China’s high-resolution optical remote sensing satellites and their mapping applications

Since the beginning of the twenty-first century,several countries have made great efforts to develop space remote sensing for building a high-resolution earth observation system.Under the great attention of the government and the guidance of the major scientific and technological project of the high-resolution earth observation system,China has made continuous breakthroughs and progress in high-resolution remote sensing imaging technology.The development of domestic high-resolution remote sensing satellites shows a vigorous trend,and consequently,a relatively stable and perfect high-resolution earth observation system has been formed.The development of high-resolution remote sensing satellites has greatly promoted and enriched modern mapping technologies and methods.In this paper,the development status,along with mapping modes and applications of China’s high-resolution remote sensing satellites are reviewed,and the development trend in high-resolution earth observation system for global and ground control-free mapping is discussed,providing a reference for the subsequent development of high-resolution remote sensing satellites in China.

Multiuser subcarriers and bit allocation combining adaptive mapping for SC-FDMA system

In this article, a multiuser single carrier frequency division multiple access （SC-FDMA） system is considered, based on which an adaptive subcarrier and bit allocation algorithm is investigated. The algorithm has been used to achieve a subcarrier mapping mode in this system, which combines the advantages of single- and multi-carrier transmissions, such as, low peak to average power ratio, orthogonality of signals of different users, and low complexity. Simulation results show that it has a similar performance as that of the adaptive allocation algorithm in the orthogonal frequency division multiple （OFDM） system and the proposed mapping mode has a performance gain over the two existing mapping modes at the link level.

A Novel Electric Dual Motor Transmission for Heavy Commercial Vehicles

As a vital vehicle part,the powertrain system is undergoing a fast transition towards electrification.The new integrated electric drive system has been widely used,especially for passenger cars.In this work,a novel electric dual motor transmission is proposed for heavy commercial vehicles.The transmission scheme is firstly introduced,which can achieve 9 different operating modes including 5 single motor modes and 4 dual motor modes.Then,the mode shift map with minimum energy consumption is designed based on the motor efficiency map and the proposed energy management strategy.The driving power is appropriately distributed between the two motors in dual motor modes under the condition of minimum power consumption.In addition,a coordinated control strategy is developed for mode shift control without power interruption.The results show that the electric dual motor transmission has advantages in power consumption and power shift ability compared with the conventional single motor automated manual transmission.