JPH06213989A - Azimuth measuring device and time interval measuring device - Google Patents

Abstract

PURPOSE:To enable measuring azinuth three dimensionally in measuring the azimuth of coming RF signals without degradation of measuring accuracy due to the characteristics variation in antenna and receiver. CONSTITUTION:The differences in arrival time of RF signals input in three antennas 101a to 101c placed at constant intervals are measured with a time interval measuring circuit 105 and the arrival direction of the input RF signals is obtained from the intervals of the antennas 101a to 101c and propagation velocity of the RF signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in the field of azimuth measuring apparatus for measuring the arrival direction of an input RF signal, communication equipment, radar apparatus and the like, and a time interval measuring apparatus for measuring a time interval between two input signals. It is about.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing a conventional bearing measuring device disclosed in Japanese Patent Laid-Open No. 3-59481.
In the figure, 101a and 101b are two antennas and 10
2a and 102b are two receivers for receiving the RF signals captured by the antennas 101a and 101b, and 103 is the receiver 10
2a and 102b are amplitude comparison circuits for comparing the reception levels A and B, and 104 is an output terminal.

Next, the operation will be described. Two directional antennas 101a, 101 installed at a certain distance
The RF signals input to b are the rear receivers 102a, 102a,
Each of the reception levels A and B received at 102b is input to the amplitude comparison circuit 103, converted into azimuth data, and output to the output terminal 104.

For example, now two antennas 101a, 10
If the directional gain of 1b is as shown in FIG. 8, if an RF signal is input at an angle θ here, a difference occurs between the reception levels A and B, and this difference is processed as azimuth data by a circuit in the subsequent stage. , The angle θ is obtained.

As described above, the azimuth is measured by comparing the reception levels A and B of the two input signals 204 and 205, and the measurement accuracy is determined by each antenna 101a ,.
It is determined by the gain of 101b and the gain of each receiver 102a, 102b.

FIG. 9 shows another conventional example, in which the same reference numerals as those in FIG. 7 indicate the same or corresponding portions, and 108 is a phase comparison circuit.

Next, the operation will be described. When the RF signals are input to the two antennas 101a and 101b at a certain angle θ, a phase difference occurs, and the angle θ is obtained by processing this difference in a circuit in the subsequent stage.

As described above, the azimuth is measured by comparing the phases of two input signals, and for that purpose, the propagation phase in the device must be always constant. Further, only the azimuth measurement can be performed on the plane including the two antennas 101a and 101b. That is, in FIG. 10, only the horizontal angle θ in the x, y plane can be measured when the vertical angle β on the x, y, z axes is small.

FIG. 11 is a block diagram showing a conventional time interval measuring apparatus. In the figure, 201 is an oscillating circuit and 2 is a circuit diagram.
Reference numeral 02 is a reference time generation circuit that generates a reference signal based on the output of the oscillation circuit 201, 203 is a gate circuit, and 206 is a gate control circuit that receives the start signal 204 and the stop signal 205 as input and controls the operation of the gate circuit 203. , 207 are counters for counting the counting pulses from the gate circuit 203.

Next, the operation will be described. In FIG. 12, based on the output signal of the oscillation circuit 201, a pulse (see FIG. 12D) that serves as a reference time signal is output from the reference time generation circuit 202 to the gate circuit 203. Then, the start signal 204, the stop signal 205 (FIG. 12A,
(B)) is input to the gate control circuit 206 and converted into a gate opening / closing signal (FIG. 12 (c)). Further, the gate circuit 203 opens the gate of the gate circuit 203 from the input of the start signal 204 to the input of the stop signal 205 by the gate opening / closing signal, and outputs a counting pulse to the counter 207. The counter 207 counts this counting pulse (FIG. 12E) and displays the input time interval from the input of the start signal 204 to the input of the stop signal 205.

As described above, the time interval is measured by counting the number of pulses of the reference time signal, and the measurement resolution at that time is the period (1 / frequency) of the reference time signal.
Determined by

[0012]

Since the conventional azimuth measuring apparatus is constructed as described above, the input R as shown in FIG.
When the angle of arrival is obtained from the difference in the reception level of the F signal, the antennas 101a and 101 are used to improve the performance.
Since the gain of b and the gain of each of the receivers 102a and 102b must be set with high accuracy and the gains must be constant at all times, the device becomes complicated, large in size, expensive, and reliable. There was a problem such as falling. Further, when the arrival angle is obtained from the phase difference of the input RF signal,
The phase in the propagation path from the antennas 101a and 101b to the phase comparison circuit 108 needs to be always constant,
Not only is the device expensive, but when the antenna is a one-dimensional array, there is a problem that the error in the measured value of the horizontal arrival angle (coning error) increases as the vertical arrival angle of the RF signal increases. In addition, it is difficult to widen the band due to amplitude and phase changes due to the received frequency,
There is a problem that the measurement accuracy is deteriorated due to antenna pattern distortion and phase disturbance due to reflection of the structure surrounding the antenna.

Furthermore, in the conventional time interval measuring device, in order to increase the measurement resolution of the time interval, it is necessary to increase the frequency of the reference time signal. However, in order to obtain a resolution of several ns or less, the UHF to microwave band is used for the frequency of the reference time signal, which makes it difficult to realize the gate circuit 203 and the counter 207 and also becomes expensive. There was a problem.

The present invention has been made to solve the above-mentioned problems, and includes an antenna, a gain of a receiver, a phase,
An object of the present invention is to obtain an azimuth measuring device capable of measuring azimuth three-dimensionally without the measurement accuracy being affected by changes in frequency and temperature. Also, it is cheap and several ns
An object of the present invention is to obtain a time interval measuring device that can easily obtain the following resolutions.

[0015]

An azimuth measuring apparatus according to the invention of claim 1 comprises three antennas installed at regular intervals and three antennas for receiving RF signals captured by the respective antennas. The receiver includes a receiver, a time interval measuring circuit 105 for obtaining a difference in arrival times of RF signals received by the receivers, and an azimuth calculating circuit 106 for obtaining an arrival direction of the RF signal from the obtained time intervals. .

An azimuth measuring apparatus according to a second aspect of the present invention is provided with four or more antennas and receivers according to the first aspect.

According to a third aspect of the present invention, there is provided a time interval measuring device which includes a signal generating circuit for generating a voltage which changes with time and two A / D circuits to which outputs of the signal generating circuit are added.
It is provided with a converter and a signal processing circuit for obtaining the time interval from the voltage value obtained from the A / D converter.

A time interval measuring apparatus according to a fourth aspect of the present invention uses a sawtooth wave generating circuit or a sine wave generating circuit as the signal generating circuit.

[0019]

In the azimuth measuring device according to the invention of claim 1, the time interval measuring circuit measures the arrival time difference caused by receiving the RF signal coming from a certain direction by a plurality of antennas installed at a certain distance interval. However, in the azimuth calculation circuit, the above R is calculated from the distance between the antennas and the propagation speed of the RF signal.
The arrival direction of the F signal can be obtained in three dimensions.

The azimuth measuring device according to the invention of claim 2 is
By providing four or more antennas and receivers, it is possible to measure the horizontal angle and the vertical angle of the RF signal regardless of the direction from which the RF signal comes.

According to a third aspect of the present invention, the time interval measuring device A / D-converts the time-converted output voltage of the signal generating circuit at two different input signal timings, and converts the signal processing circuit to time data. By so doing, it is possible to capture the time interval between the two input signals as the output voltage of the signal generating circuit that has changed during that time,
The resolution can be easily improved.

In the time interval measuring device according to the invention of claim 4, the sawtooth wave voltage or the sine wave voltage is used as the time-varying voltage so that the time between two input signals is regarded as a continuous analog quantity. Therefore, the time interval is several ns with a simple configuration without using a high frequency band signal.
It can be measured with the following resolutions.

[0023]

【Example】

Example 1. An embodiment of the invention of claim 1 will be described below with reference to the drawings. FIG. 1 is a block diagram showing an azimuth measuring apparatus according to a first embodiment. In the figure, 101a, 101b,
101c is three antennas 102a, 102b, 102c installed at a certain fixed distance interval.
01c is three receivers for capturing RF signals, and 105 is a time interval measurement circuit for measuring the arrival time difference of the RF signals received by the receivers 102a to 102c.
An azimuth calculation circuit 06 outputs the horizontal angle and the vertical angle of the incoming RF signal from the obtained arrival time difference. 107a, 1
Reference numerals 07b are output terminals having a horizontal angle and a vertical angle, respectively.

Next, the operation will be described. As shown in FIG. 2, the coordinate A of the antenna 101a is (0, 0), and the antenna 1
The coordinates B and C of 01b and 101c are (xb, y
Consider a coordinate system of b) and (xc, yc). However,
It is assumed that A, B and C are not on the same straight line. Now xz
When an RF signal having an angle of θ with respect to the plane and β with respect to the xy plane arrives, the following relationship holds. c (ta-tb) cos β = xb cos θ + y b sin θ (1) c (ta-t c) cos β = x c cos θ + y c sin θ (2) where ta, tb, and tc are antennas 101a and 101a, respectively.
RF signal arrival times at 101b and 101c, and c is the propagation speed of the RF signal. Therefore, from equations (1) and (2), RF
The horizontal arrival angle θ and the vertical arrival angle β of the signal can be obtained from the following equations.

Θ = tan ⁻¹ {xc · (ta-tb) −xb · (ta / tc)} / {yb · (ta-tc) −yc · (ta-tb)} (3) β = cos ⁻¹ (sin θ / c) · {(xc · yb-xb · yc) / {xc · (ta-tb) -xb · (ta-tc)}} (4)

The RF signal arrival time differences ta-tb and ta-tc expressed by the equations (3) and (4) are the time interval measuring circuit 10.
5, θ and β are calculated by the azimuth calculation circuit 104 and output to the output terminals 107a and 107b.

As described above, according to the first embodiment, the three antennas 101a to 101a, which are installed at regular intervals,
101c, three receivers 102a to 102c for capturing an RF signal in each antenna, and a time interval measuring circuit 10 for measuring the arrival time difference between the RF signals received by each receiver.
5 and the azimuth calculation circuit 106 that obtains the horizontal angle θ and the vertical angle β from the obtained arrival time difference, even if the gain, phase, frequency, and temperature change in each antenna and receiver, Measurement accuracy is not affected by this, and since only the rising time of the input signal is measured, the measurement accuracy is not affected even if there is a reflection signal from the surrounding structure, and highly accurate three-dimensional azimuth measurement is possible. It can be performed.

Example 2. FIG. 3 is a block diagram showing an azimuth measuring apparatus according to an embodiment of the invention of claim 2. In this embodiment 2, the azimuth is provided over the entire space by providing another system of the antenna and the receiver in the embodiment 1. It is designed to be measurable. In the figure, 101d, 10
2d is an antenna and a receiver of another system, respectively.

Next, the operation will be described. Aerial 101
It is assumed that d is located outside the plane determined by the coordinates of the antennas 101a to 101c. By selecting an appropriate three of the four antennas 101a to 101d according to the arrival direction of the RF signal, the horizontal angle and the vertical angle of the RF signal can be measured regardless of the direction.

Although the antenna and the receiver have four systems in the second embodiment, the number of systems may be four or more.

Example 3. FIG. 4 is a block diagram showing a time interval measuring device according to an embodiment of the invention of claims 3 and 4. In the figure, the same reference numerals as those in FIG. 9 indicate the same or corresponding portions, and 208 is a signal generating circuit, In the third embodiment, a sawtooth wave generation circuit (signal generation circuit) is used.
209a and 209b are A / D converters that operate at the rising edges of the start signal 204 and the stop signal 205, respectively.
210 is a signal processing circuit for converting the voltage data of the A / D converters 209a and 209b into time interval data, and 211 is an output terminal. In addition, the sawtooth wave generation circuit described above includes, for example, an operational amplifier 208a and a capacitor 20.
8b, 208f, transistor 208c, resistor 208d
To e, a DC power source 208g, and a pulse generator 208h, and outputs a sawtooth voltage TH. The start signal 204 and the stop signal 205 are two input signals input at different timings.

Next, the operation will be described. As shown in FIG. 5, the output of the A / D converter 209a when operating at the rising edge of the start signal 204 is Vs, and the stop signal 2 is
A / D converter 209 when operating at the rising edge of 05
If the output of b is Ve, the start signal 20
4. The time interval Δt between the stop signals 205 is expressed as follows. Δt = ΔV / α = (Ve−Vs) / α (5) where α represents the slope of the sawtooth wave. The processing represented by the equation (5) is performed by the signal processing circuit 210, and the output terminal 211
The time interval data is output to. After calculating the time interval data, the signal processing circuit 210 outputs a reset signal to the two A / D converters and waits for the next start signal 204 and stop signal 205.

As described above, according to the third embodiment, since the time data is obtained from the sawtooth wave voltage TH which changes between the input of the start signal 204 and the input of the stop signal 205, the start is started. The time between the signal 204 and the stop signal 205 is regarded as a continuous analog amount, and the time interval can be measured with a resolution of several ns or less with a simple configuration without using a signal in a high frequency band.

Example 4. FIG. 6 is a block diagram showing a time interval measuring device according to another embodiment of the present invention.
In the fourth embodiment, a sine wave generation circuit (signal generation circuit) 212 is used as a sawtooth wave generation circuit (signal generation circuit), and the voltage-time relationship of the sine wave voltage S in the signal processing circuit 210 is used. , A / D converters 209a, 2
Two storage circuits 213a and 213b for converting the voltage data input from 09b into time data are provided. In addition, the sine wave generation circuit (signal generation circuit) 212
Is a sine wave oscillator 212a and a 180 ° phase converter 212.
b, a switch 212c, a comparator 212d, a DC power source 212e and a resistor 212f. As the sine wave voltage S, a waveform in which the phase is inverted by 180 ° for each maximum amplitude is used here as shown in the figure.

Next, the operation will be described. Start signal (input signal) 204, Stop signal (input signal) 205
A / D converter 209 that operates at each rising edge
a and 209b, the two voltage data obtained from the memory circuits 213a and 213b are converted into time data corresponding to the voltage-time relationship of the sine wave voltage S, and the difference between them is calculated, whereby the start signal 204 , The time interval between the stop signals 205 can be obtained.

As described above, according to the fourth embodiment, the time interval between two input signals is regarded as a voltage that changes corresponding to a known voltage-time relationship, and converted into time data. Therefore, the time interval can be easily measured with the same resolution as that of the third embodiment. In the third and fourth embodiments, a sawtooth wave and a sine wave are used as the voltage that changes with time, but other waveforms may be used.

Further, by using the time interval measuring device described in the third and fourth embodiments in the first and second embodiments, it is possible to realize a highly accurate three-dimensional azimuth measuring device.

[0038]

As described above, according to the first aspect of the invention, the arrival directions of the RF signals are determined to be 3 from the arrival time difference of the RF signals arriving at the three antennas installed at a certain distance.
Since it is configured to measure in two dimensions, the measurement accuracy is not affected by changes in gain, phase, frequency, temperature, and reflected signals of surrounding structures in each antenna and receiver, and high accuracy that eliminates Corning error There is an effect that accurate three-dimensional azimuth measurement can be performed at low cost.

According to the second aspect of the present invention, since four or more antennas and receivers are used, the horizontal angle and vertical angle of the RF signal coming from all directions can be measured.

According to the third aspect of the present invention, the time interval between the two input signals is regarded as a time-varying voltage,
Since the voltage is converted into time and measured, there is an effect that high-resolution time interval measurement can be easily performed.

According to the fourth aspect of the invention, the time interval between the two input signals is regarded as a change in the sawtooth wave or sine wave voltage, and the voltage is converted into time for measurement. There is an effect that a high-resolution time interval measuring device can be obtained at low cost without using a signal.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an azimuth measuring device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the operation of the azimuth measuring apparatus according to the first embodiment.

FIG. 3 is a configuration diagram of an azimuth measuring device according to a second embodiment of the invention of claim 2;

FIG. 4 is a configuration diagram of a time interval measuring device according to a third embodiment of the present invention.

FIG. 5 is a waveform diagram showing an operation of the time interval measuring device according to the third embodiment.

FIG. 6 is a configuration diagram of a time interval measuring device according to a fourth embodiment of the invention of claims 3 and 4.

FIG. 7 is a block diagram of a conventional azimuth measuring device.

FIG. 8 is a characteristic diagram for explaining the operation of the azimuth measuring device.

FIG. 9 is a block diagram of another conventional azimuth measuring device.

FIG. 10 is an explanatory diagram for explaining a measurement azimuth of the azimuth measuring device.

FIG. 11 is a block diagram of a conventional time interval measuring device.

FIG. 12 is a waveform diagram showing an operation of the time interval measuring device.

[Explanation of symbols]

 101a to 101d Antenna 102a to 102d Receiver 105 Time interval measurement circuit 106 Direction calculation circuit 204 Start signal (input signal) 205 Stop signal (input signal) 208 Sawtooth wave generation circuit (signal generation circuit) 209a to 209b A / D converter 210 signal processing circuit 212 sine wave generation circuit (signal generation circuit)

Claims (4)

[Claims] 1. A set of three antennas, which are installed at regular intervals, a set of three receivers for receiving RF signals captured by the antennas, and a set of RFs received by the receivers.
An azimuth measuring device comprising: a time interval measuring circuit for obtaining a signal arrival time difference; and an azimuth calculating circuit for obtaining an arrival direction of the RF signal from the arrival time difference obtained from the time interval measuring circuit. 2. The azimuth measuring device according to claim 1, wherein four or more antennas and receivers are provided. 3. A signal generation circuit for outputting a time-varying voltage in a time interval measuring device for measuring a time interval between two input signals input at different timings,
Two A / s operating at the timing of the above two input signals
The D converter and the output voltage of each A / D converter are
A signal processing circuit for converting each time into a time corresponding to the relationship between the output voltage of the signal generating circuit and the time, and obtaining the time interval between the two input signals based on the converted time. And time interval measuring device. 4. The time interval measuring device according to claim 3, wherein a sawtooth wave generating circuit or a sine wave generating circuit is used as the signal generating circuit.