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In this article, we propose a new particle swarm optimization–based satellite selection algorithm for BeiDou Navigation Satellite System/Global Positioning System receiver, which aims to reduce the computational complexity of receivers under the multi-constellation Global Navigation Satellite System. The influences of the key parameters of the algorithm—such as the inertia weighting factor, acceleration coefficient, and population size—on the performance of the particle swarm optimization satellite selection algorithm are discussed herein. In addition, the algorithm is improved using the adaptive simulated annealing particle swarm optimization (ASAPSO) approach to prevent converging to a local minimum. The new approach takes advantage of the adaptive adjustment of the evolutionary parameters and particle velocity; thus, it improves the ability of the approach to escape local extrema. The theoretical derivations are discussed. The experiments are validated using 3-h real Global Navigation Satellite System observation data. The results show that in terms of the accuracy of the geometric dilution of precision error of the algorithm, the ASAPSO satellite selection algorithm is about 86% smaller than the greedy satellite selection algorithm, and about 80% is less than the geometric dilution of precision error of the particle swarm optimization satellite selection algorithm. In addition, the speed of selecting the minimum geometric dilution of precision value of satellites based on the ASAPSO algorithm is better than that of the traditional traversal algorithm and particle swarm optimization algorithm. Therefore, the proposed ASAPSO algorithm reduces the satellite selection time and improves the geometric dilution of precision using the selected satellite algorithm. [ABSTRACT FROM AUTHOR]

A dual mode square‐ring defected ground waveguide (SR‐DGW) with defected square patch is first proposed to excite a single‐feed dual mode circularly polarized (CP) patch antenna, which can improve the impedance bandwidth and achieve the CP radiation pattern. The defected square patch is called the perturbation element. By optimizing the size of the perturbation, the degenerate modes of the dual mode SR‐DGW are split and their orthogonal modes can be excited simultaneously. Due to the dual mode of the SR‐DGW, the TM01 mode, and TM10 mode of the square patch antenna are excited simultaneously, which can improve the impedance bandwidth of the antenna. Meanwhile, owing to the orthogonal modes, CP radiation pattern of the antenna is obtained. Then, for a better impedance matching, an L‐shaped spurline embedded in the feedline is introduced. The simulated and measured results show a good performance of the proposed antenna. The measured −10 dB impedance bandwidth is 10.4% (3.56 GHz‐3.95 GHz). The measured 3 dB axial ratio bandwidth is 5.36% (3.63 GHz‐3.83 GHz). Detailed designs and experiments are described and discussed. [ABSTRACT FROM AUTHOR]