JP2005189101A - Angle detection apparatus and inclination angle measurement apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an angle detection apparatus which directly measures a phase of a radio wave without using a modulated wave, uses antennas with extremely short intervals without using antennas with longer intervals, allows detection with high precision, and can be used also as an azimuth (direction) sensor. <P>SOLUTION: The angle detection apparatus comprises two receiving antennas 3, 4 which receive radio waves from a transmitting antenna 2, distributors 5 to 7, 8 to 10 which distribute radio waves received by the two receiving antennas 3, 4 into a plurality of ones, phase shifters 11 to 14, 15 to 18 which shift the phases of a plurality of radio waves distributed by the distributors to different values, synthesizers 19 to 20 which synthesize a plurality of outputs from the phase shifters, detectors 23 to 26 which detect the synthesized outputs by the synthesizers, and an arithmetic and control circuit 27 which performs arithmetic computations of radio waves arrival angles on the basis of the outputs of the detectors. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an angle detection device and an inclination angle measurement device, and more particularly to an angle detection device and an inclination angle measurement device suitable for use when performing an optical axis control of a vehicle headlight.

2. Description of the Related Art Conventionally, there is an apparatus that receives radio waves transmitted from antennas at distant positions with two antennas and detects the orientation of the transmitting antenna. This device emits a carrier wave modulated by a modulated wave as a radio wave from a transmission antenna, adds a signal from a local transmitter to the radio wave received by two antennas on the reception side, and demodulates the signal modulated on the transmission side Then, the phase of the low-frequency modulated wave is measured with a clock signal and a counter, and the direction of the transmitting antenna is detected from the time difference between the radio waves received by the two antennas (for example, Patent Document 1). reference).
In addition, radio waves simultaneously emitted from multiple transmitting antennas are received by multiple antennas and detected to be received in the same phase to detect whether they are moving toward the center of the multiple transmitting antennas or are shifted, There is an apparatus that detects that a plurality of receiving antennas are received with phases shifted so that an error from the center can be recognized (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 4-220881 (paragraphs [0015] to [0021] and FIG. 1) JP-A-10-288655 (paragraphs [0036] to [0039], FIG. 1 and FIG. 3)

  In the case of the conventional device described in Patent Document 1, since a clock signal and a counter are used, a time difference in an extremely short time cannot be measured. Therefore, a low frequency signal is intentionally sent by a modulated wave, and the arrival time difference of radio waves is large Thus, it was necessary to use two receiving antennas installed at a distance.

  Further, in the case of the conventional device described in Patent Document 2, it is possible to indicate an analog pointer as to whether it is the center or whether the deviation is large, but it is highly accurate that the direction of the transmitting antenna is in which direction several times. There was a problem that the direction could not be indicated.

This invention has been made to solve the above-described problems, and can directly measure the phase of a transmitted radio wave, can use an antenna with a very short interval, and can detect with high accuracy. An object of the present invention is to obtain an angle detection device that can also be used as an azimuth (direction) sensor and a tilt angle measurement device using the angle detection device.
It is another object of the present invention to provide a tilt angle measuring device that measures the tilt angle of a vehicle with respect to a road and controls the optical axis of the vehicle headlight.

  The angle detection device according to the present invention distributes radio waves received by two receiving antennas into a plurality of distributors, synthesizes the two received radio waves by a combiner after passing through different phase shifters, and detects the combined output. The angle at which a radio wave arrives is detected by a plurality of analog values obtained by detecting with a detector.

The present invention can directly measure the phase of a radio wave transmitted without using a modulated wave, can use an antenna with a very short interval without using an antenna with a long interval, and can perform highly accurate detection. There is.
Furthermore, if a small inclination angle measuring device is applied to a vehicle, the inclination angle of the vehicle with respect to the road can be measured, and the optical axis control system of the headlight can be easily configured.

An embodiment of the present invention will be described below.
Embodiment 1 FIG.
1 is a block diagram showing an angle detection apparatus according to Embodiment 1 of the present invention.
In FIG. 1, a transmitter 1, a transmission antenna 2 connected to the transmitter 1, and reception antennas 3 and 4 for receiving radio waves transmitted from the transmission antenna 2 are provided. Supplied to the distributor 5 and distributed to two radio waves. Two further distributors 6 and 7 are provided on the output side of the distributor 5. Similarly, the radio wave from the receiving antenna 4 is supplied to the distributor 8 and is divided into two radio waves. Two further distributors 9 and 10 are provided on the output side of the distributor 8.
A -60 degree phase shifter 11 and a +60 degree phase shifter 12 are provided on the output side of the distributor 6, and a 0 degree phase shifter 13 and a +90 degree phase shifter are provided on the output side of the distributor 7. 14 is provided. Similarly, a +60 degree phase shifter 15 and a −60 degree phase shifter 16 are provided on the output side of the distributor 9, and a 0 degree phase shifter 17 and −90 degrees are provided on the output side of the distributor 10. The phase shifter 18 is provided.
Between the phase shifter 11 and the phase shifter 15, between the phase shifter 12 and the phase shifter 16, between the phase shifter 13 and the phase shifter 17, and between the phase shifter 14 and the phase shifter 18, respectively. The circuit system is provided with synthesizers 19, 20, 21 and 22 for synthesizing the outputs of the respective phase shifters, and detectors 23, 24 and 25 for detecting the outputs on the output side of the respective synthesizers. And 26 are provided.
The output sides of the detectors 23, 24, 25, and 26 are connected to a calculation control circuit 27 as an angle calculation means, and the output terminals 28 are connected to the output terminals 28 based on the analog values detected by the detectors 23, 24, 25, and 26. The angle at which the radio wave arrives is output.

Next, the operation will be described with reference to FIGS.
Now, when radio waves from the transmitting antenna 2 on the transmitter 1 side are received by the receiving antennas 3 and 4, the receiving antennas 3 and 4 respectively show the solid lines in FIGS. 2 (a) and (b). Received radio waves W1 and W2 are output and supplied to distributors 5 and 8, respectively. The output of distributor 5 is further divided into two by distributor 6 and supplied to phase shifters 11 and 12. Therefore, the phase shifter 11 obtains an output W3 that is delayed by 60 degrees with respect to the received radio wave W1, as shown by a broken line in FIG. 2A, and the phase shifter 12 receives the output radio wave W1. An output W4 advanced by 60 degrees as shown by a broken line in FIG. 2A is obtained.
Similarly, the output of the distributor 8 is further divided into two by the distributor 9 and supplied to the phase shifters 15 and 16. Accordingly, the phase shifter 15 obtains an output W5 that is advanced by 60 degrees with respect to the received radio wave W2, as shown by a broken line in FIG. 2B, and the phase shifter 16 outputs the output W5 to the received radio wave W2. An output W6 delayed by 60 degrees as shown by a broken line in FIG. 2B is obtained.
The output of the distributor 5 is further divided into two by the distributor 7 and supplied to the phase shifters 13 and 14. Therefore, the phase shifter 13 obtains an output W7 having the same phase as the received radio wave W1, and the phase shifter 14 obtains an output W8 advanced by 90 degrees with respect to the received radio wave W1.
Similarly, the output of the distributor 8 is further divided into two by the distributor 10 and supplied to the phase shifters 17 and 18. Therefore, the phase shifter 17 obtains an output W9 in phase with the received radio wave W2, and the phase shifter 18 obtains an output W10 delayed by 90 degrees with respect to the received radio wave W2.

The output W7 of the phase shifter 13 and the output W9 of the phase shifter 17 are supplied to the synthesizer 21 and synthesized, further detected by the detector 25, and on the output side, as shown in FIG. An output having a value (analog value) A obtained by substantially smoothing the half waves of the received radio waves W1 and W2 is obtained.
Further, the output W4 of the phase shifter 12 and the output W6 of the phase shifter 16 are supplied to the synthesizer 20 and synthesized, and further detected by the detector 24, on the output side, as shown in FIG. An output having a value (analog value) B obtained by smoothing a half wave of the output W4 substantially advanced by 60 degrees with respect to the received radio wave W1 and the output W6 delayed by 60 degrees with respect to the received radio wave W2. can get.
Similarly, the output W3 of the phase shifter 11 and the output W5 of the phase shifter 15 are supplied to the synthesizer 19 and synthesized, further detected by the detector 23, and on the output side thereof, as shown in FIG. As shown, it has a smoothed value (analog value) C of a half wave of an output W3 delayed by 60 degrees with respect to the received radio wave W1 and an output W5 advanced by 60 degrees with respect to the received radio wave W2. Output is obtained.
Although the waveform is not particularly shown in FIG. 2, the output W8 of the phase shifter 14 and the output W10 of the phase shifter 18 are supplied to the synthesizer 22 and synthesized, and further detected by the detector 26, On the output side, a half wave of an output W8 substantially advanced by 90 degrees with respect to the received radio wave W1 and an output W10 delayed by -90 degrees with respect to the received radio wave W2 (analog value) ) Is obtained.
In this way, if a +60 degree and -60 degree phase shifter is combined, a synthesizer with a phase difference of +120 degrees or -120 degrees can be obtained for radio waves received by two antennas, and there is no phase difference. In addition to the combiner, ideally, signals having at least three analog values of A, B, and C can be extracted. Further, from the signals having three types of analog values extracted at positions shifted by 120 degrees, it is possible to specify the phase difference between the two radio waves input based on the ratio.
Further, the same three types of signals have the property of being equivalent to the remaining one if the two are added so that, for example, A = B + C, such as three-phase AC.

FIG. 3 shows detection outputs each having the above-described three types of analog values A, B, and C. If the phase difference angle of the received radio wave is d, the analog values A, B, and C of the respective detection outputs are shown. Is expressed by the following equation.
A = 1/2 · cos (d / 2)
B = 1/2 · cos {(d + 120 °) / 2}
C = 1/2 · cos {(d−120 °) / 2}

FIG. 4 shows waveforms obtained by diode detection in the detectors 23-26.
4, assuming that the received wave has a waveform as shown in FIG. 4A, an ideal waveform after detection is as shown in FIG. 4B, for example, when the circuit system of the detector 25 is viewed. The waveform by the diode detection of the detector 25 is, as shown by the solid line in FIG. 4C, the analog value A of the ideal waveform after the detection indicated by the broken line. It has a low analog value a.
Therefore, in an actual detector, there is a detection loss because it is detected by a diode or the like. For this reason, if the diode loss when detecting a high-frequency alternating current is k, it is synthesized, for example, by the detectors 25, 24, 23. If the analog values of the three detection outputs detected and extracted by the diode are a, b, and c, the ideal analog values A, B, and C of the ideal detection output with no loss to be detected are
A = a + k B = b + k C = c + k
For example, when A = B + C, using detected actual analog values a, b, c, a + k = (b + k) + (c + k)
k = a− (b + c)
Therefore, the diode loss k can be easily calculated, and the detection output value without the original loss, for example, the analog value A can be easily obtained.
Further, the phase difference D of the radio waves input to the original two receiving antennas can be easily identified from the signals having the detected analog values A, B, and C that are shifted by 120 degrees.

FIG. 5 is a diagram for explaining a method of detecting the direction of arrival of radio waves.
FIG. 5A is a plan view showing the positional relationship between the transmission antenna 2 and the reception antennas 3 and 4. In FIG. 5A, P represents the distance between the reception antenna 3 and the reception antenna 4, and D Represents substantially the phase difference time between the radio wave arriving at the receiving antenna 3 and the radio wave arriving at the receiving antenna 4, that is, the phase difference angle d.
FIG. 5B is a cross-sectional view showing the positional relationship between the transmitting antenna 2 and the receiving antennas 3 and 4, where E is the point of the transmitting antenna 2, F is the point of the receiving antenna 3, and FIG. When the point is G, the distance P from the receiving antenna 3 to the receiving antenna 4 represents the distance P between the point E and the point G, and the phase difference time D is the distance between the point E and the point F, and the point E and the point G. It can be substantially represented by the difference in distance between the points.
Therefore, the arithmetic and control circuit 27 to which the detection outputs of the detectors 23 to 26 are supplied uses the phase difference time D of the radio wave, the propagation speed of the radio wave, and the distance P from the receiving antenna 3 to the receiving antenna 4 to arrive. The direction or angle is calculated.
Assuming that the angle of arrival of radio waves is θ as shown in FIG. 5B, the calculation performed by the arithmetic control circuit 27 is expressed by the following equation.
θ = tan ⁻¹ (Radio wave speed × D / P)
In this way, the direction (angle) of arrival of the radio wave can be obtained by substantially obtaining the phase difference of the radio wave, that is, the time difference of the incoming radio wave.

  As described above, according to the first embodiment, the radio waves received by the two receiving antennas are divided into a plurality by the distributors, and after passing through different phase shifters, the two received radio waves are synthesized and detected. Since the angle at which the radio wave arrives is detected by a plurality of analog values obtained in this way, the phase of the carrier wave, that is, the radio wave can be directly measured without using a modulated wave, and an extremely short interval without using a long-spaced antenna The antenna can be used, and high-precision detection is possible.

Embodiment 2. FIG.
FIG. 6 is a block diagram showing an inclination angle measuring apparatus according to Embodiment 2 of the present invention. This embodiment shows a case where the angle detection device in the first embodiment described above is applied to an inclination angle measurement device that measures the inclination angle of a vehicle with respect to a road as an example.
In FIG. 6, this tilt angle measuring device includes a transmitter 30 that generates a specific frequency pulse, and converts the frequency pulse from the transmitter 30 into a radio wave, which is directed to an object that reflects the radio wave, for example, a road surface 35. The horn antenna 31 functioning as a transmitting antenna for transmitting and receiving, the horn antennas 32 and 33 functioning as receiving antennas for receiving the radio waves reflected by the road surface 35, and the radio waves from the horn antennas 32 and 33 are input. An angle for calculating a tilt angle with respect to the road surface of the vehicle based on the phase difference detection means 34 for detecting the phase difference, the output of the phase difference detection means 34, the propagation speed of the radio wave, and the distance from the horn antenna 32 to the horn antenna 33. And an arithmetic control circuit 36 as arithmetic means. The phase difference detecting means 34 has a circuit configuration including the distributor, phase shifter, synthesizer, detector, and the like described in FIG. Here, the detection output from the phase difference detection means 34 is representatively shown as an example of analog values A, B, and C of the detection output from the detectors 25, 24, and 23 in FIG.

Next, the operation will be described.
The transmitter 30 generates a specific frequency pulse of 10 GHz, for example, and supplies it to the horn antenna 31. The horn antenna 31 converts the frequency pulse obtained from the transmitter 30 into a radio wave, and transmits the radio wave toward the road surface 35 where there is a reflector.
The radio waves hit the road surface 35 and are reflected, and the horn antennas 32 and 33 receive the radio waves reflected by the road surface 35, convert them into electric signals of frequency pulses corresponding to those radio waves, and supply them to the phase difference detection means 34. As described with reference to FIG. 1, the phase difference detecting means 34 distributes the radio wave input by the distributor and supplies it to a plurality of phase shifters. Each phase shifter has a predetermined angle, for example, 60 with respect to the received radio wave. Two outputs that are advanced or delayed in phase are obtained, the obtained two outputs are synthesized by a synthesizer, and detected by a detector to obtain a phase difference as an analog value detection output. The detection output from the phase difference detection means 34 is supplied to the arithmetic control circuit 36, which receives the phase difference of the received radio wave, the propagation speed of the radio wave, and the horn antenna 32 to the horn antenna 33. The inclination angle of the vehicle with respect to the road is calculated according to the distance. The calculated inclination angle is used, for example, for headlight optical axis adjustment (auto levelizer) and suspension strength control.
In addition, a tilt angle measuring device using radio waves is not affected by wind or natural winds caused by traveling of a vehicle like ultrasonic waves, and the antenna opening is covered with a resin that easily transmits radio waves. The opening of the facing antenna becomes a flat surface, and adhesion of snow, ice, mud and the like is reduced, and the influence of the attached matter can be reduced. In addition, for example, a 20 KHz ultrasonic wave has a wavelength of 17 mm, whereas a 10 GHz radio wave has a wavelength of 30 mm, and a more averaged road surface can be detected.

  As described above, according to the second embodiment, by using a horn antenna as a transmission or reception antenna, directivity can be adjusted, radio waves can be concentrated in a necessary direction, and the radio wave intensity is increased. A wide range of radio waves can be received and sensitivity can be improved. Accordingly, since a weak radio wave transmitter can be used as a transmitter, power can be saved and unnecessary radio waves can be prevented from being emitted. Further, since the phase of the received radio wave can be detected even at a high frequency, it is possible to use a G (giga) band radio wave. If a horn antenna is used, the azimuth or the tilt angle can be detected with a small device. The measurement bottleneck is the phase of the radio wave, but this embodiment does not require frequency accuracy as in the case of a so-called communication device, and the transmitter has sufficient characteristics with a simple configuration. Is obtained.

Embodiment 3 FIG.
7 and 8 are configuration diagrams showing an inclination angle measuring apparatus according to Embodiment 3 of the present invention.
In FIG. 7, the horn antenna 31 that is a transmitting antenna for transmitting radio waves and the horn antennas 32 and 33 that are two receiving antennas are arranged at equal distances, and are arranged in a straight line with the transmitting antenna of the horn antenna 31 at the center. In FIG. 8, a horn antenna 31 that is a transmitting antenna for transmitting radio waves and horn antennas 32 and 33 that are two receiving antennas are arranged at the vertices of an isosceles triangle.

  As described above, according to the third embodiment, by using a horn antenna as a transmission or reception antenna, directivity can be adjusted, radio waves can be concentrated in a necessary direction, and the strength of radio waves is increased. A wide range of radio waves can be received and sensitivity can be improved. Therefore, since a weak radio wave transmitter can be used, power can be saved and at the same time unnecessary radio waves can be prevented from being emitted.

Embodiment 4 FIG.
FIG. 9 is a block diagram showing an inclination angle measuring apparatus according to Embodiment 4 of the present invention. 9, parts corresponding to those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the present embodiment, the opening of the transmitting horn antenna 31 protrudes from the opening of the receiving horn antennas 32 and 33, and the receiving horn antennas 32 and 33 are reflected in the directivity shadow of the transmitting horn antenna 31. Arrange them so that they are substantially hidden.
By arranging the horn antenna in this way, it is difficult for the transmission radio wave that wraps around from the transmitting horn antenna 31 to directly enter the receiving horn antennas 32 and 33, and the S / N ratio of the receiving circuit is improved and the sensitivity is improved. improves.

  As described above, according to the fourth embodiment, the S / N of the receiving circuit is obtained by projecting the opening of the horn antenna that transmits radio waves to the object side from the opening of the horn antenna for receiving radio waves. Sensitivity can be improved.

Embodiment 5 FIG.
10 is a block diagram showing a distributor in an inclination angle measuring apparatus according to Embodiment 5 of the present invention.
In this embodiment, as shown in FIG. 10, a circuit pattern 41 on a substrate such as a Wilkinson distributor that branches an input into two outputs OUT1 and OUT2 is used as a distributor. Further, after branching into two branches, it may be further split into two branches, which is an extra circuit, but each can be equally distributed. If a slight error is allowed, it can be branched into three branches without creating a useless circuit. Of course, this distributor is also applicable to the angle detection apparatus of FIG.

  As described above, according to the fifth embodiment, the circuit configuration is simplified and the cost can be reduced by using the circuit pattern of the substrate such as the Wilkinson distributor as the distributor.

Embodiment 6 FIG.
FIG. 11 is a configuration diagram showing a distributor and a λ / 6 phase shifter in an inclination angle measuring apparatus according to Embodiment 6 of the present invention.
In the present embodiment, as shown in FIG. 11, as a distributor, the input is branched into two outputs, and the circuit pattern of one of the branched boards is changed by, for example, λ / 6 according to the required phase shift amount. A circuit pattern 42 of the substrate that is shorter than the circuit pattern of the substrate is used. The circuit pattern 42 on the substrate substantially has both functions of a distributor and a phase shifter. Of course, the length of the circuit pattern of the substrate that also serves as the phase shifter can be set longer or shorter depending on the required amount of phase shift.

  As described above, according to the sixth embodiment, the speed of propagation of radio waves in the circuit board is the same as the speed in the air, and the circuit pattern of the board can be lengthened or shortened according to the required phase shift amount. Therefore, it is possible to arbitrarily shift the phase of the radio wave and contribute to the versatility of the circuit. Note that this distributor and phase shifter are also applicable to the angle detection device of FIG.

Embodiment 7 FIG.
FIG. 12 is a block diagram showing a transmitter using a dielectric resonator and its peripheral circuit in the tilt angle measuring apparatus according to Embodiment 7 of the present invention.
In FIG. 12, a dielectric resonator 50 is provided, circuit patterns 51 and 52 are arranged on both sides thereof, one end of the circuit pattern 51 is connected to the gate terminal of the MOS transistor 53, and one end of the circuit pattern 52 is connected to the transistor 53. Connect to the drain terminal. The drain terminal of the transistor 53 is connected to the + side of the power source 56 via the coil 54 and the resistor 55, and the connection point between the coil 54 and the resistor 55 is grounded via the capacitor 57. The resistor 55 and the capacitor 57 substantially constitute a filter.
The source terminal of the transistor 53 is connected to one end of the circuit patterns 59 and 60 through the circuit pattern 58, and the common connection point is grounded through the coil 61 and the resistor 62. The other end of the circuit pattern 60 is connected to the output terminal 66 through the capacitor 63 and resistors 64 and 65, and the connection point of the resistors 64 and 65 is grounded through the resistor 67.
Here, the circuit elements 50 to 57 constitute a transmitter, the circuit element 58 to the resistor 62 constitute a stabilization circuit, and the circuit elements 63 to 65 and 67 constitute a filter.
By the way, in the tilt angle measuring apparatus, the measurement bottleneck is the phase of the radio wave, and the angle error becomes an acceptable value even if the frequency error is not as strict as the so-called communication device. Therefore, it is sufficient if the accuracy of the frequency can be secured to some extent, and as described above, sufficient characteristics can be obtained even with a transmitter using a dielectric resonator having a simple configuration. Of course, this transmitter can also be applied to the angle detection device of FIG.

  As described above, according to the seventh embodiment, the circuit configuration can be simplified and the cost can be reduced by using the dielectric resonator as the transmitter.

Embodiment 8 FIG.
FIG. 13 is a block diagram schematically showing a case where a PIN diode is used as a detector in the phase difference detecting means in the tilt angle measuring apparatus according to the eighth embodiment of the present invention.
In FIG. 13, receiving antennas 70 and 71 are provided, the received radio wave from the receiving antenna 70 is distributed by a distributor 72, and one of the radio waves is phase-shifted by a predetermined amount by a phase shifter 73. Similarly, the received radio wave from the receiving antenna 71 is distributed by the distributor 74, and one radio wave is phase-shifted by a predetermined amount by the phase shifter 75. Then, the combiner 76 combines the outputs from the phase shifters 73 and 75, detects it with a detector 77 using a PIN diode, and outputs an analog value to the output terminal 78 as a detection output. This detector can also be applied to the angle detection device of FIG.

  As described above, according to the eighth embodiment, an inclination angle measuring device for a short-distance object or a PIN diode having a small junction capacitance is used in an environment where a strong radio wave is obtained, particularly at a high frequency in the GHz band. By using a diode for a detector, that is, using a diode for high-frequency detection, a sufficient detection output can be obtained with a simple circuit configuration, which can contribute to simplification of the circuit configuration and cost reduction.

Embodiment 9 FIG.
FIG. 14 is a block diagram showing an inclination angle measuring apparatus according to Embodiment 9 of the present invention. 14, parts corresponding to those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof is omitted.
Normally, if the radio wave reflected and returned from the object is weak, the analog value after detection becomes small, and the detection accuracy may deteriorate. If a received radio wave of the same level is always obtained, a tilt angle with a stable accuracy can be detected, the distance to the object is far away, or the received radio wave that is composed of a substance that is difficult to reflect is weak. Needs to control the transmitter, that is, the transmitter so that the intensity of the received radio wave is the same and the intensity of the received radio wave is the same.
Therefore, in the present embodiment, as the angle calculation means having the function of calculating the tilt angle as described above and controlling the output level of the transmitter 30 so as to make the input to the phase difference detection means 34 constant. An arithmetic control circuit 37 is provided between the phase difference detection means 34 and the transmitter 30 so that the received radio waves from the horn antennas 32 and 33 always have the same intensity, that is, the input to the phase difference detection means 34 is always performed. The output level of the transmitter 30 is controlled by the arithmetic control circuit 37 so as to be constant.
Note that the function of the arithmetic control circuit 37 that controls the output level of the transmitter 30 so that the input to the phase difference detecting means 34 is constant can also be applied to the angle detection device of FIG. The output level of the transmitter 1 may be controlled by the control circuit 27 so that the input to the distributors 5 and 8 is constant.

  As described above, according to the ninth embodiment, the output level of the transmitter is controlled so as to make the input to the phase difference detecting means constant, that is, the level of the transmitter is made variable to reduce the received radio wave. By controlling to the same level, it is possible to always obtain the received radio wave at the same level, and to measure the tilt angle with stable accuracy.

Embodiment 10 FIG.
FIG. 15 is a block diagram showing an inclination angle measuring apparatus according to Embodiment 10 of the present invention. 15, parts corresponding to those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof is omitted.
As described in the ninth embodiment, if the radio wave reflected and returned from the object is weak, the detection accuracy deteriorates. Where the radio wave is weak, the influence of the diode to be detected is large. Therefore, it is necessary to control so that a sufficient input is obtained and the detection output becomes a constant value.
Therefore, in the present embodiment, the amplifier 38 having a variable amplification factor between the horn antennas 32 and 33 as receiving antennas and the input side of the phase difference detecting means 34 to make the input to the phase difference detecting means 34 constant. , 39 and an arithmetic control circuit 40 having a function of calculating the tilt angle and controlling the amplification factor of the amplifiers 38, 39 as described above is provided on the output side of the phase difference detecting means 34, and the phase difference detecting means A so-called AGC circuit is configured to control the amplification factors of the amplifiers 38 and 39 by the arithmetic and control circuit 38 in accordance with the level of the detection output from the circuit 34 so as to make the input to the phase difference detection means 34 constant. Control is performed so that the value of the detection output from the means 34 is always a constant value.
Also in this case, the function of the arithmetic control circuit 40 for making the input to the phase difference detecting means 34 constant is also applicable to the angle detecting device of FIG. 1, in which case the receiving antennas 3 and 4 and the distributor 5 and 8, amplifiers with variable amplification factors are provided to make the input to the distributors 5 and 8 constant, and the input of the amplifiers to the distributors 5 and 8 is made constant by the operation control circuit 27. Control may be performed so that

As described above, according to the tenth embodiment, before detection, sufficient input to the phase difference detection means is obtained and control is performed so that the detection output becomes a constant value. A high tilt angle can be measured.
Further, if the tilt angle detection device in each of the above embodiments is applied to a vehicle, the tilt angle of the vehicle with respect to the road can be measured, and the optical axis system of the headlight can be easily configured.

It is a block diagram which shows the angle detection apparatus by Embodiment 1 of this invention. It is a wave form diagram which shows the received waveform and detection value in the angle detection apparatus by Embodiment 1 of this invention. It is a figure which shows the phase difference and detection output of a received radio wave in the angle detection apparatus by Embodiment 1 of this invention. It is a figure which shows the waveform by the diode detection in the angle detection apparatus by Embodiment 1 of this invention. It is a figure for demonstrating the direction detection method of the electromagnetic wave in the angle detection apparatus by Embodiment 1 of this invention. It is a block diagram which shows the inclination-angle measuring apparatus by Embodiment 2 of this invention. It is a block diagram which shows the inclination-angle measuring apparatus by Embodiment 3 of this invention. It is a block diagram which shows the inclination-angle measuring apparatus by Embodiment 3 of this invention. It is a block diagram which shows the inclination-angle measuring apparatus by Embodiment 4 of this invention. It is a block diagram which shows the divider | distributor in the inclination-angle measuring apparatus by Embodiment 5 of this invention. It is a block diagram which shows the divider | distributor and (lambda) / 6 phase shifter in the inclination-angle measuring apparatus by Embodiment 6 of this invention. In the inclination angle measuring apparatus according to Embodiment 7 of the present invention, it is a configuration diagram showing a transmitter using a dielectric resonator and its peripheral circuit. In the inclination angle measuring apparatus according to the eighth embodiment of the present invention, it is a configuration diagram schematically showing a case where a PIN diode is used as a detector in the phase difference detecting means. It is a block diagram which shows the inclination-angle measuring apparatus by Embodiment 9 of this invention. It is a block diagram which shows the inclination-angle measuring apparatus by Embodiment 10 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Transmitter, 2 Transmitting antenna, 3,4 Receiving antenna, 5, 6, 7, 8, 9, 10 Divider, 11, 12, 13, 14 Phase shifter, 19, 20, 21, 22 Synthesizer, 23 , 24, 25, 26 Detector, 27 Operation control circuit, 30 Transmitter, 31 Horn antenna (transmitting antenna), 32, 33 Horn antenna (receiving antenna), 34 Phase difference detecting means, 35 Road surface, 36, 37, 40 Calculation control circuit (angle calculation means), 38, 39 Amplifier.

Claims (13)

  Two receiving antennas that receive radio waves from the transmitting antenna, a distributor that distributes the radio waves received by the two receiving antennas, and a phase of the radio waves that are distributed by the distributor to different values. A phase shifter, a combiner that combines a plurality of outputs from the phase shifter, a detector that detects the output combined by the combiner, and an electric wave arrives based on the output of the detector An angle detection device comprising angle calculation means for calculating an angle.   Radio waves received by the two receiving antennas are distributed to at least three or more circuit systems by a distributor, and at least one circuit system combines and detects the received radio waves from the two receiving antennas at the same phase position, and at least 1 The circuit system shifts the received radio wave from the two receiving antennas by the first phase shifter and performs synthetic detection at a phase difference of 120 degrees, and at least one circuit system is shifted by the second phase shifter. The angle detection device according to claim 1, wherein the received radio waves from the two receiving antennas are phase-shifted, and the combined detection is performed at a phase difference of -120 degrees.   3. The angle detection device according to claim 1, wherein at least the phase shifter and the distributor are configured by a circuit pattern of the substrate.   4. The phase shifter according to claim 3, wherein the circuit pattern of the substrate is adjusted to a length corresponding to the amount of phase shift, and an equal length circuit pattern is used for a circuit guided in the same phase. Angle detection device.   The angle detector according to any one of claims 1 to 4, wherein the detector uses a diode for high-frequency detection.   6. The angle detection device according to claim 1, wherein a dielectric resonator is used for the transmitter connected to the transmission antenna.   7. The angle detection apparatus according to claim 6, wherein the output level of the transmitter is varied based on the output of the angle calculation means, and the received radio wave is controlled to the same level.   The amplifier according to any one of claims 1 to 7, wherein an amplifier capable of varying an amplification factor is provided between each of the two receiving antennas and the distributor to amplify the received radio wave to a constant level. Angle detection device.   An angle detection device according to any one of claims 1 to 8, comprising an angle detecting device according to any one of claims 1 to 8, wherein the radio wave transmission direction from the transmitting antenna and the radio wave receiving direction by the two receiving antennas are reflected in substantially the same direction. An inclination angle measuring apparatus for measuring an inclination angle with respect to an object toward the object.   The transmitting antenna and the two receiving antennas are arranged at an equal distance, and the transmitting antenna and the two receiving antennas are arranged at the vertices of an isosceles triangle, or in a straight line with the transmitting antenna at the center. The tilt angle measuring device according to claim 9.   11. The tilt angle measuring apparatus according to claim 9, wherein a horn antenna is used for at least one of the transmitting antenna and the two receiving antennas.   12. The tilt angle measuring apparatus according to claim 11, wherein an opening portion of the transmitting horn antenna protrudes toward the object side from an opening portion of the receiving horn antenna.   The inclination angle measuring device according to any one of claims 9 to 12, wherein an inclination angle of the vehicle with respect to a road is measured.

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