JPH11271418A - Radio wave positioning system, device, and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio wave positioning system, device, and a method for it wherein, related to radio wave positioning, the position of a wireless station is obtained by measuring a radio wave arrival time between two wireless stations whose positions are known and a wireless station which is to be positioned. SOLUTION: Wireless stations 21 and 22 of definite position wherein question signal is sent and its reply signal is received to provide transmission and reception time data, a wireless station 23 wherein, of unknown position and to be measured for positioning, the question signal is received and the reply signal is sent back after a specified time, another wireless station of known position which receives the reply signal and provides the position data corresponding to the reception time, and a positioning means wherein, based on position data of the question signal and reply signal, the elliptic coordinates and hyperbolic coordinates where the wireless station 23 of unknown position are obtained and one of the intersections is selected to obtain the position of the wireless station 23 whose position is unknown, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio position locating system, method and apparatus used in navigation and mobile communication, and more particularly to a radio position locating system between two radio stations whose positions are unclear and radio stations whose positions are not clear. The present invention relates to a radio wave position locating system, device and method for locating a radio station whose position is unclear by measuring a radio wave arrival time.

[0002]

2. Description of the Related Art FIG. 1 shows the principle of a conventional position locating method based on a hyperbolic method. As shown in FIG. 1, in the case of position locating based on a hyperbola, three radio stations 11 to 13 (stations A, B and C) whose positions are clear are used, and a radio station 14 (station D) whose position is unclear is used. Is located.

The radio waves transmitted from the radio station 14 are received by the radio stations 11 to 13. For example, the radio wave transmission time of the wireless station 14 is t _T , and the reception time at the receiving station 11 is t _A.
Then, the distance L _AD between the transmitting station 14 and the receiving station 11 is given by L _AD = (t _A −t _T ) C (C is the propagation speed of the radio wave). Therefore, if the radio wave transmission time t _T of the wireless station 14 is unknown, the receiving station 11 alone cannot directly determine the distance from the wireless station 14.

However, from the above equation, the transmitting station 14
The differences L _AD -L _BD and L _AD -L _CD between the distance and the respective receiving stations 11 to 13 can be obtained as constants even if the radio wave transmission time t _T of the wireless station 14 is unknown. Since the trajectory drawn by a point where the difference in distance from a certain two points is constant draws a hyperbola, the transmitting station 14 is on the hyperbola 1 where the difference in distance from the receiving stations 11 and 12 is constant as shown in FIG. And receiving stations 11 and 13
Is present on the hyperbola 2 where the difference in distance from is constant. Accordingly, the position of the transmitting station 14 can be located by finding the intersection of the two hyperbolas 1 and 2. In addition,
In the following description of FIG. 4A, details of the hyperbolic method are described.

[0005]

The hyperbolic method described above is:
As shown in FIG. 1, generally three radio stations 11 whose positions are clearly defined.
Applied to the range of the triangle of
The position accuracy can be widest when the arrangement of the triangles is an equilateral triangle. In that case, the position of the transmitting station 14 where the geometric precision is highest can be the center of the equilateral triangle, and the intersection angle between the two hyperbolas 1 and 2 is 60 °.

However, in the hyperbolic method described above, when trying to locate the position of the radio station 14 whose position is unclear outside the triangle having three radio stations 11 to 13 whose positions are clear as vertices, the hyperbola 1 and the hyperbolic 1 There is a disadvantage that the intersection angle of the two becomes small and the measurement accuracy at that position sharply decreases.

FIG. 2 shows the relationship between the intersection angle and the positional accuracy. FIG. 2A shows an example of the intersection angle α (0 ° ≦ α ≦ 60 °) of the hyperbolas 1 and 2 by the hyperbolic method, and shows the distance between the double lines representing the hyperbolas 1 and 2. Represents the measurement error range ε of each of the hyperbolas 1 and 2.

In this case, the measurement error range (shaded area) at the intersection of the hyperbolas 1 and ² is ε ² / sin α
As a result, when the intersection angle α decreases, the measurement error range increases in proportion to the reciprocal of sinα, and becomes infinite at the intersection angle of 0 ° in calculation. Incidentally, FIG. 2B shows an example in which the intersection angle α is 90 °. Range of measurement error at the intersection point of this case (the area of the shaded portion) is epsilon ^2, always less than that of the example of the hyperbolic method. In addition,
The case of FIG. 2 (b) will be revisited later in connection with the present invention.

As described above, the conventional radio wave position locating by the hyperbolic method requires 1) three radio stations whose positions are clear, and 2) the position locating is a range of a triangle having the three radio stations as vertices. And 3) there is a limit to the measurement accuracy of the position, and so on, and there is a problem that the application target of the hyperbolic method is limited.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to use a clear radio station having a smaller number of positions than in the conventional hyperbolic method, and to obtain a more accurate position locator in a wide application range. It is an object of the present invention to provide a radio wave position locating method and device, and a system, which enable the following. Another object of the present invention is to provide a more accurate and wide-ranging navigation service by applying the radio wave position locating device to a mobile communication system, a remote control system, or the like.

[0011]

According to the present invention, there is provided a radio station which transmits an interrogation signal, receives a response signal from the interrogation signal, and provides the transmission and reception time data. A radio station whose position is to be unclear for receiving and returning the response signal after a lapse of a predetermined time, and a radio station whose position is unclear which receives the response signal and gives the reception time data And, from the transmission time data of the interrogation signal from the radio station at the one location and the reception time data of the response signal at the radio station at the another location, the radio station at the one location and the The sum of the distance between the radio station whose position is not clear and the distance between the radio station whose position is not clear and the radio station whose position is not clear is calculated by the radio station whose position is not clear. Get the existing elliptical coordinates and the one position From the difference between the reception time data of each response signal at the definite radio station and the definite radio station at the different location, the distance between the definite radio station at the one location and the definite radio station at the location is Determining the difference in distance between the distinct radio station at the another location and the radio station at the uncertain location to obtain hyperbolic coordinates at which the radio station at the uncertain location exists; and Position locating means for determining two intersection coordinates of coordinates, and further locating one of the two intersection coordinates as coordinates at which a radio station whose position is unclear is located from the arrival direction of the response signal. A radio location system is provided.

When the short axis of the elliptical coordinate is equal to or smaller than a predetermined value, the position locating means may determine whether the radio station at one position is clear or the radio station at another position is clear. Switch to a radio station whose location is clear. Further, the apparatus further includes a future position predicting means for predicting a future position of the wireless station whose position is unclear, wherein the position locating means includes one of the one or the other clear wireless station based on the prediction. A clear radio station at a position other than those that can be switched and the switching timing thereof are determined in advance.

[0013] The prediction of the future position is performed by measuring the Doppler effect of a radio signal from the radio station whose position is not clear, or the prediction of the future position is performed by a predetermined radio station whose position is not clear. This is performed by comparing the past position before the current time with the current position.

Further, according to the present invention, the interrogation signal is transmitted from a radio station whose position is clear, and the radio station whose position is to be located is unclear after a predetermined time has elapsed from the reception of the interrogation signal. Returning the response signal; receiving the response signal at the one distinct radio station; receiving the response signal at another distinct radio station; From the transmission time of the interrogation signal from the radio station and the reception time of the response signal at the radio station at the other location, the time between the radio station at the one location and the radio station at the uncertain location is determined. Determining the sum of the distance and the distance between the distinct radio station at the another location and the radio station at the uncertain location, thereby determining elliptical coordinates at which the radio station at the uncertain location is present; One location clear radio station and said From the difference between the reception times of the respective response signals at the radio station whose position is clear, the distance between the radio station whose position is clear and the radio station whose position is not clear, Determining the distance difference between a station and the radio station whose position is ambiguous, thereby obtaining the hyperbolic coordinates where the radio station whose position is ambiguous is located; two intersection coordinates of the elliptic coordinates and the hyperbolic coordinates; , And locating one of the two intersection coordinates from the arrival direction of the response signal as coordinates at which a radio station whose position is unclear is located.

Further, according to the present invention, there is provided a wireless device, comprising: a switch for controlling conduction of a signal input; level detecting means for detecting a signal having a predetermined level or more input through the switch; An instantaneous interruption means for instantaneously interrupting a predetermined level of the continuous signal inputted by turning off the switch, and the level detecting means detecting the continuous signal of the predetermined level immediately after the instantaneous interruption of the predetermined time ends. And a measuring unit for measuring a time required to perform the operation as a reception system delay time of the wireless device.

The wireless device is a device that returns a corresponding signal after a lapse of a predetermined time after receiving the signal,
Further, time setting means for setting the constant elapsed time,
A calibration means for calibrating a fixed elapsed time set in the time setting means by a receiving system delay time measured by the measurement means, and the calibration always causes a fixed elapsed time after receiving a signal. The corresponding signal will be returned later.

[0017]

FIG. 3 is a diagram schematically showing the principle of radio wave position locating according to the present invention. 4 to 6 show FIG.
FIG. FIG. 4 is an explanatory diagram of position locating using a hyperbola and an ellipse according to the present invention, FIG. 5 is an explanatory diagram of an intersection angle between the hyperbola and an ellipse, and FIG. 6 is a comparison diagram of a position locating applicable range between the conventional example and the present invention. is there.

As shown in FIG. 3, the present invention comprises two radio stations (stations A and B) 21 and 22 whose positions are clear, and a radio station (station C) 23 whose position is not clear. . The two radio stations (stations A and B) 21 and 22 whose positions are clear are precisely synchronized with each other by transmission and reception of a system synchronization signal ().

At this point, an interrogation signal is sent from one of the radio stations 21 whose position is clear to the radio station 23 to be located ((2)). The wireless station 23 returns a response signal after a lapse of a predetermined time after receiving the inquiry signal (). This response signal is received by the wireless station 21 that is the transmission source of the interrogation signal and the wireless station 22 that is clearly located at the other position.

The radio stations 21 and 22 receive the response signal from the radio station 23, and thereby determine the distance between the radio stations 21 and 23 and the radio stations 22 and 23 as described with reference to FIG.
Is obtained (L _AC −L _BC ). In this example, the position data (corresponding to the signal transmission / reception time data) required for calculating the distance difference is transmitted from the wireless station 22 to the wireless station 21 (). The locus of a point at which the difference between the distances to the two points is constant is a hyperbola, and the wireless station 23 recognizes the specific hyperbola 2
4 above. The above is the same as the conventional hyperbolic method.

Further, according to the present invention, the wireless station 22 measures the time from when the interrogation signal is sent from the wireless station 21 (the sending time is clear) to the time when the response signal is received. (L _AC + L _BC ) is calculated. In this example, the position data required for calculating the sum of the distances is transmitted from the wireless station 22 to the wireless station 21 ().

The locus of the point where the sum of the distances to the two points is constant is an ellipse, and it can be seen from the above measurement that the wireless station 23 is on a specific ellipse 25. First, two intersection points (x) are obtained from the hyperbola 24 and the ellipse 25. Here, the condition of the direction of arrival of the radio wave is further given, and finally, in this example, one upper point is selected and determined as the location of the wireless station 23.

Next, with reference to FIG. 4, a description will be given of a formula for calculating a position location using a hyperbola and an ellipse according to the present invention. In FIG. 4, the coordinates F (c, 0), F ′ (− c, 0), and P (x, y) are the radio stations (A, B, and C) 21, 22, and 23 in FIG. Corresponds to the position. Here, the difference between the time T ₁ to time T ₀ and the radio station 22 to the radio station 21 has fired an interrogation signal is received by the response signal t (=
T ₁ −T ₀ ) can be expressed as follows.

T = t ₁ + t ₂ + t ₃ (1) where t ₁ = time required for radio waves to propagate between the wireless stations A and C (distance L _AC ) t ₂ = wireless station C delay time t ₃ = radio station B, between C (distance L _BC) time required for the wave to propagate between up returns a response signal after receiving an interrogation signal

At this time, when t ₂ is a known constant value, the distance L from the wireless stations 21 and 23 to the wireless station 22 is calculated.
_ACB (= L _AC + L _BC ) can be expressed by the following equation. L _ACB = (t−t ₂ ) * C (2) where C = propagation speed of radio wave

The radio station 2 is located between the radio stations 21 and 23.
Difference in distance between 2 and 23 (= L_AC-L _BC) At the same time
Can be L_AC-L_BC= (T₁-T_Three) * C From the above, from two focal points (base stations 21 and 22)
Ellipse that is the locus of a point where the sum of the distances is constant, and two focal points
Using the hyperbola, which is the trajectory of a point at a constant distance from
The position of the wireless station 23 can be determined.

First, a conventional hyperbolic coordinate formula is obtained by using FIG. Let any point on the hyperbola be P (x,
y), the focus is F (−c, 0), F ′ (c, 0), and the difference between the distances from F and F ′ is 2a, PF = √ ((x−c) ² + y ² ) , PF ′ = √ ((x + c) ² + y ² ) Since equation (3) is satisfied, √ ((x−c) ² + y ² ) to √ ((x + c) ² + y ² ) = 2a equation (4) ( The symbol ~ indicates that the smaller one is subtracted from the larger one, and so on.)

{((X−c) ² + y ² ) +}
By multiplying ((x + c) ² + y ² ), ((x−c) ² + y ² ) to ((x + c) ² + y ² ) = 2a (√ ((x−c) ² + y ² ) + √ ((x + c) ² + y ² )) Equation (5) From this, (x−c) ² + y ² = (a− (c / a) x) ² Equation (6) Accordingly, the following hyperbolic equation is obtained. y ² = (a− (c / a) x) ² − (x−c) ² Equation (7)

Next, the formula of the coordinates of the ellipse according to the present invention is obtained with reference to FIG. Let an arbitrary point on the ellipse be P (x,
y), the focus is F (−c, 0), F ′ (c, 0), and the sum of the distances from F and F ′ is 2a ′, PF = √ ((x−c) ² + y ² ), PF ′ = √ ((x + c) ² + y ² ) Since equation (8) holds, √ ((x−c) ² + y ² ) + √ ((x + c) ² + y ² ) = 2a ′ ... 9)

{((X−c) ² + y ² ) −}
((X + c) ² + y ² ) multiplied by ((x−c) ² + y ² ) − ((x + c) ² + y ² ) = 2a ′ (′ ((x−c) ² + y ² ) −√ ((x + c ) ² + y ² )) Equation (10) From this, (x−c) ² + y ² = (a ′ − (c / a ′) x) ² Equation (11) Accordingly, the following elliptic equation is obtained. y ² = (a ′ − (c / a ′) x) ² − (x−c) ² (12)

Finally, from the hyperbolic equation (7) and the elliptical equation (12), the coordinates of the intersection of each P (x, y) point × (x, y)
(See x in FIG. 3). (A− (c / a) x) ² − (x−c) ² = (a ′ − (c / a ′) x) ² − (x−c) ² (13) a ′ − (c / a ′) x = a− (c / a) x Equation (14)

Accordingly, the following intersection coordinates x (x, y) are obtained. x = (aa ′) / (c / ac / a ′) Equation (15) y = ± √ ((a− (c / a) ((aa ′)) / (c / a−) c / a ′)) ² − ((a−a ′) / (c / ac−a /) ′ − c) ² ) (16) where a, a ′, and c are known values. is there.

In equations (15) and (16), a = L _AC −
If L _BC , a '= L _ACB , c = distance between stations A and B, two intersections are obtained. Therefore, the position of the wireless station 23 can be determined by using the radio wave arrival direction to select one correct intersection, or by performing similar processing using a separately provided wireless station (for example, station D). Can be determined.

FIG. 5 shows the relationship between the intersection angle between the hyperbola and the ellipse in the present invention. As described in the related art, when performing position localization only by the hyperbolic method, the shape of the radio station that can obtain the position accuracy most widely is an equilateral triangle, and the position that can be obtained with the highest geometric accuracy is the center of the center. And
The intersection angle between the two hyperbolas at that time is 60 °. When this is constituted by a hyperbola and an ellipse according to the present invention, the range of the intersection angle of 60 ° or more can be considered as follows.

As shown in FIG. 5A, the radio station 23
When the distance between (P) and each of the wireless stations 21 and 22 (F, F ') is significantly longer than the distance between the wireless stations 21 and 22 (F, F') (according to the wireless stations 21 and 22). If the hyperbola 24 is long enough to be considered a hyperbolic asymptote 24 '), the ellipse 25 approaches a circle and the hyperbola 24 approaches its asymptote 24'. Therefore, the intersection angle α between the ellipse 25 and the hyperbola 24 is approximately 90 °. Therefore, the measurement accuracy in this case is good, and the position location is limited by the radio wave receivable range.

On the other hand, FIG. 5 (b) shows the radio station 23 (P)
The case where the distance between the wireless stations 21 and 22 (F, F ') is short is shown. As shown in the figure, the asymptote 24 'of the hyperbola 24 is 6 degrees with respect to the x-axis connecting the radio stations 21 and 22.
When 0 °, the hyperbola is 6 ° with respect to the line x-axis.
At 0 ° or more (≒ intersection angle α), the hyperbola substantially passes through the middle point between the center between the wireless stations 21 and 22 and each wireless station. Therefore, the measurement accuracy in this case is also good.

When the position of the wireless station 23 (P) approaches a straight line (x-axis) passing through the wireless stations 21 and 22, an ellipse 2
5, the short axis (length in the y-axis direction) becomes short, and as a result, two intersections of the ellipse 25 and the hyperbola 24 may approach so that they cannot be distinguished from each other in terms of resolution.

In this case, the intersection can be determined using a system other than the system by the wireless stations 21 and 22. The condition for switching the system is when the distance between the two intersections by the wireless station 23 approaches the resolution of the direction finder provided in the wireless station 21 or 22, and specifically, the length of the short axis of the ellipse This is when the distance is reduced to near the resolution of the direction finder.

The switching of the system is as follows: 1) a system in which only the wireless station 21 is switched to another wireless station 21 'and an ellipse and a hyperbola are obtained with the wireless station 22;
2) a system that obtains an ellipse and a hyperbola with the wireless station 21 by switching to 2 ′, 3) a system that obtains an ellipse and a hyperbola by switching both the wireless stations 21 and 22 to another wireless station 21 ′ and 22 ′,
Either may be used.

FIG. 6 is a drawing in which the target range of position location using the conventional hyperbolic method is compared with the target range of position location using the ellipse and the hyperbola according to the present invention. The conventional hyperbolic position locating requires at least three radio stations whose positions are clear, and is limited to a range of a triangle having the three radio stations as vertices in relation to the accuracy of position measurement.

On the other hand, in the position locating using the ellipse and the hyperbola according to the present invention, the position locating is possible if there are two clear radio stations. In addition, high-precision position locating can be performed in a wide applicable range in which radio waves can be received. However, the above 2
When the measurement target is near or near a straight line connecting wireless stations with clear positions, it is necessary to switch the system.

Hereinafter, specific embodiments of the radio wave position locating device and the position locating system using the same according to the present invention will be described. FIG. 7 shows a configuration example of a position locating system using the radio wave position locating device according to the present invention. The configuration in FIG. 7 is basically the same as the configuration described in the explanation of the operation principle in FIG.

In FIG. 7, first, the position of a mobile station (station C) 23 whose position is unclear in a system (system A) composed of two radio stations (stations A and B) 21 and 22 whose positions are clear. Orientation is performed. If the mobile station 23 comes close to the vicinity of a straight line connecting the two wireless stations 21 and 22, the one wireless station (station B) 22 and the wireless station (B ') at a third position are clearly defined.
Station (system B) 31 and the mobile station (C
Station 23 is continued to be located.

In this example, the radio stations 21 and 2 at each location are clear.
The monitoring station 32 receives the position data sent from the stations 2 and 31, and performs the position determination of the mobile station 23 by using the above-described position calculation formula (16) using the ellipse and the hyperbola according to the present invention. As will be described later, the future position of the mobile station 23 is predicted from the past position data y, and necessary system switching is performed. The monitoring station 32 also uses each of the base stations 2
1, 22 and 31 are instructed to transmit a system synchronization signal and an interrogation signal. The transmission / reception sequence of each control signal such as an interrogation signal is the same as in FIG. Further, in FIG. 7, a control signal when the B system is used is shown by a dotted line.

FIG. 8 shows an example of a basic operation flow of the system of FIG. FIG. 9 shows an example of the transmission timing of the various signals shown in FIG. In addition,
Here, the description of the synchronization operation of the entire system by the system synchronization signal (), which is the related art, is omitted.

In FIG. 8, first, the interrogation signal () is transmitted from the radio station 21 whose position is clear, and the radio station 23 whose position is not clear transmits a response signal () (S10 and 1).
1). The response signals from the base station 23 are received by the radio stations 21 and 22 whose positions are clear, and the ellipse is obtained from the position data () based on the transmission time of the interrogation signal and the reception time of the response signal at the radio station 22 whose position is clear. Is calculated (S1
2).

Next, it is determined whether or not the minor axis of the ellipse is equal to or greater than a predetermined value. If the minor axis is equal to or less than the predetermined value, it is determined that orientation cannot be performed. 31 (S13 and S14). If the value is equal to or greater than a certain value, a hyperbola is obtained from the difference between the position data () based on the time when the response signals from the base station 23 are received by the radio stations 21 and 22 whose positions are clear, and the two ellipses with the ellipse are obtained. The intersection is obtained (S13 and S15). Finally, one of the intersections is determined as the position of the radio station 23 whose position is unclear from the direction of arrival of the radio wave (S16).

FIGS. 10 to 17 show an embodiment of the radio wave position locating device according to the present invention. FIG. 10 shows a configuration example of a transmitting unit of a radio station whose position is clear (hereinafter, referred to as a “base station”). As shown in FIG. 10, the transmission unit is roughly divided into a system synchronization signal generation unit 41 and an interrogation signal generation unit. In the system synchronizing signal generating section 41, the ID transmitting means 45 outputs an ID signal for a system synchronizing signal including a station number and the like, and the FM modulation means 46 at the next stage outputs the ID signal to, for example, 7
Modulates to 0 MHz FM signal.

The position locating pulse transmitting means 47 outputs a position locating pulse for synchronizing the base stations at a predetermined period, and the AM modulation means 48 at the next stage outputs the position locating pulse to, for example, 70 MHz.
Is modulated to an AM pulse signal. The system synchronization signal including the ID signal for the system synchronization signal and the position locating pulse is output from the transmission antenna 44 to another base station via the transmission unit 43 including a power amplifier or the like.

In the interrogation signal generation section 42, the ID
The sending unit 49, the calibration request signal sending unit 50, and the calibration period sending unit 51 are each an ID signal for an interrogation signal including a station number and the like, and a target station whose position is unclear (hereinafter, referred to as a "mobile station"). And a calibration reference signal used for delay time correction during the calibration period. The next-stage FM modulator 53 sequentially converts them into, for example, 70
Modulates to FM signal of MHz.

The position locating pulse transmitting means 52 outputs a position locating pulse for clarifying the transmission time of the interrogation signal at a predetermined period, and the next-stage AM modulating means 54 outputs the position locating pulse to, for example, 70.
Modulates to an AM pulse signal of MHz. The interrogation signal including the interrogation signal ID signal and the position locating pulse is output from the transmission antenna 44 to the mobile station via the transmission unit 43 including a power amplifier and the like.

FIG. 11 shows an example of an interrogation signal and its response signal. The interrogation signal shown in FIG. 11A is composed of an interrogation signal ID signal, a calibration request signal, a calibration period, and a position locating pulse, as described above. The mobile station returns a response signal shown in FIG. 11 (b) to the base station after a certain time delay after receiving the inquiry signal. The response signal includes an ID signal for a response signal including a station number and the like, and a position locating pulse signal for defining the transmission time.

In the present invention, since the ellipse is calculated such that the sum of the distances is constant, the fluctuation of the delay time from when the mobile station receives the interrogation signal to when the mobile station returns the response signal is immediately changed between the mobile station and each base station. Appear as a cause of the error in the distance between
It becomes a serious problem. Although the description is made on the base station side, since the delay time is given by the mobile station side, the configuration of the mobile station which is the opposite device of the transmission unit will be described here.

FIG. 12 shows an example of the configuration of a mobile station according to the present invention. FIG. 13 shows a timing chart of the circuit delay time compensation operation in the reception system of the mobile station.
In FIG. 12, the mobile station receives the interrogation signal ((a) in FIG. 11) from the base station by the FM detector 64 via the switch 62 and the receiving amplifier 63 described later. The ID detecting means 65 detects the ID type and the base station number included therein, and when detecting the ID from the base station, the calibration signal generating means 6
7 and the signal level detecting means 70 are enabled.

The calibration request signal detecting means 66 detects a calibration request signal included in the received inquiry signal, and activates the calibration signal generating means 67 accordingly. Calibration signal generation means 6
Numeral 7 outputs a calibration signal consisting of a one-shot pulse signal during the calibration period following the calibration request signal by the activation (FIG. 13 (a)). The switch 62 controls the conduction of the input signal, and is turned off during the calibration signal period (FIG. 13B). At the same time, the delay time detecting means 68 constituted by a counter or the like is reset.

During the calibration period following the calibration request signal, the calibration reference signal is received. The calibration reference signal is a carry signal of a certain level or more, for example, a 70-MHz unmodulated signal. Therefore, an intermittent control of the switch 62 by the calibration signal generates a pseudo AM pulse signal. When the switch 62 returns from the disconnected state to the conductive state, the delay time detecting means 68 starts counting,
The pseudo AM pulse signal is detected by the AM detector 69 and the signal level detector 70 (FIG. 13C).

The delay time detecting means 68 stops the counting, for example, or holds the count value at that time according to the detection signal from the signal level detecting means 70. The count value is actually calculated by the receiving system in the apparatus from the rise of the input AM pulse signal (position locating pulse).
The circuit delay time until the detection of the M pulse signal is shown ((b) and (c) in FIG. 13). Therefore, the predetermined duration independent of the circuit delay characteristic of the receiving system is given to the delay means 71 in which the predetermined duration from the reception of the interrogation signal to the return of the response signal is calibrated for the circuit delay time. Time can be realized.

After the predetermined duration, the response signal generating section 72 has the ID transmitting section 73 and the position locating pulse generating section 74.
A response signal shown in FIG. 11B is generated by the modulation means 75, and the modulation means 75 performs FM modulation on the former and AM modulation on the latter. The signal is output from the transmitting antenna 77 to the base station via the transmitting means 76 including a transmitting amplifier and the like.

Returning to the description of the base station, the receiving section of the base station will be described below. 14 and 15 show configuration examples of a signal receiving unit in the receiving unit of the base station. FIG. 14 shows an example of the signal receiving unit, and FIG. 15 shows an example of the position calculating unit. Note that FIG.
In the example of FIG. 14, the signal receiving unit of FIG.
15 and the position calculation unit of FIG.

In FIG. 14, the ID signal portion of the system synchronizing signal from another base station or the response signal from the mobile station received by the receiving means 83 comprising a receiving amplifier or the like is output by the FM detecting means 84 and the position detecting means. The orientation pulse signal portion is received by the AM detection means 86. The ID detecting means further detects the ID type and the station number, thereby enabling the position locating pulse detecting means 87.

The phase comparing means 89 measures the phase (time position) of the position locating pulse detected by the AM detecting means 86 and the position locating pulse detecting means 87 by counting the number of reference pulses supplied from the internal reference signal generating means 88. I do. In the case of the system synchronization signal received first, the phase of the position locating pulse from each base station including its own station is recorded.

As the reference signal generating means 88, an ultra-high-stability oscillator such as a rubidium oscillator is used, and an independent synchronization system for independently synchronizing each station is employed. Therefore, a system synchronization signal is periodically transmitted from a certain base station, and each station generates phase calibration data between the received system synchronization signal and an internal reference signal. Then, the relative time between the base stations is managed by correcting the position data based on the phase signal of the position locating pulse of the interrogation signal and the response signal which are transmitted subsequently by the calibration data.

In the position calculating section 91 of FIG. 15, the position data from each base station is given to the switching means 92.
Which combination of base stations uses the position data of the system (A system or B system in FIG. 7 or the like) is determined by the switching signal from the control means 97. The control unit 97 also performs various device controls such as transmission control of a system synchronization signal and an inquiry signal.

The calculating means 93 calculates the coordinate formulas (15) and (16) of the intersection of the ellipse and the hyperbola using the position data from the two base stations selected by the switching means 92, and further adds the calculation results. Given the data condition from the direction finder, the position coordinate data of one mobile station 23 is obtained. The display control means 94 displays the position coordinate data on a display means 95 such as a display.

By the way, when the mobile station approaches a straight line connecting the base stations or moves farther than the propagation distance of the radio wave, a situation occurs in which the position cannot be located. Therefore, when the movement of the mobile station is detected, the movement speed and the movement direction are calculated in advance, and based on the calculation result, the future position of the mobile station is predicted in advance, and it is necessary to switch the system of the wireless station in the future. If the switching timing and the system to be switched are determined in advance, efficient system switching can be performed.

The position predicting means 9 based on the Doppler effect shown in FIG.
Position prediction means 96 based on the change of position 0 and FIG.
Is provided for the purpose described above. The control unit 97 gives an appropriate system switching instruction to the switching unit 92 based on the position prediction data from the position prediction units 90 and 96. In addition, transmission of an inquiry signal to a corresponding base station (transmitting unit) is controlled.

FIG. 16 shows an example of the configuration of the position predicting means 90 based on the Doppler effect. In FIG. 16, a mobile station transmission frequency 105 of, for example, 70 MHz is given to the frequency shift detecting means 101, and a frequency transition near the frequency caused by the Doppler effect due to the movement of the mobile station is detected. The relative speed calculation means 102 calculates the relative speed of the mobile station as viewed from the own station based on the frequency transition (a vector amount including speed / direction information).

True moving speed / true moving direction calculating means 103
Calculates the true speed and direction of the mobile station from the relative speed information for the own station and the similar relative speed information 106 obtained from another base station. The future position calculating means 104 predicts the future position of the mobile station by adding the calculated true speed / direction information of the mobile station to the past mobile station position information 107. The control means 96 determines in advance the system to be switched and the system switching time based on the future position information. The position predicting means 90 using the Doppler effect in the present embodiment provides effective system switching control especially for a moving body moving at high speed.

FIG. 17 shows an example of the configuration of the position estimating means 95 based on a change in position. The position storage means 121 updates and records the current position calculated by the calculation means or the position of the mobile station measured by another dedicated device or the like at regular time intervals (fixed periods). The moving true speed / moving true direction calculating means 122 calculates the moving speed at the current position of the mobile station based on the current position information of the mobile station and the past position information recorded in the moving true direction calculating means 122 at the predetermined time intervals. And the moving direction.

The future position calculating means 123 predicts the future position of the mobile station from the moving speed and the moving direction at the current position of the mobile station. The control means 96 determines a system to be switched and a system switching time in advance based on the information. The position predicting means 95 for predicting the change of the movement at regular intervals as in this example provides efficient system switching control especially for a moving body moving at a low speed.

[0071]

As described above, conventionally, in position locating by a hyperbola, three or four radio stations whose positions are clear are required. However, in the present invention, it is possible to perform the position locating by two or three stations one station smaller than that. In addition, in the localization by the hyperbola, the measurement accuracy is deteriorated because the intersection angle of the hyperbola is narrow outside the triangle having each station as the vertex, but the present invention uses the ellipse and the hyperbola to make the intersection angle nearly orthogonal, and as a result, A more accurate location service can be provided over a wider range than the hyperbolic location.

Further, in conventional communication with a mobile station, a method of selecting a system having a maximum reception level and performing communication is generally used. In this method, a plurality of systems constantly monitor the reception level of the transmission radio wave from the mobile station, and control the switching timing and the switching system by notifying each other of the reception status. On the other hand, in the present invention, a system switching timing and a system to be switched are controlled by predicting a future position based on a current position and a moving state of the mobile station.

Therefore, in the present invention, there is no need to continuously monitor the state of the mobile station in a plurality of systems, and only the system communicating with the mobile station and the system starting communication in the near future need monitor the mobile station. . As a result, the number of mobile stations to be monitored in each communication system decreases, and efficient communication can be performed.

In the conventional mobile station, a large number of adjustment points are provided particularly to absorb the variation in the electrical characteristics of the reception system circuit, and the stable operation is guaranteed at the time of shipping, maintenance and inspection work, or at the start of operation. Needed to be adjusted. Since the present invention has a function of compensating the electrical characteristics of the receiving system at any time during the operation of the mobile station, stable operation with no adjustment and high accuracy is guaranteed in various environments.

[Brief description of the drawings]

FIG. 1 is a diagram showing the principle of a conventional position locating method based on a hyperbolic method.

FIG. 2 is a diagram illustrating a relationship between an intersection angle and positional accuracy.

FIG. 3 is a diagram schematically illustrating the principle of radio wave location according to the present invention.

FIG. 4 is an explanatory diagram of position location using a hyperbola and an ellipse.

FIG. 5 is an explanatory diagram of an intersection angle between a hyperbola and an ellipse.

FIG. 6 is a comparison diagram of a position locating applicable range between a conventional example and the present invention.

FIG. 7 is a diagram showing a configuration example of a position locating system using the radio wave position locating device according to the present invention.

FIG. 8 is a diagram showing an example of a basic operation flow of FIG. 7;

FIG. 9 is a diagram illustrating an example of transmission timings of various signals illustrated in FIG. 7;

FIG. 10 is a diagram illustrating a configuration example of a transmission unit of a radio station whose position is clear.

FIG. 11 is a diagram showing an example of an interrogation signal and a response signal thereof.

FIG. 12 is a diagram illustrating a configuration example of a mobile station according to the present invention.

FIG. 13 is a diagram illustrating an example of a circuit delay time compensation operation timing in a reception system of a mobile station.

FIG. 14 is a diagram illustrating a configuration example of a signal receiving unit in a receiving unit of a base station.

FIG. 15 is a diagram illustrating a configuration example of a position calculation unit in a reception unit of a base station.

FIG. 16 is a diagram illustrating an example of a configuration of a position prediction unit based on the Doppler effect.

FIG. 17 is a diagram illustrating a configuration example of a position predicting unit based on a change in position.

[Explanation of symbols]

 21, 22, 31 ... Radio station whose position is clear 23 ... Radio station whose position is not clear 24 ... Hyperbola 24 '... Asymptote of hyperbola 25 ... Ellipse 32 ... Monitoring station 41 ... System synchronization signal generator 42 ... Interrogation signal generation Unit 62: Switch 81: Signal receiving unit 90: Position predicting unit by Doppler effect 91: Position calculating unit 96: Position predicting unit by change of position

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hideki Yoshidome 2-2-6 Jomi, Chuo-ku, Osaka-shi, Osaka Fujitsu Kansai Digital Technology Co., Ltd.

Claims (10)

[Claims] A wireless station at one position which transmits an interrogation signal and receives a response signal thereof, and provides transmission and reception time data; and said interrogation signal is received, and said response signal is transmitted after a predetermined time has passed. A radio station whose position is unclear to be signaled, a radio station at another location which receives the response signal and gives the reception time data, and a radio which is clear at the one location From the transmission time data of the interrogation signal from the station and the reception time data of the response signal at the radio station at another location, the radio station between the radio station at one location and the radio station at the location uncertain And the sum of the distance between the radio station at the different position and the radio station at the uncertain position is obtained to obtain the elliptical coordinates at which the radio station at the uncertain position exists; One location clear radio station and said another location From the difference between the reception time data of each response signal at the definite radio station, the distance between the definite radio station at the one location and the definite radio station at the one location and the definite radio station at the another location are Determining a difference in distance between the radio station whose position is uncertain and obtaining hyperbolic coordinates at which the radio station whose position is unclear exists; and obtaining two intersection coordinates of the elliptical coordinates and the hyperbolic coordinates; Position locating means for locating one of the two intersection coordinates from the arrival direction of the response signal as coordinates at which a radio station whose position is unclear is located;
A radio wave position locating system comprising: 2. The position locating means further comprising, when the minor axis of the elliptical coordinate is equal to or less than a predetermined value, declaring either the clear radio station at one position or the clear radio station at another position. The system according to claim 1, wherein the system switches to a radio station whose position is different from that of the radio station. 3. The apparatus further comprises a future position predicting unit for predicting a future position of the radio station whose position is unclear, wherein the position locating unit determines the one or another position based on the prediction. 3. The system according to claim 1, wherein a definite radio station to be switched to one of the radio stations and a definite radio station at a position other than those are determined in advance. 4. The system according to claim 3, wherein the prediction of the future position is performed by measuring a Doppler effect of a radio signal from a radio station whose position is unclear. 5. The system according to claim 3, wherein the prediction of the future position is performed by comparing a current position with a past position of the wireless station whose position is unclear for a predetermined time. 6. Sending an interrogation signal from a radio station whose position is unambiguous, and returning a response signal after a lapse of a predetermined time from the reception of the interrogation signal by an unclear radio station whose position is to be located. Receiving the response signal at an explicit radio station at the one location; receiving the response signal at an explicit radio station at another location; interrogating the explicit radio station at the one location; From the transmission time of the signal and the reception time of the response signal at the radio station at another location, the distance between the radio station at one location and the radio station at the other location and the another Determining the sum of the distances between the radio station whose position is unclear and the radio station whose position is unclear, thereby obtaining elliptical coordinates where the radio station whose position is unclear exists; Clear radio station and said another location clear From a difference between the reception time of each response signal on line station, the 1
Determining the difference between the distance between the clear radio station at one location and the radio station at the uncertain location and the distance between the clear radio station at the other location and the radio station at the uncertain location; Thereby obtaining hyperbolic coordinates at which the radio station whose position is unclear exists; obtaining two intersection coordinates of the elliptic coordinates and the hyperbolic coordinates; and calculating one of the two intersection coordinates from the arrival direction of the response signal. Locating the coordinates as coordinates at which a radio station whose position is unclear is located. 7. When the short axis of the elliptical coordinates is equal to or smaller than a predetermined value, either the clear radio station at the one position or the clear radio station at another position is changed to a clear radio station at other positions. 7. The method of claim 6, comprising switching to a wireless station. 8. Predicting a future position of the radio station whose position is uncertain, and other positions that are switched based on the prediction with one of the definite radio stations of the one or another position. 8. The method according to claim 6, further comprising the step of determining in advance the specific radio station and its switching time. 9. A wireless device, comprising: a switch for controlling conduction of a signal input; level detection means for detecting a signal having a predetermined level or higher input through the switch; and a predetermined level input via the switch. An instantaneous interruption means for instantaneously interrupting a predetermined level of signal by turning off the switch, and a time from immediately after the instantaneous interruption of the predetermined time until the level detecting means detects the continuous signal of the predetermined level. Measuring means for measuring the reception system delay time of the wireless device,
A wireless device comprising: 10. The wireless device is a device for returning a signal corresponding to a predetermined elapsed time after receiving a signal, further comprising: a time setting unit for setting the constant elapsed time; and the time setting unit. A calibration means for calibrating a fixed elapsed time set in the reception system delay time measured by the measuring means, and a signal corresponding to the signal always after a fixed elapsed time after receiving the signal by the calibration 10. The apparatus according to claim 9, wherein