JPS6256470B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radio distance measuring method.

The conventional method of measuring radio distance is approximately 10Kc.
A method based on the hyperbolic method using the Omega system using the VLF band frequency, the Loran system using the LF band frequency of about 100Kc, or the Detsuka system using the HF band frequency of about 2MHz, and the method based on the hyperbolic method using the UHF band frequency There are methods such as a phase comparison method using a microwave band frequency and a pulse propagation time method.

The radio distance measurement method using the hyperbolic method has the following advantages and disadvantages.

〔Strong Points〕

(1) In principle, there are no restrictions on the mobile stations that perform measurements.

(2) Non-line-of-sight propagation is possible.

[Disadvantages] (1) Because it is a terrestrial wave, there is a difference in radio wave propagation speed between land and sea.

(2) It is susceptible to external radio interference such as static electricity and lightning.

(3) Since the position is determined by counting the number of lanes from a certain point using equal phase lines (called lanes) that repeat every λ/2, the position cannot be directly indicated.

(4) The Omega system and the Loran system require an atomic clock or an ultra-high precision crystal oscillator to align the phase of the distance measurement frequency signal that serves as the standard for distance measurement, making the equipment extremely expensive.

(5) In the Detsuka system, in order to align the phase of the frequency signal for distance measurement, it is necessary to return to the fixed point and perform fixed point alignment, which is troublesome and results in a lot of time loss.

(6) The conventional hyperbolic method has the best measurement accuracy, but it is ±100 m for civilian systems and ±10 m for military systems, and it is difficult to improve accuracy beyond this, making it unsuitable for surveying. It is.

The radio wave distance measuring method using the phase comparison method and the pulse propagation time method has the following advantages and disadvantages.

〔Strong Points〕

(1) Because space waves are used, radio wave propagation speed is unrelated to land and sea.

(2) Not affected by static electricity, lightning, etc.

(3) The distance between a fixed station and a mobile station can be directly measured.

[Disadvantages]

(1) Generally, only one mobile station can be installed per fixed station. Even if time division or the like is performed, only a very limited number of mobile stations are allowed.

(2) Only line-of-sight propagation can be used.

As described above, the conventional methods have opposite advantages and disadvantages, and therefore they are currently used depending on the measurement accuracy. In other words, (a) if the distance is within 100km and an error of ±1m is required, use the phase comparison method, (b) if the distance is within 80km and an error of ±5m is required, use the pulse propagation measurement method, and (c) if the distance is within 200km or less, use the pulse propagation measurement method.
The hyperbolic method is used when an error within ±10 mm is required within 300 km.

With recent marine development and the expansion of fishing rights over 200 miles of sea, not only the preparation of detailed nautical charts is of course necessary, but the confirmation of maritime locations for purposes such as construction of marine airports is becoming an increasingly urgent need.
Unlike terrestrial development, ocean development is just beginning and requires a huge amount of surveying, and moreover, it requires short-term work.
In particular, offshore development and offshore structure work requires a large number of work vessels to work at predetermined locations.

For this reason, there is a desire in the industry for a radio distance measuring method that combines the advantages of each of the conventional methods, that is, that can measure the positions of a large number of work vessels and that can also measure with high accuracy. Conventionally, it has been difficult to satisfy the above requirements because only a certain bandwidth of a certain frequency is allowed for position measurement.

An object of the present invention is to provide a radio distance measuring method that can measure the position of a mobile station even if the frequency bandwidth is limited, without theoretically limiting the number of mobile stations. .

Another object of the present invention is to provide a radio distance measuring method that can precisely align the phase of a frequency signal for distance measurement, which is a reference for distance measurement even with the hyperbolic method, without using extremely expensive equipment such as an atomic clock. It's about doing.

Another object of the present invention is to provide a radio wave distance measuring method that does not require counting the number of lanes from a fixed point each time using the hyperbolic method and can measure the position of a mobile station with high accuracy.

Another object of the present invention is to provide a radio wave distance measuring method that can measure the position of a mobile station without installing a computer in the mobile station.

Hereinafter, specific examples of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the present invention requires three fixed stations S1, S2, and S3. In principle, there is no limit to the number of mobile stations M for this purpose. Each fixed station S1, S2, S3 is installed at an appropriate location on the sea or land on the earth. In such a case, fixed station S
The distances between fixed stations S1 and S2 and between fixed stations S1 and S3 are constant, and can be measured in advance. In this state, when radio waves are emitted with the same phase from the fixed stations S1 and S2 and the fixed stations S1 and S3, a hyperbolic line of equal phase is generated every λ/2 as shown in the figure. Once the frequency is determined, the number of isophase lines and their respective positions are uniquely determined on the nautical chart or map. In this case, equiphase lines with a phase difference of zero are generated linearly on the bisector of the line connecting fixed stations S1 and S2 and between fixed stations S1 and S3.

When the fixed stations S1 and S2 and the fixed stations S1 and S3 emit radio waves with the same phase, at the mobile station M, which is the receiving point, the phase of each radio wave from the fixed stations S1 and S2 at the position of the mobile station M is φ ₁ and φ ₂ can be measured, and therefore their phase difference (φ ₁ - φ ₂ ) can be measured, and similarly, the phases φ ₁ and φ ₃ of each radio wave from the fixed stations S1 and S3 at the position of the mobile station M can be measured. can be measured, and therefore its phase difference (φ ₁ −φ ₃ ) can be measured. Therefore, equiphase lines of these phase differences (φ ₁ −φ ₂ ) and phase differences (φ ₁ −φ ₃ ) can be drawn.
The number changes depending on the frequency. The mobile station M is located at any position on the equiphase line AB due to the phase difference (φ ₁ - _{φ 2} ), and at any position on the equiphase line CD due to the phase difference (φ ₁ - φ ₃ ). be. Therefore, the position of the mobile station M is the position where both conditions can be satisfied, that is, the position of the intersection of both equiphase lines AB and CD. Its position is fixed station S1, S2
By using a microcomputer or the like to calculate the equation of the equal phase line defined by the mobile station M, and the equation of the equal phase line defined by the fixed stations S1, S3 and the mobile station M, it is possible to calculate specific numerical values.
In this case, there are multiple intersection positions, but the polarity of the phase difference (φ ₁ −φ ₂ ) and the phase difference (φ ₁ −φ ₂ )
If the polarity of is also taken into consideration, there is only one value that satisfies these conditions, and the position of the mobile station M can be specified. For example, centering on the central equiphase line EF between fixed stations S1 and S2, the right side in the drawing is a region where the phase difference (φ ₁ −φ ₂ ) is positive, and the left side is a region where the phase difference is negative, Also, centering on the equiphase line IJ at the center between fixed stations S1 and S3, the upper side in the drawing is an area where the phase difference (φ ₁ - φ ₃ ) is positive, and the lower side is an area where the phase difference is negative. For example, the position of mobile station M in the drawing is (φ ₁ −φ
The position of the intersection in the region where ₂ ) is positive and (φ ₁ -φ ₃ ) is negative, that is, the intersection on the right side of the broken line divided by I-K-F is the location of mobile station M.

Generally, equiphase lines repeat every λ/2, so it is not possible to determine which of equiphase lines EF, AB, or GH the mobile station M exists on. To solve this problem, the present invention uses VHF, UHF, microwave, or millimeter waves, which are radio waves that propagate in a straight line, as a carrier wave, and modulates this carrier wave with a plurality of distance measurement frequency signals having different frequencies. Distance is measured using modulated waves. The frequency for distance measurement is
For example, three waves are used to perform coarse, medium, and fine measurements. Once the frequency for accurate distance measurement is determined, the frequencies of these three waves are determined to be 1/10 and 1/100 of that frequency. The frequency for accurate distance measurement is determined depending on the measurement accuracy, and is, for example, 1.5MHz.

The measurement begins with a frequency signal for coarse distance measurement. Since this frequency is low, the number of equiphase lines is 1
Since there is only one line between a pair of fixed stations, and the frequency is selected so that this is the case, it is possible to know which equiphase line the mobile station M is located on without counting. By knowing at what phase position the mobile station M is located from the equiphase line, the approximate position of the mobile station M can be determined. Next, increase the number of equal phase lines between fixed stations using the frequency signal for distance measurement,
A similar measurement is performed with the interval between the equal phase lines narrowed to increase the measurement accuracy and to know the position of the mobile station M in more detail. In this case, even if the number of equiphase lines increases, the approximate position of the mobile station M is known by rough distance measurement, so you can determine which equiphase line the mobile station M is on by calculating the number of equiphase lines. It can be determined without counting. Finally, how to increase the measurement accuracy by increasing the number of equal-phase lines between fixed stations using the frequency signal for accurate distance measurement, and performing similar measurements with narrower intervals between the equal-phase lines. , the location of mobile station M is known in detail. In this case, no matter when the number of equiphase lines increases, the mobile station M
Since the location of mobile station M is known in more detail,
It is possible to determine on which equiphase line the is on without counting the number of equiphase lines.

Prior to such measurements, in the present invention, the fixed station S
It is necessary to phase-align the distance measurement frequency signals between fixed stations S1 and S2 and between fixed stations S1 and S3. Therefore, in the present invention, a frequency signal for accurate distance measurement is used as a phase matching signal and is sent in advance from one fixed station to another fixed station to perform phase matching between the fixed stations. The phase matching signal is sent out as a modulated signal by modulating a carrier wave at one fixed station S1. Therefore, in the fixed station S1, it is necessary to modulate two signals: the distance measurement frequency signal and the phase matching signal. Therefore, the frequency signal for distance measurement is FM modulated (frequency modulation)
Alternatively, phase modulation is performed, and the phase matching signal is subjected to AM modulation (amplitude modulation) having orthogonal characteristics to the modulation method. Since the present invention uses VHF, UHF, microwave, or millimeter waves as carrier waves, such multiple modulation can be performed without any problem. Also,
Even in multiple modulation, the modulation methods have mutually orthogonal characteristics
Since it uses FM modulation (or phase modulation) and AM modulation, the distance measurement frequency signal and the phase matching signal do not interfere with each other.

Next, the configuration of the equipment at each station that implements the method of the present invention will be explained with reference to FIGS. 2 to 4.

FIG. 2 shows an example of the configuration of the fixed station S1. In the figure, 1 is a carrier wave generator, and 2 is a carrier wave generator.
FM modulator, 3 is an AM modulator, 4 is a frequency signal generator for precise distance measurement, 5 is a frequency signal generator for intermediate distance measurement, 6 is a frequency signal generator for rough distance measurement, 7
is a circulator, 8 is an antenna, 9 is a mixer, 10 is an intermediate frequency amplifier, 11 is an AM demodulator,
12 is a filter amplifier, and 13 is a signal processing and control unit.

FIG. 3 shows an example of the configuration of the fixed station S2. In the figure, 14 is an antenna, 15 is a circulator, 16 is a mixer, 17 is an intermediate frequency amplifier, 18 is an AM demodulator, 19 is a phase compensator,
20 is a phase comparator, 21 is a voltage controlled oscillator, 22
23 is a frequency signal generator for intermediate distance measurement, 24 is a frequency signal generator for rough distance measurement, 25 is a carrier wave generator, and 26 is an FM modulator.

FIG. 4 shows an example of the configuration of the mobile station M. In the figure, 27 is an antenna, 28 is a circulator, 29, 30, 31 are RF filters, 32, 33, 34 are mixers, 35, 36,
37 is an intermediate frequency amplifier, 38, 39 are phase compensators, 40, 41, 42 are FM demodulators, 43a, 4
3b, 43c, 44a, 44b, 44c, 45
a, 45b, 45c are signal separation filters, 4
6, 47, 48, 49, 50, 51 are phase comparators, 52 is a signal processing and control unit, and 53 is a phase comparator.
54 is a carrier wave generator, and 55 is an AM modulator.

Next, a method of measuring radio wave distance according to the present invention using the above-mentioned device will be specifically explained. The carrier wave generator 1 of the fixed station S1 generates a carrier wave CW1 with a frequency ω _O1 . The frequency signal generator 4 for accurate distance measurement generates the frequency signal MS1 for accurate distance measurement with frequency ω _n1 and the phase matching signal FS1, and the frequency signal generator 5 for intermediate distance measurement divides the frequency ω _n1 into 1/10. Frequency signal MS for distance measurement with frequency ω _n2 (<ω _n1 )
The frequency signal generator 6 for coarse distance measurement divides the frequency ω _n1 to 1/100 to generate the frequency ω _n3 (<
A frequency signal MS3 for rough distance measurement of ω _n2 ) is generated. Therefore, fixed station S1 transmits carrier wave CW1.
Frequency signal for accurate distance measurement in FM modulator 2
MS1 is FM-modulated with a frequency signal for intermediate distance measurement MS2 and a frequency signal for rough distance measurement MS3 to obtain a modulated wave for distance measurement MMW1, and an AM modulator 3 converts the carrier wave CW1 into a phase matching signal FS of frequency ω _n1 .
AM modulated by 1 and modulated wave MFW for phase matching
1 is obtained, and these are sent to the fixed station S2 and the mobile station M via the circulator 7 and the antenna 8.

At the fixed station S2, the antenna 14 receives the transmitted radio wave from the fixed station S1, and applies it to the mixer 16 via the circulator 15. In the mixer 16, the received wave is converted to a frequency ω given from the carrier wave generator 25.
Mix with the carrier wave CW2 of _O2 to obtain an intermediate frequency signal,
This is amplified by an intermediate frequency amplifier 17, and then AM
A demodulator 18 performs AM demodulation to extract a phase matching signal FS1, which is applied to a phase comparator 20 via a phase compensator 19. The phase comparator 20 compares the phase of the frequency ω _n1 of the phase matching signal FS1 with the distance precision measurement frequency signal MS2' of the frequency ω _n1 from the voltage controlled oscillator 21, and locks the phase so that the phase difference becomes zero. A circuit 22 performs phase matching of the distance precision measurement frequency signal MS1' of the voltage controlled oscillator 21 to match the phases. The phase-aligned frequency signal MS1' for accurate distance measurement is given to the frequency signal generator 23 for intermediate distance measurement, and is divided into 1/10 to obtain the frequency ω _n2.
The intermediate distance measurement frequency signal MS2' is obtained, and it is supplied to the coarse distance measurement frequency signal generator 24 to convert it to 1/
The frequency is divided by 100 to obtain a frequency signal MS3' for coarse distance measurement having a frequency ω _n3 . These signals MS1', MS2',
The MS 3' performs FM modulation on the frequency ω _O2 carrier wave CW2 in the FM modulator 26 to obtain a distance measuring modulated wave MMW2, which is sent to the mobile station M from the antenna 14 via the circulator 15.

In this case, if the initial phase of the frequency signal for coarse, medium, and fine distance measurements at the fixed station S1 is φ ₁ , then the phase when it reaches the fixed station S2 is φ ₁ +L ₁ /c. Here, L ₁ is the distance between fixed stations S1 and S2,
c is the speed of light. Since L ₁ is constant, L ₁ /c is constant. Furthermore, the delay time due to the electric circuits within the fixed stations S1 and S2 is also constant. Including these,
By correcting the phase in advance with the phase compensator 19, the phase of the distance precision measurement frequency signal MS1' output from the voltage controlled oscillator 21 becomes _φ1 .

Although fixed station S3 is not shown, it has the same configuration as fixed station S2, and performs phase matching in the same manner using radio waves sent from fixed station _S1 . A frequency signal for measurement MS1'', a frequency signal for intermediate distance measurement MS2'' of frequency ω _n2 , and a frequency signal for rough distance measurement MS3'' of frequency ω _n3 are created, and these are used to create a carrier wave of frequency ω _O3 .
The CW3 is FM-modulated to obtain a distance measuring modulated wave MMW3, which is sent to the mobile station M.

However, fixed stations S1, S2, and S3 are not always within line of sight. At that time, as shown in Figure 1, relay stations R are installed at points where they can see each other, and S
It is relayed as 1→R→S2. L ₁ /
Instead of c, L' ₁ /c (L' ₁ is fixed station S1 - relay station R
- total distance between fixed stations S2), and the fact that it is a fixed value does not change.

Mobile station M receives radio waves from fixed stations S1, S2, and S3 using antenna 27, and transmits them to circulator 2.
The RF filter 29 takes out the radio waves from the fixed station S1 and gives them to the mixer 32, and the RF filter 30 takes out the radio waves from the fixed station S2 and gives them to the mixer 33. The RF filter 31 extracts the radio waves from the fixed station S3 and supplies them to the mixer 34. Each mixer 32, 33, 34 receives an input radio wave and a carrier wave of frequency ω _O4 from the carrier wave generator 54.
Mixing with CW4 is performed to create respective intermediate frequency signals, which are then sent to corresponding intermediate frequency amplifiers 35,
Amplify at 36 and 37. Next, in the phase compensator 38, the fixed station S1 connected to the RF filter 29
The phase difference between the circuit that processes the signal of the fixed station S2 connected to the RF filter 30 and the circuit that processes the signal of the fixed station S2 is compensated for. Moreover, in the phase compensator 39,
The phase difference between the circuit that processes the signal of the fixed station S1 connected to the RF filter 29 and the circuit that processes the signal of the fixed station S3 connected to the RF filter 31 is compensated. Corresponding to each amplified intermediate frequency signal
FM demodulators 40, 41, and 42 respectively.
Demodulates FM. From the FM demodulator 40, the fixed station S1
Extract the frequency signals MS1, MS2, and MS3 for fine, medium, and coarse distance measurements sent from. From the FM demodulator 41, the distance accuracy sent from the fixed station S2,
Frequency signals for medium and coarse measurements MS1', MS2', MS
Take out 3'. From the FM demodulator 42, the fixed station S
The frequency signals MS1'', MS2'', and MS3'' for fine, medium, and coarse distance measurements sent from 3 are taken out.

The output signal of the FM demodulator 40 is separated into a frequency signal MS1 for accurate distance measurement, a frequency signal MS2 for intermediate distance measurement, and a frequency signal MS3 for coarse distance measurement by three signal separation filters 43a, 43b, and 43c. MS1 is applied to phase comparators 46 and 49, signal MS2 is applied to phase comparators 47 and 50, and signal MS3 is applied to phase comparators 48 and 51.

Similarly, the output signal of the FM demodulator 41 is divided into three signal separation filters 44a, 44b, and 44c into a frequency signal MS1' for accurate distance measurement, a frequency signal MS2' for medium distance measurement, and a frequency signal MS for coarse distance measurement.
3', signal MS1' is applied to phase comparator 46, signal MS2' is applied to phase comparator 47, and signal MS3' is applied to phase comparator 48.

The output signal of the FM demodulator 42 is similarly divided into three signal separation filters 45a, 45b, and 45c into a frequency signal MS1'' for precise distance measurement, a frequency signal MS2'' for intermediate distance measurement, and a frequency signal MS for rough distance measurement.
The signal MS1'' is applied to a phase comparator 49, the signal MS2'' is applied to a phase comparator 50, and the signal MS3'' is applied to a phase comparator 51.

Phase comparators 46, 47, 48 are connected to fixed stations S1 and S.
The phases of the distance measuring frequency signals sent from No. 2 with matched phases are compared at each of the fine, medium, and coarse frequencies. The initial phase of each distance measurement frequency signal is φ
₁ , the wavelength is λ, and the distance between fixed station S1 and mobile station M is
l ₁ , the distance between fixed station S2 and mobile station M is l ₂ , and the distance between fixed station S3 and mobile station M is l ₃ , the outputs of phase comparators 46, 47, and 48 are (φ ₁ +l ₁ / λ)−(φ
₁ +l ₂ /λ)=1/λ(l ₁ −l ₂ ).

Phase comparators 49, 50, 51 are connected to fixed stations S1 and S.
The phases of the distance measuring frequency signals sent from No. 3 with their phases matched are compared at each of the fine, medium, and coarse frequencies. The initial phase of each distance measurement frequency signal is φ
₂ , the output of the phase comparators 49, 50, 51 is (φ ₂ +l ₁ /λ)−(φ ₂ +l ₃ /λ)=1/λ(
l ₁ − l ₃ ).

These two pieces of phase information are input into the signal processing and control unit 52, and from these two pieces of phase information, the intersection point of the equiphase hyperbola is determined, and the position is determined. In this case, first, the approximate position of the mobile station M is obtained by finding the intersection point using the phase information obtained from the measurement using the frequency signal for coarse distance measurement, and then the phase information obtained from the measurement using the frequency signal for intermediate distance measurement. The intersection point is determined using the phase information obtained from the measurement using the distance measurement frequency signal, and the accuracy of reading the intersection point is further improved. In this way, the position can always be determined without counting the number of lanes from a certain fixed point as in the conventional hyperbolic method.

A system implementing the method of the present invention is a receiving system, and in principle it is possible to determine the position of an infinite number of mobile stations on each mobile station side.

The mobile station M can easily draw a lane or draw it using orthogonal coordinates using the signal processing and control unit 52 based on the phase difference from the fixed stations S1, S2, S3 and the known position values of the fixed stations S1, S2, S3. Yes, and can be performed online at the mobile station M.

Moreover, the advantage of this method is that by using a carrier wave, multiple modulation is possible, and in principle, mutually orthogonal AM modulation and FM modulation (or phase modulation) can be performed. Since these can be separated from each other and their modulated waves can be extracted, the following method can also be used. That is, if the number of mobile stations is limited to a certain extent, the fixed station S1 can be used as a control station, for example. For example, fixed station S1
The signal processing and control units 13 to 5
A synchronization signal SY as shown in the figure is generated, applied to the AM modulator 3, AM-modulated, and transmitted. In this case, each mobile station is numbered at predetermined time intervals based on the synchronization signal SY. Then, the received signal at each mobile station M is demodulated by the AM demodulator 53 in FIG. Only at a certain time, the position information is given to the AM modulator 55 for AM modulation and transmitted from the antenna 27. The location information sent from each mobile station in a time-divided manner is received by the fixed station S1,
Mixer 9 mixes with carrier wave CW1 to create an intermediate frequency signal, which is amplified by intermediate frequency amplifier 10, then AM demodulated by AM demodulator 11 to extract position information of each mobile station, and then passed through filter amplifier 12. The signals are input to a signal processing and control unit 13 for processing. In this manner, the fixed station S1 can know the positions of all mobile stations and can perform two-way communication using different carrier waves.

In addition, in order to reduce the cost of mobile station equipment, the phase comparison value is transmitted as it is to the fixed station S1 as an AM modulated signal, and is processed by the computer of the fixed station S1.
The position of each mobile station can also be measured by transmitting the results to each mobile station.

In addition, by assigning frequencies to each mobile station within a given frequency band, for example, by using SSB modulation in combination with narrowband filters, or by combining these with time division, a large number of mobile stations can be fixed at the same time. Communication and control with station S1 becomes possible.

Due to the relationship between the frequency and the height of the antenna, RF carrier waves using space waves may interfere with direct waves and reflected waves from the sea surface, etc., resulting in interference or unreceivable reception. In this case, reception is possible by changing the height of the antenna, but it is difficult to change the height of the antenna every time the mobile station is moving. Therefore, as shown in Figure 6, two
It is also possible to prepare two antennas 27A and 27B so that reception can always be performed using the antenna with the best reception level. In this case, as shown in the figure, the antenna automatic switching device 56 is driven by the signal from the signal processing and control unit 52, and the antennas 27A, 27
B.

In the measurement method of the present invention, it is not necessary to always switch the frequency of the distance measurement frequency signal between coarse, medium, and fine, and depending on the accuracy of the required position value, the measurement may be stopped after only coarse measurement. In addition, there are cases where the measurement is stopped after reaching the middle measurement, and there are cases where the frequency is further increased than the measurement of the precision measurement. In addition, when measuring at a frequency that provides the required accuracy at a certain location, and then making the next measurement at another location near that location, the approximate location of the mobile station is known from the previous measurement. Therefore, instead of starting the measurement at the coarse frequency, it is also possible to start the measurement at the medium or fine frequency above it.

In the above embodiment, three fixed stations were used to form two sets of fixed stations, but four fixed stations were used to form two sets of fixed stations with completely different combinations of fixed stations for each set. Of course, you can do it.

As explained above, in the radio wave distance measuring method according to the present invention, two sets of fixed stations each consisting of two stations are made to correspond to a mobile station, and these two sets of fixed stations are
A common fixed station of these two sets of fixed stations modulates the carrier wave with a phase matching signal using a certain modulation method to generate a modulated wave and sends it to the other fixed station of each set. The distance measurement frequency signals of each set of fixed stations are phase-aligned based on the distance between the fixed stations, and then each set of fixed stations modulates the carrier wave using a modulation method that has orthogonal characteristics to the modulation method. Modulating the phase-matched distance measurement frequency signal to create modulated waves, and constantly transmitting the modulated waves of the fixed station from each fixed station in each set to the mobile station, The mobile station simultaneously receives each modulated wave from one set of said fixed stations and each modulated wave from another set of said fixed stations, demodulates these, and extracts each of said distance measurement frequency signals. For each set, the phase difference of the distance measurement frequency signals of that set is detected, and the position of the mobile station is determined from the intersection of equiphase lines based on the phase difference of each set, so the frequency bandwidth is limited. However, the number of mobile stations is not limited in principle, and the position of not only one mobile station but also any required number of mobile stations can be measured. In particular, in the present invention, since the phase alignment of the distance measurement frequency signals of each set of fixed stations is performed based on the known distance between each fixed station, extremely expensive equipment such as an atomic clock is not used. It can be performed with high precision using inexpensive equipment. In addition, two sets of fixed stations each have one station in common, and this common fixed station sends signals to other fixed stations to perform phase alignment, so the phases of the two sets of fixed stations are Easy to match.
Furthermore, in the present invention, since the fixed stations are common, the number of fixed stations is substantially reduced, and equipment costs can be reduced, and the number of carrier waves can be reduced to at least three waves, which is useful when performing large-scale measurements. implementation becomes easier. Furthermore, in the present invention, since the modulation methods for phase matching and distance measurement are different, using modulation methods that have orthogonal characteristics, it is possible to avoid mutual interference between the frequency signal for distance measurement and the phase matching signal, and the measurement can be performed easily. Can be done correctly. In addition, in the present invention, each fixed station always sends out a signal, and the mobile station simultaneously receives signals from two sets of fixed stations to measure distance, so the distance can be measured by switching between fixed stations and receiving signals. It is possible to perform measurements without introducing errors due to differences in various conditions before and after switching, as in the case of carrying out the switching. Moreover, according to the present invention, measurements can be performed with inexpensive equipment without using expensive equipment such as artificial satellites or atomic clocks.

Furthermore, according to the second and subsequent inventions of the present application,
In addition to the above effects, the following effects can also be obtained. In the second invention, measurements are performed by changing the frequency signal for distance measurement by 10 times and 100 times, so the number of equiphase lines gradually increases from one between a pair of fixed stations, and each time Positions can be measured without the need to count the number of lanes from a fixed point, and measurement accuracy can be improved. In particular, as in this second invention, the frequency signal for distance measurement is
By changing the magnification by 100 times or 100 times, the measurement accuracy can be gradually increased, and distances can be measured with the goal of a measurement accuracy of about ±1 m. Next, according to the third invention of the present application, there is no need to install a computer in the mobile station, and when there are a plurality of mobile stations, the equipment cost is significantly reduced, which is very suitable for implementation. .

[Brief explanation of the drawing]

FIG. 1 is an isophase diagram showing a specific example of position determination using the method of the present invention; FIGS. 2 and 3 are block diagrams showing examples of two types of fixed stations used in the method of the present invention;
FIG. 4 is a block diagram showing an example of a mobile station used in the method of the present invention, FIG. 5 is a waveform diagram of a synchronization signal, and FIG.
The figure is a block diagram showing a specific example of an antenna switching device. S1, S2, S3...fixed station, M...mobile station,
AB, CD...Equiphase line, 1...Carrier wave generator, 2
...FM modulator, 3...AM modulator, 4...Frequency signal generator for accurate distance measurement, 5...Frequency signal generator for intermediate distance measurement, 6...Frequency signal generator for rough distance measurement, 7 ... Circulator, 8 ... Antenna, 9 ... Mixer, 10 ... Intermediate frequency amplifier,
11...AM demodulator, 13...signal processing and control unit, 14...antenna, 15...circulator, 16...mixer, 17...intermediate frequency amplifier, 18...AM demodulator, 20...phase comparison 21... Voltage controlled oscillator, 22... Phase lock circuit, 23... Frequency signal generator for medium distance measurement, 24... Frequency signal generator for coarse distance measurement, 2
5... Carrier wave generator, 26... FM modulator, 27
...Antenna, 28...Circulator, 29,
30, 31...RF filter, 32, 33, 3
4... Mixer, 35, 36, 37... Intermediate frequency amplifier, 40, 41, 42... FM demodulator, 43
a, 43b, 43c, 44a, 44b, 44c,
45a, 45b, 45c... Signal separation filter, 46, 47, 48, 49, 50, 51... Phase comparator, 52... Signal processing and control unit,
53...AM demodulator, 54...carrier wave generator, 5
5...AM modulator.

Claims (1)

[Claims] 1. When measuring the position of the mobile station using at least three fixed stations on the earth and a required number of mobile stations, each of the fixed stations uses VHF band, UHF band, microwave band. Or, the carrier wave is any frequency in the millimeter wave band, and each of the fixed stations is a set of two stations.
A set of fixed stations is made to correspond to the mobile station, and these two sets of fixed stations have one station in common, and the common fixed station of these two sets of fixed stations uses a certain modulation method to generate a phase-aligned signal for the carrier wave. A modulated modulated wave is generated and sent to the other fixed station in each group, and the distance measurement frequency signals of the fixed stations in each group are matched in phase based on the distance between each fixed station. In each set of fixed stations, the modulation method is a modulation method having orthogonal characteristics, and the carrier wave is modulated with the distance measurement frequency signal whose phase is matched for each set to create modulated waves. The modulated waves of the fixed station are constantly transmitted from each of the fixed stations to the mobile station, and the mobile station transmits each modulated wave from one set of the fixed stations and another set of the modulated waves from the fixed stations. simultaneously receive the modulated waves, demodulate them, take out the distance measurement frequency signals, detect the phase difference of the distance measurement frequency signals for each group, and detect the phase difference of each group. A radio distance measuring method characterized by determining the position of a mobile station from the intersection of equiphase lines. 2. When measuring the position of the mobile station using at least three fixed stations on the earth and the required number of mobile stations, each fixed station uses either the VHF band, UHF band, microwave band, or millimeter wave band. This frequency is used as a carrier wave, and each of the fixed stations is a set of two stations.
A set of fixed stations is made to correspond to the mobile station, and these two sets of fixed stations have one station in common, and the common fixed station of these two sets of fixed stations uses a certain modulation method to generate a phase-aligned signal for the carrier wave. A modulated modulated wave is generated and sent to the other fixed station in each group, and the distance measurement frequency signals of the fixed stations in each group are matched in phase based on the distance between each fixed station. In each set of fixed stations, the modulation method is a modulation method having orthogonal characteristics, and the carrier wave is modulated with the distance measurement frequency signal whose phase is matched for each set to create modulated waves. The fixed station always transmits the modulated waves of the fixed station to the mobile station, and the mobile station transmits each modulated wave from one set of the fixed stations and another set of the modulated waves from the fixed stations. Receive each modulated wave simultaneously, demodulate them, take out the distance measurement frequency signals, detect the phase difference of the distance measurement frequency signals for each group, and detect the phase difference between the distance measurement frequency signals of each group. The position of the mobile station is determined from the intersection of the equiphase lines, and the same distance measurement frequency signals are used that have frequencies 10 and 100 times higher than the distance measurement frequency signals and whose phases are matched for each set. A method for measuring a radio wave distance, characterized in that measurements are carried out sequentially to improve the accuracy of measuring the position of the mobile station. 3. When measuring the position of the mobile station using at least three fixed stations on the earth and the required number of mobile stations, each fixed station uses either the VHF band, UHF band, microwave band, or millimeter wave band. This frequency is used as a carrier wave, and each of the fixed stations is a set of two stations.
A set of fixed stations is made to correspond to the mobile station, and these two sets of fixed stations have one station in common, and the common fixed station of these two sets of fixed stations uses a certain modulation method to generate a phase-aligned signal for the carrier wave. A modulated modulated wave is generated and sent to the other fixed station in each group, and the distance measurement frequency signals of the fixed stations in each group are matched in phase based on the distance between each fixed station. In each set of fixed stations, the modulation method is a modulation method having orthogonal characteristics, and the carrier wave is modulated with the distance measurement frequency signal whose phase is matched for each set to create modulated waves. The modulated waves of the fixed station are constantly transmitted from each of the fixed stations to the mobile station, and the mobile station transmits each modulated wave from one set of the fixed stations and another set of the modulated waves from the fixed stations. simultaneously receive the modulated waves of , demodulate them, take out the frequency signals for distance measurement, detect the phase difference of the frequency signals for distance measurement for each set, and calculate the position of these two sets. The phase difference signal is carried on a carrier wave and transmitted to one of the fixed stations, and the fixed station's computer determines the position of the mobile station from the intersection of the equal phase lines of the two sets of phase difference signals, and the value of this position is transmitted to the carrier wave. A method for measuring a radio wave distance, characterized in that the radio wave is transmitted to the mobile station on a radio wave.