The above and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following detailed description, taken in conjunction with the accompanying drawings of which:
Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The exemplary embodiments are described below to explain the present invention by referring to the figures.
In this case, the first position 210 and the second position 220 are fixed, respectively, and a distance between the two positions is L. The first position 210 transmits a first impulse positioning signal P1 to the object 230, and the second position 220 transmits a second impulse positioning signal P2 to the object 230. The object 230 receives the first impulse positioning signal P1 and the second impulse positioning signal P2 and measures an azimuth of the object 230 by using the azimuth measurement apparatus according to an exemplary embodiment of the present invention.
The positioning signal receiver 310 receives the first impulse positioning signal P1 and the second impulse positioning signal P2 from the first position and the second position, respectively. In this case, the first impulse positioning signal P1 and the second impulse positioning signal P2 are transmitted at a predetermined interval in time, and the object 230 has recognized the predetermined interval in time between the two impulse positioning signals. Accordingly, the positioning signal receiver 310 receives the first impulse positioning signal P1 and the second impulse positioning signal P2, transmitted at the predetermined interval in time, and outputs the two impulse positioning signals P1 and P2 by removing the predetermined interval in time.
The phase difference detector 320 detects a phase difference between the first impulse positioning signal P1 and the second impulse positioning signal P2, received by the positioning signal receiver 310. Namely, a delay time of the two impulse positioning signals P1 and P2 inputted to the phase difference detector 320 is detected. The detected phase difference may be digitized and outputted.
The azimuth calculator 330 calculates an azimuth of the object 230 by using the phase difference between the two impulse positioning signals P1 and P2, detected at the phase difference detector 320. In this case, the azimuth is calculated as shown in Equation 1.
θ=cos−1(Δd/L) [Equation 1]
In this case, θ indicates the azimuth of the object 230, L indicates the distance between the first position 210 and the second position 220 shown in
Thus, according to the present invention, Δd is precisely measured by using the phase difference between the two impulse positioning signals P1 and P2 instead of the distances d1 and d2.
In this case, Δd is acquired as shown in Equation 2.
Δd=c·Δτ [Equation 2]
In this case, c indicates the speed of light and Δτ indicates a phase difference time of the two impulse positioning signals P1 and P2. Namely, when the phase difference between the two impulse positioning signals is detected, Δd may be acquired by Equation 2 and the azimuth of the object 230 may be calculated by Equation 1.
The positioning signal phase detection unit 410 outputs a pulse signal of the phase difference between the first impulse positioning signal P1 and the second impulse positioning signal P2. The pulse-voltage conversion unit 420 converts the pulse signal of the phase difference, outputted from the positioning signal phase detection unit 410, into a voltage signal. The A/D conversion unit 430 digitizes and outputs the voltage signal converted from the pulse signal of the phase difference, to the azimuth calculator 330.
The operations illustrated in
Referring to
When the pulse signal of the phase difference between the two impulse positioning signals is outputted, the pulse-voltage conversion unit 420 converts the waveform of C that is the pulse signal, into a voltage signal to digitize. Specifically, after converting the waveform of C into a waveform of D, the A/D conversion unit 430 digitizes and outputs the waveform of D to the azimuth calculator 330.
The buffer delay line unit 610 includes a plurality of buffer cells connected in series. The buffer delay line unit 610 receives the first impulse positioning signal P1 and outputs the first impulse positioning signal P1 delayed by a predetermined amount of time at each of the buffer cells.
The phase offset detection unit 620 receives a plurality of delayed first impulse positioning signals outputted from the buffer delay line unit 610 and the second impulse positioning signal P2 and outputs a value of the digitized phase difference between the two impulse positioning signals P1 and P2, to the azimuth calculator 330. In this case, the phase offset detection unit 620 includes a plurality of AND gate circuits, and the second impulse positioning signal P2 is inputted to each of the AND gate circuits via an inverter. The operations illustrated in
The buffer delay line unit 720 includes a plurality of buffer cells connected in series, and a delay time of the buffer cells is controlled by a control voltage inputted from outside. Namely, since a phase delay time of the buffer cell is controlled depending on a magnitude of the voltage inputted from the phase delay time control unit 710, a total delay time of the buffer delay line unit 720 may be controlled. In this case, the delay time of the buffer delay line unit 720 is delayed by half-period multiples of a period T, i.e. T/2, T, 3T/2, . . . of a reference signal inputted to the buffer delay line unit 720. In this case, the reference signal may be inputted by a reference signal generation apparatus while the period of the reference signal is predetermined.
The phase delay time control unit 710 receives the reference signal and a signal made from the reference signal passing through the buffer delay line unit 720 and outputs the control voltage controlling the delay time of the buffer cells forming the buffer delay line unit 720, depending on a phase difference between the two signals. In this case, the same control voltage is inputted to each of the buffer cells forming the buffer delay line unit 720.
The phase offset detection unit 730 receives a plurality of the first impulse positioning signals P1 inputted to the buffer delay line unit 720 and delayed by a predetermined amount of time at each of the buffer cells, and the second impulse positioning signal P2 and outputs a value of a digitized phase difference of the two impulse positioning signals, to the azimuth calculator 330. In this case, since the variance of the delay time of the first impulse positioning signal P1 is controlled by the phase delay time control unit 710, the error occurring due to the buffer cells forming the buffer delay line unit 720 may be reduced. Accordingly, an error of the phase difference between the two detected impulse positioning signals is reduced, thereby improving reliability.
In this case, the phase offset detection unit 730 includes a plurality of AND gate circuits, and the second impulse positioning signal P2 is inputted to each of the AND gate circuits via an inverter.
The phase delay detection part 810 receives a reference signal {circle around (1)} and a signal {circle around (2)} made from the reference signal {circle around (1)} passing through the buffer delay line unit 720 and outputs a pulse signal {circle around (3)} of a phase difference between the two signals.
The pulse-voltage conversion part 820 converts the pulse signal of the phase difference between the reference signal {circle around (1)} and the signal {circle around (2)}, into a voltage signal that determines a magnitude of a control voltage {circle around (4)} for controlling the delay time of the buffer cells.
The voltage control part 830 identically inputs the control voltage {circle around (4)} controlling the delay time of the buffer cells forming the buffer delay line unit 720 based on the voltage signal {circle around (4)} converted at the pulse-voltage conversion part 820, to all of the buffer cells.
The operations of the phase difference detector 320 having the configurations shown
The pulse-voltage conversion part 820 converts the pulse signal {circle around (3)} of the phase difference, into the voltage signal. The voltage control part 830 inputs the determined control voltage {circle around (4)} to all of the buffer cells of the buffer delay line unit 720, based on the converted voltage signal.
As shown in
When the variance with respect to the buffer delay line unit 720 is controlled, the phase offset detection unit 730 receives the first impulse positioning signal P1 passing through the buffer delay line unit 720 and the second impulse positioning signal P2, detects the phase difference between the first impulse positioning signal P1 and the second impulse positioning signal P2, and outputs a result of the phase difference as a digital value.
Specifically, since the variance with respect to the buffer delay line unit 720 is previously controlled, a phase delay variance of the first impulse positioning signal passing through the buffer delay line unit 720 does not occur and the phase offset detection unit 730 may precisely detect the phase difference between the first impulse positioning signal and the second impulse positioning signal. Accordingly, the object 230 may precisely measure the position of the object 230 by using the detected phase difference via Equations 1 and 2.
In this case, the first impulse positioning signal and the second impulse positioning signal are received from a first fixed position and a second fixed position such as the first and second positions 210 and 220 of
In this case, operation S1120 of detecting a phase difference may include operations of detecting the phase difference and digitizing the detected phase difference. Specifically, the digital value of the phase difference, capable of being used when measuring the azimuth, may be included in operation S1120 of detecting a phase difference.
In this case, measuring the azimuth by using the phase difference may be performed via Equations 1 and 2.
Next, a process of detecting the phase difference between the two impulse positioning signals will be described in detail.
The operations shown in
The operations shown in
Namely, comparing
The operations shown in
Via the series of the above-described processes, the variance of the buffer delay line is controlled and the phase difference between the first impulse positioning signal and the second impulse positioning signal may be precisely measured by using the buffer delay line whose variance is controlled.
The azimuth measurement method using a phase difference, according to the present invention, may be embodied as a program instruction capable of being executed via various computer units and may be recorded in a computer-readable recording medium. The computer-readable medium may include a program instruction, a data file, and a data structure, separately or cooperatively. The program instructions and the media may be those specially designed and constructed for the purposes of the present invention, or they may be of the kind well-known and available to those skilled in the art of computer software arts. Examples of the computer-readable media include magnetic media (e.g., hard disks, floppy disks, and magnetic tapes), optical media (e.g., CD-ROMs or DVD), magneto-optical media (e.g., optical disks), and hardware devices (e.g., ROMs, RAMs, or flash memories, etc.) that are specially configured to store and perform program instructions. The media may also be transmission media such as optical or metallic lines, wave guides, etc. including a carrier wave transmitting signals specifying the program instructions, data structures, etc. Examples of the program instructions include both machine code, such as produced by a compiler, and files containing high-level language codes that may be executed by the computer using an interpreter. The hardware elements above may be configured to act as one or more software modules for implementing the operations of this invention.
An aspect of the present invention provides an azimuth measurement apparatus and method using a phase difference, capable of precisely detecting a position of an object by measuring an azimuth of the object by using a phase difference of two impulse positioning signals.
An aspect of the present invention also provides an azimuth measurement apparatus and method using a phase difference, in which an object may quickly move to a desired position because a position of the object may be precisely detected by using a phase difference. For example, when the object is a robot vacuum cleaner, since a present position may be precisely known, the robot vacuum cleaner may quickly move to other positions to vacuum.
An aspect of the present invention provides an azimuth measurement apparatus and method using a phase difference, capable of reducing an error of the phase difference between two impulse positioning signals, occurring due to a variance of a buffer delay line, and precisely detecting the phase difference by controlling the variance of the buffer delay line.
Although a few exemplary embodiments of the present invention have been shown and described, the present invention is not limited to the described exemplary embodiments. Instead, it would be appreciated by those skilled in the art that changes may be made to these exemplary embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Number | Date | Country | Kind |
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10-2006-0066704 | Jul 2006 | KR | national |