The technological development status of new generation low cost small-lift launch vehicles applied to small satellite launch is investigated in this paper. The development trends are summarized, including low cost and...The technological development status of new generation low cost small-lift launch vehicles applied to small satellite launch is investigated in this paper. The development trends are summarized, including low cost and rapid response capability, utilization of mature rocket and missile technology, the development of mobile launch technology adopting air-based platforms and use of innovative technology. Moreover, the external power and internal demand of the small-lift launch vehicle are analyzed and the market prospect is forecasted. Finally, proposals for the development of small-lift launch vehicles are put forward, including exploration of the potential of existing rocket and missile technology, development of multi-platform mobile launch technology and further application of innovative technology and ideas.展开更多
A gradient descent algorithm with adjustable parameter for attitude estimation is developed,aiming at the attitude measurement for small unmanned aerial vehicle(UAV)in real-time flight conditions.The accelerometer and...A gradient descent algorithm with adjustable parameter for attitude estimation is developed,aiming at the attitude measurement for small unmanned aerial vehicle(UAV)in real-time flight conditions.The accelerometer and magnetometer are introduced to construct an error equation with the gyros,thus the drifting characteristics of gyroscope can be compensated by solving the error equation utilized by the gradient descent algorithm.Performance of the presented algorithm is evaluated using a self-proposed micro-electro-mechanical system(MEMS)based attitude heading reference system which is mounted on a tri-axis turntable.The on-ground,turntable and flight experiments indicate that the estimation attitude has a good accuracy.Also,the presented system is compared with an open-source flight control system which runs extended Kalman filter(EKF),and the results show that the attitude control system using the gradient descent method can estimate the attitudes for UAV effectively.展开更多
The oceans cover almost three-quarters of the earth's surface and provide a highway for commerceor conquest and constitute a rich source of nutrients, materials and energy. The exploration and exploitation of ocea...The oceans cover almost three-quarters of the earth's surface and provide a highway for commerceor conquest and constitute a rich source of nutrients, materials and energy. The exploration and exploitation of oceanic resources accelerated in the 1970s because of the emerging offshore oil and gasindustry. The extraction and national protection of these and other resources will increase rapidlyin the next century and in support of these activities one of the most useful tools will be the smallunderwater vehicle. However, if these vehicles are to carry out the envisaged tasks in a cost--effectiveand mission-effective manner they will require high performance energy systems. A number of suchsystems are being developed and the problem arises as which one to select for a particular task. In thispaper the development of software based techniques for the selection of energy systems is described.展开更多
This paper presents a hierarchical simultaneous localization and mapping（SLAM） system for a small unmanned aerial vehicle（UAV） using the output of an inertial measurement unit（IMU） and the bearing-only observati...This paper presents a hierarchical simultaneous localization and mapping（SLAM） system for a small unmanned aerial vehicle（UAV） using the output of an inertial measurement unit（IMU） and the bearing-only observations from an onboard monocular camera.A homography based approach is used to calculate the motion of the vehicle in 6 degrees of freedom by image feature match.This visual measurement is fused with the inertial outputs by an indirect extended Kalman filter（EKF） for attitude and velocity estimation.Then,another EKF is employed to estimate the position of the vehicle and the locations of the features in the map.Both simulations and experiments are carried out to test the performance of the proposed system.The result of the comparison with the referential global positioning system/inertial navigation system（GPS/INS） navigation indicates that the proposed SLAM can provide reliable and stable state estimation for small UAVs in GPS-denied environments.展开更多
On July 24,2012,the State Council of the People’s Republic of China implemented'a toll-free program for small passenger vehicles during major vacations1).In the several months that followed,local governments issu...On July 24,2012,the State Council of the People’s Republic of China implemented'a toll-free program for small passenger vehicles during major vacations1).In the several months that followed,local governments issued implementation articles.The current Major Vacation Tollfree Program for small passenger vehicles(MVTP)pioneers the concept(Xu and Gao,2016),'Benefaction to People.'The current MVTP has received展开更多
文摘The technological development status of new generation low cost small-lift launch vehicles applied to small satellite launch is investigated in this paper. The development trends are summarized, including low cost and rapid response capability, utilization of mature rocket and missile technology, the development of mobile launch technology adopting air-based platforms and use of innovative technology. Moreover, the external power and internal demand of the small-lift launch vehicle are analyzed and the market prospect is forecasted. Finally, proposals for the development of small-lift launch vehicles are put forward, including exploration of the potential of existing rocket and missile technology, development of multi-platform mobile launch technology and further application of innovative technology and ideas.
基金supported by the Fundamental Research Funds for the Central Universities(No.56XAA17075)
文摘A gradient descent algorithm with adjustable parameter for attitude estimation is developed,aiming at the attitude measurement for small unmanned aerial vehicle(UAV)in real-time flight conditions.The accelerometer and magnetometer are introduced to construct an error equation with the gyros,thus the drifting characteristics of gyroscope can be compensated by solving the error equation utilized by the gradient descent algorithm.Performance of the presented algorithm is evaluated using a self-proposed micro-electro-mechanical system(MEMS)based attitude heading reference system which is mounted on a tri-axis turntable.The on-ground,turntable and flight experiments indicate that the estimation attitude has a good accuracy.Also,the presented system is compared with an open-source flight control system which runs extended Kalman filter(EKF),and the results show that the attitude control system using the gradient descent method can estimate the attitudes for UAV effectively.
文摘The oceans cover almost three-quarters of the earth's surface and provide a highway for commerceor conquest and constitute a rich source of nutrients, materials and energy. The exploration and exploitation of oceanic resources accelerated in the 1970s because of the emerging offshore oil and gasindustry. The extraction and national protection of these and other resources will increase rapidlyin the next century and in support of these activities one of the most useful tools will be the smallunderwater vehicle. However, if these vehicles are to carry out the envisaged tasks in a cost--effectiveand mission-effective manner they will require high performance energy systems. A number of suchsystems are being developed and the problem arises as which one to select for a particular task. In thispaper the development of software based techniques for the selection of energy systems is described.
基金supported by National High Technology Research Development Program of China (863 Program) (No.2011AA040202)National Science Foundation of China (No.51005008)
文摘This paper presents a hierarchical simultaneous localization and mapping（SLAM） system for a small unmanned aerial vehicle（UAV） using the output of an inertial measurement unit（IMU） and the bearing-only observations from an onboard monocular camera.A homography based approach is used to calculate the motion of the vehicle in 6 degrees of freedom by image feature match.This visual measurement is fused with the inertial outputs by an indirect extended Kalman filter（EKF） for attitude and velocity estimation.Then,another EKF is employed to estimate the position of the vehicle and the locations of the features in the map.Both simulations and experiments are carried out to test the performance of the proposed system.The result of the comparison with the referential global positioning system/inertial navigation system（GPS/INS） navigation indicates that the proposed SLAM can provide reliable and stable state estimation for small UAVs in GPS-denied environments.
基金jointly supported by the National Natural Science Foundation of China (Grant Nos: 71422010, 71621001 and 71771015)
文摘On July 24,2012,the State Council of the People’s Republic of China implemented'a toll-free program for small passenger vehicles during major vacations1).In the several months that followed,local governments issued implementation articles.The current Major Vacation Tollfree Program for small passenger vehicles(MVTP)pioneers the concept(Xu and Gao,2016),'Benefaction to People.'The current MVTP has received
