KR101031890B1 - The apparatus and method for wireless ranging - Google Patents

Abstract

The present invention relates to a wireless distance measuring device and a method for measuring the distance precisely in cm class wirelessly without using an expensive complex device such as a high-speed ADC in measuring the distance using an ultra-wideband impulse signal, A pulse transmitting / receiving module for measuring a time difference between transmitting and receiving an impulse signal by using an analog TDC (Time to Digital Converter); And a distance calculation module for calculating a distance by using the time difference measured by the pulse transmission / reception module and the transmission speed of the impulse signal, thereby reducing complexity, power consumption, price, etc. of a precision wireless range finder, which is seconds Combined with the advantages of ultra-wideband impulse signals capable of data communication at low power, it can be applied to various fields such as RFID, robot movement control, vehicle driving control, and intelligent sensor node.

UWB, Impulse, Distance Measurement, Receive Point, TDC

Description

Wireless distance measuring apparatus and its method {The apparatus and method for wireless ranging}

The present invention relates to a wireless distance measuring device and a method thereof, and more particularly to a wireless distance measuring device which can precisely measure the reception point of a signal to reduce an error range of the distance measurement even without using an expensive and complicated device. It's about how.

Recently, research has been actively conducted to fuse wireless data communication and precision location recognition technology and apply it to location recognition RFID, robot movement control, and intelligent sensor node.

The dual precision location recognition technology can be classified into a method using narrowband signals such as WLAN, Bluetooth, and zigbee, and an impulse signal having a time width of less than 10 seconds (10 ^-9 seconds).

However, in the case of using a narrowband signal, the error range for position recognition is more than 1m, so it is difficult to precisely recognize the position. However, in the case of using the impulse signal, the application range is limited to within 15 cm. It is possible to recognize the position in the error range and has a low power level in the ultra-wide band, so the interference to other electronic devices is insignificant.

On the other hand, in the case of using the impulse signal, in order to accurately measure the cm class, the ultra-wideband impulse receiver needs to perform high-speed sampling at least 1 Gsps (sample per second) for the received impulse signal.

Therefore, for this purpose, a high speed ADC (Analog to Digital Converter) or multiple ADCs are connected in parallel. These high speed ADCs are relatively expensive, and high systems in gigahertz (GHz) are required for operation. Since the clock frequency must be generated, power consumption increases. In addition, connecting multiple ADCs in parallel is costly and causes a complicated circuit due to the parallel connection.

Accordingly, the present invention is to improve the above-described problems, and to measure the distance by using an ultra-wideband impulse signal to enable accurate distance measurement in cm class wirelessly without using expensive complex elements such as high-speed ADCs. A new wireless distance measuring device and method thereof are proposed.

More specifically, the wireless distance measuring apparatus according to an embodiment of the present invention includes a pulse transmission and reception module for measuring the time difference between transmitting and receiving an impulse signal using an analog time to digital converter (TDC); And a distance calculation module for calculating a distance by using the time difference measured by the pulse transmission / reception module and the transmission speed of the impulse signal, thereby reducing complexity, power consumption, price, etc. of a precision wireless range finder, which is seconds Combined with the advantages of ultra-wideband impulse signals capable of data communication at low power, it can be applied to various fields such as RFID, robot movement control, vehicle driving control, and intelligent sensor node.

In addition, the wireless distance measuring method according to an embodiment of the present invention comprises a first step of generating and transmitting an impulse signal; A second step of measuring a time difference between a point in time at which reception is received and an actually received point in time using an analog TDC (Time to Digital Converter) for the impulse signal received in response to the impulse signal; And a third step of calculating a distance to a reflector or an arbitrary point using the measured time difference, so that the distance can be measured more simply and precisely than in the related art.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a diagram schematically illustrating a wireless distance measuring method according to the present invention.

The measurement method utilized in the wireless distance measuring apparatus according to the present invention can be largely divided into two types, as shown in FIG. 1 (a), an ultra-wideband impulse signal at time t1 in one wireless distance measuring apparatus 10. Generates and transmits a signal, and when the transmitted pulse is reflected back from a person, an object, or the like, the returned pulse signal is received. Therefore, the time difference from the returned pulse signal to the received t2 time can be calculated and converted into a distance. In addition, as shown in Figure 1 (b), when a plurality of wireless distance measuring apparatus according to an embodiment of the present invention is provided, when the first wireless distance measuring apparatus 10a generates and transmits an impulse at time t1, The second wireless distance measuring device 10b, which is spaced apart from the first wireless distance measuring device 10a, receives it at time t2, and generates a response pulse and transmits it at time t3. When the first wireless distance measuring device receives the response pulse at time t4, the first wireless distance measuring device calculates (t2-t1) + (t4-t3), which is a time difference from when the impulse is transmitted to when the response pulse is received. It can be converted into

Accordingly, a wireless distance measuring apparatus according to an embodiment of the present invention generates and transmits an ultra-wideband impulse signal, and transmits and receives a pulse transceiving module for measuring a time interval during transmission and reception, and converts the measured time interval into a person, an object, and the like. And a distance calculating module for calculating a distance from the reflector or the second wireless distance measuring device.

In the wireless distance measuring apparatus according to an embodiment of the present invention, the time interval measurement of the reception pulse performed in the pulse transmission / reception module may be made with the following concept. 2 is a diagram illustrating a time measurement concept of a reception pulse in the wireless distance measuring apparatus according to the present invention.

In the wireless distance measuring apparatus according to an embodiment of the present invention, the pulse transmission / reception module has a system clock CLK having a predetermined period as a reference clock. The transmission pulse is generated and transmitted in synchronization with the rising edge time t1 of the system clock. Even when a pulse is received, the received signal is recognized at the time of the rising edge of the system clock. Thus, the approximate reception time is recognized at the rising edge time t2 of the system clock after the pulse is received. The time difference between reception times (w_d) is measured to calculate the reception time of the reception pulse. That is, the time interval between the transmission pulse and the reception pulse is (t2-w_d) -t1, and the distance calculation module uses the measured time interval data and the propagation speed of the impulse signal to separate the distance from the reflector or another wireless distance measuring device. Can be calculated.

Therefore, the more precisely measuring the time difference (w_d) between the actual receiving time of the pulse and the first rising edge of the system clock after the reception, the more precise the distance can be measured. It is proposed to measure precisely, and the pulse transceiving module for this is composed as follows.

In this case, the synchronization of the system clock may be adjusted based on the rising edge or falling edge time, but in the present specification, the operation is based on the rising edge time as an example, but the present disclosure is not limited thereto and may be modified to operate based on the falling edge time. Of course.

3 is a block diagram illustrating a circuit configuration of a pulse transmitting and receiving module in a wireless distance measuring apparatus according to an embodiment of the present invention.

In the wireless distance measuring apparatus according to an embodiment of the present invention, the pulse transmission and reception module, as shown in Figure 3, the trigger circuit 50, flip-flop 52, pulse width generator 54, analog TDC circuit And a timer circuit 58.

The trigger circuit 50 is triggered when the voltage level of the received impulse signal s_A is greater than or equal to a predetermined value, and outputs a high signal. As a non-linear device, high-speed switching such as a schottky diode is performed. It is preferable to use a device capable of).

The output signal s_B of the trigger circuit 50 is input to the flip-flop 52 together with the system clock s_C. The flip-flop 52 is at the rising edge of the input system clock s_C. The output signal of the trigger circuit 50 is maintained.

The pulse width generator 54 inputs the output signal s_B of the trigger circuit 50 and the output signal s_D of the flip-flop 52, and from the two input signals, the actual reception time and the rising edge time of the system clock are input. The time difference between them can be represented by the pulse width. That is, a high signal is output from the time when the output signal s_B of the trigger circuit 50 becomes equal to or greater than a predetermined voltage to the time when the output signal s_D of the flip-flop 52 becomes high, thereby outputting a pulse of the output signal. The width is a time difference, which will be described in detail later with reference to FIG. 4.

)가 아날로그 TDC 회로(56)로 입력될 수 있다. 아날로그 TDC 회로(56)는 상기 제 1 출력신호(s_E)와 제 2 출력신호(

)를 일정 배수로 증폭시키고 시스템 클럭(s_C)을 이용하여 카운트 함으로써 펄스 폭에 해당하는 시간을 계측할 수 있다.The analog TDC circuit 56 is connected to the pulse width generator 54 so that the output signal s_E output from the pulse width generator 54 is an input signal. The time difference between the actual reception time and the rising edge time of the system clock a first output signal s_E output as a high signal and a second output signal inverting and outputting the first output signal (

) May be input to the analog TDC circuit 56. The analog TDC circuit 56 includes the first output signal s_E and the second output signal (

) Can be amplified by a certain multiple and counted using the system clock s_C to measure the time corresponding to the pulse width.

The timer circuit 58 transmits an impulse signal using the time value s_F measured by the analog TDC circuit 56, the output signal s_D of the flip-flop 52, and the system clock s_C as input signals. Can be calculated from the time until the received (D).

The waveform of the signal for each part of the pulse transmission / reception module according to the embodiment of the present invention configured and operated as described above is as follows. FIG. 4 is a diagram illustrating waveforms in respective parts of a pulse transmitting and receiving module in a wireless distance measuring apparatus according to an exemplary embodiment of the present invention.

As shown in FIG. 4, when the magnitude of the received impulse signal s_A becomes equal to or greater than the first reference voltage TH_tr, the trigger circuit becomes active and outputs a logic "high" signal. At this time, for example, when 0V is set to "low" and 5V is set to "high", and the high signal is output, the actual output signal s_B takes some time to rise from 0V to 5V, and 5V is not output correctly. Therefore, the reference voltage that is determined to be "high" in logic is set. Therefore, the trigger circuit is triggered to have a first time point t_B at which the voltage of the output signal rises rapidly and becomes equal to or greater than the second reference voltage TH_h that is logically determined to be "high".

In the flip-flop, when the system clock signal s_C reaches the rising edge while the output signal s_B of the trigger circuit maintains the high signal, the logic high signal is output and maintained at the second time point t_D.

At this time, the output signal s_B of the trigger circuit and the output signal s_D of the flip-flop are input together to the pulse width generator, and at the first time point t_B at which the output signal s_B of the trigger circuit is determined to be "high". In synchronization, the high signal is output (s_E), and the low signal is output (s_E) at the second time point t_D at which the output signal s_D of the flip-flop becomes high. Therefore, the high signal is output only during the time from the first time point t_B to the second time point t_D, and if it is determined that the time when the high signal is output from the trigger circuit is when the actual impulse signal is received, the high signal The output pulse width is equal to the time difference w_d between the time when it is detected that the received signal is to be obtained and the actual time when it is obtained.

The analog TDC (Time to Digital Converter) circuit may measure the pulse width of the output signal s_E output from the pulse width generator by the unit of time as described above.

In general, TDC can be divided into digital and analog methods. Digital TDC used in the wireless distance measuring device according to the prior art requires a high-precision, high-speed clock with high time resolution. The disadvantage is high power. Therefore, in the wireless distance measuring apparatus according to the present invention, an analog TDC circuit having a relatively low system clock input is applied. A specific example thereof will be described later with reference to FIG. 5.

On the other hand, the timer circuit can calculate the transmission and reception time difference of the impulse signal using the system clock (s_C) and the output (s_F) of the TDC circuit, the impulse signal is generated and transmitted in synchronization with the rising edge of the system clock, so The arithmetic calculation of the number of system clocks, the number of system clocks at the time of reception, and the output value of the TDC circuit can be used to derive the transmission / reception time difference.

In addition, the derived time difference data can be transferred to a distance calculation module to calculate a separation distance to a reflector or another wireless distance measuring device, and by measuring the time difference with more precise resolution, the error range with respect to the actual distance can be greatly reduced. have.

On the other hand, in the wireless distance measuring apparatus according to an embodiment of the present invention, the TDC circuit for measuring the output signal of the pulse width generator with a precise time resolution may be configured as follows.

5 is an exemplary diagram showing an analog type TDC circuit in the wireless distance measuring apparatus according to an embodiment of the present invention.

As shown in FIG. 5, an analog TDC circuit according to an embodiment of the present invention includes a plurality of current sources I1 and I2 and capacitors C1 and C2 to amplify an input signal by a predetermined multiple. By comparing the clock s_C, the time corresponding to the pulse width can be measured.

)는 각각 TDC 회로를 구성하는 트랜지스터의 게이트 신호로 입력된다. 이때, 에미터 단에 각각 연결된 전류원(I1, I2)과 콜렉터 단에 각각 연결된 커패시터(C1, C2)에 의해 증폭될 수 있으며, 증폭 배수는 트랜지스터에 연결된 두 커패시터(C1, C2)의 용량비(M)와 두 전류원(I1, I2)의 전류비(N)의 곱에 해당하는 배수가 될 수 있다. 또한, 증폭된 입력신호는 시간을 두고 방전하게 되는데, 방전하는 동안 비교기는 일정한 신호를 발생시키며, AND 게이트로 비교기의 출력신호와 시스템 클럭(s_C)이 입력된다. 또한, 신호의 방전이 끝날 때까지 AND 게이트의 출력신호에 대해 카운터를 작동시킨다.More specifically, the two output signals (s_E, outputted from the pulse width generator)

Are input to the gate signals of the transistors constituting the TDC circuit. In this case, amplification may be amplified by current sources I1 and I2 connected to the emitter stage and capacitors C1 and C2 respectively connected to the collector stage, and the amplification factor is the capacity ratio M of the two capacitors C1 and C2 connected to the transistor. ) May be a multiple corresponding to the product of the current ratio N of the two current sources I1 and I2. In addition, the amplified input signal is discharged over time. During the discharge, the comparator generates a constant signal, and the output signal of the comparator and the system clock s_C are input to the AND gate. The counter is also operated on the output signal of the AND gate until the discharge of the signal is completed.

That is, the pulse width of the input signal corresponds to the time difference between the rising edge of the system clock and the point in time at which the actual pulse is received, and this pulse is expanded by MxN times by the current ratio (N) and the capacitor capacity ratio (M), resulting in the system. Accurate time measurement is possible by 1 / (MxN) times the clock (s_C) period.

Therefore, the time interval between transmit and receive pulses can also be measured with a resolution of 1 / (MxN) times the system clock period. That is, for example, if the system clock is 10 MHz and the product of the current ratio and the capacity ratio is 100, the time can be measured at a resolution of 1 nsec, which is 1/100 of 100 nsec of the system clock period. Thus, even if a low system clock is generated instead of a high system clock of gigahertz, The precise time measurement with nano-scale resolution can reduce the complexity and cost as well as the power consumption of the rangefinder. In addition, it combines the advantages of ultra-wideband impulse signal that enables data communication at broadband power and low power, and is suitable for many applications such as precision range finder using microwave, RFID for location recognition, robot movement control, vehicle driving control, intelligent sensor node, and logistics location management. Applicable in the field

As described above, the wireless distance measuring apparatus and method thereof according to the present invention have been described with reference to the illustrated drawings, but by using an analog TDC circuit to accurately measure the time difference between transmitting and receiving pulses, power consumption and cost of the measuring apparatus can be lowered. It is apparent that the technical idea of the present invention can be easily applied by those skilled in the art within the scope of protection.

1 is a simplified view showing a wireless distance measuring method according to the present invention,

2 is a view illustrating a time measurement concept of a reception pulse in the wireless distance measuring apparatus according to the present invention;

3 is a block diagram showing a circuit configuration of a pulse transmitting and receiving module in a wireless distance measuring apparatus according to an embodiment of the present invention;

4 is a view illustrating a waveform in each part of a pulse transmission / reception module in a wireless distance measuring apparatus according to an embodiment of the present invention; and

5 is an exemplary diagram showing an analog type TDC circuit in the wireless distance measuring apparatus according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10, 10a, 10b: wireless distance measuring device 50: trigger circuit

52: flip-flop 54: pulse width generator

56: analog TDC circuit 58: timer circuit

Claims (8)

A pulse transmitting / receiving module for calculating a time difference between receiving a reflector or an impulse signal transmitted to an arbitrary point again; And And a distance calculation module for calculating a distance to the reflector or the arbitrary point by using the time difference measured by the pulse transmission / reception module and the transmission speed of the impulse signal, The pulse transmitting / receiving module receives the impulse signal transmitted to the reflector or the arbitrary point in synchronization with the rising edge time of a system clock having a predetermined period as a reference clock, and then the magnitude of the received impulse signal is equal to or greater than a predetermined value. In this case, a trigger circuit for outputting a high signal, and a pulse width generator for outputting a high signal during an interval from the time at which the high signal is received to the next rising edge of the system clock after receiving the high signal output from the trigger circuit. Using an analog time to digital converter (TDC) for measuring time while the high signal output from the pulse width generator maintains a high state, and using the time value measured by the TDC and the system clock. Timer to calculate the difference between the transmission and reception of the impulse signal Wireless distance measuring apparatus comprising a. delete delete The method of claim 1, The trigger circuit comprises a schottky diode. delete The method of claim 1, The pulse transceiving module includes a flip-flop to maintain the output signal of the trigger circuit from the rising edge time of the system clock to the next rising edge time, and transmits it to the pulse width generator. A first step of generating an impulse signal and transmitting it to a reflector or any point to be synchronized with the rising edge time of the system clock having a predetermined period as a reference clock; After receiving the transmitted impulse signal again, a high signal is generated and output from a time point when the magnitude of the received impulse signal becomes a predetermined value or more to a next rising edge time point of the system clock, and the output high signal is high. A second step of measuring a time during the maintenance by using an analog time to digital converter (TDC); Calculating a difference between transmission and reception of the impulse signal by using the time value measured by the TDC and the system clock; And A fourth step of calculating a distance to the reflector or the arbitrary point by using the calculated difference between transmission and reception of the impulse signal and a transmission speed of the impulse signal Wireless distance measuring method comprising a. delete

Images