practices. This means that the existing simulators cannot achieve simulation of multiple GNSS signals by reconfiguration of the software and hardware on the same platform. In this paper, a new reconfigurable platform for navigation signal simulation is proposed and studied, aiming to simulate multi-mode and multi-frequency navigation signals. The performance of the proposed platform is validated from three perspectives: mathematic simulation software, output signals and receiver operation. The result shows that the platform can generate multi-mode and multi-frequency navigation signals through reconfiguration of the software and hardware on the same platform, hence supporting design of a number of navigation systems including Beidou, Global Positioning System (GPS), Russian Global Navigation Satellite System (GLONASS) and European Galileo system. The GNS8000 series navigation satellite signal simulator, designed based on such platform, have been successfully applied to the Beidou navigation satellite systems and widely used in the related fields of research and industries.

Dexiang Ming

Papers

Design of a Reconfigurable Platform for Navigation Signal Simulation