JP2002202364A - Method and apparatus for measuring distance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a distance between radio devices by applying a range-finding method adopted in spectral diffusion communication also to a generally used narrow band communication system. SOLUTION: In a method and an apparatus for measuring a distance between one's own station A and the other station B with the use of the narrow band communication system, a first narrow band communication signal S is transmitted from the station A to the other station B, and a relative time difference between a first narrow band communication signal Rs received by the other station and a second narrow band communication signal Ss transmitted to the station A from the other station B is detected. Data of the relative time difference is added to the second narrow band communication signal Ss, which is then transmitted to the station A. A time difference is detected between a second narrow band communication signal R received by the station A and the first narrow band communication signal S (R') transmitted by the station A. The distance L between the station A and the other station B is calculated from the detected value and demodulated data of the relative time difference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring method and a distance measuring apparatus for measuring a distance between objects such as radio equipment using a narrow band communication system.

[0002]

2. Description of the Related Art As a distance measuring method, a radar method for measuring a distance between objects using a radio wave (laser) or a spread spectrum communication method is used to measure a distance between objects using a return of a radio wave. There are known distance measuring methods. In the radar system, a distance to an object is obtained by irradiating a measured object with a radio wave (laser) and measuring a delay time of a radio wave reflected from the object. In the ranging method using spread spectrum communication, a spread spectrum signal transmitted from the own station is received by another station, its frequency is converted and transmitted back to its own station, and the distance between objects (from the round trip time of the signal) is calculated. This is for calculating the distance between the own station and another station).

[0003]

In the distance measuring method using the radar system, since the system is specialized for distance measuring, data communication using the same system cannot be performed. Therefore, when data communication is desired, a data communication system is separately required. In the ranging method using the spread spectrum communication method, data communication is possible, but there is a problem that the modulation method can be applied only to a radio device using the spread spectrum modulation method.

Accordingly, an object of the present invention is to use a narrow band communication system generally used at present and apply a distance measurement method performed in a spread spectrum communication system to apply a distance measurement between objects such as radio equipment. To provide a distance measuring method and a distance measuring device.

[0005]

According to the first aspect of the present invention,
A distance measuring method for measuring the distance between the own station and another station using a narrow band communication method, a step of transmitting a first narrow band communication signal from the own station to another station, and received by the other station The relative time difference between the first narrowband communication signal and the second narrowband communication signal transmitted from the other station to the own station is detected, and the data of the relative time difference is added to the second narrowband communication signal to control the local station. And transmitting the, to detect the time difference between the second narrowband communication signal received by the own station and the first narrowband communication signal transmitted by the own station,
Calculating a distance between the own station and the other station from the detected value and the demodulated data of the relative time difference.

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 are phase-modulated (PM), frequency-modulated (FM) and amplitude-modulated (AM). ) Is a signal modulated based on one of the modulation methods.

According to a third aspect of the present invention, in the distance measuring method according to the first aspect, a step of detecting a relative time difference between the first narrowband communication signal and the second narrowband communication signal in another station; Each of the steps of detecting the time difference between the second narrowband communication signal and the first narrowband communication signal in the station generates a correlation clock signal in each of the other stations and the own station, and in each station, the correlation clock signal and each The method includes a step of detecting a relative time difference between the own station and another station by correlating the narrowband communication signal with a baseband signal.

According to a fourth aspect of the present invention, in the distance measuring method according to the third aspect, the step of detecting the relative time difference between the own station and the other station includes the first narrowband communication signal and the second narrowband communication signal. Based on transmission data that is a baseband signal of a communication signal or reception data demodulated from the transmission data, a data waveform of the transmission data or the reception data is binarized by providing an appropriate threshold value to detect a data change point. And generating a first pulse signal of an appropriate width smaller than the period of the data clock for each change point; and a correlated clock generated at its own station and another station at a frequency different from the frequency of the data clock. From, the step of generating a second pulse signal having the same width as the first pulse signal, and the first pulse signal and the second pulse signal Multiplied and is characterized by comprising the steps of: obtaining a correlation signal by passing the low-pass filter.

According to a fifth aspect of the present invention, in the distance measuring method according to the fourth aspect, an envelope signal is generated from a correlation signal obtained after passing through a low-pass filter, and a peak position of the envelope signal is detected to determine the position. As a reference position of the correlation signal.

According to a sixth aspect of the present invention, in the distance measuring method of the fifth aspect, in the step of generating the envelope signal of the correlation signal, if the correlation signal pulse is missing,
The method further comprises an interpolation step of interpolating the missing pulse by inserting a pulse having an intermediate value between the peak values of the pulses before and after the missing pulse.

According to a seventh aspect of the present invention, in the distance measuring method according to the fifth aspect, the other stations use the first narrowband communication signal and the second narrowband communication based on the time difference between the reference positions of the correlation signals. A relative time difference between signals is obtained, and a local station obtains a time difference between the second narrowband communication signal and the first narrowband communication signal.

According to an eighth aspect of the present invention, in the distance measuring method according to the seventh aspect, the other station adds the data representing the relative time difference to a second narrowband communication signal and transmits the second narrowband communication signal to the own station. Is characterized in that a distance between the own station and another station is calculated based on the time difference obtained by the own station and the time difference data added to the second narrowband communication signal.

According to a ninth aspect of the present invention, there is provided a distance measuring apparatus provided in each station for measuring a distance between the own station and another station by using a narrow band communication system, wherein the first station transmits the first station to the other station. A transmitting unit for transmitting a narrowband communication signal, and a receiving unit for receiving a second narrowband communication signal transmitted from another station in response to receiving the first narrowband communication signal, The narrowband communication signal incorporates data relating to the relative time difference between the first narrowband communication signal and the second narrowband communication signal in another station, and the receiving unit transmits from the own station. The time difference between the first narrowband communication signal and the second narrowband communication signal transmitted from another station and received by the own station, based on the relative time difference incorporated in the second narrowband communication signal. And measuring the distance between the own station and other stations.

According to a tenth aspect of the present invention, in the ninth aspect, the receiving unit receives a part of the first narrowband communication signal and the second narrowband communication signal. Pulse means for pulsing the received signal, correlation clock pulse generating means for generating a correlation clock pulse, and correlation means for performing a correlation process between the pulsed received signal and the correlation clock pulse to obtain a correlation signal Interpolating means for interpolating a correlation signal from the correlating means to compensate for the lack of a correlation pulse; and peak detection for detecting a peak position based on an output signal of the interpolating means and outputting it as a reference peak signal. Means, calculates the delay time between each signal based on the reference peak signal of the first narrowband communication signal and the second narrowband communication signal obtained by the peak detection means, and calculates the delay time between the own station and another station. It is characterized in that it has a delay time calculating means for measuring a distance.

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 even in a narrow band communication conventionally used by using a distance measuring method performed in a spread spectrum communication. As a method for realizing the distance measurement, first, a received data waveform is 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 is continuous, a missing correlation waveform occurs. To compensate for this, a desired correlation waveform is generated by interpolating or estimating the waveform. This makes it possible to apply the ranging method used in spread spectrum communication to narrowband communication.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, a distance measuring method according to the present invention will be described.

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 a radio wave. Here, the object on the side that performs distance measurement (such as a wireless device), that is, the side that first transmitted the modulation signal for distance measurement is referred to as its own station, and the object that performs the distance measurement (such as a wireless device);
That is, the side receiving the first modulation signal for distance measurement is referred to as another station. Therefore, any object can be the own 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 modulated signal from the own station A received by the other station B and the transmission signal from the other station B. FIG. 3 shows a case where the local station A and the remote station B have a time delay between the modulated signal from the local station A received by the remote station B and the transmission signal from the remote station B. 4 shows the timing relationship of each signal of B.

In FIGS. 1 and 2, when the distance L between the own station A and the other station B is to be obtained using the return of the radio wave, the modulated signal (first signal) is transmitted from the own station A to the other station B. Modulation signal)
Send S. At this time, the own station A receives the modulated signal S transmitted by itself, or sends a part of the modulated signal S to the receiving section (this received signal is referred to as R ′), and distance measurement is performed based on the reception timing at this time. I do. In the other station B, if there is no time delay (Δτ) between the modulated signal from the own station A and the modulated signal (second modulated signal) R to be transmitted from the other station B, The modulation signal R is transmitted to the own station A. The own station A detects a phase difference (T) between the modulated signal (R ') transmitted and received by the own station A and the modulated signal R transmitted and received by the other station B and received by the own station A. The distance L is calculated based on the phase difference (T). Here, 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.

Distance L = c · T / 2 (c is the speed of light) In FIGS. 1 and 2, Δt is required for a radio wave to reach another station B from own station A (other station B to own station A). Time. Also, τ
m is a delay time from when the modulated signal transmitted from the own station A is received by the own station A itself and the reference position is calculated.

On the other hand, a time delay (Δτ) occurs between the modulated signal (Rs) from the own station A received by the other station B and the modulated signal (Ss) from the other station B to the own station A. If there is, the phase difference (τs) between the modulated signals (Rs, Ss) is detected, and this phase difference information is carried on the transmission modulated signal (Ss) and transmitted to the local 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 detects the phase difference data (R ′) transmitted from the other station B (T). τs) is demodulated, the error generated 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 represented by the following equation using the phase difference T and τs.

Distance L = c · (T−τs) / 2 (c is the speed of light) The above-described modulation signal is a modulation method other than the spread spectrum method, for example, PM (phase modulation), FM (frequency modulation), or This is a signal modulated based on AM (amplitude modulation). In the case of the distance measuring method using spread spectrum communication, the reference position (reference peak) can be detected by performing despreading (correlation) on the modulated signal using 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, the data (R
D) needs to be pulsed to enable correlation.

FIG. 4 is a timing chart showing the pulsing of the narrow band signal and the correlation operation. By this operation, the reference position (reference peak) of each modulated signal can be detected.

As shown in FIG. 4, in the own station A, a change point (0 → 1, 1 → 0) of a modulated signal (received data (RD)) from another station B is binary-coded with a certain threshold value. To generate a narrow pulse signal (Rp) (FIG. 4A,
(B), (c)). Further, the other pulse (Cp) for obtaining the correlation is supplied to the correlation clock (Cp) shown in FIG.
K) (FIG. 4E). The correlation clock is slightly different in frequency from the clock of the transmission / reception data. A correlation operation (multiplication of Rp and Cp) of the two pulse signals is performed (FIG. 4F),
A correlation waveform (RCp) is generated by passing through a 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 supplemented (FIG. 4 (h)), and the envelope signal (R) based on the peak value of each correlation pulse is obtained.
C) (FIG. 4 (i)), and the position of the maximum value of the signal is set as a reference peak signal (R) (FIG. 4 (j)). A similar process is performed on the signal transmitted and received by the own station A to generate a reference peak signal (R ′).

The above processing makes it possible to detect the reference peak (reference position) of the received signal even if a narrow band signal is used, and to perform distance measurement based on the delay time difference (phase difference) of the received signal.

FIG. 5 shows an embodiment of the configuration provided in the own station and another station in the distance measuring system based on the above-described distance measuring method.

The distance measuring system shown in FIG. 5 includes a transmitting unit for transmitting data (modulated signal) for distance measurement, and a receiving unit for receiving the modulated signal and a transmission signal from another station. .

The transmitting section emits transmission data 2 based on the data clock “FD” generated by the data clock generating section 1. The transmission data is modulated by the carrier (f) after passing through the band-pass filter (BPF) 3, amplified by the amplifier 4, and transmitted through 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 unit, a part of the transmission signal or the reception signal is amplified by the amplifier 5, modulated by the carrier (f), passed through a band-pass filter (BPF) 6, and then subjected to an AGC (automatic gain controller) 7 to signal level Constant. After that, the output signal from the AGC 7 is sent to the data demodulation unit 8 to demodulate the received data. The received data is pulsed by the pulse generator 9, multiplied by a correlation clock pulse, and 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 signal subjected to the correlation processing passes through an LPF (low-pass filter) 12 and then a waveform shaping unit 1
At 3, the lack of the correlation pulse is compensated, and the peak detector 14 generates an envelope signal of the correlation pulse to generate the reference peak signal (R ′, R) of the correlation. The interpolation of the missing of the correlation pulse is performed by inserting a pulse having a peak value of an intermediate value between the pulse values before and after the missing.

A similar process is performed on the data clock "Fd" of the transmission unit. That is, the data clock “Fd” generated by the data clock generation unit 1 is pulsed by the pulse generation unit 15, correlated with a correlation clock pulse, passed through an LPF (low-pass filter) 16, and then subjected to a waveform shaping unit. Interpolation of the waveform is performed at 17, and a reference peak signal of the correlation is obtained at the peak detector 18 (S).

Here, the reference peak signal (S or R ')
Is compared with the reference peak signal (R) of the received signal transmitted from another station, and the phase difference is detected by the time difference detection unit 20. At this time, when the wireless device is on the other station side, the time difference data represents a time delay (Δτ) between the received signal and the transmission signal, and is transmitted to the own station side as data. Thereafter, the distance is calculated by the delay time calculation unit 21 together with the reception signal (Δτ) sent from another station.

[0031]

As described above, according to the present invention,
A distance measuring function can be easily added to a narrow band radio currently used, and the position of the radio can be grasped.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a distance measurement method for measuring a distance between objects by using a return of a radio wave.

FIG. 2 is a timing relationship between signals of the own station A and the other station B when there is no time delay between a modulated signal from the own station A received by the other station B and a transmission signal from the other station B; It is shown.

FIG. 3 is a timing relationship between signals of the own station A and the other station B when a modulated signal from the own station A received by the other station B and a transmission signal from the other station B have a time delay. It is shown. FIG. 4 is a schematic diagram illustrating a distance measuring method according to the present invention.

FIG. 4 is a timing chart showing pulsing of a narrow band signal and a correlation operation.

FIG. 5 shows an embodiment of a configuration provided in a local station and another station in a 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 generation section 8 data demodulation section 9, 11, 15 pulse generation section 10 correlation clock generation section 13, 17 waveform shaping section 14, 18 peak detection section 20 time difference detection section 21 delay time calculation section

Claims (10)

[Claims] 1. A distance measuring method for measuring a distance between a self-station and another station using a narrow-band communication method, comprising: transmitting a first narrow-band communication signal from the self-station to another station; Detect the relative time difference between the first narrowband communication signal received by the station and the second narrowband communication signal transmitted from another station to the own station, and convert the data of the relative time difference into a second narrowband communication signal. Adding and transmitting to the own station, detecting the time difference between the second narrowband communication signal received by the own station and the first narrowband communication signal transmitted by the own station, and the detected value is demodulated with the detected value. Calculating a distance between the own station and the other station from the relative time difference data. 2. The first and second narrowband communication signals are:
The distance measuring method according to claim 1, wherein the signal is a signal modulated based on one of a modulation method of phase modulation (PM), frequency modulation (FM), and amplitude modulation (AM). Detecting a relative time difference between a first narrowband communication signal and a second narrowband communication signal in another station; and transmitting a second narrowband communication signal and a first narrowband communication in the own station. In each of the steps of detecting a time difference from the signal, a correlated clock signal is generated in each of the other station and the own station,
2. The method according to claim 1, further comprising the step of detecting a relative time difference between the own station and another station by correlating between the correlation clock signal and the baseband signal of each narrowband communication signal at each station. Distance measuring method. 4. The step of detecting the relative time difference between the own station and the other station includes transmitting data as baseband signals of a first narrowband communication signal and a second narrowband communication signal, or receiving data demodulated therefrom. A step of detecting a data change point by binarizing the data waveform of the transmission data or the reception data based on the data by providing an appropriate threshold value; Generating a first pulse signal having a width, and from a correlated clock generated at a frequency different from the frequency of the data clock in the own station and another station, a second pulse signal having a width similar to that of the first pulse signal. Generating a second pulse signal; multiplying the first pulse signal and the second pulse signal; 4. A distance measuring method according to claim 3, further comprising the step of: 5. The method according to claim 1, further comprising the step of generating an envelope signal from the correlation signal obtained after passing through the low-pass filter, detecting a peak position of the envelope signal, and using the detected peak position as a reference position of the correlation signal. 5. The distance measuring method according to claim 4, wherein: 6. In the step of generating an envelope signal of a correlation signal, if a correlation signal pulse is missing, a pulse having an intermediate value is inserted based on the peak values of the pulses before and after the missing. 6. The distance measuring method according to claim 5, further comprising an interpolation step of interpolating the missing pulse. 7. The other station determines a relative time difference between the first narrowband communication signal and the second narrowband communication signal based on the time difference between the reference positions of the correlation signals, and the second station determines the second narrowband communication signal. The method according to claim 5, wherein a time difference between the communication signal and the first narrowband communication signal is obtained. 8. The other station adds data representing the relative time difference to the second narrowband communication signal and transmits the second narrowband communication signal to the own station. The own station compares the time difference obtained by the own station with the second narrowband communication signal. 8. The distance measuring method according to claim 7, wherein a distance between the own station and the other station is calculated based on the time difference data added to the distance. 9. A distance measuring device provided in each station for measuring a distance between the own station and another station using a narrow band communication system,
A transmitting unit that transmits a first narrowband communication signal from the own station to another station, and a receiving unit that receives a second narrowband communication signal transmitted from another station in response to receiving the first narrowband communication signal The second narrowband communication signal, the data related to the relative time difference between the first narrowband communication signal and the second narrowband communication signal in another station is incorporated, the reception The time difference between the first narrowband communication signal transmitted from the own station and the second narrowband communication signal transmitted from another station and received by the own station, and the second narrowband communication signal A distance measuring apparatus for measuring a distance between the own station and another station based on the incorporated relative time difference. 10. A receiving unit for receiving a part of the first narrowband communication signal and the second narrowband communication signal, a pulse unit for pulsing the received signal, and a correlation clock. Correlation clock pulse generation means for generating a pulse, correlation processing between the pulsed received signal and the correlation clock pulse to obtain a correlation signal, and interpolation processing for the correlation signal from the correlation means Interpolating means for compensating for the lack of the correlation pulse, a peak detecting means for detecting the peak position based on the output signal of the interpolating means and outputting it as a reference peak signal, and a first peak obtained by the peak detecting means. A delay time calculating means for calculating a delay time between each signal based on a reference peak signal of the narrowband communication signal and the second narrowband communication signal, and measuring a distance between the own station and another station. The distance measuring apparatus according to claim 9, wherein