JP4520633B2 - Ranging method and ranging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a distance measuring method and a distance measuring apparatus that measure a distance between objects such as a wireless device using a narrowband communication method.
[0002]
[Prior art]
As a distance measurement method, there are a radar method that measures the distance between objects using radio waves (laser) and a distance measurement method that measures the distance between objects using the spread of radio waves using the spread spectrum communication method. Are known. In the radar system, the distance to an object is obtained by irradiating a measurement object with a radio wave (laser) and measuring the delay time of the radio wave reflected from the object. In the ranging method using spread spectrum communication, the other station receives the spread spectrum signal transmitted from the own station, converts the frequency and sends it back to the own station. The distance between the own station and other stations is calculated.
[0003]
[Problems to be solved by the invention]
The distance measurement method using the radar method is a system specialized for distance measurement, and therefore cannot perform data communication using the same system. Therefore, a separate data communication system is required to perform data communication. In addition, although the distance measurement method using the spread spectrum communication method enables data communication, there is a problem that the modulation method can be applied only to a radio device using the spread spectrum modulation method.
[0004]
Therefore, an object of the present invention is to use a narrowband communication method that is generally used at present and apply a distance measurement method performed in a spread spectrum communication method to obtain a distance between objects such as a radio. A distance method and a distance measuring device are provided.
[0005]
[Means for Solving the Problems]
The invention according to claim 1 is a distance measuring method for measuring a distance between the own station and another station using a narrowband communication method, and a step of transmitting a first narrowband communication signal from the own station to the other station. And a relative time difference between the first narrowband communication signal received at the other station and the second narrowband communication signal transmitted from the other station to the local station, and the relative time difference data is detected as the second narrowband communication signal. Detecting the time difference between the step of adding to the communication signal and transmitting to the local station, and the time difference between the second narrowband communication signal received by the local station and the first narrowband communication signal transmitted by the local station, and the detected value And calculating the distance between the local station and the other station from the demodulated relative time difference data, and calculating the relative time difference between the first narrowband communication signal and the second narrowband communication signal in the other station. Detecting the second narrowband communication signal and the first narrowband communication signal at the local station Each of the steps of detecting the difference between the respective stations generates a correlation clock signal in the other station and the own station, and obtains a correlation between the correlation clock signal and the baseband signal of each narrowband communication signal in each station, Detecting a relative time difference between the local station and the other station, the step of detecting a relative time difference between the local station and the remote station comprising: a baseband of the first narrowband communication signal and the second narrowband communication signal; Detecting a data change point by binarizing the transmission data or the reception data by setting an appropriate threshold value based on the transmission data as a signal or reception data demodulated from the transmission data; Generating a first pulse signal having an appropriate width narrower than the period of the data clock for each point; and the frequency of the data clock at the local station and other stations A step of generating a second pulse signal having a width comparable to that of the first pulse signal from a correlation clock generated at a frequency obtained by multiplying the first pulse signal by the second pulse signal. And obtaining a correlation signal by passing through a low-pass filter .
[0006]
According to a second aspect of the present invention, in the distance measuring method according to the first aspect, the first and second narrowband communication signals include phase modulation (PM), frequency modulation (FM), and amplitude modulation (AM). This is a signal modulated based on one of the modulation methods.
[0009]
According to a third aspect of the invention, the distance measuring method according to claim 1, wherein, to generate an envelope signal from the correlation signal obtained after passing through the low-pass filter, the correlation signal of the position by detecting the peak position of the envelope signal The method further includes a step of setting the reference position.
[0010]
According to a fourth aspect of the present invention, in the distance measuring method according to the third aspect , in the step of generating the envelope signal of the correlation signal, if the correlation signal pulse is missing, the peak values of the pulses before and after the missing are calculated. The method further includes an interpolation step of interpolating missing pulses by inserting pulses of intermediate values thereof.
[0011]
According to a fifth aspect of the present invention, in the distance measuring method according to the third aspect , based on the time difference between the reference positions of the respective correlation signals, the other station determines whether the first narrowband communication signal is the second narrowband communication signal. A relative time difference is obtained, and the own station obtains a time difference between the second narrowband communication signal and the first narrowband communication signal.
[0012]
According to a sixth aspect of the present invention, in the distance measuring method according to the fifth aspect , the other station adds data representing the relative time difference to the second narrowband communication signal and transmits it to the own station. The distance between the local station and the other station is calculated on the basis of the time difference obtained in step 1 and the time difference data added to the second narrowband communication signal.
[0013]
The invention according to claim 7 is a distance measuring device provided in each station for measuring the distance between the own station and the other station using a narrowband communication method, wherein the first narrowband is transmitted from the own station to the other station. A transmission unit that transmits a communication signal; and a reception unit that receives a second narrowband communication signal transmitted from another station in response to reception of the first narrowband communication signal. The communication signal incorporates data relating to the relative time difference between the first narrowband communication signal and the second narrowband communication signal in the other station, and the receiving unit receives the first narrowband communication signal. Receiving means for receiving a part of the second narrowband communication signal, pulse means for pulsing the received signal, correlation clock pulse generating means for generating a correlation clock pulse, and a pulsed received signal, Correlation is performed with the correlation clock pulse, and the correlation signal is Correlating means, interpolating means for compensating for missing correlation pulses by interpolating the correlation signal from the correlating means, detecting the peak position based on the output signal of the interpolating means, and outputting it as a reference peak signal Calculating a delay time between the signals based on the peak detection means, the reference peak signal of the first narrowband communication signal and the second narrowband communication signal obtained by the peak detection means, and the delay time, And delay time calculating means for measuring a distance between the own station and another station based on the relative time difference incorporated in the second narrowband communication signal .
[0015]
According to the distance measuring method and the distance measuring apparatus of the present invention, there is provided a method capable of measuring a distance using a conventionally used narrowband communication by using a distance measuring method performed by spread spectrum communication. As a method for realizing the distance measurement, the received data waveform is first processed into a pulse shape so that the correlation operation performed in the spread spectrum communication can be performed, and the correlation operation is performed. Next, when data continues, a correlation waveform is lost. To compensate for this, waveform interpolation or estimation is performed to generate a desired correlation waveform. This makes it possible to apply the distance measurement method performed in spread spectrum communication to narrowband communication.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0017]
First, the distance measuring method of the present invention will be described.
[0018]
FIG. 1 is a schematic diagram for explaining a distance measuring method for measuring the distance between objects (for example, between wireless devices) using the return of radio waves. Here, an object (such as a wireless device) that performs distance measurement, that is, a side that first transmits a modulation signal for distance measurement is referred to as an own station, and an object (such as a wireless device) that performs distance measurement, that is, the first The side that has received the modulation signal for distance measurement will be referred to as another station. Therefore, an arbitrary object can be the local station or another station depending on the situation. FIG. 2 shows the timing relationship between the signals of the own station A and the other station B when there is no time delay between the modulation signal from the own station A and the transmission signal from the other station B received on the other station B side. FIG. 3 shows the local station A and the other station when there is a time delay between the modulation signal from the local station A and the transmission signal from the other station B received on the other station B side. The timing relationship of each signal of B is shown.
[0019]
1 and 2, when the distance L between the own station A side and the other station B side is to be obtained using the return of the radio wave, a modulation signal (first modulation signal) is transmitted from the own station A to the other station B. ) Send S. At this time, the own station A receives the modulation signal S transmitted by itself or sends a part of the modulation signal S to the receiving unit (this reception signal is R ′), and distance measurement is performed with reference to the reception timing at this time. I do. In the other station B, if there is no time delay (Δτ) between the modulation signal from the own station A side and the modulation signal (second modulation signal) R to be transmitted from the other station B, it remains as it is. The modulation signal R is transmitted to the own station A. The own station A detects the phase difference (T) between the modulated signal (R ′) transmitted and received by the own station A and the modulated signal R transmitted by the other station B and received by the own station A. The distance L is calculated based on the phase difference (T). Here, since the phase difference (T) corresponds to the round-trip delay time of the radio wave between the own station A and the other station B, the distance L is expressed by the following equation using the phase difference T.
[0020]
Distance L = c · T / 2 (c is the speed of light)
1 and 2, Δt is the time required for radio waves to reach from the own station A to the other station B (from the other station B to the own station A). Further, τm is a delay time until the modulation signal transmitted from the own station A is received by the own station A itself and its reference position is calculated.
[0021]
On the other hand, when there is a time delay (Δτ) between the modulation signal (Rs) received from the other station B from the own station A and the transmission modulation signal (Ss) from the other station B to the own station A. The phase difference (τs) between the modulation signals (Rs, Ss) is detected, and this phase difference information is placed on the transmission modulation signal (Ss) and transmitted to the own station A side. The own station A detects the phase difference (T) between the modulated signal (R ′) transmitted and received by itself and the received signal R from the other station B, and further, the phase difference data ( τs) is demodulated, an error caused by the phase difference on the other station B side is corrected, and the distance L to the other station B is calculated. Here, the distance L is expressed by the following equation using the phase difference T and τs.
[0022]
Distance L = c · (T−τs) / 2 (c is the speed of light)
The modulated signal described above is a signal modulated based on a modulation method other than the spread spectrum method, for example, PM (phase modulation), FM (frequency modulation), or AM (amplitude modulation). In the case of the ranging method using spread spectrum communication, the modulation signal can detect the reference position (reference peak) by performing despreading (correlation) with the reference PN code. If the modulated signal is used as it is, such a correlation operation of spread spectrum communication cannot be performed. Therefore, it is necessary to pulse the narrowband communication data (RD) so that correlation can be achieved.
[0023]
FIG. 4 is a timing chart showing the pulsing and correlation operation of the narrowband signal. By this operation, the reference position (reference peak) of each modulation signal can be detected.
[0024]
As shown in FIG. 4, the own station A binarizes the change point (0 → 1, 1 → 0) of the modulation signal (received data (RD)) from the other station B with a certain threshold value, A narrow pulse signal (Rp) is generated (FIGS. 4A, 4B, and 4C). Further, the other pulse (Cp) for correlation is generated from the correlation clock (CK) shown in FIG. 4 (d) (FIG. 4 (e)). This correlation clock has a very small frequency with respect to the clock of transmission / reception data. A correlation operation (multiplication of Rp and Cp) of these two pulse signals is performed (FIG. 4 (f)), and a correlation waveform (RCp) is generated by passing through the filter (FIG. 4 (g)). At this time, if there is no data change point in the received data, no correlation signal is output. Therefore, the missing correlation signal is compensated (FIG. 4 (h)), an envelope signal (RC) based on the peak value of each correlation pulse is generated (FIG. 4 (i)), and the maximum value of the signal is obtained. Is the reference peak signal (R) (FIG. 4 (j)). Similar processing is performed on the signal transmitted by the local station A and received by itself, and the reference peak signal (R ′) is generated.
[0025]
With the above processing, it is possible to detect the reference peak (reference position) of the received signal even if a narrowband signal is used, and distance measurement based on the delay time difference (phase difference) of the received signal becomes possible.
[0026]
FIG. 5 shows an embodiment of the configuration provided in the own station and other stations of the distance measuring system based on the distance measuring method described above.
[0027]
The ranging system shown in FIG. 5 includes a transmitting unit that transmits ranging data (modulated signal) and a receiving unit that receives the modulated signal and a transmission signal from another station.
[0028]
The transmission unit emits transmission data 2 based on the data clock “FD” generated by the data clock generation unit 1. The transmission data is modulated by the carrier wave (f) after passing through the band-pass filter (BPF) 3, amplified by the amplifier 4 and transmitted via the antenna. At this time, a part of the transmission signal is sent to the receiving unit side.
On the other hand, in the receiving section, a part of the transmission signal or the reception signal is amplified by the amplifier 5, modulated by the carrier wave (f), passed through the band pass filter (BPF) 6, and then signal level by the AGC (automatic gain controller) 7. To be constant. Thereafter, the output signal from the AGC 7 is sent to the data demodulator 8 to demodulate the received data. The received data is pulsed by the pulse generation unit 9 and multiplied with a correlation clock pulse to be correlated. Here, the correlation clock pulse is obtained by pulsing the correlation clock “Fc” generated by the correlation clock generation unit 10 by the pulse generation unit 11. After that, the correlation-processed signal passes through the LPF (low-pass filter) 12, the waveform shaping unit 13 compensates for the lack of the correlation pulse, the peak detector 14 generates the correlation pulse envelope signal, and the correlation signal A reference peak signal (R ′, R) is generated. Interpolation of the missing correlation pulse is performed by inserting a pulse having a pulse height intermediate between the pulse height values before and after the loss.
[0029]
A similar process is performed on the data clock “Fd” of the transmitter. That is, the data clock “Fd” generated by the data clock generation unit 1 is pulsed by the pulse generation unit 15, and after correlation with the correlation clock pulse, after passing through the LPF (low-pass filter) 16, the waveform shaping unit The waveform is interpolated at 17, and a correlation reference peak signal is obtained at the peak detector 18 (S).
[0030]
Here, using the reference peak signal (S or R ′) as a reference, the reference peak signal (R) of the received signal transmitted from another station is compared by the comparator 19, and the phase difference is compared by the time difference detection unit 20. To detect. At this time, when the wireless device is on the other station side, the time difference data represents the time delay (Δτ) between the received signal and the transmission signal, and therefore the data is transmitted to the own station side as data. Thereafter, the delay time calculation unit 21 calculates the distance together with the received signal (Δτ) sent from another station.
[0031]
【The invention's effect】
As described above, according to the present invention, a ranging function can be easily added to a currently used narrowband radio, and the position of the radio can be grasped.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining a distance measuring method for measuring a distance between objects by using radio wave folding;
FIG. 2 is a timing relationship between signals of own station A and other station B when there is no time delay between the modulation signal from own station A and the transmission signal from other station B received on the other station B side; Is shown.
FIG. 3 is a timing relationship between signals of own station A and other station B when there is a time delay between the modulated signal from own station A and the transmission signal from other station B received on the other station B side; Is shown. It is the schematic which showed the ranging method by this invention.
FIG. 4 is a timing chart showing pulsing of narrowband signals and correlation operations.
FIG. 5 shows an embodiment of a configuration provided in the own station and other stations of the distance measuring system based on the distance measuring method of the present invention.
[Explanation of symbols]
A own station B other station 1 data clock generating unit 8 data demodulating unit 9, 11, 15 pulse generating unit 10 correlation clock generating unit 13, 17 waveform shaping unit 14, 18 peak detecting unit 20 time difference detecting unit 21 delay time calculating unit

Claims (7)

A distance measurement method for measuring a distance between a local station and another station using a narrowband communication method, wherein the first narrowband communication signal is transmitted from the local station to the other station, and received by the other station. Detecting the relative time difference between the first narrowband communication signal and the second narrowband communication signal transmitted from the other station to the local station, and adding the relative time difference data to the second narrowband communication signal Detecting the time difference between the second narrowband communication signal received at the local station and the first narrowband communication signal transmitted at the local station, and the detected value and the demodulated relative time difference Calculating the distance between the own station and other stations from the data ,
Detecting a relative time difference between the first narrowband communication signal and the second narrowband communication signal in the other station; and a time difference between the second narrowband communication signal and the first narrowband communication signal in the local station. Each of the detecting steps generates a correlation clock signal in each of the other station and the own station, and correlates between the correlation clock signal and the baseband signal of each narrowband communication signal in each station, Detecting a relative time difference at another station,
The step of detecting the relative time difference between the local station and the other station is based on transmission data which is a baseband signal of the first narrowband communication signal and the second narrowband communication signal or reception data demodulated therefrom. A step of detecting a data change point by binarizing the data waveform of the transmission data or the reception data by providing an appropriate threshold value, and a first of an appropriate width narrower than the cycle of the data clock at each change point A step of generating a pulse signal, and a second pulse signal having a width similar to that of the first pulse signal from a correlation clock generated at a frequency different from the frequency of the data clock at the local station and another station. Generating a correlation signal by multiplying the first pulse signal and the second pulse signal and passing through a low-pass filter. Ranging method characterized by comprising the flop.   The first and second narrowband communication signals are signals modulated based on one modulation method of phase modulation (PM), frequency modulation (FM), and amplitude modulation (AM). The distance measuring method according to claim 1. Generating an envelope signal from the correlation signal obtained after passing through the low-pass filter, according to claim 1, characterized in that it further comprises a step of the reference position of the correlation signal of the position by detecting the peak position of the envelope signal Ranging method. In the step of generating the envelope signal of the correlation signal, if the correlation signal pulse is missing, the missing pulse is inserted by inserting the pulse of the intermediate value based on the peak value of the pulse before and after the missing. 4. The distance measuring method according to claim 3 , further comprising an interpolation step for performing interpolation. Based on the time difference of the reference position of each correlation signal, the other station obtains the relative time difference between the first narrowband communication signal and the second narrowband communication signal, and the own station determines the second narrowband communication signal and the first narrowband communication signal. 4. The distance measuring method according to claim 3 , wherein a time difference between the narrowband communication signals is obtained. In other stations, data representing the relative time difference is added to the second narrowband communication signal and transmitted to the local station, and the local station adds the time difference obtained by the local station and the second narrowband communication signal. 6. The distance measuring method according to claim 5 , wherein a distance between the own station and another station is calculated based on the time difference data. A distance measuring device provided in each station for measuring a distance between the own station and another station using a narrowband communication method, wherein the transmitter transmits a first narrowband communication signal from the own station to the other station; A reception unit that receives a second narrowband communication signal transmitted from another station in response to reception of the first narrowband communication signal, and the second narrowband communication signal includes Data relating to the relative time difference between the first narrowband communication signal and the second narrowband communication signal is incorporated,
The receiving unit includes a receiving unit that receives a part of the first narrowband communication signal and the second narrowband communication signal, a pulse unit that pulses the received signal, and a correlation that generates a correlation clock pulse. Correlation processing is performed between the clock pulse generation means, the pulsed received signal and the correlation clock pulse to obtain a correlation signal, and the correlation signal from the correlation means is interpolated to perform correlation processing. Interpolating means for compensating for the omission, peak detecting means for detecting the peak position based on the output signal of the interpolating means, and outputting as a reference peak signal, the first narrowband communication signal obtained by the peak detecting means, and Based on the reference peak signal of the second narrowband communication signal, the delay time between each signal is calculated, and based on this delay time and the relative time difference incorporated in the second narrowband communication signal Distance measuring apparatus characterized by having a delay time calculating means for measuring a distance between the own station and other stations.

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