JP2011163833A - Satellite positioning system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a satellite positioning system at low cost, in which a mobile terminal can determine the position of a self-station with high accuracy. <P>SOLUTION: In the satellite positioning system that uses a plurality of quasi-zenith satellites 201 and 301a-301d, one of the plurality of quasi-zenith satellites positioned at a relatively high elevation angle is used as a reference station 201, at a stage where the plurality of quasi-zenith satellites have been launched toward satellite orbits in an integrated fashion to have the plurality of quasi-zenith satellites, integrally and stably flying along the satellite orbits. Remaining quasi-zenith satellites are dispersed to prescribed orbits, in the periphery of the reference station as relay stations 301a-301d. By making first positioning signals transmitted from the reference station and second positioning signals transmitted from each relay station synchronize, it is possible for the mobile terminal to determine with high accuracy the position of own station. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

In the present invention, one of a plurality of quasi-zenith satellites positioned at a relatively high elevation angle is used as a reference station, and the remaining quasi-zenith satellites arranged around the reference station are configured as relay stations. By synchronizing the first positioning signal transmitted and the second positioning signal transmitted from each relay station, a mobile terminal can realize a satellite positioning system that can measure the position of the own station with high accuracy at low cost. Is.

Conventionally, an apparatus or a system for positioning the position of a moving body using a quasi-zenith satellite has been proposed. (For example, see Patent Documents 1 to 4)
JP 2003-187395 A JP 2004-144709 A JP 2004-309364 A JP 2005-106568 A

FIG. 9 illustrates a conventional “quasi-zenith satellite vehicle-mounted device, quasi-zenith satellite, and quasi-zenith satellite system” described in Patent Document 1. In FIG. 9, as a method for exchanging various kinds of information between a mobile body and a satellite, there is a method using a synchronous orbit satellite that rotates in a high orbit in synchronization with the rotation of the earth, for example, a geostationary satellite. In this case, since the elevation angle of the satellite is as low as about 45 °, there is a problem that when various information is exchanged while moving, various information is interrupted by being blocked by buildings, topography and the like.
By using several quasi-zenith satellites located at higher elevation angles than geostationary satellites, various information exchanges are not obstructed by buildings, topography, and the like. Also, since the quasi-zenith satellite has a high elevation angle and is always above, there is no need to worry about the direction of the satellite as in the case of using a geostationary satellite. Yes.
However, there is a problem that a specific method for positioning the position of the mobile terminal using several quasi-zenith satellites is not described.

In Patent Document 2, for example, a positioning signal receiving unit that receives a positioning signal from a quasi-zenith satellite and a center data reception that receives center data including error correction data for correcting an error included in the positioning signal from a center station. And a positioning processing unit for positioning the position of the mobile terminal using the positioning signal and correcting the position of the mobile terminal using the error correction data and outputting the position data. For this reason, the position of the mobile terminal is measured with a positioning accuracy of cm class. In addition, a terminal data transmission unit that transmits the corrected position data to the center station is provided. For this reason, the center station side is supposed to collectively manage the positions of mobile terminals managed by the center station with the accuracy of cm level.
However, since there are a mixture of quasi-zenith satellite stations and non-quasi-zenith satellite stations, it is necessary to receive error correction data for correcting errors included in the positioning signal from the center station, and there is a problem that it becomes a complicated system. is there.

In Patent Document 3, positioning information is provided based on a signal transmitted from the quasi-zenith satellite 140. A plurality of reference stations 110 placed on the ground receive signals from a plurality of positioning satellites 170, 181, and 182. The communication station 130 corrects the signal received by the reference station and transmits it to the quasi-zenith satellite. The positioning information providing device 150 is supposed to transmit a signal transmitted from the quasi-zenith satellite and its own positioning information to the positioning device 160.
However, since there are a mixture of quasi-zenith satellite stations and non-quasi-zenith satellite stations, it is necessary to correct the signal received by the reference station and transmit it to the quasi-zenith satellite, resulting in a complicated system.

In Patent Document 4, the satellite direction detection unit 10 detects the direction in which one quasi-zenith satellite system 500 exists. The extraction unit 30 extracts satellite direction correspondence information corresponding to the direction detected by the satellite direction detection unit 10 from the positioning information transmitted by the one quasi-zenith satellite system 500. The positioning position approximating unit 61 obtains a user rough position from the detected direction and the extracted satellite direction correspondence information. The range equation creation / calculation unit 62a creates range equations using three pieces of positioning information transmitted from one quasi-zenith satellite system 500 at three different times, and calculates user position candidates. The comparison determination unit 62b determines the user position from among the user position candidates by comparing the user position candidate calculated by the range equation creation / calculation unit 62a with the rough user position.
However, it is necessary to detect the direction in which one quasi-zenith satellite system 500 exists, and a positioning device having a parabolic antenna is necessary, which causes a problem that the system becomes complicated.

A problem to be solved by the present invention is that one of a plurality of satellites positioned at a relatively high elevation angle is used as a reference station, and the remaining satellites arranged around the reference station are configured as relay stations, By synchronizing the positioning signal transmitted from the reference station and the positioning signal transmitted from each relay station, a satellite positioning system capable of positioning the position with high accuracy by the mobile terminal is realized at low cost.

In the satellite positioning system according to the present invention, while a plurality of satellite stations are individually launched using a rocket and a large cost is required to place them in a predetermined orbit, a reference satellite station (hereinafter referred to as a reference station) is used. A plurality of satellite stations (hereinafter referred to as "relay stations") are attached together and launched using a single rocket, and the plurality of satellites integrally fly along the satellite orbit, At least one of the plurality of satellites is used as a reference station serving as a position reference, and the remaining satellites are separated as relay stations around the reference station and arranged in a predetermined orbit so that the launch cost is reduced. The merit that can be saved significantly is obtained.
In order to disperse and arrange the plurality of relay stations, a three-dimensional relative position between the reference station and each relay station is detected with high accuracy, and the detected three-dimensional relative position is used. Thus, it is necessary to control the thruster of each relay station so that the three-dimensional relative position falls within a predetermined error.

In addition, when transmitting a radio signal including a positioning signal from the reference station and a plurality of relay stations to the ground, the positioning signal generated by the reference station and the positioning signal generated by each relay station are synchronized with high accuracy. And the frequency of the carrier signal must be the same.
Regarding the problem of detecting the three-dimensional relative position between the reference station and each relay station with high accuracy, the distance between the reference station and each relay station is measured with high accuracy, and each relay station is located. This can be solved by measuring the direction with high accuracy and detecting the three-dimensional relative position with high accuracy from the measurement results of the distance and direction.

On the other hand, regarding the problem of synchronizing the positioning signal generated at the reference station and the positioning signal generated at each relay station with high accuracy and making the frequency of the carrier signal the same, the first positioning signal transmitted from the reference station is used. A radio signal including a signal is received by the relay station, and a second positioning signal having a different spreading code is synchronized with or orthogonal to the first positioning signal while keeping the frequency of the carrier signal of the radio signal the same. This can be solved by converting to a wireless signal including the signal and transmitting it to the mobile terminal.
In addition, in order to maintain the three-dimensional relative position between the reference station and each relay station with high accuracy, fuel consumption for position control of each relay station becomes large, so that a certain amount of relative position error is allowed. However, this can be solved by including the error information of the three-dimensional relative position as data in the positioning signal transmitted from the reference station, each relay station, or both.

In the satellite positioning system of the present invention, at the stage where a plurality of satellites fly together stably along the satellite orbit, at least one of the plurality of satellites is centered on a reference station serving as a position reference, and the rest Are separated as relay stations and arranged in a predetermined orbit, positioning signals transmitted from the reference station signal, and positioning signals transmitted from a plurality of relay stations arranged around the reference station. Synchronizing with high accuracy and making the frequency of the carrier wave signal the same has the effect of realizing an inexpensive satellite positioning system that measures the position of the mobile terminal with high accuracy.

  The satellite positioning system according to the present invention is a satellite using a plurality of satellites 201, 301a to 301d as shown in FIGS. 1, 3, 5, and 1 according to the first embodiment of the present invention. In the positioning system, the plurality of satellites are integrally launched toward the satellite orbit, and the plurality of satellites integrally fly along the satellite orbit at a stable stage, at least of the plurality of satellites. One is used as a reference station 201 serving as a position reference, and the remaining satellites are arranged as relay stations 301a to 301d in a predetermined orbit around the reference station,

  The reference station 201 includes at least first position detection means, remote control means, and transmission means, and the first position detection means determines the distance from each of the relay stations 301a to 301d and each of the relays. The direction in which the station is located is measured to detect a three-dimensional relative position with respect to each relay station, and the remote control means uses the result detected by the first position detection means to use each relay station. Remote control is performed so that the three-dimensional relative position with respect to 301a to 301d is maintained within a prescribed value, and the transmission means transmits a wireless signal including a reference first positioning signal to the mobile terminal 101 and each relay station 301a. To 301d, or both, and each of the relay stations 301a to 301d has at least second position detection means, position control means, and wireless relay means,

  The second position detection unit measures a distance from the reference station 201 and a direction in which the reference station is located, detects a three-dimensional relative position with respect to the reference station, and the position control unit includes the second position detection unit. Control the position of the own station so as to keep the three-dimensional relative position from the reference station within a specified value in accordance with an instruction from the remote control means of the reference station and / or in accordance with an instruction from the remote control means of the reference station. The wireless relay means receives a wireless signal including a first positioning signal transmitted from the reference station, and synchronizes with or orthogonally intersects the first positioning signal and outputs a second positioning signal having a different spreading code. Converted to a wireless signal that is transmitted to the mobile terminal,

  The mobile terminal has at least receiving means, positioning signal reproducing means, synchronous oscillation means, phase measuring means, and position measuring means, and the receiving means transmits a radio signal transmitted from the reference station, Receiving the radio signal transmitted from each relay station, or both of them, reproducing the first positioning signal, the second positioning signal, or both of them, and the synchronous oscillating means reproduces the reproduced first signal The first positioning signal, the second positioning signal, or a clock signal that is synchronized or orthogonal with high precision to the first positioning signal, the second positioning signal, or both of them, and the phase measuring means generates the first positioning signal, 2 positioning signals, or both of them, the propagation time, the propagation phase, or both of them are measured, or the difference between them is measured. To positioning position with high accuracy.

Moreover, as shown in claim 2, some or all of the plurality of satellites 201, 301a to 301d are a plurality of quasi-zenith satellites.
Further, as shown in FIGS. 2, 5, 6, 7, 8, and 3 according to the second embodiment of the present invention, the first position detecting means 10 and the second position detecting means are used. The means 10 includes at least a transmission means 12, a reception means 13, a control means 11, an antenna switching means 14, and a plurality of directional antennas 15a to 15d, and the transmission means includes at least a starting signal, a distance. A radio signal including a measurement signal, a direction measurement signal, or a combination thereof is transmitted by periodically switching a plurality of directional antennas by the antenna switching unit and / or switching to a transmission unit in a time division manner,

  The reception means receives the wireless signal by periodically switching a plurality of directional antennas by the antenna switching means and / or switching to the reception means in a time division manner, and the control means at least the starting signal, Signal generation means for generating a distance measurement signal, direction measurement signal, or a combination thereof; signal reproduction means for reproducing the origin signal, distance measurement signal, direction measurement signal, or combination thereof; and the reproduction Synchronization detecting means for detecting the timing of the rising point, falling point, or zero crossing of the generated origin signal or distance measurement signal with high accuracy;

Synchronized oscillation means for establishing a synchronization with the origin signal or distance measurement signal in a short time at the detected timing, and generating a clock signal while maintaining the synchronization, and a phase of the reproduced distance measurement signal And a phase measurement means for measuring the phase of the direction measurement signal in real time with high accuracy, and a three-dimensional relative between the first position detection means and the second position detection stage from the measured phase. Position calculation means for calculating the position.
According to a fourth aspect of the present invention, the origin signal, the distance measurement signal, the direction measurement signal, or a combination thereof is a carrier signal, a subcarrier signal, a modulation signal, a spread spectrum code, or a combination thereof.

  According to a fifth aspect of the present invention, the radio relay unit of the relay station includes at least a reception antenna, a reception unit, a synchronous oscillation unit, a second positioning signal generation unit, an intermediate frequency amplification unit, and a transmission Means and a transmitting antenna, wherein the receiving antenna receives a radio signal transmitted from a reference station, reproduces a carrier wave signal and a first positioning signal from the radio signal received by the receiving means, and the synchronous oscillation A clock signal is generated by establishing synchronization with the first positioning signal reproduced by the means with high accuracy,

The second positioning signal generating means generates a second positioning signal synchronized with or orthogonal to the clock signal and having at least different spreading codes, and the intermediate frequency amplifying means converts the reproduced carrier signal into an intermediate frequency signal. Amplified, converted to a carrier signal having the same frequency as the original carrier signal, spread spectrum by the second positioning signal generated by the transmission means, and retransmits the radio signal spread by the transmitting antenna. Send.
In addition, as shown in claim 6, the coupling loss between the receiving antenna and the transmitting antenna is larger than the value obtained by subtracting the process gain of the spectrum spread positioning signal from the amplification factor of the intermediate frequency signal amplifying means. is required.

Further, as shown in claim 7, when the mobile terminal measures the position of its own station, the frequency of the clock signal generated by the synchronous oscillation means is variable according to the positioning range of the phase measuring means, or A high positioning accuracy is realized by selecting an optimum signal according to the positioning range of the phase measuring means from a plurality of clock signals generated by the synchronous oscillating means having different frequencies.
Further, as shown in claim 8, the positioning range of the phase measuring means is changed from a long scale to a short scale, or the positioning range of the phase measuring means is changed from a long scale to a short scale sequentially. By switching to the selected one, the position of the local station is measured with high accuracy using the optimum positioning range.

  In addition, as described in claim 9, in the signal generation means, the signal reproduction means, or both, the origin signal, distance measurement signal, or direction measurement signal is a carrier signal or subcarrier signal of a radio signal In some cases, an analog demodulator with low delay error or a high frequency is passed through a band-pass filter with low group delay distortion and delay error, or a modulated signal obtained by modulating a carrier signal or subcarrier signal of a radio signal. After being demodulated by a digital demodulator with a small delay error using this clock signal, it is reproduced through the band pass filter.

  Further, according to a tenth aspect of the present invention, the synchronous oscillating means is constituted by a counter with a set or reset or a numerically controlled oscillator driven by a phase synchronous oscillator, and the synchronous detecting means has a frequency of at least 16 MHz or more. By setting or resetting the counter or numerically controlled oscillator at the timing of the rising point, falling point, or zero crossing point of the starting point signal or distance measurement signal detected using the clock signal, the starting point signal or Synchronization with the distance measurement signal can be established in a short time, and the synchronization can be maintained for a relatively long time after the origin signal or the distance measurement signal has disappeared.

In addition, as shown in claim 11, the phase measuring means converts the signal into a digital signal using an analog-digital converter having a sampling frequency that is an integral multiple of 4 of the signal frequency to be measured and 4 bits or more. Use 0, 1, 0, -1 or 1, 1, -1, -1 as the lookup table, and 1, 0, -1, 0 or 1, -1, -1, as the Cos lookup table 1 is used to perform a product-sum operation on the converted digital signal and the lookup table.
Further, as shown in claim 12, as the frequency of the radio signal, a frequency assigned to GPS, a frequency in the vicinity thereof, a frequency defined by laws and regulations, a spreading code different between the reference station and each relay station, or a combination thereof Is assigned.

(Embodiment 1)
1, 3 and 4 are a configuration diagram and a timing chart of the satellite positioning system according to the first embodiment of the present invention. In FIG. 1, 101 is a mobile terminal, 201 is a reference station, 301a to 301d are relay stations, 1a to 1d are propagation paths of radio signals transmitted from the reference station to the relay station, and 2 and 3a to 3d are relay stations 301a to 301a. This is a propagation path of a radio signal relayed by 301d and transmitted toward the mobile terminal 101 existing on the ground 400.

  In a satellite positioning system using a plurality of satellites 201, 301a to 301d, the plurality of satellites are launched together toward a satellite orbit, and the plurality of satellites integrally fly along the satellite orbit. In this step, at least one of the plurality of satellites is used as a reference station 201 serving as a position reference, and the remaining satellites are arranged as relay stations 301a to 301d in a predetermined orbit around the reference station,

  The reference station 201 includes at least first position detection means, remote control means, and transmission means, and the first position detection means determines the distance from each of the relay stations 301a to 301d and each of the relays. The direction in which the station is located is measured to detect a three-dimensional relative position with respect to each relay station, and the remote control means uses the result detected by the first position detection means to use each relay station. Remote control is performed so that the three-dimensional relative position with respect to 301a to 301d is maintained within a prescribed value, and the transmission means transmits a wireless signal including a reference first positioning signal to the mobile terminal 101 and each relay station 301a. To 301d, or both, and at least the first positioning signal transmitted from the reference station 201 includes data on a three-dimensional relative position with each relay station,

  Each of the relay stations 301a to 301d includes at least a second position detection unit, a position control unit, and a wireless relay unit, and the second position detection unit determines the distance from the reference station 201 and the reference station. Is measured to detect a three-dimensional relative position with respect to the reference station, the position control means uses a result detected by the second position detection means, and / or is remote from the reference station. According to an instruction from the control means, the position of the own station is controlled so as to keep the three-dimensional relative position from the reference station within a specified value, and the wireless relay means outputs a first positioning signal transmitted from the reference station. Including a radio signal including the second positioning signal synchronized with or orthogonal to the first positioning signal and converted to a radio signal including a second positioning signal of a different spreading code, and transmitted to the mobile terminal,

  The mobile terminal has at least receiving means, positioning signal reproducing means, synchronous oscillation means, phase measuring means, and position measuring means, and the receiving means transmits a radio signal transmitted from the reference station, Receiving the radio signal transmitted from each relay station, or both of them, reproducing the first positioning signal, the second positioning signal, or both of them, and the synchronous oscillating means reproduces the reproduced first signal Generating a clock signal that is synchronized or orthogonal with high accuracy to one positioning signal, a second positioning signal, or both,

  The phase measuring means measures a propagation time, a propagation phase, or both of the first positioning signal, the second positioning signal, or both from the clock signal, or both of them. A difference is measured, and the positioning means measures the position of the own station from the measurement result with high accuracy, and the positioning result is obtained from data relating to a three-dimensional relative position with each of the relay stations 301a to 301d separately received. to correct.

  In FIG. 3, 400 is the ground, 301a and 301b are relay stations, 302a is a position directly below the intermediate point of the relay station, 302b is a position immediately below the relay station 301b, and 302c is a position immediately below the intermediate point. 302a to 10,000km, 303a is the distance between the relay stations, 303b is the altitude of each relay station, and 303c and 303d are the distances from 302a directly below the intermediate point to points 302b and 302c. It is assumed that the relay stations 301a and 301b are quasi-zenith satellites, the orbit of the altitude 303b is 40,000 km above the ground 400, and the interval 303a is about 24 km.

  When the mobile terminal 101 is at the point 302a, the second positioning signal included in the radio signal received from each of the relay stations 301a and 301b is in phase, but when it is at the point 302b and 302c, it is received from the relay station 301a. Therefore, the second positioning signal included in the wireless signal to be transmitted is delayed from the second positioning signal included in the wireless signal received by the relay station 301b. Here, the distance from the relay station 301a to the point 302b is 40,000,007.2m, which is 7.2m longer than the distance from the relay station 301b to the point 302b.

  If the frequency of the clock signal generated by the synchronous oscillating means of the mobile terminal 101 is 30 MHz, the positioning range is 10 m. Therefore, the phase difference ΔΦ corresponding to the distance difference of 7.2 m is ΔΦ = 360 ° × ( 7.2 m / 10 m) = 259.2 °. As the phase measurement accuracy of the phase measuring means, an average value of about ± 1 ° can be realized for 10 milliseconds, so that a moving average value of 1 second can achieve about ± 0.1 °. Since the distance 303c is 12 km, ΔL = 0.1 × (12 km / 7.2 m) /259.2°≈±64 cm. In addition to these, when positioning is performed by hyperbolic navigation using four relay stations, the positioning error can be further reduced to about one half, and a positioning error of about ± 30 cm can be realized.

Also, the distance from the relay station 301a to the point 302c is about 41,236,883m, the distance from the relay station 301b to the point 302c is about 41,231,056m, and the distance difference between them is 5,827m. Assuming that the frequency of the clock signal generated by the synchronous oscillation means of the mobile terminal 101 is 50 kHz, the positioning range is 6,000 m. Therefore, the phase difference ΔΦ corresponding to the distance difference of 5,827 m is ΔΦ = 360 °. X (5,827m / 6,000m) = 349.6 [deg.]. Since the distance 303d is 10,024 km, the positioning accuracy ΔL is ΔL = 0.1 × (10,024 km / 5,827 m) /349.6°≈±49 cm. When positioning by hyperbolic navigation, A positioning error of about ± 30 cm can be realized.

  On the other hand, in FIG. 4, 61a is a first positioning signal transmitted from the reference station 201, 61b is a first positioning signal received by the relay station 301a, and 62a is a second positioning signal retransmitted by the relay station 301a. 63a is a second positioning signal received by the mobile terminal 101, 64a is a second clock signal synchronized with the second positioning signal, 61c is a first positioning signal received by the relay station 301b, and 62b is a relay The second positioning signal retransmitted by the station 301b, 63b is the second positioning signal received by the mobile terminal 101, 64b is the first clock signal synchronized with the second positioning signal, and 65 is the first positioning signal. Phase difference between the clock signal and the second clock signal, 66a is the time axis of the reference station 201, 67a and 68a are the time axis of the relay station 301a, and 67b and 68b are relays Time axis 301b, 69a, 69b, 70a, the 70b time axis of the mobile terminal 101, 1a, 1b, 3a, is 3b is the propagation path.

Here, the first measurement signal 61b received by the relay station 301a, the second measurement signal 62a generated by the relay station 301a, and the first measurement signal 61c received by the relay station 301b and the relay station 301b. It is assumed that the second measurement signal 62b generated in step (b) is synchronized with high accuracy although the spreading code is different.
In addition, the frequency of the first clock signal and the frequency of the second clock signal are switched or selected according to the positioning range.
In addition, the header part of each spreading code sequence is common and used as a starting point of synchronization with the clock signal.

(Embodiment 2)
2, 5, 6, 7, and 8 are a configuration diagram and a timing chart of a satellite positioning system according to the second embodiment of the present invention. 2, 201 is a reference station, 301a to 301d are relay stations, 4a to 4d are radio signal propagation paths transmitted and received between the reference station and the relay station,

  The reference station 201 measures at least the distance from each of the relay stations 301a to 301d and the direction in which each relay station is located via the propagation paths 4a to 4d, and the three-dimensional relative to each of the relay stations. Remote control so that the first position detection means 10 for detecting the position and the result of detection by the first position detection means are used to maintain the three-dimensional relative position with each relay station within a specified value. Remote control means for

  Each of the relay stations 301a to 301d measures at least the distance from the reference station 201 and the direction in which the reference station 201 is located via the propagation paths 4a to 4d, and determines the three-dimensional relative position with respect to the reference station 201. Using the second position detection means 10 for detection and the result detected by the second position detection means, and in accordance with an instruction from the remote control means, the three-dimensional relative position from the reference station is within a specified value. And a position control means for controlling the position so as to be disposed in the position.

  5 and 6, 10a is a first position detection means, 10b is a second position detection means, 11 is a control means, 12 is a transmission means, 13 is a reception means, 14 is an antenna switching means, 15a to 15d is a plurality of directional antennas, 41 is a reference oscillator, 42 is a position specifying means, 43 is a phase measuring means, 44 is a distance measuring signal reproducing means, 45 is a starting signal generating means, 46 is a synchronous oscillating means, 47 is a distance measuring A signal generating means, 48 is a phase-locked oscillator, 49 is a synchronization detecting means, and 50 is a starting point signal reproducing means.

  The starting point signal generating unit 45 of the first position detecting unit 10a generates a starting point signal, and the transmitting unit 12 converts a radio signal including at least the starting point signal, a system synchronization signal, and an identification number into a burst signal. And intermittently, the antennas 15a to 15d are switched to the transmission unit 12 and periodically switched while being transmitted via the propagation paths 4a to 4d. The reception unit 13 of the second position detection unit 10b The radio signal is received via the propagation paths 4a to 4d while the antennas 15a to 15d are switched to the receiving means 13 and periodically switched.

  The starting point signal reproducing means 50 of the second position detecting means 10b reproduces the starting point signal included in the radio signal received from the first position detecting means 10a, and the synchronization detecting means 49 reproduces the reproduced starting point signal. The timing of the rising point, falling point, or zero-crossing point is detected, and the synchronous oscillation means 46 instantly establishes synchronization with the starting signal at the detected timing, and generates a clock signal while maintaining synchronization. The distance signal generator 47 generates a distance measurement signal that is synchronized with or orthogonal to the clock signal, and at least the generated distance measurement from the transmitter 12 together with a direction measurement signal generated separately from the distance measurement signal. A radio signal including the signal and the direction measurement signal is transmitted as a burst signal at time-division intervals through the antennas 15a to 15d and the propagation paths 4a to 4d. And send it via,

  The receiving means 13 of the first position detecting means 10a receives the radio signal transmitted from the second position detecting means 10b via the antennas 15a to 15d, and the distance measurement signal reproducing means 44 is The distance signal and the direction measurement signal included in the radio signal received from the second position detection unit 10b are reproduced, and the phase of the distance measurement signal is determined by the phase measurement unit 43 with reference to the origin signal generated by the own station. Separately, the phase of the direction measurement signal corresponding to the antennas 15a to 15d is measured, and the position specifying means 42 determines the phase measurement signal from the measurement result of the phase of the distance measurement signal and the phase of the direction measurement signal. While detecting the position of the second position detection means 10b,

  The synchronization detection means 49 detects the timing of the rising point, falling point, or zero crossing of the reproduced distance measurement signal, and the synchronous oscillation means 46 synchronizes with the distance measurement instantly at the detected timing. The distance signal generating means 47 generates a distance measurement signal that is synchronized with or orthogonal to the clock signal, and generates a clock signal separately from the direction signal, A radio signal including at least the generated distance measurement signal and direction measurement signal from the transmission unit 12 is transmitted as time-division intervals and burst signals via the antennas 15a to 15d and the propagation paths 4a to 4d. Send

  The receiving means 13 of the second position detecting means 10b receives the radio signal transmitted from the first position detecting means 10a via the antennas 15a to 15d, and the distance measurement signal reproducing means 44 is The distance signal and the direction measurement signal included in the radio signal received from the first position detection unit 10a are reproduced, and the received distance measurement signal is received by the phase measurement unit 43 with reference to the distance measurement signal generated by the own station. In addition, the phase of the direction measurement signal received corresponding to the antennas 15a to 15d is measured, and the position specifying means 42 determines the phase of the distance measurement signal and the phase of the direction measurement signal. From the measurement result, the three-dimensional position of the first position detecting means 10a is detected.

According to the above procedure, the positions of the other party can be detected with high accuracy on both sides of the first position detecting means 10a and the second position detecting means 10b. The other party can be remotely controlled by the means, or the position of the own station can be controlled by the position control means.
The channel quality is analyzed from the result of measuring the power of the radio signal or the signal-to-noise ratio received by the detection means 10a, 10b, and the detection result of the position is filtered, weighted, corrected, and supplemented. Alternatively, the position detection accuracy can be improved by performing a combination thereof.

Further, the origin signal, the distance measurement signal, or both of them are a carrier signal, a subcarrier signal, a modulation signal, a spread spectrum code, or a combination thereof.
Further, in the starting point signal reproducing means 50 or the distance measuring signal reproducing means 44, when the starting point signal, the distance measuring signal or the direction measuring signal is a carrier signal or subcarrier signal of a radio signal, direct group delay distortion is performed. And a delay signal using an analog demodulator with a small delay error or a high-frequency clock signal when the signal is passed through a band-pass filter with a small delay error or is a modulated signal obtained by modulating a carrier signal or subcarrier signal of a radio signal. The position identification accuracy can be improved by demodulating with a digital demodulator with a small amount of data and reproducing through the band-pass filter.

  The synchronous oscillating means 46 is constituted by a counter with a set or reset or a numerically controlled oscillator driven by a phase-locked oscillator 48, and a rising point, a falling point of the reproduced starting point signal or distance measuring signal, or The zero crossing timing is detected by the synchronization detecting means 49 using a sampling frequency of at least 16 MHz, and the counter signal or the numerically controlled oscillator is set or reset at the detected timing to thereby measure the starting point signal or the distance. Synchronization with the signal can be established in a short time, and the synchronization can be maintained for a relatively long time even after the origin signal or the distance measurement signal has disappeared.

  The phase measuring means converts the signal into a digital signal using an analog-to-digital converter having a sampling frequency of 4 times or more of the signal frequency to be measured and 4 bits or more, and 0, 1, 0 as a Sin lookup table , −1, or 1, 1, −1, −1, and 1, 0, −1, 0 or 1, −1, −1, 1 as the Cos lookup table, and the converted digital By performing a product-sum operation between the signal and the lookup table, the phase can be measured with high accuracy and in real time.

  FIG. 7 is a configuration diagram of radio signals used in the satellite positioning system of the present invention. 71a to 71f are system synchronization signals, 72a to 72f are MAC layers, 73a to 73f are origin signals or distance measurement signals, and 74 is a reference station. The time axis of the radio signal transmitted from the relay station 74 is the time axis of the radio signal transmitted from the relay station. A portion surrounded by a thick line indicates what is transmitted, and a thin line portion indicates what is received.

The system synchronization signals 71a to 71f are unique words of a plurality of bits, and the control timing between the reference station and the relay station can be adjusted with an accuracy of about ± 100 nanoseconds. Is detected, the distance measurement error increases to several tens of meters.
The MAC layers 72a to 72f include at least a code length, an identification number, a partner number, a broadcast signal, an error correction code, or a combination thereof, and are generated as a set with the system synchronization signals 71a to 71f. .

  Initially, the system synchronization signal 71a, the MAC layer 72a, and the origin signal 73a are transmitted from the reference station, and after the time division interval, the system synchronization signal 71d, the MAC layer 72d, and the first distance origin from the relay station. The signal 73d is transmitted, and subsequently, after the time division interval, the system synchronization signal 71e, the MAC layer 72e, and the second distance start signal 73e are transmitted from the reference station.

  Here, if the durations of the MAC layers 72a to 72f are about 0.5 ms to 1 ms, respectively, and the durations of the origin signal or distance measurement signals 73a to 73f are about 1 ms, respectively, the total is about 1.5 ms to 2 ms. Therefore, if the frequency stability of the reference oscillator is set to about ± 0.25 ppm, the synchronization holding error is ± 2 ns, so that synchronization can be maintained with high accuracy.

  FIG. 8 is a timing chart of a radio signal according to the second embodiment of the present invention, in which 81a is a start signal generated by the first position detecting means 10a, and 81b is received by the second position detecting means 10b. 82a is a first distance measurement signal generated by the second position detection means 10b, 82b is a first distance measurement signal reproduced by the first position detection means 10a, and 83a is a first position. The second distance measurement signal generated by the detection means 10b, 83b is the second distance measurement signal received by the second position detection means 10b, 4aa and 4ac are the second positions from the first position detection means 10a. Radio signal propagation path toward the detection means 10b, 4ab is a radio signal propagation path from the first position detection means 10a to the second position detection means 10b,

  84a is a phase difference between the phase of the origin signal generated by the first position detection means 10a and the reproduced first distance measurement signal, and 84b is a first distance measurement generated by the second position detection means 10b. The phase difference between the signal and the reproduced second distance measurement signal, 85a and 85b are time division intervals, 86a to 86c are time axes of the first position detecting means 10a, and 87a to 87c are second position detecting means. It is a time axis of 10b.

Assuming that the starting signal 81a generated by the first position detecting means 10a and transmitted from the reference station 201 is ASin (2πf1t), the starting signal 81a propagates through the propagation path 4aa of the distance L1 (m), and the relay station When the signal is received by 301a and reproduced as the starting signal 81b by the second position detecting means 10b, the phase changes to BSin {2πf1t + (2πL1 (f1 / C)}.
When the distance measurement signal 82a synchronized with the reproduced starting point signal 81b and the synchronization establishment error is zero, the generated distance measurement signal 82a is also expressed by BSin {2πf1t + (2πL1 (f1 / C)}. .

  After the time division interval 85a, the generated distance measurement signal 82a is transmitted from the relay station 301a, propagates through the propagation path 4ab of the distance L1 (m), and is transmitted by the first position detection means 10a of the reference station. The reproduced distance measurement signal 82b is represented by CSin {2πf1t + (2L1) (2πf1) / C)}. Here, C is the speed of light.

When the phase of the distance measurement signal 75a reproduced by the first position detecting means 10a is measured using a clock signal synchronized with the starting point signal generated by the first position detecting means 10a, the phase difference 84a is measured. Since ΔΦ = {4π (2L1) (f1 / C)}, the distance L1 (m) can be calculated from L1 = CΔΦ / 4πf1.
Similarly, the distance L1 (m) can be calculated from the phase difference 84b also on the relay station 301a side.

  In the above description, a case where a single frequency distance measurement signal is retransmitted as the distance measurement signal transmitted from the relay station has been described. However, when a single frequency distance measurement signal is used, ΔΦ changes. Must be limited to 0 <ΔΦ <2π, and using a plurality of distance measurement signals synchronized with or orthogonal to the reproduced starting signal 81b and having at least different frequencies, the position can be detected in a plurality of positioning ranges. Therefore, by adjusting the optimum positioning range to the position to be detected, the merit that precise position detection is possible can be obtained.

Further, the distance measurement signal transmitted from the relay station can be transmitted simultaneously by the frequency division multiplexing method.
In addition, by connecting a plurality of antennas to one or both of the relay station and the relay station, transmitting and receiving distance measurement signals while periodically switching, and measuring a phase difference corresponding to the plurality of antennas By reducing, correcting, or complementing a detection error caused by multipath generated in a radio signal propagation path, a highly reliable and highly accurate position detection system can be realized.

Moreover, an ultrasonic signal, a high frequency signal, or an optical signal can be used as the wireless signal. In the case of an ultrasonic signal or an optical signal, a transducer is used instead of an antenna.
The same effect can be obtained by using a frequency division simultaneous transmission / reception (FDD) method as a radio signal instead of the time division simultaneous transmission / reception (TDD) method.
In addition, as a frequency of the radio signal, a frequency assigned to GPS, a frequency in the vicinity thereof, a frequency stipulated by laws and regulations, a spreading code different between the reference station and each relay station, or a frequency of a combination thereof can be assigned. , GPS can be complemented.

According to the present invention, a plurality of quasi-zenith satellites can be launched in an economical manner, and a highly accurate satellite positioning system can be realized, so that the current GPS can be supplemented.
Note that the satellite positioning technology of the present invention is a basic technology and can be expected to be used in many fields other than the above.

Configuration diagram of the satellite positioning system according to the first embodiment of the present invention The block diagram of the satellite positioning system by the 2nd Embodiment of this invention Another block diagram of the satellite positioning system according to the first embodiment of the present invention Positioning signal timing chart according to the first embodiment of the present invention The block diagram of the position detection means by the 2nd Embodiment of this invention The block diagram of the control means by the 2nd Embodiment of this invention Configuration diagram of radio signal according to second embodiment of the present invention Radio signal timing chart according to the second embodiment of the present invention Configuration diagram showing a conventional example

1a to 1d Radio positioning signal propagation path 2, 3a to 3d between the reference station and the relay station Radio signal propagation path 4a to 4d between the mobile terminal and the reference station, and the mobile terminal and the relay station Between the reference station and the relay station Position detection signal propagation path 100 Satellite positioning system 101 Mobile terminal 200 Relay station position control system 201 Reference stations 301a to 301d Relay stations 10a and 10b First and second position detection means 11 Control means 12 Transmission means 13 Reception means 14 Antenna switching means 15a to 15d Multiple antennas

Claims (12)

In a satellite positioning system for positioning a mobile terminal with high accuracy using multiple satellites,
The plurality of satellites are integrally launched into a satellite orbit, and at least one of the plurality of satellites is positioned when the plurality of satellites integrally fly along the satellite orbit stably. The reference station serving as the reference of the reference, and the remaining satellites as relay stations arranged in a predetermined orbit around the reference station,
The reference station has at least first position detection means, remote control means, and transmission means,
The first position detecting means measures a distance from each relay station and a direction in which each relay station is located, and detects a relative position to each relay station;
The remote control means is remotely controlled so as to maintain the relative position with each relay station within a specified value using the result detected by the first position detection means,
The transmission means transmits a radio signal including a first positioning signal as a reference to the mobile terminal, each relay station, or both,
Each relay station has at least second position detection means, position control means, and wireless relay means,
The second position detecting means measures a distance from the reference station and a direction in which the reference station is located, and detects a relative position with respect to the reference station;
The position control means uses the result detected by the second position detection means and / or keeps the relative position from the reference station within a specified value according to an instruction from the remote control means of the reference station. Control the position of
The wireless relay means receives a wireless signal including a first positioning signal transmitted from the reference station, and synchronizes with or orthogonally intersects the first positioning signal and outputs a second positioning signal having a different spreading code. Converted to a wireless signal that is transmitted to the mobile terminal,
The mobile terminal has at least receiving means, positioning signal reproducing means, synchronous oscillation means, phase measuring means, and position measuring means,
The receiving means receives a radio signal transmitted from the reference station, a radio signal transmitted from each relay station, or both, and receives the first positioning signal, the second positioning signal, or these Play both
The synchronous oscillation means generates a clock signal that is synchronized with or orthogonal to the reproduced first positioning signal, the second positioning signal, or both of them with high accuracy;
The phase measuring means measures a propagation time, a propagation phase, or both of the first positioning signal, the second positioning signal, or both from the clock signal, or both of them. Measure the difference
The satellite positioning system, wherein the position measuring means measures the position of the own station with high accuracy from the measurement result.
The satellite positioning system according to claim 1, wherein a part or all of the plurality of satellites are quasi-zenith satellites.
The first position detection means and the second position detection means include at least a transmission means, a reception means, a control means, an antenna switching means, and a plurality of directional antennas,
The transmitting unit periodically switches a plurality of directional antennas by the antenna switching unit and / or transmits to the transmitting unit a radio signal including at least a starting point signal, a distance measurement signal, a direction measurement signal, or a combination thereof. Switch by split and send,
The receiving means receives the radio signal by periodically switching a plurality of directional antennas by the antenna switching means and / or switching to the receiving means in a time division manner,
The control means includes at least signal generation means for generating the origin signal, distance measurement signal, direction measurement signal, or a combination thereof; and the origin signal, distance measurement signal, direction measurement signal, or a combination thereof. Signal reproducing means for reproducing, synchronization detecting means for detecting the timing of the rising point, falling point, or zero crossing of the reproduced starting point signal or distance measurement signal with high accuracy, and the detected timing The synchronous oscillation means for establishing the synchronization with the origin signal or the distance measurement signal in a short time and generating the clock signal while maintaining the synchronization, and the phase and direction measurement signal of the reproduced distance measurement signal A phase measuring means for measuring the phase in real time with high accuracy; and from the measured phase, the first position detecting means and the second Satellite positioning system of claim 1 wherein which comprises a position calculating means for calculating the relative position between the location detection stage.
4. The origin signal, distance measurement signal, direction measurement signal, or a combination thereof is a carrier signal, a subcarrier signal, a modulation signal, a spread spectrum code, or a combination thereof. Satellite positioning system.
The radio relay unit of the relay station has at least a reception antenna, a reception unit, a synchronous oscillation unit, a second positioning signal generation unit, an intermediate frequency amplification unit, a transmission unit, and a transmission antenna.
The reception antenna receives a radio signal transmitted from a reference station, reproduces a carrier wave signal and a first positioning signal from the radio signal received by the reception means, and a first positioning signal reproduced by the synchronous oscillation means; The synchronization is established with high accuracy to generate a clock signal, and the second positioning signal generating means generates a second positioning signal synchronized with or orthogonal to the clock signal and having at least a different spreading code, and the intermediate frequency amplifying means The carrier signal reproduced by the transmitter is converted to an intermediate frequency signal, amplified, converted to a carrier signal having the same frequency as the original carrier signal, and spread by the second positioning signal generated by the transmitting means. The satellite positioning system according to claim 1, wherein the transmitting antenna retransmits a radio signal subjected to spectrum spread.
6. The coupling loss between the receiving antenna and the transmitting antenna is larger than a value obtained by subtracting a process gain of a spectrum spread positioning signal from an amplification degree of the intermediate frequency signal amplifying means. The satellite positioning system described.
When the mobile terminal measures the position of its own station, the frequency of the clock signal generated by the synchronous oscillating means is variable according to the positioning range of the phase measuring means, or the frequency generated by the synchronous oscillating means is different. 2. The satellite positioning system according to claim 1, wherein a high positioning accuracy is realized by selecting an optimum signal from a plurality of clock signals according to a positioning range of the phase measuring means.
By changing the positioning range of the phase measurement means from a long scale to a short scale sequentially, or by switching and selecting the positioning range of the phase measurement means from a long scale to a short scale in order 8. The satellite positioning system according to claim 7, wherein the position of the local station is measured with high accuracy using the positioning range.
In the signal generation means, the signal reproduction means, or both, when the origin signal, distance measurement signal, or direction measurement signal is a carrier signal or subcarrier signal of a radio signal, direct group delay distortion and delay Low-error delay using an analog demodulator with low delay error or a high-frequency clock signal when the signal is passed through a band-pass filter with low error or is a modulated signal obtained by modulating a carrier signal or subcarrier signal of a radio signal 6. The satellite positioning system according to claim 1, wherein the satellite positioning system reproduces through the band pass filter after demodulating by a digital demodulator.
The synchronous oscillating means is constituted by a counter with a set or reset or a numerically controlled oscillator driven by a phase synchronous vibrator, and detected by the synchronous detection means using a clock signal having a frequency of at least 16 MHz, By setting or resetting the counter or numerically controlled oscillator at the timing of the rising point, falling point, or zero-crossing point of the origin signal or distance measurement signal, synchronization with the origin signal or distance measurement signal is established in a short time 6. The satellite according to claim 1, 3 or 5, wherein the synchronization can be maintained for a relatively long time after the origin signal or the distance measurement signal disappears. Positioning system.
The phase measuring means converts the signal into a digital signal using an analog-to-digital converter having a sampling frequency that is an integer multiple of 4 of the signal frequency to be measured and 4 bits or more, and uses 0, 1, 0, -1, or 1, 1, -1, -1 and 1, 0, -1, 0 or 1, -1, -1, 1 as the Cos lookup table, and the converted digital signal 6. The satellite positioning system according to any one of claims 1, 3, and 5, wherein a sum-of-products operation is performed with a lookup table.
  The frequency of the radio signal is assigned to a frequency assigned to GPS, a frequency in the vicinity thereof, a frequency determined by laws and regulations, a spreading code different between the reference station and each relay station, or a combination thereof. The satellite positioning system described in item 1.

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