JP2010071757A - Positioning apparatus and positioning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioning apparatus hardly affected by a noise and having a high reliability. <P>SOLUTION: The positioning apparatus is configured to include, a transmission unit 10 for transmitting a TSP (Time Stretched Pulse) signal in which the frequency component changes in a pulse, a plurality of receiving units 21, 22, 23 for receiving the TSP signal disposed at a predetermined distance from the transmission unit 10 and in mutually separated locations, a memory unit 30 for storing the position information of each of the receiving units 21, 22, 23, and a calculation unit 40 for calculating the time difference of the receiving of the TSP signal by each of the receiving units based on the changing pattern of the frequency component of the TSP signal received by each of the receiving units and calculating the position of the transmission unit 10 based on the time difference and the position information obtained from the memory unit 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a positioning device and a positioning method.

  In recent years, position measurement of a moving body using GPS (Global Positioning System) typified by a car navigation system has been widely performed. However, there is a problem that it does not function in indoor spaces where radio waves from satellites do not reach.

Therefore, Patent Document 1 (Japanese Patent Laid-Open No. 6-130141) discloses a wireless transmitter that transmits weak radio waves and a plurality of radio field strength measurement receptions that obtain received field strength information from weak radio waves transmitted from the wireless transmitter. A computer connected to each of the plurality of radio field strength measurement receivers via an information transmission line provided with a plurality of reception field strength information received by the plurality of radio field strength measurement receivers, and There has been proposed a positioning device including an image display device that displays a result of comparing each electric field intensity from an input signal from the information transmission line input to a computer. Further, in this positioning device, when there are a plurality of positioning targets, the individual radio transmitters are configured to transmit weak radio waves modulated with different identification codes.
JP-A-6-130141

  However, in the positioning device of Patent Document 1, the signal processing itself of comparing the electric field strengths from the input signal from the information transmission line is greatly affected by noise, so that it is reliable unless the conditions are very limited. There is a problem that high positioning is not possible.

  Further, when the wireless strength receiver and the portable wireless transmitter are at a short distance, the received electric field strength of the transmitted and received wireless signals hardly changes, so that the measurement error becomes large and the measurement itself cannot be performed. Conversely, when the distance between the wireless strength receiver and the portable wireless transmitter is a long distance, the measurement error increases because it is easily affected by noise.

  Furthermore, since weak radio waves modulated with different identification codes are radio waves in a single frequency band, if there is noise of the corresponding frequency, there is a possibility that the identification code is disturbed and cannot be recognized.

  The present invention solves the above-described problems, and an object of the present invention is to provide a highly reliable positioning apparatus that can be applied to a relatively wide measurement region and is not easily affected by noise, at a low cost.

  According to the present invention, the positioning device is disposed apart from each other at a predetermined distance from the transmitter that transmits a TSP (Time Stretched Pulse) signal whose frequency component changes in the pulse. A plurality of reception units that receive the TSP signal, a storage unit that stores position information of each reception unit, and each reception based on a frequency component change pattern of the TSP signal received by each reception unit. A calculation unit that calculates a time difference when the unit receives the TSP signal, and calculates a position of the transmission unit based on the time difference and the position information acquired from the storage unit.

  Further, according to the present invention, the positioning method includes a step of transmitting a TSP (Time Stretched Pulse) signal in which a frequency component changes in a pulse in a pulse, and a predetermined distance interval from the transmitter. A plurality of receiving units arranged in the manner of receiving the TSP signal, and a time difference at which the receiving unit receives the TSP signal based on a change pattern of a frequency component of the TSP signal received by the receiving unit. A step of calculating, and a step of calculating the position of the transmitting unit based on the time difference and the position information of each receiving unit.

  The TSP signal is a signal obtained by extending the time axis by changing the phase of the impulse in proportion to the square of the frequency. Since the frequency continuously changes in the pulse, a TSP signal can be discriminated in a frequency band excluding the frequency band including a plurality of frequency components in one pulse and having noise in a specific frequency band. it can. In addition, since the change pattern of the frequency component of the TSP signal does not change with distance, the error is relatively small even when positioning is performed when the transmitter and the receiver are at a long distance. Therefore, the positioning device and positioning method of the present invention can be applied to a comparatively wide measurement region, and are highly resistant to noise and have high reliability.

  The radio signal transmitted by the transmitting unit may be any signal as long as the frequency component changes in the pulse. A chirp wave, a phase-encoded sine wave based on a Barker sequence, a phase code based on an M sequence are well known to those skilled in the art. A sine wave or a phase-encoded sine wave using a complementary sequence may be used. Here, the frequency component change pattern means a state in which the phase of the TSP signal changes in the time axis direction.

  The calculation unit in the positioning device of the present invention selects the first receiving unit and the second receiving unit among the receiving units, and the change pattern of the first TSP signal received by the first receiving unit and the second receiving unit are Based on the similarity to the change pattern of the received second TSP signal, the difference between the reception time of the first reception unit and the reception time of the second reception unit can be calculated as the time difference.

  Here, the difference between the reception time of the first reception unit and the reception time of the second reception unit may be a difference between the reception time of the first reception unit and the reception time itself of the second reception unit, or the first reception unit. May be the difference between the time when the arithmetic unit acquires the first TSP signal from the time when the arithmetic unit acquires the second TSP signal from the second receiver. The transmission time between the reception unit and the calculation unit is sufficiently shorter than the time during which the TSP signal is transmitted through the space, and can be ignored in the positioning accuracy of the present invention.

  In addition, the calculation unit in the positioning apparatus of the present invention can calculate the similarity using a plurality of sampling values obtained by sampling each of the first TSP signal and the second TSP signal at a predetermined period. .

  By directly using the sampling value for the calculation, it is possible to omit the processing of restoring the signal waveform from the sampling value of the received TSP signal and comparing the restored signal waveform, so that the configuration of the apparatus becomes relatively simple. . As a result, there are effects such as downsizing the transmitter, extending the life of the transmitter, and reducing the power consumption of the positioning device.

  Furthermore, the arithmetic unit in the positioning device of the present invention associates the sampling value obtained from the first TSP signal and the sampling value obtained from the second TSP signal on a one-to-one basis so that the difference between the respective time components is constant. The values obtained by the multiplication are accumulated and averaged to represent the similarity of the periodic patterns, and the difference in time components that maximizes the similarity of the periodic patterns can be used as the time difference.

  The arithmetic processing as described above is a technique called cross-correlation function processing. Since the sampling values in the two signal waveforms are multiplied, accumulated, and averaged, the influence on the calculation result can be suppressed even if the influence of noise occurs in some frequency bands.

  Furthermore, the transmitter of the positioning device of the present invention can change the time interval for transmitting the TSP signal. Thereby, the TSP signal to be compared can be specified based on the time interval for receiving the TSP signal.

  Furthermore, the positioning device of the present invention includes at least three receiving units, and the calculating unit can calculate the position of the transmitting unit moving in space three-dimensionally.

  Furthermore, the positioning device of the present invention includes at least two receiving units, and the calculating unit can calculate the position of the transmitting unit moving on a predetermined line.

  Note that the frequency band of the TSP signal may be an audible range. By making the TSP signal an audible frequency band, that is, an audio signal, the transmitter and the receiver can be configured with commercially available general-purpose products, so that the cost can be reduced.

  As described above, the positioning device of the present invention can be applied to a relatively wide range of measurement areas, and can provide a highly reliable positioning device that is not easily affected by noise and at low cost.

   FIG. 1 is a configuration diagram of a positioning apparatus according to an embodiment of the present invention. The positioning device of the present embodiment includes a transmitting unit 10 that transmits a TSP (Time Stretched Pulse) signal whose frequency component changes in a pulse, and TSPs that are spaced apart from each other by a predetermined distance from the transmitting unit 10. A plurality of receiving units 21, 22, and 23 that receive signals, a storage unit 30 that stores position information of each receiving unit 21, 22, and 23, and a frequency component change pattern of the TSP signal received by each receiving unit And a calculation unit 40 that calculates the time difference at which each reception unit receives the TSP signal based on the time difference and calculates the position of the transmission unit 10 based on the time difference and the position information acquired from the storage unit 30. Thus, since the TSP signal includes a plurality of frequency components, the influence of the noise of a specific frequency is small, and the positioning device of this embodiment can have high noise resistance. In addition, since the change pattern of the frequency component of the TSP signal does not change depending on the distance between the transmission unit and the reception unit, the positioning device of this embodiment can be used in a relatively wide space.

  The frequency band of the above TSP signal may be an audible range, that is, an audio signal. When the TSP signal is in an audible frequency band, the transmitter 10 and the receivers 21, 22, and 23 can be configured with commercially available general-purpose products, so that the cost can be suppressed.

ただし、ｊは虚数単位、ＮはＴＳＰ信号のサンプル長、ｍはＴＳＰ信号の幅を表すパラメータ（０≦ｍ≦Ｎ／２）、上記式（１）においてｎは０≦ｎ≦Ｎ／２、上記式（２）においてｎは（Ｎ／２）＋１≦ｎ＜Ｎ である。 The TSP signal is obtained by extending the time axis by changing the phase of the impulse in proportion to the square of the frequency. FIG. 2 shows the waveform and spectrogram of the TSP-UP signal (with the phase delayed), which are defined by the following equations (1) and (2).

Here, j is an imaginary unit, N is a sample length of the TSP signal, m is a parameter indicating the width of the TSP signal (0 ≦ m ≦ N / 2), and n in the above formula (1) is 0 ≦ n ≦ N / 2, In the above formula (2), n is (N / 2) + 1 ≦ n <N.

ただし、上記式（３）においてｎは０≦ｎ≦Ｎ−１である。 A TSP signal is obtained by performing N-point inverse discrete Fourier transform (IDFT) on the TSP-UP signal defined by the above equations (1) and (2). The following equation (3) represents the signal waveform of the TSP signal.

However, in the said Formula (3), n is 0 <= n <= N-1.

  In the present embodiment, the calculation unit 40 selects the first reception unit 21 and the second reception unit 22 among the reception units, and the change pattern of the first TSP signal received by the first reception unit 21 and the second reception unit 22. The difference between the reception time of the first reception unit 21 and the reception time of the second reception unit 22 may be calculated as a time difference based on the similarity of the change pattern of the second TSP signal received by the. The first receiving unit and the second receiving unit selected by the calculation unit 40 are not limited to the combination of the receiving unit 21 and the receiving unit 22, and may be any combination of selecting two of the plurality of receiving units.

  The frequency component change pattern means a state in which the waveform of the TSP signal changes in the time axis direction, and includes a signal period change pattern in one pulse included in the TSP signal.

  Further, in the present embodiment, the calculation unit 40 may calculate the similarity using a plurality of sampling values obtained by sampling each of the first TSP signal and the second TSP signal at a predetermined period.

  In general, an apparatus that compares a plurality of signal waveforms often includes a process for restoring a signal waveform from a sampled value of a received TSP signal and a process for comparing restored signal waveforms. However, in the present embodiment, the processing as described above is not necessarily provided. By omitting these, a simple device configuration can be obtained. As a result, there are effects such as downsizing of the transmitter, extending the life of the transmitter, and reducing power consumption of the positioning device.

  Furthermore, in the present embodiment, the arithmetic unit 40 associates the sampling value obtained from the first TSP signal and the sampling value obtained from the second TSP signal on a one-to-one basis so that the difference between the respective time components is constant. And a cumulative average of the values obtained by multiplication is used to represent the similarity of the periodic pattern, and the difference between the time components at which the similarity of the periodic pattern is maximized is expressed as the first reception unit 21 receiving time and the first It may be a time difference from the reception time of the reception unit 22.

ただし、τは時間の変数である。 The arithmetic processing as described above is a method called cross-correlation function processing, and is a method for evaluating how similar two different time series signals are. For example, when the signal waveform h1 (t) of the TSP signal received by the reception unit 21 and the signal waveform h2 (t) of the TSP signal received by the reception unit 22, the cross-correlation function is expressed by the following equation (4). .

Where τ is a time variable.

  The above equation (4) is expressed as follows: h1 (t) composed of N sampling values and h2 (t + τ) obtained by shifting h2 (t) composed of N sampling values by τ on the time axis as time components. The parts associated one-to-one so as to make the difference constant are multiplied and accumulated and averaged. The above equation (4) is maximized in that the two signal waveforms are most similar.

  FIG. 4 is a schematic diagram for calculating a reception time difference using a cross-correlation function. When the phase difference from the signal waveform h2 (t) is τ compared to the signal waveform h1 (t), the time when the waveform of h1 (t) is shifted by τ in the time axis direction is h1 (t) and h2 (t). And the cross-correlation function of the above equation (4) is the maximum value. That is, τ at which the cross-correlation function of the above formula (4) is the maximum value is the same value as the reception time difference between the reception unit 21 and the reception unit 22. Therefore, the reception time difference can be calculated using the cross-correlation function of the above equation (4).

  The cross-correlation function is a method of multiplying and accumulating sampling values in two signal waveforms, and averaging them. Therefore, even if noise occurs in some frequency bands, the influence can be suppressed.

  The processing for calculating the reception time difference between the reception unit 21 and the reception unit 22 has been described so far. Similarly, the processing for calculating the reception time difference between the reception unit 22 and the reception unit 23, between the reception unit 23 and the reception unit 21. Processing for calculating the reception time difference is also possible.

  The transmission part 10 can change the time interval which transmits a TSP signal. Thereby, the TSP signal to be compared can be specified based on the time interval for receiving the TSP signal. This will be described in detail with reference to FIG. When the time interval between the pulses is equal, the arithmetic unit 40 cannot determine whether the pulse B of the first TSP signal can be compared with the pulse A ′, the pulse B ′, or the pulse C ′ of the second TSP signal. . However, when the time interval differs between pulses, the arithmetic unit 40 determines that the pulse A is compared with the pulse A ′, the pulse B is compared with the pulse B ′, and the pulse C is compared with the pulse C ′ from the time interval when the TSP signal is received. be able to.

  FIG. 5 is a flowchart of the positioning method in the present embodiment. The transmitting unit 10 transmits a TSP (Time Stretched Pulse) signal whose frequency component changes in the pulse (step S101), and a plurality of receptions arranged at a predetermined distance from the transmitting unit 10 and spaced apart from each other. Steps where the units 21, 22, and 23 receive the TSP signal (Step S102), and each receiving unit received the TSP signal based on the change pattern of the frequency component of the TSP signal received by each receiving unit 21, 22, and 23 A step of calculating the time difference (step S103) and a step of calculating the position of the transmitting unit 10 based on the time difference and the position information of each receiving unit (step S104) can be provided.

  FIG. 6 is a diagram showing an example in which the positioning device of the present invention is arranged in an indoor space 50 where radio waves from a satellite do not reach. The transmitter 10 transmits a TSP signal in the indoor space 50, and the receivers 21, 22, and 23 each receive a TSP signal. The computing unit 40 computes the reception time difference at which the receiving units 21, 22, and 23 receive the TSP signal from the waveform similarity of the TSP signal. Furthermore, the difference in distance interval from the transmitter 10 to each receiver 21, 22, 23 can be calculated based on the calculated reception time difference and the propagation speed of the TSP signal. In the present embodiment, the distance interval difference A = (distance interval from the transmitting unit 10 to the receiving unit 21−the distance interval from the transmitting unit 10 to the receiving unit 22) and the distance interval difference B = (the transmitting unit 10 to the receiving unit). Distance interval from 22 to the distance interval from the transmission unit 10 to the reception unit 23) and distance interval difference C = (distance interval from the transmission unit 10 to the reception unit 23-distance interval from the transmission unit 10 to the reception unit 21) And the difference between the three distance intervals can be calculated.

  Based on the calculated difference between the three distance intervals and the position information of each of the reception units 21, 22, and 23 stored in the storage unit 30, the distance interval between the reception unit 21 and the reception unit 22 is the distance interval difference A. A curved surface 61 whose distance interval between the receiving unit 22 and the receiving unit 23 is a distance interval difference B, and a curved surface 63 whose distance interval between the receiving unit 23 and the receiving unit 21 is a distance interval difference C; (Both are shown as curves in FIG. 5 for convenience). The position where the curved surface 61, the curved surface 62, and the curved surface 63 intersect is specified as the position of the transmitting unit 10. As described above, the positioning device of the present embodiment includes at least three receiving units 21, 22, and 23, and the calculating unit 40 calculates the position of the transmitting unit 10 that moves in the space in three dimensions. be able to. Note that the number of receiving units is not limited to three, and positioning with higher accuracy is possible by increasing the number of receiving units.

  As mentioned above, although this embodiment was described with reference to drawings, these are one form of this invention, and various structures other than the above are also employable.

  For example, the position information of the receiving unit stored in the storage unit changes depending on the arrangement of each receiving unit, and the positioning device of the present invention may include means that can change the position information of the receiving unit in a timely manner. As a result, it is possible to cope with a change in the arrangement of each receiving unit.

  In addition, as described above, the operation unit 40 can determine the pulse to be compared by arranging the pulses of the TSP signal at different time intervals. For example, the pulse length of each pulse included in the TSP signal is changed. Similarly, by giving each pulse a characteristic, the calculation unit 40 can also determine a pulse to be compared.

  Further, since the propagation speed of the TSP signal varies depending on the temperature of the space, the calculation unit includes means for measuring the temperature of the space through which the TSP signal propagates, and calculates the propagation speed of the TSP signal based on the measured temperature. It is good also as a possible structure. As a result, positioning with higher accuracy is possible.

  Furthermore, in the said embodiment, although it was set as the structure provided with three receiving parts, the calculating part can calculate the position of the transmission part which moves on a known line by providing at least two receiving parts. For example, in the space 50 of FIG. 6, information indicating the position is stored in advance in the storage unit 30 or the like, and the transmitting unit is placed on a known line from which the calculation unit 40 can acquire the information when necessary. 10 is located, a point at which the curved surface 61 obtained by calculating from the time difference at which each receiving unit 21 and 22 receives the TSP signal and the positional information of each receiving unit 21 and 22 intersects a known line intersects with the transmitting unit 10. Can be identified as However, the known line must meet the following conditions: That is, no matter where the transmitting unit 10 is on the known line, the intersection of the curved surface 61 obtained by calculation and the known line must be one point. The known line may be a straight line or a curve as long as the line satisfies the above conditions. Further, the known line can only ignore the movement of the transmitter 10 in the width direction, but does not exclude it. In the case of a closed space such as a tunnel, the transmission path of the transmission unit is inevitably limited, so that positioning is possible by providing at least two reception units as described above. However, in the closed space, since it is necessary to arrange the receiving unit so that at least two receiving units can directly receive the TSP signal from the transmitting unit, there are two receiving units because the closed space is bent. Then, when there is a transmission position where the TSP signal cannot be directly received from the transmission unit, three or more reception units may be arranged.

It is a block diagram of the positioning apparatus which is embodiment of this invention. It is a figure showing the waveform and spectrogram of a TSP signal. It is a schematic diagram which calculates a reception time difference with a cross correlation function. It is a schematic diagram which calculates a reception time difference with a cross correlation function. It is a flowchart of the positioning method which is embodiment of this invention. It is the figure which showed an example which has arrange | positioned the positioning apparatus of this invention in indoor space.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Transmission part 21 Reception part 22 Reception part 23 Reception part 30 Storage part 40 Calculation part 50 Indoor space 61 Curved surface 62 Curved surface 63 Curved surface

Claims (9)

A transmitting unit that transmits a TSP (Time Stretched Pulse) signal whose frequency component changes in a pulse;
A plurality of receiving units for receiving the TSP signals arranged at a predetermined distance from the transmitting unit and spaced apart from each other;
A storage unit storing position information of each receiving unit;
Based on the change pattern of the frequency component of the TSP signal received by each receiving unit, the receiving unit calculates a time difference at which the TSP signal is received, and based on the time difference and the position information acquired from the storage unit. A calculation unit for calculating the position of the transmission unit;
A positioning device comprising:   The computing unit selects a first receiving unit and a second receiving unit from among the plurality of receiving units, and the change pattern of the first TSP signal received by the first receiving unit and the second TSP received by the second receiving unit. The positioning according to claim 1, wherein a difference between a reception time of the first reception unit and a reception time of the second reception unit is calculated as the time difference based on a similarity with a signal change pattern. apparatus.   The calculation unit according to claim 2, wherein the calculation unit calculates the similarity using a plurality of sampling values obtained by sampling each of the first TSP signal and the second TSP signal at a predetermined period. Positioning device.   The computing unit multiplies the sampling value obtained from the first TSP signal and the sampling value obtained from the second TSP signal in a one-to-one correspondence so that the difference between the respective time components is constant, and 4. The positioning device according to claim 3, wherein a value obtained by multiplication is cumulatively averaged to represent the similarity, and a difference between the time components that maximizes the similarity is defined as the time difference.   The positioning device according to claim 1, wherein the transmission unit changes a time interval for transmitting the TSP signal. Comprising at least three receiving units;
The positioning device according to claim 1, wherein the calculation unit calculates the position of the transmission unit moving in space three-dimensionally. Comprising at least two receiving units;
The positioning device according to claim 1, wherein the calculation unit calculates a position of the transmission unit that moves on a known line.   The positioning device according to any one of claims 1 to 7, wherein the frequency band of the TSP signal is an audible range. A transmitting unit transmitting a TSP (Time Stretched Pulse) signal whose frequency component changes in a pulse;
A plurality of receiving units arranged at a predetermined distance from the transmitting unit and spaced apart from each other, and receiving the TSP signal;
Calculating a time difference at which each receiving unit receives the TSP signal based on a change pattern of a frequency component of the TSP signal received by each receiving unit;
Calculating the position of the transmitter based on the time difference and the position information of each receiver;
A positioning method characterized by comprising:

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