KR102287086B1 - An apparatus for determining time difference of arrival and method thereof - Google Patents

Abstract

A signal reception time difference determining apparatus is provided. The apparatus includes a first receiving unit and a second receiving unit each receiving periodic signals transmitted at a first interval from a target terminal, an oscillating unit having a first interval and generating a clock having a clock offset in each period, A converter that samples and digitizes the signals received from the first and second receivers, respectively, according to the clock generated by the oscillator, and receives a signal for the periodic signal of the first and second receivers based on the sampled and digitized values It includes a calculation unit that determines the visual difference.

Description

Apparatus and method for determining signal reception time difference

The present invention relates to an apparatus and method for determining a signal reception time difference, and more particularly, to an apparatus and method for determining a location of a target terminal based on a signal reception time difference at a plurality of locations.

In general, as a location tracking technology of a target terminal, a time-based TOA (Time of Arrival) method using time information between transmission and reception, a time-based time difference of arrival (TDOA) method using time difference information between received signals, and reception Various methods are used, such as angle of arrival (AOA) using the angle of a signal, received signal strength (RSS) using the sensitivity of a received signal, and a footprint technique.

Recently, in BAN (Body area network), impulse-based wireless positioning technology (time-based) in UWB system, wireless positioning technology using broadband chirp signal (time-based), and RSS-based positioning technology using the strength of magnetic field of magnet, etc. The application of various methods is being studied, and various techniques described above are combined and developed in order to reduce the position error.

Here, the time-based positioning technique requires different information depending on whether there is synchronization, and in particular, in the case of the synchronous type, accurate synchronization between the target and a plurality of nodes (receiving end) is required for accurate positioning, so the system structure is complicated.

One of the most important requirements in the time-based positioning technique is information on the initial arrival time of the received signal. To measure this more accurately, the sampling rate of analog-to-digital conversion (ADC) is generally increased. For example, when sampling at 1 GHz, theoretically, there is a distance error of 30 cm. In order to reduce this, higher sampling is required, which leads to difficulties in implementation and increases the cost for implementation.

Korean Patent Publication No. 10-1427846 ("Method and Apparatus for Dynamic Scaling of Analog-to-Digital Converter Sampling Rate to Avoid Receiver Interference", Qualcomm Incorporated)

It is an object of the present invention to solve the above-mentioned problems if a higher clock is not used in the actual oscillator based on the clock offset of the oscillator, which is the basis of the sampling rate of analog-to-digital conversion for the received signal. Another object of the present invention is to provide an apparatus and method capable of more accurately determining a signal reception time difference between a plurality of points by achieving an improved sampling rate as a result.

Another object of the present invention for solving the above problems is to provide an apparatus and method for determining a location of a target terminal capable of performing location determination with improved accuracy with respect to a target terminal based on a more accurate signal reception time difference.

However, the problem to be solved by the present invention is not limited thereto, and may be variously expanded without departing from the spirit and scope of the present invention.

A signal reception time difference determining apparatus according to an embodiment of the present invention for achieving the above object includes: a first receiver and a second receiver for receiving periodic signals transmitted at first intervals from a target terminal, respectively; an oscillator for generating a clock having a clock offset in each period with the first interval; a converter for sampling and digitizing the signals received by the first and second receivers according to the clock generated by the oscillator; and a calculator configured to determine a signal reception time difference with respect to the periodic signal of the first receiver and the second receiver based on the sampled and digitized value.

According to an aspect, the converter performs sampling more densely than the first interval based on the clock offset when summing sampling over a plurality of periods, so that the actual sampling rate is higher than the sampling rate according to the first interval. can have

According to an aspect, the clock offset may be based on an error margin of the oscillator, and the converter may perform the sampling without synchronization correction for the clock offset.

According to an aspect, the converter may include a first converter for sampling the signals received by the first receiver and a second converter for sampling the signals received by the second receiver.

According to an aspect, the calculator includes a first time point that is a zero crossing point of a value sampled from the first receiver, and a second time point that is a zero crossing point of a value sampled from the second receiver. Based on the difference, a signal reception time difference between the first receiver and the second receiver may be determined.

According to one aspect, the calculator may further use a difference between the number of clocks counted up to the first time point of the first receiver and the number of clocks counted up to the second time point of the second receiver to obtain the first receiver and the second time point. 2 It is possible to determine the signal reception time difference of the receiver.

According to an aspect, the operation unit determines the actual sampling rate of the operation unit based on a clock counting number from a zero crossing point to a next zero crossing point of a value sampled by at least one of the first receiving unit and the second receiving unit. can

According to an aspect, the oscillator may be a crystal oscillator.

Positioning apparatus according to another embodiment of the present invention for achieving the above object, the first receiving unit, the second receiving unit and the third receiving unit for receiving the periodic signals transmitted at first intervals from a target terminal, respectively; an oscillator for generating a clock having a clock offset in each period with the first interval; a converter for sampling and digitizing the signals received by the first receiver, the second receiver, and the third receiver according to the clock generated by the oscillator; and determining a first time difference, which is a signal reception time difference for the periodic signal of the first receiver and the second receiver, based on the sampled and digitized value, and for the periodic signal of the first receiver and the third receiver and a calculating unit for determining a second time difference that is a signal reception time difference, and determining the location of the target terminal based on the first time difference, the second time difference, and the positions of the first receiver, the second receiver, and the third receiver can do.

A method for determining a signal reception time difference according to another embodiment of the present invention for solving the above-described problem includes: receiving periodic signals transmitted in a first period from a target terminal at a first receiving unit and a second receiving unit, respectively; sampling and digitizing the signals received by the first receiver and the second receiver, respectively, based on clocks having the first interval and having a clock offset in each period; and determining a signal reception time difference for the periodic signal of the first receiver and the second receiver based on the sampling and digitized value.

According to one aspect, in the digitizing, when sampling over a plurality of periods is summed, sampling is performed more densely than the first interval based on the clock offset, so that the sampling rate according to the first interval is substantially higher than the sampling rate according to the first interval. The received signals may be sampled at a sampling rate.

According to an aspect, the clock offset may be based on an error margin of an oscillator generating the clocks, and the digitizing may include performing the sampling without synchronization correction for the clock offset.

According to an aspect, the digitizing may include sampling the signals received from the first receiving unit by a first converting unit and sampling the signals received by the second receiving unit by a second converting unit.

According to an aspect, the determining includes: a first time point that is a zero crossing point of a value sampled from the first receiver, and a second time point that is a zero crossing point of a value sampled from the second receiver It is possible to determine a signal reception time difference between the first receiver and the second receiver based on the time difference of .

According to an aspect, in the determining, the first receiver further uses a difference between the number of clocks counted up to the first time point of the first receiver and the number of clocks counted until the second time point of the second receiver and a signal reception time difference of the second receiver may be determined.

According to one aspect, the determining may include: based on a clock counting number from a zero crossing point to a next zero crossing point of a value sampled by at least one of the first receiver and the second receiver, the actual value of the signals The sampling rate can be calculated.

According to an aspect, the oscillator may be a crystal oscillator.

In a method for determining a location of a target terminal according to another embodiment of the present invention for solving the above-described problems, the first receiving unit, the second receiving unit and the third receiving unit receive periodic signals transmitted in a first period from the target terminal, respectively. ; sampling and digitizing the signals received by the first receiver, the second receiver, and the third receiver, respectively, based on the clocks having the first interval and having a clock offset in each period; determining a first time difference, which is a signal reception time difference for the periodic signal of the first receiver and the second receiver, based on the sampling and digitized value; determining a second time difference, which is a signal reception time difference for the periodic signal of the first receiver and the third receiver, based on the sampling and digitized value; and determining the location of the target terminal based on the first time difference, the second time difference, and the positions of the first receiver, the second receiver, and the third receiver.

A computer-readable storage medium according to another embodiment of the present invention for solving the above problems is a computer-readable storage medium including processor-executable instructions, which, when executed by the processor, cause the processor to , The first receiving unit and the second receiving unit receive periodic signals transmitted in a first period from the target terminal, respectively, and based on the clocks having the first interval and having a clock offset in each period, the second to sample and digitize signals received by the first receiver and the second receiver, respectively, and to determine a signal reception time difference for the periodic signal of the first receiver and the second receiver based on the sampled and digitized values can

A computer-readable storage medium according to another embodiment of the present invention for solving the above problems is a computer-readable storage medium including processor-executable instructions, which, when executed by the processor, cause the processor to , the first receiving unit, the second receiving unit, and the third receiving unit receive periodic signals transmitted in a first period from the target terminal, respectively, and have the first interval, based on clocks having a clock offset in each period , respectively, by sampling and digitizing the signals received by the first receiving unit, the second receiving unit, and the third receiving unit, and receiving a signal for the periodic signal of the first receiving unit and the second receiving unit based on the sampled and digitized values Determine a first time difference that is a time difference, and determine a second time difference that is a signal reception time difference with respect to the periodic signal of the first receiver and the third receiver based on the sampling and digitized value, the first time difference; It may be configured to determine the position of the target terminal based on the second time difference and the positions of the first receiver, the second receiver, and the third receiver.

The disclosed technology may have the following effects. However, this does not mean that a specific embodiment should include all of the following effects or only the following effects, so the scope of the disclosed technology should not be construed as being limited thereby.

According to the signal reception time difference determining apparatus and method according to an embodiment of the present invention described above, an actual higher clock is determined based on the clock offset of the oscillator, which is the basis of the sampling rate of analog-to-digital conversion for the received signal. By achieving an improved sampling rate as a result without using it, it is possible to more accurately determine the signal reception time difference between multiple points.

That is, while using an oscillator having a relatively inexpensive low-speed clock cycle, digital sampling of the analog signal is performed at a more detailed cycle as a result based on the clock offset generated for each clock, so that a plurality of The difference in signal reception time in the receiver can be more precisely determined as in the case of using an oscillator having a high clock cycle.

Furthermore, according to the apparatus and method for determining the location of the target terminal according to another embodiment of the present invention, it is possible to perform positioning of the target terminal with improved accuracy based on the more accurately determined difference in signal reception time at a plurality of points.

1 is an example of different counting results due to different clock offsets.
2 is an exemplary diagram of a positioning operation method of a unidirectional transmission method.
3 is an exemplary diagram of positioning using the signal reception time difference of FIG. 2 .
4 shows a sampling point change according to a clock offset.
5 shows the effect of increasing the sampling rate of the ADC based on the clock offset.
6 shows a difference in arrival time of a periodic signal.
7 is an exemplary diagram of determining a signal reception time difference based on a zero crossing point.
8 is a block diagram illustrating a configuration of an apparatus for determining a signal reception time difference according to an embodiment of the present invention.
9 is a block diagram illustrating a configuration of an apparatus for determining a location of a target terminal according to an embodiment of the present invention.
FIG. 10 shows an implementation example of the apparatus for determining the location of the target terminal of FIG. 9 .
11 shows an implementation example of a near-precision positioning system in a human body region.
12 is a flowchart of a method for determining a signal reception time difference according to an embodiment of the present invention.
13 is a flowchart of a method for determining a location of a target terminal according to an embodiment of the present invention.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail.

However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being “connected” or “connected” to another component, it is understood that the other component may be directly connected or connected to the other component, but other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that no other element is present in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate the overall understanding, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

Position determination based on signal reception time difference

Among the time-based positioning methods, a positioning method based on a time difference of arrival (TDOA) is a reference signal emitted by a target terminal (hereinafter, also referred to as a 'target') in the air is transmitted to a plurality of receivers. (hereinafter, also referred to as a 'beacon' or a 'node') may determine the location of the target terminal based on a difference in arrival time. 2 is an exemplary diagram of a positioning operation method of a unidirectional transmission method, and FIG. 3 is an exemplary diagram of positioning using the signal reception time difference of FIG. 2 .

As shown in FIG. 2 , in a situation where a plurality of positioning nodes 10 , 20 , 30 is fixed at a position where line-of-sight (LOS) is guaranteed between the target 40 and the target 40, the target (40) may continuously transmit periodic signals. The positioning nodes 10 , 20 , 30 may receive this, calculate the first arrival time information, and then calculate the time difference information between the nodes to obtain the signal reception time difference (TDOA) information. As shown in FIG. 2 , the difference in reception time of the signals arriving at the node A 10 and the node B 20 among the nodes _{can be expressed as AB TDOA} , and the node B 20 and the node C ( _{30) may be expressed as BC TDOA} , and the difference in reception time between signals arriving at node A 10 and node C 30 may be expressed as _{AC TDOA.} Each TDOA may have a time value as a reception time difference.

The positioning technique using TDOA information is one of the most applied techniques in wireless positioning because it simply uses the time difference of the received signal. Such TDOA information can be obtained through two unidirectional transmissions in a synchronous system, and TDOA information can also be obtained from TOA information obtained through bidirectional transmission. For positioning, two or more pieces of TDOA information are required from at least three positioning nodes, and the intersection point of the two hyperbolas is determined as the location of the target 40 . _{As shown in FIG. 3 , based on AB TDOA} , which is the signal reception time difference between node A 10 and node B 20, the AB _TDOA is satisfied between node A 10 and node B 20. A point that satisfies _{the AC TDOA} between the node A 10 and the node C 30 based on the _{AC TDOA} , which is the signal reception time difference between the node A 10 and the node C 30, showing the hyperbola of the points. By showing a hyperbola of , the intersection of both hyperbolas can be determined as the position of the target terminal 40 .

In order to improve the accuracy of the measurement position in positioning based on the signal reception time difference as described above, it is necessary to accurately determine the signal reception time difference, and ultimately, it is important to accurately determine the initial signal reception time . In this regard, the radio signal transmitted from the target terminal is received at each node in the form of analog, and the received analog is sampled and digitized at a predetermined interval, so the sampling rate for digitization, that is, the sampling rate is the signal It directly affects the accuracy of the reception time. When the sampling interval is wide, even when the signal arrives at an intermediate point between the first sampling point and the second sampling point, it is recognized that the signal has arrived at the second sampling point, resulting in an error in the signal reception time. It results in an error in the position measurement.

Therefore, although it is important to increase the sampling rate for accurate positioning, there is a problem in that complexity and implementation cost are greatly increased in order to increase the sampling rate. In addition, there is a problem in that it is difficult to implement a sampling rate for precise position measurement within a short distance.

An apparatus and method for determining a signal reception time difference and an apparatus and method for determining a location of a target terminal according to an embodiment of the present invention are for solving the above-mentioned problems (high sampling rate, increased complexity), and time-based high-precision location tracking As a method for estimating first arrival time information, a sub-sampling technique using clock offset information (hereinafter, also referred to as 'clock drift') of the oscillator may be used. This sub-sampling technique can obtain high-speed sampled data while using a low-speed oscillator, and for example, an analog-to-digital conversion (ADC) effect of THz can be obtained.

Since the apparatus and method for determining the signal reception time difference and the apparatus and method for determining the location of a target terminal according to an embodiment of the present invention can use the simplest time-based TDOA method in implementation, the processing structure of the target is very simple and The processing structure of the node (receiver) is also very simple because only the time difference information between the received signals is required.

That is, according to one aspect of the present invention, in relation to a problem requiring sampling of GHz or higher, it can be solved by using a sub-sampling technique using clock offset information, and a synchronization problem in a plurality of nodes (receivers) In relation to this, it can be solved by adopting a structure in which a plurality of nodes are operated according to a single clock. For this reason, the signal reception time difference determination and the target terminal location determination according to an aspect of the present invention may be advantageous for short-distance location measurement.

Effect of the oscillator's clock offset

1 is an example of different counting results due to different clock offsets. Here, the clock offset may mean a phenomenon in which the clock generation rate becomes faster or slower than a predetermined speed as the oscillator that generates the clock is slightly affected by, for example, a change in temperature or pressure, and the 'clock It may also be referred to as 'drift (Clock Drift)'.

That is, even an oscillator (eg, a crystal oscillator) of the same frequency that generates a clock having a predetermined period may have a slight error margin in the process. One of them is the clock offset, which changes slowly with time and temperature. Referring to the clock offset information of the commercial oscillator, the unit is ppm (part per million), which can be expressed as the amount of clock fluctuation during 1 million cycles. The clock offset of the oscillator may cause a considerably large measurement error when analog-digital sampling is performed based on the clock of the oscillator in a distance recognition and radio positioning technique using time information. 1 shows counting information for a given time when there is a clock drift margin between -α and +α in different systems operated with the same clock. It can be seen that due to clock drift, they are counting differently for the same time period.

In this effect, when a low-cost crystal oscillator is used in a wireless personal area network (WPAN) requiring low cost, the margin of clock drift becomes larger, which affects the counting error. In particular, when the measurement time is long, the difference in counting may become larger.

The measurement of the signal reception time difference and the position determination of the target terminal according to an embodiment of the present invention uses a sub-sampling technique that can secure a more dense analog-to-digital conversion sampling rate by using the clock offset as described above. can

Determination of signal reception time difference

8 is a block diagram illustrating a configuration of an apparatus for determining a signal reception time difference according to an embodiment of the present invention. 8, the signal reception time difference determining apparatus 800 according to an embodiment of the present invention is a target terminal (for example, refer to reference numeral 40 in FIGS. 2 to 3 and reference numeral 1010 in FIG. 10) The first receiver 810 and the second receiver 820 each receive a signal transmitted from there is.

According to the signal reception time difference determining method according to an embodiment of the present invention, the target terminal may repeatedly transmit a reference signal with a period at a first predetermined interval, and a plurality of receivers, for example, The first receiving unit 810 and the second receiving unit 820 may receive a periodic signal from the target terminal to determine a reception time difference. Here, the signal received by the first receiving unit 810 and the second receiving unit 820 is converted from analog to digital by the converter 830 based on the clock from the oscillator 840 that generates a clock having a first interval. (ADC) can be sampled and digitized. ADC may be performed on a signal received from each of the plurality of receivers based on a clock from the same oscillator 840 . Although the converter 830 is based on a clock having a first interval, by using a sub-sampling technique using a clock offset, the conversion unit 830 actually performs sampling more densely than at the first interval, which is higher than the sampling rate according to the first interval. Since it has a high substantial sampling rate, it is possible to more accurately determine the difference between the signal reception time and the signal reception time in the first receiver 810 and the second receiver 820 .

According to one aspect, in the positioning processing method according to an aspect of the present invention, a target transmits a periodic signal and the signals received through a plurality of receiving units (eg, receiving antennas) are digitized by different ADCs. In this case, the same oscillator may be applied to a plurality of ADCs, so that the same clock offset may be applied.

Here, the sampling rate applied to the ADC may correspond to the period applied to the target, and the signal may be digitized while moving by the corresponding clock offset (α ppm) in every period. Accordingly, a signal having a resolution that is resolved by an offset in the sampling rate can be digitized.

For example, assuming that the clock applied to the ADC is 10 MHz and the clock offset at this time is 100 ppm, a clock of 10 MHz + 1 KHz is generated, and when converted to resolution, sampling at 100 GHz is obtained. Here, the distance measurement error for 100 GHz is about 0.3 cm.

Here, when it is assumed that different clock offsets exist between the target and the node, and it is assumed that each clock offset is at most 100 ppm, the maximum clock offset between the two is 200 ppm. In the example above, if the clock offset is set to 200 ppm and the error for the distance is calculated, it will be about 0.6 cm, so it is suitable for near-near positioning.

Hereinafter, the sub-sampling technique will be described in more detail. 4 shows a sampling point change according to a clock offset. As shown in FIG. 4 , assuming that the periodic signal transmitted from the transmitter is periodically received by the receiver, a clock having the same first interval as the first interval, which is the signal transmission period of the transmitter, is generated, and α When the signal received from the receiver is sampled through analog-to-digital conversion based on the clock from the oscillator having a clock offset of That is, if the first point is sampled in the first period of the signal, sampling is performed by moving to the right by α in the second period, and sampling is performed by moving to the right by 2α in the third period.

5 shows the effect of increasing the sampling rate of the ADC based on the clock offset. As shown in Fig. 5, when α is one tenth of the length of the rising part of the periodic signal, for example, if an oscillator generating a clock having a frequency of 1 GHz has a clock offset of α per clock, the first In the period, sampling is performed at the position corresponding to 0 of the received signal, and in the second period, sampling is performed at the position corresponding to 1 of the received signal (moved to the right by α from the position of 0), and in the third period, receiving Sampling is performed at the position corresponding to 2 of the signal (moved to the right by 2α from the position of 0), and in the fourth cycle, sampling is performed at the position corresponding to 3 (moved to the right by 3α from the position of 0) of the received signal is carried out Accordingly, for example, if sampling is performed until the tenth period to collect sampled values, substantially the same sampling value as that obtained by sampling the received signal at 10 GHz may be obtained. As such, it is possible to bring the same effect as using an oscillator having a speed of 1 GHz that can be implemented even at low cost and a 10 GHz oscillator requiring a higher implementation cost.

6 shows a difference in arrival time of a periodic signal. As shown in FIG. 6 , when the transmitting end Tx (eg, target terminal) periodically transmits a signal, a plurality of receiving ends (eg, receiving unit, beacon, antenna, etc.) transmit the transmitted signal at different times. will receive In FIG. 6 , the first receiving unit Rx ₁ receives the signal before the second receiving unit Rx ₂ , and for the TDOA-based position measurement according to an aspect of the present invention, only the difference in reception time of the signal needs to be determined. . In order to determine the signal reception time difference between the first receiving unit Rx ₁ and the second receiving unit Rx ₂ , the same measurement criteria for the position of the signals in both receiving units need to be determined. It is possible to determine the signal reception time difference by measuring any of 6b, which is the difference between the arrival times of the end of the waveform. In addition, it is possible to determine the signal reception time difference by specifying the middle part of the waveform.

Furthermore, according to an aspect of the present invention, since the transmitting end Tx periodically transmits a signal, the first receiving unit Rx not only the signal reception time difference of the first period but also the signal reception time difference of the second, third or nth period _It is also possible to determine the signal reception time difference between the first and the second receiver Rx _{2 .} By using the sub-sampling technique according to an aspect of the present invention, it is possible to determine a signal reception time difference between both receivers in a period including a sampling section having a smaller error.

7 is an exemplary diagram of determining a signal reception time difference based on a zero crossing point. As shown in FIG. 7 , according to an aspect of the present invention, for example, when a transmission signal has a value of on/off, a zero crossing point at which a signal of off is sampled for the first time after a signal of on is sampled (Zero Crossing Point) may be determined, _{and a time difference between the zero crossing points in the first receiver Rx 1} and the second receiver Rx ₂ may be determined as a signal reception time difference in both receivers.

More specifically, referring to FIG. 7 , in the first receiving unit Rx ₁ and the second receiving unit Rx ₂ , when sampling is performed for the first time, sampling may be performed at a first position or a subsequent position of the waveform, and each receiving unit receives The sampled signal is sampled based on the clock and clock offset from the same oscillator, and in the next sampling cycle, the sampled signal is sampled at a position shifted by the clock offset α to the present than the previous cycle in the waveform of the sampling signal. As sampling is repeated in the next cycle, the sampling position moves to the right, passes through the position of (n-1)α, and eventually passes through the position of nα to perform sampling at the point where the transmission signal is off, that is, the zero crossing point where the signal value is 0. do. Accordingly, a first time point that is a sampling time of the zero crossing point in _{the first receiver Rx 1 and a second time point that is a sampling time of the zero crossing point in the second receiver Rx 2} are determined, and the first time point and the second time point are determined. By measuring the difference 6d, it is possible to determine a signal reception time difference between _{the first receiver Rx 1} and the second receiver Rx _{2 .} As shown in FIG. 6 , the difference 6d between the first time point and the second time point is the same as the difference 6c between the first reception times of the signals at _{the first receiver Rx 1} and the second receiver Rx _{2 .}

Referring back to FIG. 8 , the apparatus 800 for determining a time difference of arrival according to an embodiment of the present invention includes a first receiver 810 , a second receiver 820 , and a converter 830 . ), an oscillator 840 , and an operation unit 850 .

The first receiver 810 and the second receiver 820 may receive periodic signals transmitted by the target terminal at first intervals, respectively. The first receiver 810 and the second receiver 820 may be fixed to a predetermined location, and location information thereof may be stored in advance.

The oscillator 840 may generate a clock having the same period as the first interval, which is an interval between periodic signals transmitted by the target terminal, and a predetermined clock offset (eg, α) in each period. can be moved to the right or left to cause the clock to terminate.

The converter 830 may sample and digitize the signals received by the first receiver 810 and the second receiver 820 according to the clock generated by the oscillator 840 , respectively. According to an aspect, the converter 830 includes a first converter 831 that samples signals received by the first receiver 810 and a second converter that samples signals received by the second receiver 820 . (832) may be provided, respectively. The first converter 831 and the second converter 832 use the clock signal from the same oscillator 840 to avoid a separate synchronization process, and a drift phenomenon in which the clock offset may vary slightly from cycle to cycle. It can also be made so that no separate correction is required.

On the other hand, the conversion unit 830, as described above with reference to FIGS. 4 to 7, is the interval of the periodic signal of the target terminal based on the clock offset when summing the sampling over a plurality of periods, and the oscillator 840 Sampling is performed more densely than the first interval, which is a specified clock period, so that the sampling rate may be substantially higher than the sampling rate according to the first interval.

Here, the clock offset is not artificial, but may be due to, for example, an error margin according to a manufacturing process of the oscillator, as described with reference to FIG. 1 , and the converter 830 performs synchronization correction for the clock offset of the oscillator. A higher actual sampling rate can be secured through a rather simple process by performing sampling without the need for sampling.

The operation unit 850 may determine a signal reception time difference with respect to the periodic signal from the target terminal in the first receiver 810 and the second receiver 820 based on the digitized value sampled by the converter 830 . . Therefore, the signal reception time difference determining apparatus according to an aspect of the present invention can bring the same effect as performing ADC sampling using the high-speed oscillator while using the low-speed oscillator, and as a result, the accuracy of determining the signal reception time difference can improve

Meanwhile, according to an aspect, as described above with reference to FIG. 7 , the operation unit 850 includes a first time point that is a zero crossing point of a value sampled from the first receiver 810 and a second receiver. The first receiver 810 and the second receiver 820 determine the signal reception time difference from the target Damal based on the time difference of the second time point that is the zero crossing point of the value sampled in 820 , A procedure for determining the difference in reception time can be further simplified.

On the other hand, the operation unit 850 further uses the difference between the number of clocks counted up to the first time point of the first receiver 810 and the number of clocks counted until the second time point of the second receiver 820, and the first receiver and A signal reception time difference of the second receiver may be determined. By counting the number of clocks up to the first time point and/or the first time point, the elapsed time until the first time point and/or the second time point can be determined, and more specifically, a practical sampling rate can be calculated, and each period It is also possible to determine the time spent in Accordingly, according to an aspect, the number of clock counts up to the first time point and/or the second time point may be determined, and a signal reception time difference may be determined based on the difference.

According to another aspect of the present invention, the period of the transmission signal in the target terminal and the specified clock of the oscillator may be different. At this time, in the time difference of the zero crossing points in the plurality of receivers, one or more sampling points are included between the sampling times of the zero crossing points of the subsequent receivers, or one or more sampling points are included between the sampling times of the zero crossing points. may be In this case, the calculator may be configured to calculate an actual signal reception time difference based on the calculated actual sampling rate.

12 is a flowchart of a method for determining a signal reception time difference according to an embodiment of the present invention. As shown in FIG. 12 , in the signal reception time difference determining method according to an embodiment of the present invention, first, periodic signals transmitted in a first period from a target terminal are received by a first receiver and a second receiver, respectively (step 1210). Then, based on clocks having a first interval equal to the interval of the transmission signal of the target terminal and having a clock offset in each period, the signals received from the first and second receiving units are sampled, respectively. Can be digitized (step 1220). Subsequently, a signal reception time difference with respect to the periodic signal from the target terminal of the first receiver and the second receiver may be determined based on the sampled and digitized value (step 1230). A more detailed procedure of the method for determining a signal reception time difference according to an embodiment of the present invention may follow the operation of the signal reception time difference determining apparatus according to the embodiment of the present invention described above.

Target terminal location determination

9 is a block diagram illustrating a configuration of a device for determining a location of a target terminal according to an embodiment of the present invention, and FIG. 10 shows an implementation example of the device for determining a location for a target terminal of FIG. 9 . 9 or 10 , the apparatus 900 for determining a location of a target terminal according to an embodiment of the present invention includes a first receiver 910 , a second receiver 920 , and a third receiver 930 . , a conversion unit 940 , an oscillation unit 950 , and an operation unit 960 may be included.

The first receiver 910 , the second receiver 920 , and the third receiver 930 may receive periodic signals transmitted by the target terminal 1010 at first intervals, respectively. The first receiving unit 910 , the second receiving unit 920 , and the third receiving unit 930 may be installed in a fixed position at a predetermined position, and the position information is stored in advance in a memory (not shown) so that the operation unit 960 is operated. It can be used for calculations.

The oscillator 950 may generate a clock having the same period as a first interval, which is an interval between periodic signals transmitted by the target terminal 1010 , and a predetermined clock offset (eg, a clock offset) in each period. , α) can be moved to the right or left to cause the clock to terminate.

The converter 940 may sample and digitize the signals received by the first receiver 910 , the second receiver 920 , and the third receiver 930 according to the clock generated by the oscillator 950 , respectively. According to an aspect, the converter 940 includes a first converter 941 that samples the signals received by the first receiver 910 , and a second converter that samples the signals received by the second receiver 920 . A third conversion unit 945 for sampling the signals received by the third receiving unit 930 and 943 may be provided, respectively. The first converter 941 , the second converter 943 , and the third converter 945 use the clock signal from the same oscillator 950 to avoid a separate synchronization process, and the clock offset It is possible to eliminate the need for a separate correction even for the drift phenomenon, which may vary slightly from cycle to cycle.

The operation unit 950 is the signal reception time difference for the periodic signal from the target terminal 1010 in the first receiving unit 910 and the second receiving unit 920 based on the digitized value sampled by the converting unit 940 A first time difference (eg, AB _TDOA ) is determined, and the second time difference ( For example, AC _TDOA ) may be determined. Then, based on the first time difference (eg, AB _TDOA ), the second time difference (eg, AC _TDOA ), and the positions of the first receiver 910 , the second receiver 920 and the third receiver 930 . to determine the location of the target terminal 1010 . For positioning, for example, trilateration as described above based on FIGS. 2 to 3 may be used.

That is, the apparatus for determining the location of the target terminal according to an embodiment of the present invention can more accurately determine the signal reception time difference between a plurality of receivers based on the clock offset of the oscillator, and more accurately determine the location of the target terminal based on this there is.

11 shows an implementation example of a near-precision positioning system in a human body region. As shown in FIG. 11 , the apparatus for determining the location of a target terminal according to an embodiment of the present invention may be applied to a near-precision positioning system in a human body area. The target terminal 1100 may be an entity that moves in a human body region and transmits periodic signals, such as a capsule endoscope, and antennas 1110-1 and 1110 respectively disposed at a plurality of fixed positions in the human body region. -2, 1110-3, 1110-4, 1110-5, 1110-6) may be provided. The signal from the target terminal 1100 received by at least three or more antennas among the plurality of antennas is sampled through the position measuring unit 1120, and the signal reception time difference from the target terminal 1100 in each antenna is measured. and may be configured to determine the location of the target terminal 1100 based on this. Signals from the plurality of antennas are sampled with a clock offset according to a clock from one oscillator to achieve an improved sampling rate and more accurately determine the location of the target terminal 1100 .

13 is a flowchart of a method for determining a location of a target terminal according to an embodiment of the present invention. As shown in FIG. 13 , in the method for determining the location of a target terminal according to an embodiment of the present invention, the first receiving unit, the second receiving unit, and the third receiving unit receive periodic signals transmitted in a first period from the target terminal, respectively. do (step 1310). Thereafter, the signals received by the first receiver, the second receiver, and the third receiver may be sampled and digitized, respectively, based on clocks having a clock offset in each period with a first interval (step step) 1320). Then, based on the sampled digitized value, a first time difference that is a signal reception time difference with respect to the periodic signal of the first receiver and the second receiver is determined based on the sampled digitized value (step 1330), and the first receiver based on the sampled and digitized value and a second time difference that is a signal reception time difference with respect to the periodic signal of the third receiver may be determined (step 1340). Thereafter, the location of the target terminal may be determined based on the determined first time difference, the second time difference, and the previously stored positions of the first, second, and third receivers (step 1350). The method for determining the location of the target terminal according to an embodiment of the present invention may follow the specific operation of the apparatus for determining the location of the target terminal according to the embodiment of the present invention previously salvaged.

The above-described methods according to the present invention may be implemented as computer-readable codes on a computer-readable recording medium. The computer-readable recording medium includes any type of recording medium in which data that can be read by a computer system is stored. For example, there may be a read only memory (ROM), a random access memory (RAM), a magnetic tape, a magnetic disk, a flash memory, an optical data storage device, and the like. In addition, the computer-readable recording medium may be stored and executed as code readable in a distributed manner by being distributed in a computer system connected through a computer communication network.

Although described above with reference to the drawings and embodiments, it does not mean that the protection scope of the present invention is limited by the drawings or embodiments, and those skilled in the art will It will be understood that various modifications and variations of the present invention can be made without departing from the spirit and scope thereof.

Specifically, the described features may be implemented in digital electronic circuitry, or computer hardware, firmware, or combinations thereof. The features may be executed in a computer program product embodied in storage in a machine readable storage device, for example, for execution by a programmable processor. And the features may be performed by a programmable processor executing a program of instructions for performing functions of the described embodiments by operating on input data and generating output. The described features include at least one programmable processor, at least one input device, and at least one output device coupled to receive data and instructions from, and transmit data and instructions to, a data storage system. can be executed in one or more computer programs that can be executed on a programmable system comprising A computer program includes a set of directives that can be used directly or indirectly within a computer to perform a particular action on a given result. A computer program is written in any form of programming language, including compiled or interpreted languages, and included as a module, element, subroutine, or other unit suitable for use in another computer environment, or as a standalone operable program. It can be used in any form.

Suitable processors for execution of a program of instructions include, for example, both general and special purpose microprocessors, and either a single processor or multiple processors of a different kind of computer. Storage devices suitable for implementing computer program instructions and data embodying the described features also include, for example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices, magnetic devices such as internal hard disks and removable disks. devices, magneto-optical disks and all forms of non-volatile memory including CD-ROM and DVD-ROM disks. The processor and memory may be integrated in or added by ASICs (application-specific integrated circuits).

Although the present invention described above has been described based on a series of functional blocks, it is not limited by the above-described embodiments and the accompanying drawings, and various substitutions, modifications and changes within the scope without departing from the technical spirit of the present invention It will be apparent to those of ordinary skill in the art to which the present invention pertains.

Combinations of the above-described embodiments are not limited to the above-described embodiments, and various types of combinations may be provided in addition to the above-described embodiments according to implementation and/or necessity.

In the foregoing embodiments, the methods are described on the basis of a flowchart as a series of steps or blocks, but the present invention is not limited to the order of the steps, and some steps may occur in a different order or at the same time as other steps as described above. there is. In addition, those of ordinary skill in the art will recognize that the steps shown in the flowchart are not exclusive, other steps may be included, or that one or more steps in the flowchart may be deleted without affecting the scope of the present invention. You will understand.

The foregoing embodiments include examples of various aspects. It is not possible to describe every possible combination for representing the various aspects, but one of ordinary skill in the art will recognize that other combinations are possible. Accordingly, it is intended that the present invention cover all other substitutions, modifications and variations falling within the scope of the following claims.

Claims (20)

a first receiver and a second receiver for receiving periodic signals transmitted at first intervals from the target terminal, respectively;
an oscillator generating the clock having the first interval, the clock having a clock offset in each period;
a converter for sampling and digitizing the signals received by the first and second receivers according to the clock generated by the oscillator;
Comprising a calculation unit for determining a signal reception time difference between the first receiver and the second receiver with respect to at least one of the signals constituting the periodic signal based on the sampled and digitized values collected over a plurality of cycles of the clock , a signal reception time difference (Time Difference of Arrival) determining device.
The method of claim 1,
The conversion unit,
When sampling over a plurality of periods is summed, sampling is performed more densely than the first interval based on the clock offset, and thus has a substantially higher sampling rate than the sampling rate according to the first interval, signal reception time difference determining apparatus .
3. The method of claim 2,
The clock offset is according to the tolerance margin of the oscillator,
The converter performs the sampling without synchronization correction for the clock offset, the signal reception time difference determining device.
The method of claim 1,
The conversion unit,
A signal reception time difference determining apparatus comprising: a first converter for sampling the signals received by the first receiver; and a second converter for sampling the signals received by the second receiver.
The method of claim 1,
The calculation unit,
Based on a time difference between a first time point that is a zero crossing point of a value sampled from the first receiver and a second time point that is a zero crossing point of a value sampled from the second receiver, the first receiver and A signal reception time difference determining device for determining a signal reception time difference of the second receiving unit.
6. The method of claim 5,
The calculation unit,
A difference in signal reception time between the first receiver and the second receiver is determined by further using a difference between the number of clocks counted up to the first time point of the first receiver and the number of clocks counted until the second time point of the second receiver which is, a signal reception time difference determining device.
7. The method of claim 6,
The calculation unit,
A signal reception time difference determining apparatus for determining the actual sampling rate of the operation unit based on the number of clock counts from a zero crossing point to a next zero crossing point of a value sampled by at least one of the first receiving unit and the second receiving unit.
The method of claim 1,
The oscillator, a crystal oscillator (Crystal oscillator), signal reception time difference determining device.
a first receiver, a second receiver, and a third receiver each receiving periodic signals transmitted at first intervals from the target terminal;
an oscillator generating the clock having the first interval, the clock having a clock offset in each period;
a converter for sampling and digitizing signals received by the first, second, and third receivers according to the clock generated by the oscillator;
Determining a first time difference that is a signal reception time difference of the first receiver and the second receiver for at least one of the signals constituting the periodic signal based on the sampled and digitized values collected over a plurality of cycles of the clock, , determine a second time difference that is a signal reception time difference between the first receiver and the third receiver with respect to at least one of the signals constituting the periodic signal, the first time difference, the second time difference, and the first receiver, A device for determining the location of a target terminal, comprising a calculator configured to determine the location of the target terminal based on the location of the second receiver and the third receiver.
Receiving periodic signals transmitted at first intervals from the target terminal, respectively, by a first receiver and a second receiver;
Based on the clocks from the same oscillator having the first interval - the clock has a clock offset in each period - sampling and digitizing the signals received by the first and second receivers, respectively step;
Determining a signal reception time difference of the first receiver and the second receiver with respect to at least one of the signals constituting the periodic signal based on the sampled and digitized values collected over a plurality of cycles of the clock , a method of determining the time difference of arrival.
11. The method of claim 10,
The digitizing step is
Sampling the received signals at a substantially higher sampling rate than a sampling rate according to the first interval by performing sampling more densely than the first interval based on the clock offset when summing sampling over a plurality of periods, How to determine the difference in signal reception time.
12. The method of claim 11,
The clock offset is according to the error margin of the oscillator generating the clocks,
In the digitizing, the sampling is performed without synchronization correction for the clock offset.
11. The method of claim 10,
The digitizing step is
A signal reception time difference determining method of sampling the signals received in the first receiving unit by a first converting unit and sampling the signals received in the second receiving unit by a second converting unit.
11. The method of claim 10,
The determining step is
Based on a time difference between a first time point that is a zero crossing point of a value sampled from the first receiver and a second time point that is a zero crossing point of a value sampled from the second receiver, the first receiver and A signal reception time difference determining method for determining a signal reception time difference of the second receiver.
15. The method of claim 14,
The determining step is
A difference in signal reception time between the first receiver and the second receiver is determined by further using a difference between the number of clocks counted up to the first time point of the first receiver and the number of clocks counted until the second time point of the second receiver A method for determining the difference in signal reception time.
16. The method of claim 15,
The determining step is
Determining a signal reception time difference by calculating an actual sampling rate for the signals based on a clock counting number from a zero crossing point to a next zero crossing point of a value sampled by at least one of the first receiver and the second receiver method.
13. The method of claim 12,
The oscillator is a crystal oscillator (Crystal oscillator), signal reception time difference determining method.
Receiving the periodic signals transmitted at first intervals from the target terminal in the first receiver, the second receiver, and the third receiver, respectively;
Based on the clocks from the same oscillator having the first interval, the clock having a clock offset in each period, signals received from the first receiver, the second receiver, and the third receiver, respectively sampling and digitizing;
Determining a first time difference that is a signal reception time difference between the first receiver and the second receiver for at least one of the signals constituting the periodic signal based on the sampled and digitized values collected over a plurality of cycles of the clock step;
Determining a second time difference that is a signal reception time difference of the first receiver and the third receiver with respect to at least one of the signals constituting the periodic signal based on the sampled and digitized values collected over a plurality of cycles of the clock step; and
Comprising the step of determining the location of the target terminal based on the first time difference, the second time difference, and the positions of the first receiver, the second receiver and the third receiver, the method for determining the location of the target terminal.
A computer-readable storage medium comprising processor-executable instructions that, when executed by the processor, cause the processor to:
Receiving periodic signals transmitted at first intervals from the target terminal in the first receiver and the second receiver, respectively,
Based on the clock from the same oscillator having the first interval, the clock having a clock offset in each period, the signals received by the first and second receivers are sampled and digitized, respectively, ,
configured to determine a signal reception time difference of the first receiver and the second receiver for at least one of the signals constituting the periodic signal based on the sampled and digitized values collected over a plurality of periods of the clock, A computer-readable storage medium.
A computer-readable storage medium comprising processor-executable instructions that, when executed by the processor, cause the processor to:
Receiving periodic signals transmitted at first intervals from the target terminal in the first receiving unit, the second receiving unit and the third receiving unit, respectively,
Based on the clocks from the same oscillator having the first interval, the clock having a clock offset in each period, signals received from the first receiver, the second receiver, and the third receiver, respectively Sampling and digitizing
Determining a first time difference, which is a signal reception time difference of the first receiver and the second receiver for at least one of the signals constituting the periodic signal, based on the sampled and digitized value collected over a plurality of cycles of the clock, ,
Determining a second time difference, which is a signal reception time difference of the first receiver and the third receiver for at least one of the signals constituting the periodic signal, based on the sampled and digitized values collected over a plurality of cycles of the clock, ,
and determine the position of the target terminal based on the first time difference, the second time difference, and the positions of the first receiving unit, the second receiving unit and the third receiving unit.

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