Burdess  J.S. Wren  T. 《IEEE transactions on aerospace and electronic systems》1986,(4):410-418

The theory of a new type of vibratory rate gyroscope is considered. The design considered is based upon a disc of piezoelectric material on which are deposited drive and pick-off electrodes. The equations of motion of the disc are derived and the response of the gyroscope to constant and harmonic rates of turn determined.  相似文献   

    

Li  J. Compton  R.T.  Jr. 《IEEE transactions on aerospace and electronic systems》1993,29(3):706-716

It is shown how a uniform linear array of crossed dipoles may be used with the ESPRIT algorithm and spatial smoothing techniques to estimate the arrival directions and polarizations of incoming coherent plane waves. Some examples showing typical performance are presented. One method of smoothing can be used where it is necessary to estimate both the arrival angles and polarizations of signals. Two other methods can be used when only the arrival angles are of interest  相似文献   

    

King  R. Stuart  T.A. 《IEEE transactions on aerospace and electronic systems》1981,(2):190-198

Closed-form steady-state equations are derived for the halfbridge series resonant converter with a rectified (dc) load. Normalized curves for various currents and voltages are then plotted as a function of the circuit parameters. Experimental results based on a 10-kHz converter are presented for comparison with the calculations.  相似文献   

    

K. Shibasaki  T. Takano  S. Enome  H. Nakajima  M. Nishio  Y. Hanaoka  C. Torii  H. Sekiguchi  T. Bushimata  S. Kawashima  N. Shinohara  H. Koshiishi  Y. Shiomi 《Space Science Reviews》1994,68(1-4):217-224

The early phases of three flares, observed by the Nobeyama Radio Heliograph, are studied. Nonthermal and thermal radio sources are identified by comparison with soft X-ray images taken by the Soft X-ray Telescope onboard the Yohkoh satellite. Two of the flares are mainly of nonthermal origin and their location coincides with one of the footpoints of soft X-ray loops. Another flare has both thermal and nonthermal components which start to brighten simultaneously. This suggests that particle acceleration and plasma compression develop simultaneously.  相似文献   

    

M. Abada-Simon  A. Lecacheux  T. S. Bastian  J. A. Bookbinder  G. A. Dulk 《Space Science Reviews》1994,68(1-4):291-292

We report the first millimetric detections of the magnetic cataclysmic variable AE Aquarii, accompanied by contemporaneous microwave observations. These data show that the time-averaged spectrum is well fit by a power-law which extends to mm wavelengths. We suggest that the spectrum is consistent with that expected from a superposition of flare-like events.  相似文献   

  总被引：2，自引：0，他引：2  

Zahirniak  D.R. Sharpin  D.L. Fields  T.W. 《IEEE transactions on aerospace and electronic systems》1998,34(1):137-152

An approach is presented to realizing a digital channelized receiver for signal intercept applications that provides a hardware efficient implementation of a uniform filter bank in which the number of filters K is greater than the decimation factor M. The proposed architecture allows simple channel arbitration logic to be used and provides reliable instantaneous frequency measurements, even in adjacent channel crossover regions. In the proposed implementation of the filter bank, K is related to M by K=FM where F is an integer. It is shown that the optimum selection of F allows the instantaneous frequency measurement to be made in the channel crossover region and the arbitration function to be based solely on the instantaneous frequency measurement. The development of a filter bank structure which combines the flexibility of the short-time Fourier transform (STFT) with the implementation efficiency of the polyphase filter bank decomposition, meeting these requirements and leading to a hardware-efficient implementation, is presented  相似文献   

    

Denney  T.S.  Jr. Greene  M.E. 《IEEE transactions on aerospace and electronic systems》1991,27(4):689-695

The effects of instrumentation accuracy and configuration on estimation error are studied for the small expandable-tether deployment system (SEDS) using a continuous-discrete extended Kalman filter (CDEKF) state estimator. A twelfth order model that incorporates the rigid body modes of the tether as well as the satellite attitude dynamics is developed. Simulation results using the model and the estimator indicate that the originally planned instrumentation package could not estimate the state vector adequately. Recommendations are made and results presented that reduce the estimation error by adding instruments and increasing selected measurement accuracies  相似文献   

    

Tarn  T.J. Bejczy  A.K. Yun  X. 《IEEE transactions on aerospace and electronic systems》1988,24(5):571-583

Multiple coordinated robot arms are modeled by considering the arms as closed kinematic chains and as a force-constrained mechanical system working on the same object simultaneously. In both formulations, a novel dynamic control method is discussed. It is based on feedback linearization and simultaneous output decoupling technique. By applying a nonlinear feedback and a nonlinear coordinate transformation, the complicated model of the multiple robot arms in either formulation is converted into a linear and output decoupled system. The linear system control theory and optimal control theory are used to design robust controllers in the task space. The first formulation has the advantage of automatically handling the coordination and load distribution among the robot arms. In the second formulation, it was found that by choosing a general output equation it became possible simultaneously to superimpose the position and velocity error feedback with the force-torque error feedback in the task space  相似文献   

    

Masserant  B.J. Stuart  T.A. 《IEEE transactions on aerospace and electronic systems》1997,33(3):930-938

A battery charger is described that uses an on-line microcontroller to maximize its output power. This is done by always operating at either the maximum allowable input current or the thermal limit imposed by the charger itself. In this case the thermal limit is determined by the junction temperatures of the two main insulated gate bipolar transistors (IGBTs). Since direct measurement of these temperatures is impractical, they must be calculated by a computer algorithm that uses various on-line measurements. Experimental results for an 8 kW charger indicate a reduction in the bulk charging time of about 26% when used with a set of NiFe batteries.  相似文献   

    

Bataineh  S. Robertazzi  T.G. 《IEEE transactions on aerospace and electronic systems》1997,33(4):1189-1198

Ultimate performance limits to the aggregate processing speed of networks of processors that are processing a divisible job are described. These take the form of either closed-form expressions or numerical procedures to calculate the equivalent processing speed of an infinite number of processors. These processors are interconnected in either a linear daisy chain with load origination from the network interior or a tree topology. The tree topology is particularly general as a natural way to perform load distribution in a professor network topology with cycles (e.g., hypercube, toroidal network) is to use an embedded spanning tree. Such limits on performance are important as they provide an ideal baseline against which to compare the performance of finite configurations of processors.  相似文献