JPH08122425A - Independent synchronization system, arriving time measuring system and error correction system for location system - Google Patents

Abstract

PURPOSE: To reduce the location error as much as possible without transmitting the sync signal by determining the difference between a measured arriving time of a location reference signal at a central station receiving system and an arriving time received from a relay station and then correcting the difference thus determined. CONSTITUTION: A central station 4 radiates a location reference signal at a predetermined period and the arriving time is measured at the receiving system in a central station 4 and each relay station 6. Each relay station 6 transmits the measured arriving time to the central station 4 where the difference of arriving time is determined. When the difference thus determined deviates from a predetermined difference, it is corrected correspondingly. Consequently, the phase shift of local oscillator can be eliminated between respective stations without transmitting the sync signal from the central station 4 to each relay station 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention corrects the phase shift between the central station and the relay station without using a synchronization signal and can measure the arrival time without the arrival time error. The present invention relates to a synchronization method, an arrival time measuring method of a position locating system, and a position locating error correction method of a position locating system.

As a method for locating the position of a mobile station with respect to a central station and a relay station, hyperbolic navigation such as Decca and Omega is known. This hyperbolic navigation has the following problems.

[0003]

2. Description of the Related Art Conventional hyperbolic navigation has one central station,
At least two relay stations are provided, and the position locating signal is transmitted from the mobile stations located to these stations to the central station and each relay station. Then, a hyperbola is drawn between the central station and one relay station based on the arrival time difference between the position location signals received by the central station and one relay station. Similarly, a hyperbola is drawn between the central station and the other relay station based on the arrival time difference between the position location signals received by the central station and the other relay station. The position of the mobile station is located by finding the intersection of these two hyperbolas.

Each of the stations is provided with a reference oscillator, and the synchronization of these reference oscillators is performed by sending a synchronization signal from the central station to the relay station and the mobile station so that the reference oscillators of those stations are used as the reference of the central station. It is performed in synchronization with the oscillator.

[0005]

In the conventional hyperbolic navigation, in order to synchronize the oscillation signals of the reference oscillator of the central station with the oscillation signals of the reference oscillators of the relay station and mobile station, the synchronization signal is used as described above. It is necessary to send from the central station to the relay station and mobile station. Further, the mobile station needs to be as small as possible, but it requires a reference oscillator, which hinders its miniaturization. Further, among the constituent elements used in the hyperbolic navigation, the waveform changes due to the difference in the input level, which causes an error in the detection of the rising edge of the signal. Therefore, the accuracy of phase detection of the arriving signal is inferior, and the position locating accuracy of the mobile station becomes low. or,
Measures against aging of hardware such as central offices and relay stations and changes of radio wave propagation system are not sufficient, which causes an error in position location.

The present invention has been made in view of the above technical problems, and an independent synchronization system of a position locating system capable of reducing the position locating error as much as possible while eliminating transmission of a synchronization signal, It is an object of the present invention to provide an arrival time measuring method for a position locating system and a position locating error correction method for a position locating system.

[0007]

FIG. 1 shows a diagram for explaining the principle of the invention according to claims 1 to 7. Claim 1
As shown in FIG. 1, the described invention is such that a radio wave radiated from a mobile station 2 is received by a central station 4 and a plurality of relay stations 6, and an arrival time measured by each relay station 6 is transmitted to the central station. Synchronization of the position locating system for calculating the arrival time difference between the arrival time received by the central station 4 and the arrival time received from each relay station 6, and locating the position of the mobile station 2 by hyperbolic navigation using the arrival time difference. In the conversion system, the position locating reference signal is radiated from the central station 4 at a preset cycle,
Of the arrival time measured by the reception system of each of the relay stations 6 and the arrival time measured by each of the relay stations 6 and transmitted to the central station 4 The central station 4 calculates the arrival time difference from the received arrival time, and when the arrival time difference deviates from the arrival time difference within a predetermined time, corrects the arrival time difference by the deviation. Characterize.

According to the second aspect of the present invention, as shown in FIG. 1, the arrival time measured by each relay station 6 when the radio wave radiated from the mobile station 2 is received by the central station 4 and a plurality of relay stations 6. The arrival time difference between the arrival times received by the central office 4 and transmitted from the central office 4 and the arrival times received from the relay stations 6 is calculated, and the mobile station 6 is hyperbola-navigated using the arrival times difference.
In the arrival time measuring method of the position locating system for locating the position, the position locating reference signal is radiated from the central station 4 at a preset cycle, and the arrival time is measured by the receiving system of the central station 4 and each relay station 6. Then, the arrival time measured by each relay station 6 is transmitted to the central station 4, and the arrival time difference between the arrival time measured by the receiving system of the central station 4 and the arrival time received from each relay station 6 is calculated as the central station 6 When the arrival time difference deviates from the arrival time difference within a predetermined time, the mobile station 2 corrects the arrival time difference by the amount of the deviation.
Radiate a predetermined number of position location signals sequentially from
The central station 4 and the relay stations 6 are characterized by calculating an average value of the respective arrival times measured and using it as the arrival time of the station.

According to a third aspect of the present invention, as shown in FIG. 1, in the arrival time measuring method of the position locating system according to the second aspect, the predetermined number of times in the central station 4 and each relay station 6 is used. When measuring each arrival time of the position locating signal, first means for applying automatic gain control to the first of the predetermined number of position locating signals or only a small number of position locating signals predetermined from the beginning. , Second means for providing the gain obtained by the automatic gain control to a plurality of remaining position locating signals out of the predetermined number of position locating signals, the first means and the first means The arrival time is measured for each of the predetermined number of position location signals from the two means.

According to a fourth aspect of the present invention, as shown in FIG. 1, in the independent synchronization system of the position locating system according to the first aspect, the signal of the resolution frequency generated from the highly stable oscillator is obtained by frequency division. The timer is reset by the signal of the measurement range frequency, the counter up operation is started by the signal of the resolution frequency, the timer is stopped by the position locating signal, and the count value of the timer when the timer is stopped is reached. It is characterized by being time.

According to a fifth aspect of the present invention, as shown in FIG. 1, in the arrival time measuring method of the position locating system according to the second or third aspect, the signal of the resolution frequency generated from the highly stable oscillator is divided. When the timer is reset by the signal of the measurement range frequency obtained by circling, the counter up operation is started by the signal of the resolution frequency, the timer is stopped by the position locating signal, and the timer when the timer is stopped It is characterized in that the count value of is the arrival time.

According to the sixth aspect of the present invention, as shown in FIG. 1, the radio wave radiated from the mobile station 2 is received by the central station 4 and a plurality of relay stations 6, and the arrival time measured at each relay station is the above-mentioned arrival time. The arrival time difference between the arrival time received by the central station 4 and the arrival time received by each relay station 6 is calculated, and the position of the mobile station 2 is located by hyperbolic navigation using the arrival time difference. In the position location error correction method of the position location system, a predetermined number of position location signals are radiated from the central station 4, and the first arrival time is set in the receiving system of the central station 4 and each relay station 6. The mobile station 2 radiates a predetermined number of position locating signals from the mobile station 2, and the second arrival time is measured by the receiving system of the central station 4 and each relay station 6, and each first measured Arrival time and each second arrival time The correction reference value of the arrival time difference within the set time is calculated, and when the arrival time difference when the position locating signal is radiated from the mobile station 2 deviates from the correction reference value, the arrival time difference is calculated by the deviation. It is characterized by correction.

According to a seventh aspect of the invention, as shown in FIG. 1, in the position location error correction method of the position location system according to the sixth aspect, the signal of the resolution frequency generated from the highly stable oscillator is obtained by frequency division. The timer is reset by the signal of the measurement range frequency, the counter up operation is started by the signal of the resolution frequency, the timer is stopped by the position locating signal, and the count value of the timer when the timer is stopped is displayed. It is characterized by the arrival time.

[0014]

According to the first aspect of the present invention, the central station 2 radiates the position locating reference signal at a predetermined cycle, and the arrival time is measured by the receiving system of the central station 4 and each relay station 6. Each relay station 6
Sends the measured arrival time to the central station 4. Central station 4
Calculates the arrival time difference. When the arrival time difference deviates from the arrival time difference within a predetermined time, the arrival time difference is corrected by the amount of the deviation.

By doing so, it is possible to eliminate the phase shift between the local oscillators of each station without transmitting the synchronization signal from the central station 4 to each relay station 6. Claim 2
In the invention described in claim 1, the mobile station 2
Radiates a predetermined number of position locating signals from the central station 4 and each relay station 6 to measure the arrival time of each position locating signal, and obtains the value obtained by averaging the respective arrival times for position locating. Time. This improves the accuracy of position location.

According to a third aspect of the present invention, in the invention according to the second aspect, the first or a few points with respect to the position locating signal.
By applying automatic gain control only to the position locating signal, and fixing the remaining position locating signal to the gain obtained by the automatic gain control so that the position locating signal has a sharp rising edge. The accuracy of position location is improved by reducing the error in time measurement.

According to a fourth aspect of the present invention, in the first aspect of the invention, when measuring the arrival time, the timer is reset by the signal of the measurement range frequency, and the count-up operation is started by the signal of the resolution frequency to perform position determination. The arrival time is measured by stopping the counting operation of the timer with a signal. It is possible to increase the measurement accuracy while expanding the measurement range.

According to the invention of claim 5, in the invention of claim 2 or 3, the arrival time is measured by claim 4.
The invention is as described. In a sixth aspect of the present invention, a predetermined number of position locating signals are radiated from the central station 4 to measure the first arrival time at the central station 4 and each relay station 6. Subsequently, the mobile station 2 radiates a predetermined number of position location signals, and the central station 4 and each relay station 6 measure the second arrival time. A correction reference value for the arrival time difference is calculated using these first and second arrival times. When the arrival time difference when radiating the position location signal from the mobile station 2 deviates from the correction reference value within the predetermined time, the arrival time difference is corrected by the deviation. As a result, it is possible to correct the time difference of arrival due to the change of the hardware and the change of the radio wave propagation system and remove the position location error.

According to a seventh aspect of the invention, in the sixth aspect of the invention, the arrival time is measured as in the fourth aspect.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a block diagram of a central station for carrying out the invention described in claims 1 to 7, and FIG. 3 is a configuration of a relay station for carrying out the invention described in claims 1 to 7. The figure is shown.
FIG. 4 is a block diagram of a mobile station that implements the invention described in claims 1 to 7. FIG. 5 shows the AG shown in FIGS. 2 and 3.
The detailed block diagram of C amplifier is shown.

In FIG. 2, the central office 28 includes a transmission system 30.
And a receiving system 29. The transmission system 30 includes a control unit 32, a modulator (FSK modulator) 34, an amplifier 36,
It is composed of a 9-times multiplier 38, a switch 40, a power amplifier 42, a bandpass filter 44, a transmission / reception switch 46, and an antenna 48. Of this transmission system, the switch 40,
The power amplifier 42, the bandpass filter 44, and the duplexer 46 are related to the inventions according to claims 1 to 7. The transmission signal supplied from the control unit 32 to the modulator 34 is a signal for controlling the relay station, and when the position localization is not performed, the FSK modulator 34 outputs a certain frequency, for example, 230/9 MHz. Carrier signal is transmitted. The carrier signal is amplified by the amplifier 36 and then multiplied by the 9-multiplier 38 into a 230 MHz signal.
Switch 40, power amplifier 42, band pass filter 4
4, and is transmitted from the antenna 48 to the relay station via the transmission / reception switch 46.

The receiving system of FIG. 2 includes an antenna 48, a transmission / reception switch 46, a high frequency amplifier 50, a UHF band pass filter 52, a local oscillator (highly stable oscillator such as a rubidium oscillator) 54, a frequency converter 56, and a band pass. Filter 58,
Intermediate frequency amplifier 60 having AGC function, input detector 6
2, timer 64, digital signal processor (DS
P) 66, frequency converter 68, bandpass filter 70,
It comprises an intermediate frequency amplifier 72 and a demodulator 74. Among these components, the frequency converter 68, the bandpass filter 70, the intermediate frequency amplifier 72, and the demodulator 74 are a system that receives response data from the relay station for the above-mentioned transmission signal.

The components related to the inventions of claims 1 to 7 are a high frequency amplifier 50 and a band pass filter 5.
2, local oscillator 54, frequency converter 56, band pass filter 58, intermediate frequency amplifier 60 having AGC function, input detector 62, timer 64, and digital signal processor (DSP) 66, position calculation unit 76, and position calculation It is a part 76. These components measure the arrival time from the transmission time of the position reference signal transmitted from the transmitter of the central station to the reception of the position reference signal by the receiving system of the central station, and calculate the arrival time difference. To do and to locate the position. The position calculation unit 76 is configured to include a CPU, and is configured to perform data processing including correction of arrival time difference by a program.

The optical modulation / demodulation unit 78 includes optical fiber cables 180 ₁ and 180 from the relay station 100 ₁ and the relay station 100 ₂ .
_The position calculation unit 76 receives the arrival time received via ₂
Transfer to The position calculation unit 76 calculates an arrival time difference described later.

The relay station 100 shown in FIG. 3 is constructed similarly to the receiving system 29 of the central office 28. Antenna 148,
A transmission / reception switcher 146, a high frequency amplifier 150, a band pass filter 152, a local oscillator (a highly stable oscillator such as a rubidium oscillator) 154, a frequency converter 156, a band pass filter 158, an intermediate frequency amplifier 160 having an AGC function,
It comprises an input detector 162, a timer 164, a digital signal processor (DSP) 166, a frequency converter 168, a bandpass filter 170, an intermediate frequency amplifier 172, and a demodulator 174. Of these components, the frequency converter 168, the bandpass filter 170, the intermediate frequency amplifier 172, and the demodulator 174 are a system that receives the reception data of the transmission signal transmitted from the relay station as described above. However, the response data for the received data is sent to the central station 2
The transmission system for transmitting to 8 is omitted.

The components related to the invention described in claims 1 to 7 are a high frequency amplifier 150, a band pass filter 152, a local oscillator 154, a frequency converter 156,
A band pass filter 158, an intermediate frequency amplifier 160 having an AGC function, an input detector 162, a timer 164, a digital signal processor 166, and an optical modulator / demodulator 178. These constituent elements are the position locating reference signal or the position locating signal transmitted from the transmitting unit of the central office 28, or the position locating reference signal or the position locating signal from the transmission time of the position locating signal from the mobile station 200, or the position locating reference signal. It is to measure the arrival time until the orientation signal is received by the reception system of the relay station.

In FIG. 4, the mobile station 200 has a transmission system 2
30 and a receiving system 231. Transmission system 23
0 is a control unit 232, a modulator (FSK modulator) 234,
Amplifier 236, 9 multiplier 238, switch 240, power amplifier 242, bandpass filter 244, transmission / reception switch 2
46 and an antenna 248. Of the transmission system, the switch 240, the power amplifier 242, the bandpass filter 244, and the transmission / reception switch 246 are related to the inventions of claims 1 to 7. The transmission data signal supplied from the control unit 232 to the modulator 234 is a signal for communication, and the FSK modulator 2 is used for position location.
34 transmits a carrier signal of a certain frequency, for example, 230/9 MHz in a state where the transmission data signal is not supplied. The carrier signal is sent to the amplifier 236.
After being amplified by, the signal is multiplied by a 9-multiplier 238 into a signal of 230 MHz, and then the switch 240, the power amplifier 242,
The central station 28 and each relay station 10 ₁ , each relay station 10 ₁ ,
Sent to 100 ₂ .

The receiving system of FIG. 4 includes an antenna 248, a transmission / reception switch 246, a high frequency amplifier 250, a UHF band bandpass filter 252, a local oscillator (highly stable oscillator such as a rubidium oscillator) 254, a frequency converter 256, and a bandpass. Filter 258, intermediate frequency amplifier 260, and demodulator 26
It consists of 1.

As shown in FIG. 5, the amplifier 60 having the AGC function of FIG.
An amplifier 300 for receiving a Hz signal, an AGC amplifier 302,
It includes a distributor 304, an amplifier 306, a detector 308, a DC amplifier 310, and a sample hold circuit 312.
The sample hold circuit 312 is
230 MHz that is turned on and off in 125 microsecond cycles
, AGC is applied only by the first pulse in a pulse train of, for example, 20 pulse trains preset by the frequency band available in the position locating system, and thereafter, AGC timing pulses for fixing AGC are supplied. The AGC may be applied to a few pulses from the beginning.

1 to 3, the central station 28 corresponds to the central station 4 of FIG. 1, and the relay stations 100 ₁ and 100 ₂ are
It corresponds to the relay station 6 of FIG. The mobile station 200 corresponds to the mobile station 2 in FIG.

The operation of the position locating system thus configured will be described below. First, the synchronization of the central station and the relay station by the independent synchronization method for position location will be described before the position location.

The central station 28 is controlled by its control unit 32 at 4 KHz.
The reference signal for position location of is transmitted. With this position locating reference signal, the carrier signal of 230 MHz transmitted from the 9-times multiplier 38 of the transmission system 30 is kept for a certain time, for example, 1
It turns on / off every 25 microseconds (4 KHz). The carrier signal is power-amplified by the power amplifier 42 and is supplied to the antenna 48 via the bandpass filter 44 and the transmission / reception switch 46 switched to the transmission side, and the position reference signal is radiated from the antenna 48 (FIG. See (1) of 6).
The signal leaks into the receiving system 31 in the transmission / reception switch 46 which supplies the position locating reference signal of 230 MHz to the antenna 48. The signal is supplied to the frequency converter 56 via the high frequency amplifier 50 and the band pass filter 52. The 230 MHz signal supplied to the frequency converter 56 is frequency-converted into a 70 MHz signal by the oscillation signal from the local oscillator 54, and is input to the input detector 62 via the band pass filter 58 and the intermediate frequency amplifier 60.

In parallel with this, a signal having a resolution frequency of 50 MHz generated from the oscillation signal from the local oscillator 54 is supplied to the timer 64 (see (1) in FIG. 7). As described above, the timer 64 divides the signal having the resolution frequency of 50 MHz into 100 kHz and the signal having the measurement range frequency of 4 kHz (see (2) and (3) in FIG. 7). The timer 64 is reset at this 4 KHz signal period (see (4) in FIG. 7). From the time when this reset is applied, the timer 64
Starts the counting operation again in response to the signal of the resolution frequency. Then, when the input detector 62 detects a predetermined number, for example, two pulses, of the 70 MHz signal input thereto, the timer 64 is detected.
A count stop signal is sent to (see (5) in FIG. 7). The predetermined number of pulses is a signal rising edge test,
It is then used for signal detection.

As described above, since the timer 64 is configured to be reset in response to the signal of the measurement range frequency and to perform the count-up operation in response to the signal of the resolution frequency, the measurement range is expanded. It is possible to improve the measurement accuracy while making it possible. For example, if the resolution frequency is 50 MHz and the measurement range frequency is 4 KHz, the resolution of the measurement accuracy is 6 meters / 20 nanoseconds, and the measurement range is 75 KHz / 25 microseconds.

When the timer 64 stops counting, the count value measured by the timer 64 is based on the position locating reference from the transmission time of the radio wave (position locating reference signal) radiated from the antenna 48 of the transmission system 30 of the central office 28. It represents the arrival time t _A until the signal is received (see (2) in FIG. 6). This count value is supplied from the timer 64 to the digital signal processor 66 and used as arrival time data. Then, the arrival time data is supplied from the digital signal processor 66 to the position calculation unit 76 and is used together with the arrival time data from the relay stations 100 _{1 and} 100 ₂ which will be described later and used to calculate the arrival time difference (distance difference). .

The same time measurement as that of the central station is performed by each relay station 10
0 ₁ , 100 ₂ . The operation mode of this time measurement will be understood by sequentially following the description of the central office 28, and therefore a detailed description thereof will be omitted. The arrival times measured at the relay stations 100 ₁ and 100 ₂ are defined as t _B and t _C , respectively.

The arrival time data measured at each of the relay stations 100 ₁ and 100 ₂ is used as the digital signal processor 16
6 ₁ and 166 ₂ (however, since the relay station is shown as a representative in FIG. 3, reference numerals of the relay station are not added to the reference numbers. The same applies to the respective constituent elements below). 178 ₁ and 178 ₂ and the optical fiber cable 18
The signal is transmitted to the optical modulator / demodulator 78 of the central office 28 via 0 _{1 and} 180 ₂ .

In this way, each relay station 100 ₁ , 100
Each arrival time data transmitted from ₂ is input to the position calculation unit 76 and the difference (arrival time difference) from the arrival time data measured by the central station 28 is calculated.

As described above, assuming that the arrival time measured by the relay station 28 is t _A and the arrival times measured by the relay stations 100 ₁ and 100 ₂ are t _B and t _C , respectively, the central station 28 and The arrival time difference t _AB with the relay station 100 ₁ is

[0040]

[Equation 1]

The arrival time difference t _AC between the central station 28 and the relay station 100 ₂ is

[0042]

[Equation 2]

It becomes These arrival time differences t _AB , t
_{In AC} , t _AB is the position difference between the relay station 100 ₁ and the reception system of the central station 28, the phase of the local oscillator 54 of the reception system of the central station 28, and the relay station 100 within a relatively short time period.
₁ becomes a value determined by the phase difference between the local oscillator 154 _{1 and} the phase of the local oscillator 154 ₁ , and t _AC is the position difference between the relay station 100 ₂ and the receiving system of the central station 28 and the local oscillator 54 of the receiving system of the central station 28. since the phase and the value determined by the phase difference between the relay station 100 _second local oscillator 154 _second phase, the aforementioned arrival time difference t _AB, t _AC is considered to be the fixed value.

However, the fixed value is within the above-mentioned comparatively short time period, and when it exceeds this, the above-mentioned arrival time difference deviates. This deviation is corrected when the arrival time difference is calculated by the position calculation unit 76. The deviation occurs due to the deviation (phase difference) between the phase of the local oscillator 54 of the central station 28 and the phase of the local oscillator 154 of the relay station 128. Therefore, by performing the correction, the error in the position location due to the phase difference is corrected. Can be excluded.

Further, without transmitting the synchronizing signal as described above,
In addition to correcting the phase of the local oscillator of each station to the same phase,
There is a possibility that the deviation of the hardware of each station and the change of the propagation delay of the propagation system may occur, resulting in an error in the location of the mobile station. The cause of hardware deviation is U
The HF band pass filter 52, the 70 MHz band pass filter 58, and the intermediate frequency amplifier 60. The main cause of the change in the propagation delay of the propagation system is the occurrence of fading.

Deviation of hardware of each station and propagation system
8 and 9 show the correction when a change in the propagation delay of
Will be described below. From the central station 28 transmission system to middle
Reception system of central station 20 and relay station 100₁, 100 ₂What
Sends a predetermined number of position location signals, for example 20
I do. For convenience of explanation, the center of one position location signal
Reception system of station 20 and relay station 100₁, 100₂In front
The arrival time is measured as described above. Relay station 100₁,
100₂The arrival time measured by
80₁, 180₂To the position calculator 76 of the central office 28
Transferred.

The measured arrival times are t _A0 , t _B0 ,
If t _C0 (see (3), (4), and (5) in FIG. 9), these measurement times t _A0 , t _B0 , and t _C0 are respectively

[0048]

(Equation 3)

[0049]

[Equation 4]

[0050]

(Equation 5)

Can be expressed as T in equation (3)_AR
Is the propagation delay time of the receiving system of the central office 28,
T in (4)_AFIs the propagation delay of the feeder of the transmission system of the central office 28
Time, D_ABIs the antenna 48 of the central office 28 and the relay station 100.
₁The antenna 148₁The distance between_BFIs the relay station 10
0₁Propagation delay time of the power feeding line of the receiving system, t_BRIs relay station 1
00 ₁Is the propagation delay time of the receiving system of. Formula (5) D_ACIs
Central station 28 antenna 48 and relay station 100₂Antenna
148₂The distance between_CFIs the relay station 100₂Receiving system
Delay time of the power supply line, t_CRIs the relay station 100₂Reception of
This is the propagation delay time of the system. Note that Tx in Fig. 8 is the transmission
System, Rx indicates a receiving system.

The above equations t _AF , D _AB , t _BF , D _AC , t
_{Since CF} is known, t _BR and t _CR can be measured. Next, the position locating signal is radiated from the mobile station 200 as a radio wave. The radio waves are transmitted to the central station 28 and the relay station 10.
0 ₁ , and the reception system of the relay station 100 ₂ receives and measures the arrival time in the above-described manner. The measured values are t _A1 , t _B1 ,
If t _C1 (see (3), (4), and (5) in FIG. 9), these measurement times t _A1 , t _B1 , and t _C1 are respectively

[0053]

(Equation 6)

[0054]

(Equation 7)

[0055]

(Equation 8)

Can be expressed as D in equation (6)
_MA is the distance between the antenna 248 of the mobile station 200 and the antenna 48 of the central station 28, and D _{MB in} equation (7) is the mobile station 20.
0 antenna 248 and relay station 100 ₁ antenna 148
The distance to ₁ and D _MC in equation (8) is the distance between the antenna 248 of the mobile station 200 and the antenna 148 ₂ of the relay station 100 ₂ . The arrival times measured at the trunk line stations 100 ₁ and 100 ₂ are transferred to the central station 28 in the same manner as described above.

Following the arrival time measurement, the central station 28
And radio wave arrival time in the radio wave arrival time in the difference t _A1 -t _B1 and the central station 28, the radio wave arrival time in the relay station 100 _1, the difference t _A1 and radio wave arrival time at the relay station 100 ₂ Calculate -t _C1 . The arrival time differences are as follows.

[0058]

[Equation 9]

[0059]

[Equation 10]

Arrival time difference t_AF-T_BFAnd arrival time difference t_AF
-T_CFIs a fixed value, and the feeder length is the same.
And becomes 0. In addition, the second term (t_AR−
t_BR), And the second term (t) of equation (10)._AR-T _CR), T
_BRAnd t_CRIs, as described above, Equations (3) to (5)
The difference between the two arrival times is
Is considered to be a certain value within a short time period,
If the measurement time period of the arrival time difference is longer than
(T_AR-T_BR), And (t_AR-T_CR) As mentioned above
Due to the temperature change of the hardware, the deviation may occur in the value.
Swell. The cause is the local oscillator 5 as described above.
4, 154 temperature fluctuation and UHF band pass filter
Temperature fluctuation of the band pass filter 58 of 70 MHz and 52 MHz, etc.
Is.

Therefore, (t _AR -t _BR ) and (t
_AR- t _CR ) is considered to be a certain constant value (correction reference value) within a certain short time period as described above, but when a time longer than that is reached, it shifts to the above arrival time difference. Occurs. If this deviation is corrected by using the arrival time difference measured within the certain short time period as a reference, the error corresponding to the deviation can be eliminated, and as a result, the position localization error can be reduced.

Further, when the propagation system fluctuates due to meteorological conditions (fading, etc.), it fluctuates as D _{AB in} equation (4).
/ 3 × 10 ^8, will change in D _AC / 2 × 10 ⁸ in the formula (5), the value t _BR that is could be measured, since appears as a variation of the t _CR, also fluctuation of the arrival time aforementioned It will be included in the arrival time. Therefore, since the correction reference value can be used for the correction of the arrival time difference in the calculation of the arrival time difference in the position calculation unit 76, the position localization error can be reduced as a result.

In summary, the arrival time difference described above is

[0064]

[Equation 11]

[0065]

(Equation 12)

Therefore, if the position calculation unit 76 corrects only the deviation from the above-mentioned correction reference value, the arrival time difference becomes a time that depends only on the distance, and an error occurs in the arrival time difference due to the fluctuation of the fluctuation element included in the measurement system. Therefore, the accuracy of position location can be improved.

In the above time measurement, the mobile station 20
The description has been given on the assumption that one position locating signal is sent out from 0, but as a position locating signal radiated from a certain mobile station 200, a predetermined number, for example, 20 position locating signals (UFH) are sent. The carrier wave of the band is radiated at a predetermined time period (see (1) and (2) in FIG. 10).

Then, each position location signal is received by each station (see (3), (4) and (5) in FIG. 10). With respect to the position locating signal, the arrival time is measured at each station in the above-described manner. The arithmetic mean of each arrival time is taken and the average value is used as the arrival time to calculate the arrival time difference at the central station. As a result, the accuracy of position location can be improved.

Although an example in which the number of position locating signals is 20 has been shown, the larger the number, the higher the measurement accuracy, but a wide band is required for the measurement, so a sharp rise in arrival time measurement is required. The number of position locating signals may be determined in consideration of the hardware that enables the use of the signal, the number of mobile stations, the band allowed for the position locating, and the like.

In this averaging process, the above-mentioned intermediate frequency amplifier 60 is configured as the intermediate frequency amplifier 60 having the AGC function as shown in FIG. With this configuration, 20
The AGC function is used only for the 1st position locating signal (see (3) in Fig. 11), and the remaining 19 position locating signals are at the gain set by the 1st position locating signal. The arrival time of each position location signal is measured with a sharp rising characteristic. The reason for doing so is that the AGC function works for each position locating signal unless the above configuration is adopted. Therefore, as shown in (2) of FIG. 11, the rise of each position location signal becomes slow, the accuracy of arrival time measurement deteriorates, and an error occurs in the position location of the mobile station. However, the AGC function shown in FIG. By using the intermediate frequency amplifier 60 having, it is possible to prevent the above-mentioned problems.

Although the above embodiments have been individually described,
The apparatus may be configured by an embodiment having a configuration in which each of the characteristic portions is selected.

[0072]

As described above, according to the present invention, the position locating reference signal is radiated from the central station to measure the arrival times at each relay line station, and the arrival times and the reception system of the central station are measured. The arrival time difference (reference arrival time difference) from the reached arrival time is
When the time exceeds a predetermined time that is considered to be a fixed value, only the deviation from the reference arrival time of the arrival time difference measured when the time exceeds the predetermined time is corrected. As a result, the phases of the local oscillators of the central station and each relay line station can be matched without transmitting the synchronization signal from the central station to each relay station as in the conventional case. Further, in the state where the phases are matched, the arrival time is measured using a plurality of position locating signals radiated from the mobile station, and the average thereof is taken, whereby the accuracy of the position locating can be improved.

Then, the automatic gain control is applied only to the position locating signal such as one shot of the plurality of position locating signals, and the automatic gain control is not applied to the subsequent position locating signals. Since the sharp position locating signal is used for measuring the arrival time, the accuracy of position locating can be further improved. The arrival time is measured by setting the resolution frequency to a frequency higher than the measurement range frequency by a predetermined value, and the arrival time is measured. Therefore, the measurement distance range is expanded and the measurement accuracy is improved. Can be made.

Further, even if there is a deviation of the hardware and a change of the propagation system, a means for correcting the deviation is provided, so that the position localization error can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the principle of the invention according to claims 1 to 7.

FIG. 2 is a configuration diagram of a central office for carrying out the invention described in claims 1 to 7;

FIG. 3 is a configuration diagram of a relay station for carrying out the invention described in claims 1 to 7.

FIG. 4 is a configuration diagram of a mobile station that implements the invention described in claims 1 to 7.

5 is a diagram showing a configuration of an intermediate frequency amplifier having an AGC function used in the central office shown in FIG.

FIG. 6 is a timing chart for explaining synchronization between the central station and each relay station.

FIG. 7 is a timing chart for explaining arrival time measurement.

FIG. 8 is an explanatory diagram for correcting position localization error.

FIG. 9 is a timing chart for correcting a location error.

FIG. 10 is a timing chart used to explain arrival time measurement.

FIG. 11 is a timing chart used to explain automatic gain control.

[Explanation of symbols]

2 mobile station 4 central station 6 relay station 28 central station 32 control unit 40 switch 42 power amplifier 44 band pass filter 46 duplex switch 48 antenna 50 high frequency amplifier 52 band pass filter 54 local oscillator 56 frequency converter 58 band pass filter 60 AGC Intermediate frequency amplifier with function 62 Input detector 64 Timer 66 Digital signal processor 76 Position calculator 78 Optical modulator / demodulator 100 ₁ Relay station 100 ₂ Relay station 148 Antenna 150 High frequency amplifier 152 Band pass filter 154 Local oscillator 156 Frequency converter 158 Band Pass filter 160 Intermediate frequency amplifier having AGC function 162 Input detector 164 Timer 166 Digital signal processor 178 Optical modulator / demodulator 200 Mobile station 232 Controller 240 Switch 242 Power amplifier 244 Band pass filter 246 Transmission / reception switch 248 Antenna 302 Amplifier having AGC function 304 Distributor 308 Detector 310 DC amplifier 312 Sample and hold circuit

Claims (7)

[Claims] 1. A central station and a plurality of relay stations receive radio waves radiated from a mobile station, and the arrival time measured by each relay station is transmitted to the central station and the arrival time received by the central station and In the synchronization method of the position location system that calculates the arrival time difference from the arrival time received from the relay station and uses the arrival time difference to locate the position of the mobile station by hyperbolic navigation, the position location reference signal is preset from the central station. The arrival time is measured by the reception system of the central station and each relay station, and the arrival time measured by each relay station is transmitted to the central station and the arrival time is measured by the reception system of the central station. The arrival time difference between the arrival time and the arrival time received from each relay station is calculated at the central station, and when the arrival time difference deviates from the arrival time difference within a predetermined time, the arrival time difference is calculated by the deviation. Special correction Plesiochronous scheme of position location systems that. 2. A central station and a plurality of relay stations receive radio waves radiated from a mobile station, and the arrival time measured by each relay station is transmitted to the central station and the arrival time received by the central station and In the arrival time measurement method of the position location system, which calculates the arrival time difference from the arrival time received from the relay station and uses the arrival time difference to locate the position of the mobile station by hyperbolic navigation, the position location reference signal is sent from the central station in advance. It radiates at a set cycle, the arrival time is measured at the reception system of the central station and each relay station, the arrival time measured at each relay station is transmitted to the central station, and the arrival time is measured at the reception system of the central station. The arrival time difference between the arrival time and the arrival time received from each relay station is calculated at the central station, and when the arrival time difference deviates from the arrival time difference within a predetermined time, the arrival time difference is deviated by the deviation. After correcting A predetermined number of position location signals are sequentially radiated from the mobile station, and an average value of arrival times measured at the central station and each relay station is calculated as an arrival time of the station. The arrival time measurement method of the position location system. 3. The arrival time measuring method of the position locating system according to claim 2, wherein the arrival time of each of the predetermined number of position locating signals at the central station and each relay station is determined in advance. Of a predetermined number of position-locating signals, or first means for applying automatic gain control to only a small number of position-locating signals predetermined from the beginning, and the rest of the predetermined number of position-locating signals. And a second means for giving the gain obtained by the automatic gain control to a large number of position locating signals of the position locating signal of the first locating signal and the locating signal of the predetermined number from the first means and the second means. An arrival time measurement method for a position location system characterized by measuring the arrival time for each. 4. The independent synchronization method for a position location system according to claim 1, wherein the timer is reset by a signal of a measurement range frequency obtained by dividing a signal of a resolution frequency generated from a highly stable oscillator, and the resolution is set. An independent position location system characterized by starting a counter-up operation with a frequency signal, stopping the timer with the position location signal, and setting the count value of the timer when the timer is stopped as the arrival time. Synchronization method. 5. The arrival time measuring method for the position location system according to claim 2, or 3, wherein a timer is used with a signal of a measurement range frequency obtained by dividing a signal of a resolution frequency generated from a highly stable oscillator. A reset is performed to start a counter-up operation with the signal of the resolution frequency, the timer is stopped with the position locating signal, and the count value of the timer when the timer is stopped is set as the arrival time. Arrival time measurement method for position location system. 6. A central station and a plurality of relay stations receive radio waves radiated from a mobile station, and the arrival time measured by each relay station is transmitted to the central station and the arrival time received by the central station and the respective arrival times. In the position locating error correction method of the position locating system that calculates the arrival time difference from the arrival time received from the relay station and uses the arrival time difference to locate the position of the mobile station by hyperbolic navigation, preset from the central station. Radiating a number of position locating signals, measuring a first arrival time at each of the receiving system and each relay station of the central station, radiating a preset number of position locating signals from the mobile station, The second arrival time is measured by each reception system and each relay station, and the correction reference value of the arrival time difference within a predetermined time is measured by using the measured first arrival time and each second arrival time. Calculated from the mobile station A position orientation error correction method for a position orientation system, characterized in that, when the arrival time difference when radiating a position orientation signal deviates from the correction reference value, the arrival time difference is corrected by the amount of the deviation. 7. The position locating error correction method for the position locating system according to claim 6, wherein the counter is reset by resetting the timer with the signal of the measuring range frequency obtained by dividing the signal of the resolution frequency generated from the highly stable oscillator. A position locating error correction method for a position locating system, wherein an up operation is started, the timer is stopped by the position locating signal, and a count value of the timer when the timer is stopped is set as an arrival time.