A Method to Obtain the Moving Speed of Uncooperative Target Based on Only Two Measurements

The existing research results show that a fixed single station must conduct three consecutive frequency shift measurements and obtain the target’s moving speed by constructing two frequency difference equations. This article proposes a new method that requires only two consecutive measurements. While using the azimuth measurement to obtain the angular difference between two radial distances, it also conducts two consecutive Doppler frequency shift measurements at the same target azimuth. On the basis of this measurement, a frequency difference equation is first constructed and solved jointly with the Doppler frequency shift equation. By eliminating the velocity variable and using the measured angular difference to obtain the target’s lead angle, the target’s velocity can be solved by using the Doppler frequency shift equation again. The new method avoids the condition that the target must move equidistantly, which not only provides an achievable method for engineering applications but also lays a good foundation for further exploring the use of steady-state signals to achieve passive positioning.

Detection technique of moving target based on passive millimeter wave

To solve the problem of insufficient ability when detecting the high-speed moving target with passive millimeter wave technology, a direct-detection passive millimeter wave detecting system using the monolithic microwave integrated cir- cuit （MMIC） millimeter wave radiometer is built, and the measured data are obtained by experiment under different condi- tions. Based on feature analysis of testing signals, it points out that the peak of the first pulse and interval of two peak pulses are valid features which can reflect the motion characteristic of target. A method to calculate the moving speed of target is put forward. The calculating results indicate that the proposed method has enough accuracy and is feasible to determine the parameters of the moving target using for passive millimeter wave system.

An improvement of frozen-image model and its application in a HTS levitation system

This paper mainly reports an improvement of frozen-image model which can qualitatively describe the influence of lateral moving speed on vertical force in a HTS levitation system under lateral movement with field-cooling condition.The model is improved by introducing a dipole which represents the influence of lateral moving speed and modifying the rule of diamagnetic dipole based on frozen-image model.The vertical and lateral forces that are obtained by this improved model agree with the previous measurements qualitatively.This model can also describe the effect of finite scale of superconductor sample in a levitation system.

Ghost imaging for an axially moving target with an unknown constant speed

The influence of the axial relative motion between the target and the source on ghost imaging(GI) is investigated.Both the analytical and experimental results show that the transverse resolution of GI is reduced as the deviation of the target’s center position from the optical axis or the axial motion range increases. To overcome the motion blur,we propose a deblurring method based on speckle-resizing and speed retrieval, and we experimentally validate its effectiveness for an axially moving target with an unknown constant speed. The results demonstrated here will be very useful to forward-looking GI remote sensing.

Application of Dopplerlet matching pursuit to estimate the range and speed of a moving vessel

This paper presents a new method to estimate the range and the speed of a moving vessel by the features of line spectrum. Dopplerlet matching pursuit are used to estimate range and speed. The line spectrums of moving vessel radiated-noises show some time-frequency features. The features of line spectrum reflect the variation of moving state of the vessel. The computer simulation shows the method is practicable and effective. Moreover, the method is applied to estimate the range and the speed of a real underwater signal and the results agree with the data of the experiment on the sea.

New type of transverse moving box mechanism for pot seedling transplanting machine

The existing moving box mechanism pot seedling transplanting machine on the market moves too fast when the picked seedling is collected,which negatively impacts the seedling picking performance.In order to improve the performance,two types of variable speed continuous moving box schemes were designed in this study.The first scheme was to apply a spiral-gear moving box spiral shaft with sine curve characteristics in the box moving mechanism,whereas the second one was to change the circular gear in the moving box into an elliptical gear with a speed shifting transmission mechanism.The working mechanism of the mechanical structure was analyzed,and the kinematic model was established.A dynamic analysis of the slider mechanism was performed.A virtual prototype was established according to agronomic parameters,and the virtual prototype experiments were conducted in ADAMS.The physical prototype and the high-speed photography experiment were performed on the test bench of a transplanting machine frame.The theoretical analysis,virtual prototype and physical prototype test results were consistent,which verified the validity of the theoretical model,virtual prototype and physical prototype and ensured the feasibility of the system.