JPH10148670A - Speed measuring apparatus and position detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform measurement of relative speed or detection of position accompanying it accurately from a frequency shift based on Doppler effect using a reference frequency of lower accuracy in radio transceiver for two-way data communications. SOLUTION: Frequency shift is measured for transmitting and receiving frequencies by frequency shift detectors 104, 108 in first and second radio transceivers 100, 101. An operating unit 109 in the second radio transceiver 101 adds a frequency shift data transmitted from the first radio transceiver 100 and a frequency shift data transmitted measured by the frequency shift detector 108 to offset the error of both frequency references thus determining the relative speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed measuring device and a position detecting device, and more particularly to a speed measuring device for measuring a relative speed between two objects in a non-contact manner by using a Doppler effect of an electromagnetic wave, Further, the present invention relates to a position detection device that detects the other position viewed from one of two points based on a change point of the relative speed of two objects.

[0002]

2. Description of the Related Art There is a great demand for wireless data transmission between mobile units or between a fixed station and a mobile unit on the ground, and digital cellular and PHS (Personal Handy) are required.
phone System) and wireless LAN (Local)
Various digital wireless transmission media such as Area Network have appeared, and it is expected that various services will be developed in the future. Some of these services need to detect the moving speed of the moving object and also perform position detection. There is a considerable demand for a technology that can simultaneously perform such wireless data transmission and position detection and moving speed detection. For example, a service applying this category of technology includes a road beacon.

[0003] Some applications that use only the position detection use the reception intensity of an incoming signal.
No. 93098, “Roadside beacon method”, etc.), if more accuracy is required, and if the moving speed is to be measured, the Doppler effect is generally used. In an application to a road beacon, a device capable of performing position detection using the Doppler effect and transmitting wireless data at the same time is disclosed, for example, in Japanese Patent Laid-Open No. 4-13983 as a "road beacon position detection device". Something was done. Hereinafter, this conventional example will be described with reference to the drawings.

FIG. 11 is a block diagram showing the entire configuration of a conventional position detecting device. In FIG. 11, the position detection device includes a transmission system fixed on the road side and a reception system mounted on a moving body such as a car. The transmission system is a code converter 100
1, a low-pass filter 1002, and a carrier generator 10
03, a multiplier 1004, a π / 2 phase shifter 1005,
It includes an adder 1000, a transmission high-frequency unit 1006, and a transmission antenna 1007. On the other hand, the receiving system includes a receiving antenna 1008, a receiving high-frequency unit 1009, a band-pass filter 1011, a narrow-band filter 1012,
10 and 1013, π / 2 phase shifter 1014, low-pass filter 1015, phase comparator 1016, reference oscillator 1017, loop filter 1018, voltage divider 1019, comparator 1020, and voltage controlled oscillator 102
1 is included.

In a transmission system, transmission data is first converted by a code converter 1001 into a split phase code (hereinafter abbreviated as SP code). Multiplier 100
Reference numeral 4 denotes two-phase modulation of the carrier generated by the carrier generator 1003 with the SP code. On the other hand, the same carrier is π / 2
After the phase is rotated by 90 degrees by the phase shifter 1005, the adder 10
00, it is added to the above-mentioned modulated wave. Adder 1
000 is output from the transmitting antenna 1007 after being amplified by the transmitting high-frequency unit 1006. Therefore, the transmission wave is obtained by adding a carrier wave orthogonal to the modulated wave that has been subjected to two-phase modulation with the SP code.

The reception wave arriving at the reception system is amplified by the reception high-frequency section 1009, and is subjected to mixed low-frequency conversion by the multiplier 1010 using the oscillation signal from the voltage-controlled oscillator 1021 as a local oscillation signal. Is extracted by the band-pass filter 1011. Since the signal subjected to the two-phase modulation with the SP code has no spectral component near the carrier frequency, only the orthogonal carrier added to the signal can be easily extracted by the narrow band filter 1012.

The demodulation of data is performed by multiplying the extracted carrier wave whose phase has been adjusted by the π / 2 phase shifter 1014 and the signal in the intermediate frequency band by a multiplier 1013 and obtaining a detection output by a low-pass filter 1015. On the other hand, the position detection is performed by detecting a frequency shift of the extracted carrier wave caused by the Doppler effect accompanying the movement of the receiving system. Specifically, the phase of the extracted carrier wave is compared with the output signal of the reference oscillator 1017 whose frequency matches when the receiving system is stationary, that is, when there is no frequency shift due to the Doppler effect. Via the voltage controlled oscillator 1021
To control the frequency. This configuration is a so-called phase-locked loop (PLL), and when there is a frequency shift due to the Doppler effect, this frequency shift is tracked. As a result, the frequency of the extracted carrier is changed to the frequency of the output signal of the reference oscillator 1017. Is controlled to always match. Therefore, conversely, the control voltage of the voltage controlled oscillator 1021 represents the frequency difference between the frequency of the radio wave arriving from the transmission system and the reception center frequency (the frequency of the output signal of the reference oscillator 1017).

Since this frequency difference is obtained by superimposing a frequency shift due to the Doppler effect on an error of a reference frequency between the transmission system and the reception system, position detection can be performed by changing the control voltage. Specifically, the comparator 102
0 detects a change in the control voltage by comparing the control voltage with the comparison voltage generated by the voltage divider 1019. If there is no relative speed, that is, if there is no frequency shift due to the Doppler effect, adjusting both voltages to be equal can cancel the frequency error originally existing between the transmission system and the reception system, Before and after the receiving system mounted on the system crosses the front of the transmitting system, the sign of the frequency shift due to the Doppler effect is inverted.
The time when the determination result of 0 is reversed and the vehicle crosses the front can be detected.

[0009]

However, in the above conventional example, when one or more sets of the transmission system and the reception system exist, the frequency error between them cannot be canceled by adjusting the comparison voltage. Each transmission system and each reception system has a disadvantage that a frequency reference with sufficiently high accuracy is required as compared with the amount of frequency shift due to the Doppler effect. In particular, if the carrier frequency is low, the moving speed is low, if it is desired to improve the position detection accuracy, or if it is desired to perform not only position detection but also more accurate measurement of the moving speed itself, each transmission system and each reception The frequency reference of the system includes
There is a drawback in that a particularly high-precision one is required, which makes realization difficult.

It is therefore an object of the present invention to provide a speed measuring device and a position detecting device which do not require a highly accurate frequency reference and which can be easily manufactured.

[0011]

According to a first aspect of the present invention, there is provided a first and a second wireless transceiver capable of transmitting or receiving data using radio waves, wherein the first wireless transceiver is a second wireless transceiver. A first frequency shift detector that detects a frequency shift between a frequency of a signal transmitted from the wireless transceiver and a frequency of a signal transmitted by itself, and a detection result of the first frequency shift detector, A first communication controller that performs transmission control as one frequency shift data, wherein the second wireless transceiver transmits a frequency of a signal transmitted from the first wireless transceiver and a frequency of a signal transmitted by itself. A second frequency deviation detector for detecting a frequency deviation from a frequency, a second communication controller for controlling reception of first frequency deviation data sent from the first wireless transceiver, and a second communication controller. Frequency shift detector detection result Enter the second frequency deviation data, further, the first received via the second communication controller
And an arithmetic unit for performing an operation by inputting the frequency shift data of the first and second wireless transceivers based on the input first and second frequency shift data. It is characterized by calculating and outputting the relative speed of.

As described above, the first frequency shift data includes the frequency of the signal transmitted from the second wireless transceiver to the first wireless transceiver and the frequency of the signal transmitted by the first wireless transceiver. The second frequency deviation data represents a frequency deviation from a frequency, and the second frequency deviation data is transmitted from the first wireless transceiver to the first wireless transceiver and the frequency of a signal transmitted from the first wireless transceiver to the first wireless transceiver. This represents a frequency deviation from the frequency of the signal. In the first invention, the arithmetic unit comprises the first and the second
, The relative error between the frequency reference of the first wireless transceiver and the frequency reference of the second wireless transceiver is cancelled. Therefore, each of the frequency references of the first and second wireless transceivers is
High accuracy is not required. This facilitates the realization and manufacture of a wireless transceiver having a function of determining the relative speed, and the calculated and output relative speed has high accuracy.

According to a second aspect of the present invention, in the first, second, and third wireless transceivers capable of transmitting or receiving data using radio waves, the first wireless transceiver is transmitted from the second wireless transceiver. A first frequency shift detector for detecting a frequency shift between the frequency of the incoming signal and the frequency of the signal transmitted by itself, and transmitting a detection result of the first frequency shift detector as first frequency shift data. A first communication controller for performing control, wherein the second wireless transceiver detects a frequency shift between a frequency of a signal transmitted from the first wireless transceiver and a frequency of a signal transmitted by itself. A second frequency shift detector for performing transmission control as second frequency shift data using a detection result of the second frequency shift detector.
The third wireless transceiver includes an arithmetic unit that performs an arithmetic operation by using the first and second frequency shift data transmitted from the first and second wireless transceivers as inputs The arithmetic unit calculates and outputs a relative speed between the first wireless transceiver and the second wireless transceiver based on the input first and second frequency shift data.

According to the second aspect, the arithmetic unit provided in the third wireless transceiver calculates and outputs the relative speed in the same manner as the arithmetic unit described in the first aspect. Each machine frequency reference does not require high accuracy. This facilitates the realization and manufacture of a wireless transceiver having a function of determining the relative speed, and the calculated and output relative speed has high accuracy. Further, in the second aspect, as described above, since the third wireless transceiver includes the arithmetic unit, the relative speed between the first and second wireless transceivers is obtained at a physically different position from the first and second wireless transceivers. be able to. Thereby, for example, the first and second
When there are a large number of wireless transceivers, the third wireless transceiver can centrally manage the relative speed of each of the wireless transceivers.

According to a third aspect, in the first aspect, the first aspect is provided.
And the second wireless transceiver performs communication by switching between transmission and reception at the same frequency.

In the third invention, the first and second radio transceivers perform communication by switching between transmission and reception at the same frequency, so that each of the first and second radio transceivers measures the frequency deviation of the received signal with reference to the transmitted signal. can do. Therefore, the frequency shift detector does not require any adjustment work in manufacturing, is resistant to aging, and can easily maintain a predetermined accuracy. Therefore, the realization and production of the wireless transceiver is further facilitated.

A fourth invention is characterized in that, in the second invention, the first, second and third radio transceivers perform communication by switching between transmission and reception at the same frequency.

In the fourth aspect, the first, second, and third radio transceivers perform communication by switching between transmission and reception at the same frequency. The displacement can be measured. Therefore, the frequency shift detector does not require any adjustment work in manufacturing, is resistant to aging, and can easily maintain a predetermined accuracy. Therefore, the realization and production of the wireless transceiver is further facilitated.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the arithmetic unit calculates and outputs a relative speed based on a sum of the input first and second frequency shift data. And

According to the fifth aspect, the arithmetic unit determines the relative speed between the first wireless transceiver and the second wireless transceiver based on the sum of the input first and second frequency shift data. Output calculation. Thereby, the relative error of the frequency reference of the first and second wireless transceivers can be offset.

In a sixth aspect based on any one of the first to fourth aspects, the arithmetic unit compares an added value of the input first and second frequency shift data with a predetermined threshold value, The time when the relative speed reaches a predetermined relative speed is detected based on the time when the addition value and the threshold value intersect.

When one of the first and second radio transceivers approaches one of the other, the relative speed is determined by the relative movement direction of the other as viewed from one of the two,
It changes according to the change in the angle between both lines of sight.
In particular, the sign of the relative speed is reversed immediately before and immediately after one of the first and second wireless transceivers crosses the other. In the sixth invention, the arithmetic unit changes the relative speed from the first value to the second value based on the sum of the input first and second frequency shift data and the predetermined threshold value. Detect when to do. Therefore, the computing unit can detect the position determined by the predetermined threshold value, whereby the wireless transceiver can perform not only the function of obtaining the relative speed but also the position detection. Also when performing this position detection, the arithmetic unit performs the position detection based on the first and second frequency shift data as in the case of obtaining the relative speed, so that highly accurate position detection can be performed.

In a seventh aspect based on any one of the first to fourth aspects, the arithmetic unit compares the input first and second frequency shift data with each other, and calculates the first and second frequency shift data. When the absolute values are both equal and the signs are opposite,
It is characterized in that a change point of the sign of the relative speed is detected.

The sign of the relative speed is inverted immediately before and immediately after one of the first and second radio transceivers crosses the other. In the seventh invention,
The computing unit detects a point in time at which the sign of the relative speed is inverted, based on a point in time when the absolute values of the input first and second frequency shift data are both equal and the signs are opposite. Accordingly, the arithmetic unit can detect a point in time when one of the first and second wireless transceivers crosses the other in front, so that the wireless transceiver can perform only the function of determining the relative speed. In addition, position detection can also be performed. Also when performing this position detection, the arithmetic unit performs the position detection based on the first and second frequency shift data as in the case of obtaining the relative speed, so that highly accurate position detection can be performed.

According to an eighth invention, in any one of the first to seventh inventions, a signal transmitted by the first and / or second radio transceiver is modulated by a predetermined modulation method. And / or the second wireless transceiver transmits an unmodulated carrier when the second and / or first frequency shift detector detects a frequency shift.

According to a ninth invention, in any one of the first to seventh inventions, a signal transmitted by the first and / or second radio transceiver is modulated by a predetermined modulation method. And / or the second wireless transceiver transmits a predetermined data sequence when the second and / or first frequency shift detector detects a frequency shift.

The modulated signal may be accompanied by a frequency fluctuation, and is originally not suitable for detecting a frequency shift. In the eighth or ninth invention, the first and / or the second wireless transceiver is configured such that when the second and / or the first frequency shift detector detects a frequency shift, an unmodulated carrier or a predetermined data stream Send Unmodulated carriers have no frequency variation. In addition, the predetermined data sequence does not have a frequency variation depending on the pattern that composes it,
Even if it does, frequency fluctuation can be reduced.
Thus, the second and / or first frequency shift detector can accurately detect the frequency shift.

According to a tenth aspect, in any one of the first to ninth aspects, a signal transmitted by the first and / or second radio transceiver is modulated by a digital modulation method having a predetermined code point arrangement. The first and / or second frequency shift detector detects a frequency shift in the input signal based on a phase rotation amount of a code point in a predetermined time interval corresponding to an integral multiple of the symbol length. It is characterized by doing.

For some digital modulation schemes, the modulated signal has a predetermined code point arrangement (constellation) for each symbol length. When a frequency shift occurs in this signal, the code point rotates in phase from a predetermined arrangement.
In the tenth invention, the first and / or second frequency shift detector detects a frequency shift based on the amount of phase rotation of the code point at a predetermined time interval corresponding to an integral multiple of the symbol length. Therefore, the first and / or second frequency shift detector can detect the frequency shift from the modulated signal, that is, during data communication.

In an eleventh aspect based on any one of the first to ninth aspects, the first and / or the second frequency shift detector is a frequency discriminator, and the frequency discriminator is a second and / or a frequency discriminator. Alternatively, a frequency shift between a frequency of a signal transmitted from the first wireless transceiver and a frequency of a signal transmitted by the first and / or second wireless transceiver is detected.

In a twelfth aspect based on any one of the first to ninth aspects, the first and / or second frequency shift detector includes a counter circuit, and the counter circuit includes the second and / or first frequency shift detector. Counting the frequency of the signal transmitted from the wireless transceiver and the transmission frequency of the first and / or second wireless transceiver, and the first and / or second frequency shift detector detects Based on the counting result,
The frequency shift is detected.

[0032] Frequency discriminators and counter circuits are widely used as communication circuits. In the eleventh and twelfth inventions, by applying a frequency discriminator and a counter circuit as the first and / or second frequency shift detector, only the function of measuring the relative speed or the position detection with the function of measuring the relative speed are performed. It is possible to easily realize and manufacture a wireless transceiver having a function of performing the operation. Further, a twelfth invention is directed to
Since digitization is easy, a stable and highly accurate frequency shift detector can be configured.

According to a thirteenth aspect, in the tenth aspect,
A signal input to the first and / or second frequency shift detector is delay-detected, and a phase rotation amount is obtained based on the signal delayed-detected.

The delay detection is one of the demodulation processes of a digitally modulated signal. According to the thirteenth invention, the first
The amount of phase rotation determined by the second frequency shift detector and / or the second frequency shift detector is determined based on the delay-detected signal, and a frequency shift is detected from the determined phase rotation amount. That is, the first and / or second wireless transceiver uses the demodulation function necessary for data communication also for the function of detecting a frequency shift. As a result, the hardware scale of the wireless transceiver having the function of measuring the relative speed can be reduced, and the manufacturing cost can be reduced.

According to a fourteenth aspect, in the first and second wireless transceivers capable of transmitting or receiving data using radio waves, the first wireless transceiver is configured to transmit a signal transmitted from the second wireless transceiver. And a first frequency shift detector for detecting a frequency shift between the frequency of the signal transmitted by itself and the frequency of the signal transmitted by itself, and transmission control is performed using the detection result of the first frequency shift detector as first frequency shift data. A first communication controller, wherein the second wireless transceiver detects a frequency shift between a frequency of a signal transmitted from the first wireless transceiver and a frequency of a signal transmitted by the second wireless transceiver. Frequency shift detector and a first wireless transceiver
A second communication controller for controlling the reception of the frequency deviation data of the first and second units, and a detection result of the second frequency deviation detector is inputted as second frequency deviation data, and further received via the second communication controller. And an arithmetic unit for performing an operation by inputting the first frequency shift data, wherein the first wireless transceiver and the second wireless transceiver are operated based on the input first and second frequency shift data. The position is detected by a change in relative speed with respect to the transceiver.

As described above, the first frequency shift data includes the frequency of the signal transmitted from the second wireless transceiver to the first wireless transceiver and the frequency of the signal transmitted by the first wireless transceiver. The second frequency deviation data represents a frequency deviation from a frequency, and the second frequency deviation data is transmitted from the first wireless transceiver to the first wireless transceiver and the frequency of a signal transmitted from the first wireless transceiver to the first wireless transceiver. This represents a frequency deviation from the frequency of the signal. By the way, when one of the two objects having the relative speed crosses the front of the other, the sign of the relative speed is inverted and greatly changed. In the fourteenth invention, the arithmetic unit performs an arithmetic operation on the basis of the first and second frequency shift data to thereby determine a relative frequency between the first wireless transceiver frequency reference and the second wireless transceiver frequency reference. After offsetting the error, a change point of the relative speed is detected. Therefore, high accuracy is not required for each of the frequency references of the first and second wireless transceivers. Thereby, it is easy to realize and manufacture a wireless transceiver having a function of detecting a change point of the relative speed, that is, a function of detecting a deviation from one of the first and second wireless transceivers or a position of the other. Become.

According to a fifteenth aspect, in the first, second, and third wireless transceivers capable of transmitting or receiving data using radio waves, the first wireless transceiver is transmitted from the second wireless transceiver. A first frequency shift detector that detects a frequency shift between the frequency of the incoming signal and the frequency of the signal transmitted by itself, and a detection result of the first frequency shift detector,
A first communication controller for performing transmission control as first frequency shift data, wherein the second wireless transceiver has a frequency of a signal transmitted from the first wireless transceiver and a signal transmitted by itself. A second frequency shift detector for detecting a frequency shift with respect to the frequency of the second frequency shift, and a second control for transmitting the detection result of the second frequency shift detector as second frequency shift data.
The third wireless transceiver includes an arithmetic unit that performs an arithmetic operation by using the first and second frequency shift data transmitted from the first and second wireless transceivers as inputs The arithmetic unit performs the position detection by changing the relative speed of the first and second wireless transceivers based on the inputted first and second frequency shift data.

According to the fifteenth aspect, the arithmetic unit provided in the third wireless transceiver detects the change point of the relative speed in the same manner as the arithmetic unit described in the fourteenth aspect, so that the first and the second Each of the frequency references of the radio transceiver does not require high accuracy. This facilitates the realization and manufacture of a wireless transceiver having a function of detecting a deviation from one of the first and second wireless transceivers or the position of the other. Further, in the fifteenth invention, as described above,
Since the third wireless transceiver includes the arithmetic unit, a change point in the relative speed between the first and second wireless transceivers can be obtained at a physically different position from the first and second wireless transceivers. by this,
For example, when there are a plurality of sets of the first and second wireless transceivers, it is possible to centrally manage the change point of the relative speed for each of the sets in the third wireless transceiver.

In a sixteenth aspect based on the fourteenth or fifteenth aspect, the arithmetic unit compares the added value of the input first and second frequency shift data with a predetermined threshold value to determine the added value. The time when the relative speed reaches a predetermined relative speed is detected based on the time when the threshold value intersects.

When one of the first and second radio transceivers approaches one of the other, the relative speed changes according to the change in the angle between any of the moving directions and the line of sight of both. Change. In particular, the sign of the relative speed is reversed immediately before and immediately after one of the first and second wireless transceivers crosses the other. In the sixteenth aspect, the arithmetic unit changes the relative speed from the first value to the second value based on the sum of the input first and second frequency deviation data and the predetermined threshold value. Detect when to do. As a result, the computing unit can detect the position determined by the predetermined threshold.

In a seventeenth aspect based on the fourteenth or fifteenth aspect, the arithmetic unit compares the input first and second frequency shift data with each other, and calculates an absolute value of the first and second frequency shift data. At the time when the signs are both equal and opposite,
It is characterized in that a change point of the sign of the relative speed is detected.

The sign of the relative speed is inverted immediately before and immediately after one of the first and second radio transceivers crosses the other. In the seventeenth invention, the arithmetic unit determines when the absolute values of the input first and second frequency shift data are both equal and the signs are opposite,
The time when the sign of the relative speed is reversed is detected.
Therefore, the arithmetic unit can detect a point in time when one of the first and second wireless transceivers crosses ahead of the other, thereby enabling the wireless transceiver to perform position detection. .

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. 1 to 10 and equations (1) to (11). (Embodiment 1) FIG. 1 is a block diagram showing an overall configuration of a speed measuring apparatus according to Embodiment 1 of the present invention. FIG.
, The speed measuring device includes first and second wireless transceivers 100 and 101. The first and second wireless transceivers 100 and 101 include wireless modems 102 and 106, communication controllers 103 and 107, frequency shift detectors 104 and 108, and antennas 105 and 110. The second wireless transceiver 101 further includes a calculator 109. Hereinafter, the operation of the first and second wireless transceivers 100 and 101 will be described.

The communication controller 103 or 107 adds predetermined additional bits (lamp bits, preamble, headers such as unique words and addresses, error detection / correction bits, etc.) to the input transmission data to form a frame. Then, the data is passed to the wireless modem 102 or 106.
Then, when the frame to be transmitted has been prepared, the communication controller 103 or 107 gives a transmission instruction to the wireless modem 102 or 106. The wireless modem 102 or 106 converts the received frame into
The signal is transmitted via the antenna 105 or 110.

A reception signal is input to the radio modem 102 or 106 via the antenna 105 or 110, and the demodulated bit string is transmitted to the communication controller 103 or 10
7, the information data that has been correctly received is extracted using the additional bits added by the transmission side,
Output as received data.

The above is the operation of the data wireless transceiver capable of performing general two-way communication. In the first embodiment, the communication controller 103 of the first wireless transceiver 100 further includes: The detection result (details will be described later) of the frequency shift detector 104 is transmitted as transmission data via the wireless modem 102 and the antenna 105. Second wireless transceiver 1
The communication controller 107 has a function of receiving and extracting the detection result via the antenna 110 and the wireless modem 106 and transferring the detection result to the arithmetic unit 109. Therefore, arithmetic unit 1
In 09, the detection results of both the frequency shift detector 104 and the frequency shift detector 108 are passed. Arithmetic unit 1
09 calculates and outputs the relative speed between the first wireless transceiver 100 and the second wireless transceiver 101 based on the two received detection results. Hereinafter, more detailed operations of the first embodiment will be described using Expressions (1) to (8).

Now, let the frequency of the signal transmitted from the first wireless transceiver 100 be f ₁ (the carrier frequency in the case of a modulated wave), and similarly the signal transmitted from the second wireless transceiver 101 Is the frequency f _2, and the relative speed of both is v
(The approaching direction is defined as positive. If the directions of movement are different, the components of the directions of both lines of sight are assumed).

[0048]

(Equation 1) Is used, the frequency of the received signal observed on the other side is μf _{1 due} to the Doppler effect.
And μf ₂ . In addition, at a normal moving speed, v≪
Since it is c, the above equation (1) may be approximated by the following equation (2).

[0049]

(Equation 2) Now, in FIG. 1, the frequency shift detectors 104 and 1
Reference numeral 08 detects and outputs a shift (difference) in the reception frequency based on each transmission frequency. Now, let each shift be Δ
Assuming that f ₂₁ and Δf ₁₂ , Δf ₂₁ = μf ₂ −f ₁ (3) Δf ₁₂ = μf ₁ −f ₂ (4) The first embodiment is preferably applied to time-division duplex communication in which f ₁ and f ₂ have the same frequency, but even in such a case, the first embodiment Since it is difficult for the wireless transceiver 100 and the second wireless transceiver 101 to have a common reference oscillator, there is a finite frequency error between the two. Now, assuming that the relative error is δ, f ₂ can be expressed as f ₂ = (1 + δ) f ₁ (5), and is measured by substituting the above equation (5) into the above equations (3) and (4). The frequency shifts Δf ₂₁ and Δf ₁₂ are as follows: Δf ₂₁ = μ (f ₁ + δf ₁ ) −f ₁ = (μ−1) f ₁ + μδf ₁ (6) Δf ₁₂ = μf ₁ − (f ₁ + δf ₁ ) = ( μ−1) f ₁ −δf ₁ (7)

In the conventional example shown in FIG. 11, since only one of Δf ₂₁ and Δf ₁₂ is measured to detect the moving speed or the position, the first expression on the right side of the above equation (6) or (7) is used. The frequency error component of the second term had to be negligibly small compared to the frequency shift component due to the Doppler effect of the term. That is, when considering that μ ≒ 1 for v≪c, δ must be considerably smaller than μ−1, and the applicable range is extremely narrowed or difficult to realize. As a specific example, when the relative speed v is 10 m / s (36 km / h), μ−1 is a value of about 3 × 10 ⁻⁸ , and δ is at least about 10 ⁻⁸ , that is, 0.0
A frequency accuracy of 1 ppm or more is required, and implementation is extremely difficult.

In the first embodiment, in order to avoid such a problem, Δf ₂₁ represented by the above equations (6) and (7) is used.
And Δf ₁₂ are measured to reduce the effects of frequency errors.
In practice, first, both measurement results are added. That is, Δf is newly defined as Δf≡Δf ₂₁ + Δf ₁₂ = 2 (μ−1) f ₁ − (μ−1) δf ₁ (8) The first on the right side of equation (8)
Term is a frequency deviation component of the Doppler effect on the frequency 2f _1, the second term is the frequency error component. Comparing the above equation (8) with the previous equation (6) or (7), μ
It can be seen that -1 is added to the relative error δ, and the effect of the frequency error is significantly reduced. According to a trial calculation using a specific example similar to the above, when the relative speed v is 10 m / s (36 km / h), μ-1 is a value of about 3 × 10 ^−8.
Is also related to the second term, so that a high-precision frequency reference unlike the conventional example is not required, and a general crystal oscillator (50 pp) is used.
m), the second term is at least four digits smaller than the first term, and can be realized without any problem.

Conversely, the above equation (8) is solved for μ, the previous equation (2) is substituted, and cv is approximated to c from the condition of v≪c. As a result, the following equation (9) for v is obtained. Is obtained.

[0053]

(Equation 3) From the above equation (9), it can be seen that half of the frequency error (relative error δ) appears in the relative speed measurement result. Eventually, the calculator 109 inputs the detection results Δf ₂₁ and Δf ₁₂ of the frequency shift detectors 104 and 108 as frequency shift data, and executes the calculation of the following equation (10).

[0054]

(Equation 4) In the calculation of the above equation (10), the coefficient c / 2f ₁
If the calculation result is obtained as an amount proportional to the relative speed, there is no need to multiply the calculation result. The relative speed detection result can be obtained by simply adding the detection results Δf ₂₁ and Δf ₁₂ of the frequency shift detector 104 or 108. good.

(Embodiment 2) FIG. 2 is a block diagram showing an overall configuration of a speed measuring apparatus according to Embodiment 2 of the present invention. In FIG. 2, the speed measuring device includes first, second and third wireless transceivers 200, 201 and 211. First and second wireless transceivers 200 and 2
01 includes wireless modems 202 and 206, communication controllers 203 and 207, frequency shift detectors 204 and 208, and antennas 205 and 210. Third
The wireless transceiver 211 includes a wireless modem 212, a communication controller 213, a calculator 209, and an antenna 214. First and second wireless transceivers 200 and 201
Is similar to the first wireless transceiver 100 in the first embodiment. The second embodiment is different from the first embodiment in that the frequency shift detectors 204 and 20
8 is that the third wireless transceiver 211 receives the frequency shift data detected in 8 and calculates the relative speed. Accordingly, the communication controller 213 extracts the frequency shift data transmitted from the first wireless transceiver 200 and the second wireless transceiver 201 and received via the antenna 214 and the wireless modem 212, and transfers the data to the computing unit 209. The place is different. The operation of the arithmetic unit 209 is the same as that of the arithmetic unit 109 in the first embodiment, and a description thereof will not be repeated.

In the second embodiment, another third wireless transceiver 211 physically detects the relative speed between the first wireless transceiver 200 and the second wireless transceiver 201. Therefore, the second embodiment is suitable for a case where there are a large number of moving objects to be measured and information of relative speed is collected and processed at one place.

(Embodiment 3) FIG. 3 shows a radio modem 102 or 106 and a frequency shift detector 1 shown in FIG.
04 or 108, or the wireless modem 2 shown in FIG.
FIG. 2 is a block diagram showing a preferred configuration of a frequency shift detector 02 or 206 and a frequency shift detector 204 or 208. The wireless modem 102, 106, 202, or 206
, And the frequency shift detectors 104, 108, 204 and 208 correspond to the frequency shift detector 301 shown in FIG.

In FIG. 3, a radio modem 302 includes an antenna switch 303, a reception high-frequency unit 304, a transmission high-frequency unit 305, an original oscillator 306, a modulator 307,
The frequency shift detector 301 has a frequency discriminator 309.

Using the output signal of the original oscillator 306 as a carrier wave, the modulator 307 modulates the transmission bit sequence adjusted to a predetermined frame by the communication controller. Various modulation methods are possible, such as frequency modulation (FSK), phase modulation (PSK), and amplitude modulation (AS).
K) is common. The modulated signal that is the output of the modulator 307 is amplified to a predetermined level by the transmission high-frequency unit 305, and is sent to the antenna via the antenna switch 303. Note that the antenna switch 303 is connected to the modulator 30.
7 is controlled by the communication controller in accordance with the transmission bit string input to the communication controller 7.

On the other hand, the reception signal sent from the antenna is frequency-selected by reception high-frequency section 304, amplified to a predetermined level, passed to demodulator 308, and a demodulated bit string is passed to the communication controller. At the same time, the output of the reception high-frequency unit 304 is also supplied to the frequency discriminator 309,
The frequency discriminator 309 detects and outputs a frequency deviation, which is a difference between the frequency of the output signal of the reception high-frequency unit 304, which is the frequency of the reception signal, and the signal frequency of the original oscillator 306, which is the transmission frequency.

The frequency discriminator 309 is typically a ratio detector, Foster-seel (Foster-seel).
eye) Circuit and Quadrature
Although it is composed of a detector and the like, it is more preferable to be composed of a detector using a PLL because it is easier to achieve high sensitivity and high stability. In this case, if the reference oscillation frequency is obtained directly from the original oscillator 306 or from a frequency-divided version thereof (FIG. 3)
In this case, it is indicated by a dotted line), and the frequency deviation detection error can be reduced.
More preferred.

The transmitting high-frequency section 305 and the receiving high-frequency section 304 have a local oscillation section and a frequency converting section therein. The transmitting high-frequency section 305 raises and amplifies an input signal to a high frequency band. The receiving high-frequency unit 304 may transmit the signal, lower the frequency of the received signal to a low frequency, select the frequency, amplify the signal, and supply it to the demodulator 308 and the frequency discriminator 309. In this case, it is preferable that the transmission high-frequency unit 305 and the reception high-frequency unit 304 perform frequency conversion using a common local oscillation unit, since an error between transmission and reception frequencies does not occur in detection of a frequency shift.

Further, the frequency discriminator 309 allows the frequency fluctuation to be distributed symmetrically around the carrier frequency even if the signal is a modulated signal. Therefore, it is possible to detect a frequency shift between the modulated signal and the output signal of the original oscillator 306. However, it is preferable to transmit a specific data sequence suitable for measurement only at the time of measurement, or to transmit only an unmodulated carrier. Specifically, the communication control unit 1
03, 107, 203, or 207 respectively controls the wireless modems 102, 106, 202, or 206 to transmit a non-modulated carrier or to transmit and transmit the specific data sequence. The specific data string is FSK
Then, the alternating pattern of 0 and 1 and the sequence of 0 or 1 are different in the PSK which is differentially coded. The sequence of 0 (as a result, the carrier is transmitted) and the change of the clockwise and counterclockwise code points are changed. An alternating pattern or a random pattern (preferably removing a code change passing through the origin) is preferable, but in ASK, one continuous pattern (as a result, a carrier is transmitted) is preferable.

(Embodiment 4) FIG. 4 shows a radio modem 102 or 106 and a frequency shift detector 104 shown in FIG.
Or with the wireless modem 2 shown in FIG.
FIG. 2 is a block diagram showing a preferred configuration of a frequency shift detector 02 or 206 and a frequency shift detector 204 or 208. The wireless modem 102, 106, 202, or 206
, And the frequency shift detectors 104, 108, 204 and 208 correspond to the frequency shift detector 401 shown in FIG.

In FIG. 4, a wireless modem 402 includes an antenna switch 403, a reception high-frequency unit 404, a transmission high-frequency unit 405, an original oscillator 406, a modulator 407,
A demodulator 408 is provided. The frequency shift detector 401 includes a reception counter 410, a transmission counter 409, a latch &
And an offset 412. Note that the wireless modem 402 shown in FIG. 4 has the same configuration as the wireless modem 302 shown in FIG. 3, and a description thereof will be omitted.

The transmission counter 409 is driven by the output of the original oscillator 406 at the time of signal transmission, and supplies an output to the reception counter 410 and the latch & offset 412 at every predetermined count. The reception counter 410 is driven by the output of the reception high-frequency unit 404, and the transmission counter 4
When the output of 09 is input, its own count value is latched &
It sends to offset 412, resets the count value, and restarts counting. When the transmission frequency and the reception frequency are the same, the count value matches the predetermined count number of the transmission counter 409, but increases or decreases according to the frequency shift. The latch & offset 412 holds the count value of the reception counter 410, subtracts a predetermined count number of the transmission counter 409, sets 0 when the frequencies match, a positive value when the reception frequency is high, and a negative value when the reception frequency is low. Output as As a result, the frequency shift is measured. The function of the offset may be omitted if it is realized in a communication controller or an arithmetic unit that follows, or if it is handled in a numerical expression that may have an offset. The fourth embodiment has advantages that the frequency shift detector can be easily digitized, operates more stably, and has higher accuracy than the third embodiment.

In this case as well, the transmitting high-frequency section 405 and the receiving high-frequency section 404 have a local oscillation section and a frequency converting section inside, and the transmitting high-frequency section 405 converts the input signal into a high-frequency signal. The reception high-frequency unit 404 may reduce the reception signal to a low frequency, select a frequency, amplify the signal, and supply it to the demodulator 408 and the reception counter 410. Is also good. In this case, it is preferable that the transmission high-frequency unit 405 and the reception high-frequency unit 404 perform frequency conversion using a common local oscillation unit, since an error between transmission and reception frequencies does not occur in detection of a frequency shift.

Also in this case, the frequency shift detector 40
1 is a reception counter 4 even if the frequency variation is symmetrically distributed around the carrier frequency, even for a modulated signal.
Since averaging is performed in 10 count sections, a frequency shift can be detected without any trouble. However, only at the time of measurement,
It is preferable to transmit only a specific data sequence or an unmodulated carrier suitable for measurement. Specifically, the communication control units 103, 107, 203, or 207 respectively control the wireless modems 102, 106, 202, or 206.
To transmit a non-modulated carrier, or pass the specific data sequence and transmit it. As the specific data sequence, in FSK, an alternating pattern of 0 and 1; continuous of 0 or 1; in differentially encoded PSK, continuous of 0 (as a result, a carrier is transmitted); In an alternating pattern of point changes or a random pattern (preferably removing a code change passing through the origin), in ASK, one continuous (as a result, a carrier wave is transmitted) is preferable.

(Embodiment 5) FIG. 5 is a block diagram showing a wireless modem 102 or 106 shown in FIG.
Or with the wireless modem 2 shown in FIG.
FIG. 2 is a block diagram showing a preferred configuration of a frequency shift detector 02 or 206 and a frequency shift detector 204 or 208. The wireless modem 102, 106, 202, or 206 corresponds to the wireless modem 502 (see a portion surrounded by a dotted line) shown in FIG.
4 or 208 is a frequency shift detector 501 shown in FIG.
(See the portion surrounded by the two-dot chain line).

Referring to FIG. 5, a radio modem 502 includes an antenna switch 503, a reception high-frequency unit 504, a transmission high-frequency unit 505, an original oscillator 506, a modulator 507,
And a demodulator 501. The demodulator 501 includes a frequency discriminator 508. The frequency shift detector 501 includes a frequency discriminator 508 included in the demodulator 501.
The fifth embodiment is different from the third embodiment in that the frequency shift detector and the demodulator are constituted by a common frequency discriminator 508 and that the modulation scheme is limited to FSK. . The other configuration is the same as that of the above-described third embodiment, and the description thereof is omitted.

The frequency discriminator 508 is typically composed of a ratio detector or the like, similar to the frequency discriminator 309 of the third embodiment described above, but is preferably composed of a detector using a PLL. Higher sensitivity and higher stability are easily achieved, which is more preferable. In this case, it is more preferable to obtain the reference oscillation frequency directly from the original oscillator 506 or from a frequency-divided output of the original oscillator 506 (shown by a dotted line in FIG. 5), because it is possible to reduce a frequency deviation detection error. The fifth embodiment has a feature that the hardware scale can be reduced because the frequency shift detector and the demodulator are configured by the common frequency discriminator 508.

In this case as well, the transmitting high-frequency unit 505 and the receiving high-frequency unit 504 have a local oscillation unit and a frequency conversion unit inside, and the transmitting high-frequency unit 505 converts the input signal into a high-frequency signal. The reception high-frequency unit 504 may select the frequency, amplify it, and supply it to the frequency discriminator 508 after lowering the reception signal to a low frequency. In this case, it is preferable that the transmission high-frequency unit 505 and the reception high-frequency unit 504 perform frequency conversion using a common local oscillation unit, because an error between transmission and reception frequencies does not occur in detection of a frequency shift.

The frequency discriminator 508 is a circuit for performing an averaging operation on the output side of the frequency discriminator 508 if the frequency variation is symmetrically distributed around the carrier frequency even if the signal is modulated. Is added, it is possible to detect a frequency shift between the modulated signal and the output signal of the original oscillator 306. However, only at the time of measurement,
It is preferable to transmit a specific data sequence or only an unmodulated carrier suitable for measurement. Specifically, the communication control units 103, 107, 203, or 207 respectively control the wireless modems 102, 106, 202, or 20.
6 to transmit a non-modulated carrier or to transmit the specific data sequence and transmit it. As the specific data string, an alternating pattern of 0 and 1, a continuation of 0 or 1, and the like are preferable.

(Embodiment 6) FIG. 6 shows a radio modem 102 or 106 and a frequency shift detector 104 shown in FIG.
Or with the wireless modem 2 shown in FIG.
FIG. 2 is a block diagram showing a preferred configuration of a frequency shift detector 02 or 206 and a frequency shift detector 204 or 208. The wireless modem 102, 106, 204 or 206 corresponds to the wireless modem 602 shown in FIG. 6, and the frequency shift detector 104, 108, 204 or 208 corresponds to the frequency shift detector 601 shown in FIG. 6, a wireless modem 602 includes an antenna switch 603, a reception high-frequency unit 604 includes a transmission high-frequency unit 605, and an original oscillator 60.
6, a modulator 607, and a demodulator 608 (a portion surrounded by a two-dot chain line). The demodulator 608 includes a quadrature mixer 609 and a baseband demodulator 610. The frequency shift detector 601 includes a code point detector 611 and a code point rotation amount calculator 612. The sixth embodiment is different from the third embodiment in that the demodulator includes a quadrature mixer 609 and a baseband demodulator 610, and that the frequency shift detector 601 has a code point detector 611 and a code point detector 611. A point rotation calculator 612 is provided. Other configurations are the same as those in the third embodiment described above.
The description is omitted.

The quadrature mixer 609 includes a reception high-frequency section 604
And a signal from the original oscillator 606 to perform quasi-synchronous detection, and output a baseband signal (I-axis signal and Q-axis signal) of the received signal. Baseband demodulator 6
Reference numeral 10 performs demodulation signal processing in baseband. In order to perform demodulation processing by digital signal processing, it is advantageous to input the frequency band of the input signal as low as possible.
It is common to reduce the signal frequency to the baseband by the quadrature mixer 609.

The baseband signal from quadrature mixer 609 is supplied to code point detector 611 at the same time. Modulation schemes classified as phase modulation (MSK: Minimum S)
In the case of a frequency modulation method having a phase specific condition such as shift keying), a code point on the I axis and Q axis for each symbol exists at a predetermined position (constellation). However, if there is a difference between the carrier frequency of the input signal and the frequency of the source oscillator 606 input to the quadrature mixer 609, this code point is shifted clockwise (when the former frequency is high) or symbol by symbol. The phase is rotated counterclockwise (when the former frequency is low). Now, let the symbol rate be f _s
(Symbol / s), if the phase rotation amount of the code points after m symbol (m is a natural number) theta and (rad / symbol), frequency shift Delta] f _{c is, Δf c = (f s /} m) × (θ / 2π) (11).

The symbol clock reproduced by the baseband demodulator 610 is supplied to a code point detector 611 and a code point rotation amount calculator 612.
1 fetches and holds the code point for each symbol, and the code point rotation amount calculator 612 calculates and outputs a frequency shift from the phase rotation amount θ of the code point after m symbols by the above equation (11).

As described above, the sixth embodiment is characterized in that the frequency shift can be measured with the modulated signal as it is. However, only at the time of measurement,
More preferably, only a specific data sequence or an unmodulated carrier suitable for measurement is transmitted. This is because measurement becomes impossible if the constellation rotates in phase due to a frequency shift beyond the phase interval between adjacent code points on the constellation (arrangement of code points). The specific data sequence is a data sequence in which code point transitions are constrained such that adjacent code points on the constellation are spaced apart from each other (for example, in polyphase PSK, code points of 0 degrees and 180 degrees are alternately formed). Data strings that transition)
A data sequence that does not transition from the same code point (for example, a series of 0s in differentially encoded PSK, and as a result, a carrier wave is transmitted) is preferable.

In this case as well, the transmitting high-frequency section 605 and the receiving high-frequency section 604 have a local oscillation section and a frequency converting section inside, and the transmitting high-frequency section 605 raises the input signal to a high frequency. The signal may be amplified and transmitted, or the receiving high-frequency unit 604 may select the frequency after a receiving signal is dropped to a low frequency, amplify the signal, and
09 may be supplied. In this case, it is preferable that the transmission high-frequency unit 605 and the reception high-frequency unit 604 perform frequency conversion using a common local oscillation unit, because an error between transmission and reception frequencies does not occur in detection of a frequency shift.

(Embodiment 7) FIG. 7 is a block diagram showing a preferred configuration of demodulator 608 and frequency shift detector 601 shown in FIG. The demodulator 608 includes a quadrature mixer 709 and a baseband demodulator 710 (portion surrounded by a two-dot chain line) shown in FIG. The frequency shift detector 601 is a frequency shift detector 7 shown in FIG.
01 (portion surrounded by a dotted line). 7, an orthogonal mixer 709 and a code point rotation amount calculator 708 are:
Since it is the same as that described in the sixth embodiment, description thereof will be omitted. The difference is that the baseband demodulator 7
A part of the function of the frequency detector 10 and the frequency shift detector 701 is constituted by a delay detector 702 including a delay unit 702, a phase rotator 703, a complex multiplier 704, a clock regenerator 705, and a low-pass filter 706. That is.

The delay unit 702 delays the signal by a predetermined number of symbols when differential encoding is performed on the transmission side. After adjusting the phase of the detection axis by the phase rotator 703, the complex multiplier 7
By performing the multiplication in 04, the low-pass component of the output is extracted by the low-pass filter 706, so that a detection output is directly obtained. In the case of multi-phase modulation of two or more phases, a plurality of systems of a phase rotator 703, a complex multiplier 704, and a low-pass filter 706 are required in accordance with a plurality of detection axes. The description will be given taking the case of two-phase differential PSK as an example.

A detection output obtained as an output of the low-pass filter 706 is reproduced by a clock regenerator 705 and then passed to an identification / judgment unit 707 to be output as a demodulated bit string. On the other hand, the detection output and the symbol clock are also supplied to the code point rotation amount calculator 708. The code point rotation amount calculator 708 is used in the sixth embodiment.
In the same manner as the code point rotation amount calculator 612, a frequency shift is calculated from the phase rotation amount θ of the code point by the above equation (11) and output. In the seventh embodiment, since the delay detection unit has both functions of demodulation processing and code point detection, it has a feature that the hardware scale can be reduced.

In the seventh embodiment, similarly to the sixth embodiment, the frequency shift can be measured with the modulated signal as it is. However, it is more preferable to transmit only a specific data sequence or a non-modulated carrier suitable for measurement only at the time of measurement. This is because if the constellation rotates in phase due to a frequency shift beyond the phase interval between adjacent code points on the constellation, measurement becomes impossible. The specific data sequence is a data sequence in which code point transitions are constrained such that adjacent code points on the constellation are spaced apart from each other (for example, in polyphase PSK, code points of 0 degrees and 180 degrees are alternately formed). It is preferable to use a data string that transitions or the like and a data string that does not transition from the same code point (for example, a series of 0s in differentially encoded PSK).

(Embodiment 8) FIG. 8 is a block diagram showing a configuration of arithmetic unit 109 shown in FIG. 1 or arithmetic unit 209 shown in FIG. The arithmetic units 109 and 209 are
This corresponds to the arithmetic unit 801 shown in FIG. 8, an arithmetic unit 801 includes an adder 802 and a threshold value determiner 803.
And The eighth embodiment has a final object of detecting a position from a change in the relative speed, rather than detecting the relative speed.

Generally, when one of the first and second radio transceivers having a relative speed crosses the front of the other, the value of the relative speed changes greatly and the sign is inverted. . The adder 803 adds the two input frequency shift data, that is, calculates and outputs Δf ₂₁ + Δf ₁₂ . The output of the adder 802 is, as described above,
Since the threshold value is proportional to the relative speed, the threshold value determiner 803 can detect a change point of the relative speed by comparing the value of this output with a predetermined threshold value. It is possible to detect the position of one of the first wireless transceiver and the second wireless transceiver as viewed from the other.

FIG. 9 is a diagram for explaining position detection performed by the computing unit 801 shown in FIG. In FIG. 9, the first wireless transceiver 100 or 200 moves at a constant speed V on a straight line AB as viewed from the second wireless transceiver 101 or 201, approaches the second wireless transceiver, and moves forward. Front (position shown by arrow C in the figure)
Let's say you are moving far across At this time, Δf ₂₁ + Δf ₁₂ calculated by the computing unit 801 included in the second wireless transceiver 101 or the third wireless transceiver 211 is:
The relative speed v is proportional to Vcosα. Here, α is the moving direction of the first wireless transceiver, that is, the angle between the straight line AB and both lines of sight. In the case shown in FIG. 9, Vcos α changes from + V to −V because α changes from 0 to π. Therefore, the arithmetic unit 801
Can detect when the relative speed (v = Vcos α) has reached the relative speed defined by the predetermined threshold, so that the first wireless transceiver can be positioned in front of the second wireless transceiver in front of it. It is possible to detect not only the moment of crossing, but also immediately before crossing the front front (the position indicated by arrow D in the figure).

As described above, if the position indicated by the arrow D can be detected, there is a margin of time before the first wireless transceiver crosses the front of the second wireless transceiver. Can be used to perform other processing, and the usability of the position detection device is improved. However, when the above-mentioned moving speed V is constantly changing, or when there are a large number of objects to be measured and each of the objects to be measured is moving at a different moving speed V, etc. Even if the position is detected, the accuracy of the position detection is not so high, so that its application range is limited.

As described above, when position detection is performed based on a change in relative speed, as shown in FIG. 8, only a simple configuration of the adder 802 and the threshold value determiner 803 is used.
That goal can be achieved.

In particular, when the frequency shift data input to the adder 802 is an expression having no offset centering on zero, the threshold value judging device 803 detects only the sign, thereby detecting the relative speed. With a simpler configuration, it is possible to detect the point of time when the sign is inverted and to detect the moment when one crosses the front of the other.

(Embodiment 9) FIG. 10 is a block diagram showing a configuration of arithmetic unit 109 shown in FIG. 1 or arithmetic unit 209 shown in FIG. These arithmetic units 109 and 209
Corresponds to the arithmetic unit 904 shown in FIG. In FIG. 10, a computing unit 904 includes a sign inverter 906 and a comparator 9
05. The final purpose of the computing unit 904 according to the ninth embodiment is to detect a position from a change in relative speed, similarly to the computing unit 801 according to the eighth embodiment.
When the frequency shift data input to the arithmetic unit 904 is a representation having no offset around zero, the sign inverter 906 inverts the sign of one of the frequency shift data, and the comparator 905 outputs
The sign-inverted frequency shift data is compared with the other frequency shift data. With this, it is possible to detect the time when the sign of the relative speed reverses, that is, the moment when one crosses the front of the other with a simpler configuration.

In the above-described eighth and ninth embodiments, arithmetic units 804 and 904 perform only position detection, but this position detection and the first to seventh embodiments are performed.
It is easy to provide the arithmetic unit with both functions of the moving speed detection described in the above.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a speed measuring device according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing an overall configuration of a speed measuring device according to Embodiment 2 of the present invention.

FIG. 3 shows the wireless modem 102 or 106 and the frequency shift detector 104 or 108 shown in FIG. 1, or
FIG. 3 is a block diagram showing a preferred configuration of a wireless modem 202 or 206 and a frequency shift detector 204 or 208 shown in FIG.

FIG. 4 shows the wireless modem 102 or 106 and the frequency shift detector 104 or 108 shown in FIG. 1, or
FIG. 3 is a block diagram showing a preferred configuration of a wireless modem 202 or 206 and a frequency shift detector 204 or 208 shown in FIG.

FIG. 5 shows the wireless modem 102 or 106 and the frequency shift detector 104 or 108 shown in FIG.
FIG. 3 is a block diagram showing a preferred configuration of a wireless modem 202 or 206 and a frequency shift detector 204 or 208 shown in FIG. 2.

FIG. 6 shows the wireless modem 102 or 106 shown in FIG. 1 and the frequency shift detector 104 or 108, or
FIG. 3 is a block diagram showing a preferred configuration of a wireless modem 202 or 206 and a frequency shift detector 204 or 208 shown in FIG. 2.

7 is a demodulator 608 and a frequency shift detector 6 shown in FIG.
It is a block diagram which shows the preferable structure with 01.

FIG. 8 is a block diagram showing a configuration of a computing unit 109 shown in FIG. 1 or a computing unit 209 shown in FIG.

9 is a diagram for explaining position detection performed by a calculator 801 shown in FIG.

FIG. 10 is a block diagram showing a configuration of a computing unit 109 shown in FIG. 1 or a computing unit 209 shown in FIG.

FIG. 11 is a block diagram showing an overall configuration of a conventional speed measuring device.

[Explanation of symbols]

100, 200: first wireless transceiver 101, 201: second wireless transceiver 211: third wireless transceiver 102, 106, 202, 206, 212, 302, 4
02, 502, 602: wireless modems 103, 107, 203, 207, 213: communication controllers 104, 108, 204, 208, 301, 401, 5
01, 601, 701 ... frequency shift detectors 105, 110, 205, 210, 214 ... antennas 109, 209, 801, 904 ... arithmetic units 303, 403, 503, 603 ... antenna switches 304, 404, 504, 604 ... reception High-frequency units 305, 405, 505, 605: Transmission high-frequency units 306, 406, 506, 606: Original oscillators 307, 407, 507, 607: Modulators 308, 408, 501, 608: Demodulators 309, 508: Frequency discriminators 409: Transmission counter 410: Reception counter 412: Latch & offset 609, 709: Quadrature mixer 610, 710: Baseband demodulator 611: Code point detector 612, 708: Code point rotation amount calculator 702: Delay unit 703: Phase Rotator 704: Complex multiplier 705: Clock re-start Vessel 706 ... low pass filter 707 ... identification determiner 802 ... adder 803 ... threshold judgment unit 905 ... comparator 906 ... sign inverter

Claims (17)

[Claims] 1. A first and second wireless transceiver capable of transmitting or receiving data using radio waves, wherein the first wireless transceiver has a frequency of a signal transmitted from the second wireless transceiver. A first frequency deviation detector for detecting a frequency deviation from a frequency of a signal transmitted by the first frequency deviation detector; and a second frequency deviation detector for performing transmission control using the detection result of the first frequency deviation detector as first frequency deviation data. A communication controller, wherein the second wireless transceiver detects a frequency shift between a frequency of a signal transmitted from the first wireless transceiver and a frequency of a signal transmitted by the second wireless transceiver. 2 frequency deviation detectors, a second communication controller that controls reception of first frequency deviation data sent from the first wireless transceiver, and a detection result of the second frequency deviation detector Is the second frequency An arithmetic unit for inputting the first frequency offset data received via the second communication controller and performing an arithmetic operation, wherein the first and second input A speed measuring device, which calculates and outputs a relative speed between a first wireless transceiver and a second wireless transceiver based on the second frequency shift data. 2. A first, second, and third wireless transceiver capable of transmitting or receiving data using radio waves, wherein the first wireless transceiver is transmitted from the second wireless transceiver. A first frequency deviation detector for detecting a frequency deviation between a frequency of a signal and a frequency of a signal transmitted by the first frequency deviation detector; and a transmission control unit configured to transmit a detection result of the first frequency deviation detector as first frequency deviation data. The second wireless transceiver, the second wireless transceiver, the frequency difference between the frequency of the signal transmitted from the first wireless transceiver and the frequency of the signal transmitted by itself A second frequency deviation detector for detecting, a second communication controller for performing transmission control on the detection result of the second frequency deviation detector as second frequency deviation data, The transceiver is An arithmetic unit for performing an arithmetic operation by using first and second frequency shift data transmitted from the first and second wireless transceivers as inputs, wherein the arithmetic unit includes the input first and second frequency shift data. A speed measurement device for calculating and outputting a relative speed between the first wireless transceiver and the second wireless transceiver based on the first and second wireless transceivers. 3. The first and second wireless transceivers,
The speed measuring apparatus according to claim 1, wherein communication is performed by switching between transmission and reception at the same frequency. 4. The speed measuring apparatus according to claim 2, wherein the first, second and third wireless transceivers perform communication by switching between transmission and reception at the same frequency. 5. The arithmetic unit according to claim 1, wherein said first and second input units are:
The speed measuring device according to claim 1, wherein the relative speed is calculated and output based on a sum of the frequency shift data. 6. The computing unit according to claim 1, wherein the input first and second input units are:
Comparing the sum of the frequency deviation data of the above and a predetermined threshold value, and detecting when the relative speed has reached a predetermined relative speed, based on a point in time at which the addition value and the threshold value cross each other. The speed measuring device according to any one of claims 1 to 4, characterized in that: 7. The arithmetic unit according to claim 1, wherein said first and second input units are
Comparing the absolute value of the first and second frequency deviation data with the same sign and detecting the point of change of the sign of the relative speed at a point in time when the sign is reversed. The speed measurement device according to claim 1, wherein 8. The signal transmitted by the first and / or second wireless transceiver has been modulated by a predetermined modulation scheme, and the first and / or second wireless transceiver has a signal transmitted by the first and / or second wireless transceiver. The speed measuring device according to claim 1, wherein when the second and / or first frequency shift detector detects a frequency shift, an unmodulated carrier is transmitted. 9. A signal transmitted by the first and / or second wireless transceiver has been modulated by a predetermined modulation scheme, and the first and / or second wireless transceiver has a signal transmitted by the first and / or second wireless transceiver. The speed measuring device according to any one of claims 1 to 7, wherein a predetermined data string is transmitted when the second and / or first frequency deviation detector detects a frequency deviation. 10. The signal transmitted by the first and / or second radio transceiver has been modulated by a digital modulation method having a predetermined code point arrangement, and the first and / or second frequency has been modulated. The shift detector detects the frequency shift based on an amount of phase rotation of a code point in a predetermined time interval corresponding to an integer multiple of a symbol length in the input signal. 10. The speed measuring device according to any one of 9). 11. The first and / or second frequency shift detector is a frequency discriminator, and the frequency discriminator is transmitted from the second and / or first radio transceiver. The speed measuring device according to claim 1, wherein a frequency shift between a frequency of a signal and a frequency of a signal transmitted by the first and / or second wireless transceiver is detected. . 12. The first and / or second frequency shift detector includes a counter circuit, and the counter circuit is configured to control a frequency of a signal transmitted from the second and / or first wireless transceiver. And the transmission frequency of the first and / or second wireless transceiver are counted. The first and / or second frequency shift detector detects a frequency shift based on the count result of the counter circuit. The speed measuring device according to claim 1, wherein the speed is detected. 13. The signal input to the first and / or second frequency shift detector is subjected to delay detection, and the phase rotation amount is obtained based on the delay-detected signal. The speed measurement device according to claim 10, wherein 14. A first and second wireless transceiver capable of transmitting or receiving data using radio waves, wherein the first wireless transceiver has a frequency of a signal transmitted from the second wireless transceiver. A first frequency deviation detector for detecting a frequency deviation from a frequency of a signal transmitted by the first frequency deviation detector; and a second frequency deviation detector for performing transmission control using the detection result of the first frequency deviation detector as first frequency deviation data. A communication controller, wherein the second wireless transceiver detects a frequency shift between a frequency of a signal transmitted from the first wireless transceiver and a frequency of a signal transmitted by the second wireless transceiver. 2 frequency deviation detectors, a second communication controller that controls reception of first frequency deviation data sent from the first wireless transceiver, and a detection result of the second frequency deviation detector The second week An arithmetic unit for inputting as the number shift data, further inputting the first frequency shift data received via the second communication controller and performing an arithmetic operation, wherein the arithmetic unit has A position detecting device for detecting a position based on a change in a relative speed between a first wireless transceiver and a second wireless transceiver based on second frequency shift data. 15. The first, second, and third wireless transceivers capable of transmitting or receiving data using radio waves, wherein the first wireless transceiver is transmitted from the second wireless transceiver. A first frequency deviation detector for detecting a frequency deviation between a frequency of a signal and a frequency of a signal transmitted by the first frequency deviation detector; and a transmission control unit configured to transmit a detection result of the first frequency deviation detector as first frequency deviation data. The second wireless transceiver, the second wireless transceiver, the frequency difference between the frequency of the signal transmitted from the first wireless transceiver and the frequency of the signal transmitted by itself A second frequency deviation detector for detecting, a second communication controller for performing transmission control on the detection result of the second frequency deviation detector as second frequency deviation data, Transceiver An arithmetic unit for performing an operation by using first and second frequency shift data transmitted from the first and second wireless transceivers as inputs, wherein the arithmetic unit includes the input first and second frequency shifts A position detecting device, wherein a position is detected based on a change in a relative speed between the first wireless transceiver and the second wireless transceiver based on data. 16. The arithmetic unit compares an added value of the input first and second frequency shift data with the predetermined threshold value, and determines a time point at which the added value intersects the threshold value. 16. The position detecting device according to claim 14, wherein a time when the relative speed reaches a predetermined relative speed is detected. 17. The arithmetic unit compares the input first and second frequency shift data with each other, and when the absolute values of the first and second frequency shift data are both equal and the signs are opposite, 16. The position detecting device according to claim 14, wherein a change point of a sign of the relative speed is detected.