It is necessary that the laser inertial system is used to further improve the fire accuracy and quick reaction capability in the ballistic missile strapdown inertial navigation system. According to the guidance contro...It is necessary that the laser inertial system is used to further improve the fire accuracy and quick reaction capability in the ballistic missile strapdown inertial navigation system. According to the guidance controlling method and the output and error model of ballistic missile laser SIMU, the mathematical model of error propagation mechanism is set up and any transfer environmental function of error coefficient that affects the fire accuracy is deduced. Also, the missile longitudinal/lateral impact point is calculated using MATLAB. These establish the technical foundation for further researching the dispersion characteristics of impact point and reducing the laser guidance error.展开更多
In order to strike hard targets underground or warships and tanks with expected impact angle by missiles or guided bombs, trajectory shaping guidance law with terminal position and impact angle constraints is derived ...In order to strike hard targets underground or warships and tanks with expected impact angle by missiles or guided bombs, trajectory shaping guidance law with terminal position and impact angle constraints is derived based on linear quadratic optimal control theory. The required accelera- tion expressed by impact angle and heading error is obtained in lag-free guidance system in order to find the optimal relationship of those angles in terminal phase. The adjoint systems of miss distance and impact angle error of first-order guidance system are established based on statistical linearization adjoint method （SLAM） in order to study the impact performances of the guidance law. Simulation results show that the miss distance and impact angle error of trajectory shaping guidance law are both according with the impact position and angle constraint and the required acceleration at impact can be decreased by an optimal relationship of impact angle and heading error.展开更多
Environmental Impact Assessments (EIAs) are designed to evaluate all reasonably foreseeable environmental consequences of human activities. Appropriate governmental scientists traditionally produced EIAs for managemen...Environmental Impact Assessments (EIAs) are designed to evaluate all reasonably foreseeable environmental consequences of human activities. Appropriate governmental scientists traditionally produced EIAs for management agencies in many countries. However, many EIAs are now contracted out, often to the lowest bidder without due consideration of expertise. Others suffer from limited agency resources. Consequently, many EIAs have become insufficiently researched documents that draw heavily from previous EIAs while being rushed to completion to meet legislative deadlines or avoid delaying projects. Habitual treatment of topics often ignores recent scientific literature, perpetuating previous misconceptions and analytical flaws. Common problems in EIAs discussing wildlife include: a focus on lethal takes, with little consideration of non-lethal impacts or habitat degradation;a general dismissal of the possibility that non-significant (to the resource) impacts can, when combined, become significant;and the assumption that behavioral habituation in animals represents an end of impact. Incentive to break the cycle is somewhat lacking in this now often commercially competitive environment, where contracts are increasingly awarded by industry, generating potential conflict of interest. We believe investment in thorough, impartially written, scientifically-based and up-to-date EIAs is important for appropriately representing and managing ecosystems and their resources and avoiding potentially expensive litigation.展开更多
文摘It is necessary that the laser inertial system is used to further improve the fire accuracy and quick reaction capability in the ballistic missile strapdown inertial navigation system. According to the guidance controlling method and the output and error model of ballistic missile laser SIMU, the mathematical model of error propagation mechanism is set up and any transfer environmental function of error coefficient that affects the fire accuracy is deduced. Also, the missile longitudinal/lateral impact point is calculated using MATLAB. These establish the technical foundation for further researching the dispersion characteristics of impact point and reducing the laser guidance error.
基金Supported by the Aeronautical Science Foundation of China(20060112123)
文摘In order to strike hard targets underground or warships and tanks with expected impact angle by missiles or guided bombs, trajectory shaping guidance law with terminal position and impact angle constraints is derived based on linear quadratic optimal control theory. The required accelera- tion expressed by impact angle and heading error is obtained in lag-free guidance system in order to find the optimal relationship of those angles in terminal phase. The adjoint systems of miss distance and impact angle error of first-order guidance system are established based on statistical linearization adjoint method （SLAM） in order to study the impact performances of the guidance law. Simulation results show that the miss distance and impact angle error of trajectory shaping guidance law are both according with the impact position and angle constraint and the required acceleration at impact can be decreased by an optimal relationship of impact angle and heading error.
文摘Environmental Impact Assessments (EIAs) are designed to evaluate all reasonably foreseeable environmental consequences of human activities. Appropriate governmental scientists traditionally produced EIAs for management agencies in many countries. However, many EIAs are now contracted out, often to the lowest bidder without due consideration of expertise. Others suffer from limited agency resources. Consequently, many EIAs have become insufficiently researched documents that draw heavily from previous EIAs while being rushed to completion to meet legislative deadlines or avoid delaying projects. Habitual treatment of topics often ignores recent scientific literature, perpetuating previous misconceptions and analytical flaws. Common problems in EIAs discussing wildlife include: a focus on lethal takes, with little consideration of non-lethal impacts or habitat degradation;a general dismissal of the possibility that non-significant (to the resource) impacts can, when combined, become significant;and the assumption that behavioral habituation in animals represents an end of impact. Incentive to break the cycle is somewhat lacking in this now often commercially competitive environment, where contracts are increasingly awarded by industry, generating potential conflict of interest. We believe investment in thorough, impartially written, scientifically-based and up-to-date EIAs is important for appropriately representing and managing ecosystems and their resources and avoiding potentially expensive litigation.
