Virtual Time Delay Research Articles

Virtual Instrument Applied in Seismic Time Delay Signal Process

It is very important to do some preliminary analysis and processing of the time delay signal before the time delay estimation for the target orientation of the multi-sensor network. In this paper, a virtual instrument time delay analysis system is designed, which contains: a virtual oscilloscope, a virtual spectrum analyzer, a virtual filter and a virtual time delay analyzer. By the use of this analysis system, the spectrum of the seismic target signal collected in the field is analyzed. Analysis shows the main frequency of the target signal: 13Hz, 85Hz, 170Hz, 125Hz. Distinctness of the time delay peak is proposed to describe the validation of the cross-correlation result. Based on the three main frequency components, signals were filtered by five filters and analyzed separately. Results were shown in figures of time delay vs. time, distinctness vs. time. Each curve in a figure corresponds to a certain number of points of cross correlation. According to the results, the frequency component from 8Hz to 30Hz is much more suitable for practical use. The regular pattern of the time delay curve is consistent with the target motion. Application reveals that the system is helpful in the research of time delay estimation.

A method to test HF ray tracing algorithm in the ionosphere by means of the virtual time delay

It is well known that a 3D ray tracing algorithm furnishes the ray’s coordinates, the three components of the wave vector and the calculated group time delay of the wave along the path. The latter quantity can be compared with the measured group time delay to check the performance of the algorithm. Simulating a perfect reflector at an altitude equal to the virtual height of reflection, the virtual time delay is assumed as a real time delay. For a monotonic electronic density profile we find a very small relative difference between the calculated and the virtual delay for both analytic and numerical 3D electronic density models.

J192014 時間遅れを考慮した移動ロボットの遠隔操作手法([J19201]ロボティクスと宇宙(1))

Communication time delay in teleoperation of a moon robot from the earth is an important subject and should be considered. Mobile robot teleoperation method considering time delay is proposed in this work. The proposed method uses a synthesized bird's-eye view image which is synthesized using environmental images captured by the mounted camera on the robot in advance without reconstructing the three-dimensional environmental model of the remote site. The virtual controlled robot which can be controlled in the virtual environment where there is no communication time delay is introduced and controlled by an operator. Communication time delay is handled by the autonomous movement of the real robot which moves autonomously to realize the movement of the controlled robot based on the controlled robot and real environmental information. We have implemented the teleoperation system which can handle communication time delay based on the proposed method. It is confirmed that the proposed method can be applied to robot teleoperation which has communication time delay according to the results of conducted experiments which have virtual time delay.

Application of Virtual Instrument in Time Delay Signal Analysis

Time delay estimation is the basis of target location of multi-sensor network, while the basic analysis of the signal is of key importance to the time delay estimation. In this paper, a time delay analysis system is designed by virtual instrument development tools. The analysis system contains: virtual oscilloscope, virtual spectrum analyzer, virtual filter and virtual time delay analyzer. Using this analysis system on a set of field collected acoustic target signal, spectrum analysis and filtering is made. Then the time delay estimation has been carried out for several sampling data segments selected by certain rules, and curve of the time delay vs. time is given. Analysis shows the main frequency of the target signal: 85Hz, 13Hz, 170Hz and 125Hz. The regular pattern of the time delay curve is consistent with the target motion. Application reveals that the system is helpful in the research of time delay estimation.

Teleoperation with Additional Delay Mechanism. Introduction of Virtual Time Delay.

The existing teleoperation methods, which verify the command only as a single command not as a series of commands, have poor operability under communication time delay. This is because the inappropriate operation can only be stopped just before the execution and the following restarting operation becomes very difficult. This report suggests a new on-line teleoperation method equipped with the additional delay mechanism, which adds some additional time delay to communication time delay to maintain a command buffer. Every verfied command is temporarily stored in this buffer before transmission and, when a wrong command is generated later, part of the commands or all the commands in the buffer are automatically reedited to make a new series of commands which smoothly avoid the wrong operation. The operation continues smoothly from the last command point that was left after the reediting.

Teleoperation with Additional Delay Mechanism. Introduction of Virtual Time Delay.

The existing teleoperation methods, where teleoperation commands are verified and executed as each separated ones and not as a series of commands, have only poor operational capability under long time delay. This is because inappropriate operations can only be avoided just before they are executed and the following restarting operation requires much work. This report suggests a new online teleoperation method which introduces the additional time delay by attaching an additional delay mechanism, where all the teleoperation commands are temporarily stored before transmission or execution, verified and, if necessary, re-edited as a series of commands. So when inappropriate operations occur, the current operational point can be got back to a former point where appropriate operation is expected to be restarted smoothly.