JPS61215979A - Speed measuring method for moving target - Google Patents

Abstract

PURPOSE:To measure the speed of a moving target by receiving a measuring frequency signal and a comparing frequency signal transmitted from the fixed target, at the moving target side and obtaining the change of range by the phase shifting quantity of the phase angle obtained from a phase difference of both signals. CONSTITUTION:A measuring frequency signal S1 and a comparing frequency signal S2 apply the double modulation to a carrier signal S3, are transmitted from a fixed station A and received at a moving station B apart from which by a range L. In the first mixer 8, an originating signal S7 of the first local oscillator 7 and the signal S3 of the fixed station A are mixed and converted to an output signal S8. A frequency component and a phase component are included in the signal S8, the frequency component causes the phase delay due to the propagation. The signal S8 inputs through an amplifier 12 to the first, second detecting devices 13 and 14, the phase difference of the output of the second mixer 10 and the detecting device 14 is compared by the first phase comparator 11 and the phase of a modulating wave generating circuit 6 is controlled. For the output of the second mixer 10 and the output of the detecting device 13, are compared in phase by the second phase comparator 15 the change of the range of the fixed station A and the moving station B is obtained from the moving quantity of the phase angle, the moving quantity is differentiated by the time, and the speed of the moving target is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for measuring the speed of a moving target that can be applied to a large number of moving targets simultaneously.

[Conventional technology]

Differentiating the distance change between the fixed target and the moving target with respect to time is a method for measuring the relative velocity between a fixed target (or the same for two or less fixed stations) and a moving target (or the same for two or less mobile stations) with high accuracy. Many methods are used to measure speed.

Conventionally, in order to obtain this distance information, it was necessary to send and receive signals containing distance information between a fixed target and a moving target. Typical methods for transmitting and receiving signals include a method using a carrier wave of the same frequency in a time-division manner and a method using two carrier waves of different frequencies.

[Problem that the invention seeks to solve]

In these methods, transmitting and receiving equipment must be installed for both fixed and moving targets, and only one pair of fixed and moving targets can be combined, and other targets may interfere with measurement. In order to avoid this, we had to stop the carrier wave emission and wait. Therefore, when measuring the speed of a plurality of moving targets, there is a problem in that not only is there a restriction on operation time, but there is also a restriction on the use of public radio waves.

This invention was made in order to solve the above-mentioned problems.For one station, which is a fixed target, which is a transmitting station, the receiving side is a moving target, which can be used by an unspecified number of moving targets at the same time. The purpose is to provide a speed measurement method.

[Means for solving problems]

A method for measuring the speed of a moving target according to the present invention includes equipping a fixed target with a transmitting device and a moving target with a receiving device,
The transmitting device transmits a measurement frequency signal and a comparison frequency signal that is synchronized with the measurement frequency signal and differs by one frequency, and the reception device receives the measurement frequency signal and detects the measurement frequency signal and the comparison frequency signal. The phase difference of the signals is determined, the distance change is determined from the amount of phase shift of the phase angle obtained from this phase difference, and this distance change is differentiated with respect to time to determine the speed of the moving target.

[Operation] In this invention, the moving target side receives the measurement frequency signal transmitted from the fixed target and the comparison frequency signal, calculates the phase difference between the two signals, and calculates the phase angle obtained from this phase difference. The distance change is determined from the amount of phase shift, and this distance change is differentiated with respect to time to determine the speed of the moving target.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the present invention, in which A shows a fixed station installed on a fixed target equipped with transmitting equipment, and B shows a mobile station installed on a moving target equipped with receiving equipment.

In Fig. 1, 1 is a measurement frequency generator, and the phase (ω1
A measurement frequency signal S1 of t+φl) is generated. 2 is a comparison frequency generator that generates a frequency that is synchronized with and different from the measurement frequency signal S1, that is, a phase 1/N(ω1 t
+φ1) comparison frequency signal S2 is generated. 3 is a carrier wave generator which generates a carrier wave signal S3 of phase (Ω1 t+Φl). These measurement frequency signal S1 and comparison frequency signal S2 are transmitted by subjecting carrier wave signal S3 to double modulation. Any modulation method may be used as long as it generates sidebands of the carrier signal S3.

Moreover, instead of the above-mentioned double modulation, the subcarrier signal S4 generated by the subcarrier generator 4 shown by the dotted line in the figure is modulated in the subcarrier modulator 5 by the comparison frequency signal S2, and then the subcarrier signal It is also possible to have a configuration in addition to 3.

The above is the configuration of fixed station A, and next, the configuration of mobile station B will be explained.

6 is a modulated wave generator consisting of vCo, and the phase (ω2 t+
A modulated wave signal S6 of φ2) is generated. A first local oscillator 7 generates an oscillation signal S7 having a phase of (Ω2 t+Φ2). A first mixer 8 mixes the received signal and the oscillation signal S7 modulated by the modulated wave signal S6. 9 is the second
The local oscillator generates an oscillation signal S9 with phase (ω3 t+φ3).
occurs.

10 is a second mixer that mixes the modulated wave signal S6 and the oscillation signal S9; 11 is a first phase comparator;
0 and the output of a second detector 14, which will be described later, are compared to control the phase of the modulated wave generator 6. 12 is an amplifier, 13 is a first detector, 14 is a second detector, 15 is a second phase comparator, and the output of the first detector 13 and the second mixer 1 are
Compare the phase difference with the output of o. 16 is a phase difference indicator.

Note that in the above, ω1. ω2. ω3. Ω1. Ω2゜Ω3 is the angular frequency, φ1. φ2. φ3. Φ! , Φ2 indicates the initial phase, and t indicates time.

Next, the overall operation will be explained.

At mobile station B, which is a distance away from fixed station A, the first
The local oscillator 7 generates an oscillation signal S1 of phase (Ω2 t+Φ2)
is generated, but this is due to the phase of the modulated wave generator 6 (ω2 t
+φ2) modulated wave signal S6. In the first mixer 8, this oscillation signal S7 and the carrier wave transmitted from the fixed station A are mixed and converted into an output signal S8 of 1Ω2-Ωl1. This output signal S8 includes a frequency component (ω2-ω1) and a phase component of l/N (ωIt+φ1).

And ω1. ω2. The relationship of ω3 is as follows. The (ω2-ω1) component of the output signal S8 is
Only ω1 is generated with a phase delay due to propagation.

Now, after the output signal S8 is amplified by the amplifier 12, the first detector 13 generates a phase lag, and the second detector 14 detects the phase lag.

On the other hand, a part of the output of the modulated wave generator 6 is transmitted to the second local oscillator 9.
is mixed with the oscillation signal S9 in the second mixer 1o to obtain a component of (ω2 t+φ2)−(ω3 t+φ3). The relationship between ω2 and ω3 is as follows, so this component is ω 1 □t+φ2−φ3 ・・・・・・・・・・・・
...(3) is obtained by comparing the phases of this equation (3) and equation (2) with the first phase comparator 11. The output of the first phase comparator 11 is applied to the modulated wave generator 6 to control the phase φ2 of the modulated wave generator 6. In other words, the output of the modulated wave generator 6 is as follows. Therefore, the output of the second mixer 10 (3rd
) is the formula. Since φ2 in Equation (1) is, after all, Equation (1) is obtained by comparing the phases of Equation (4) and Equation (1a) using the second phase comparator 15. ...(5) is obtained. This output is displayed on the phase difference indicator 16.

In equation (5), let A be the localization sum term.

In Equation (8), C=fl input + (f frequency.

Substituting the input wavelength), we get becomes.

In equation (7), when input l is determined, the phase angle changes as L changes. In this way, L, that is, the change in distance between fixed station A and mobile station B can be determined from the amount of phase shift of the phase angle.

When the amount of phase shift of the phase angle is expressed as follows, the speed can be determined by differentiating this amount of phase shift with respect to time.

FIG. 2 shows details of the second phase comparator 15 and phase difference indicator 16 in the embodiment of FIG. This is what we seek.

In FIG. 2, 17 and 18 are input terminals, and the first
The output of the first detector 13 and the second mixer 1o in the figure
The outputs of are added respectively.

19.20 is a limiter amplifier, 21 is a distance clock signal generator, 22.23 is a gate circuit, 24 is a time clock generator, 25 is a distance display, 26 is a distance counter, 27
is a time counter, and 28 is a time display.

Next, the operation will be explained. The input signal from the input terminals 17 and 18 is set to a constant amplitude by the limiter amplifier 19.20, and the gate circuit 22.23 is opened and closed. Gate circuit 2
2 is open, the clock signal of the distance clock signal generator 21 is applied to the distance counter 26 and the distance indicator 2
The distance traveled is displayed at 5.

Further, in order to display the time required to travel a predetermined distance, the output signal of the time clock generator 24 can be applied to the time counter 27 through the gate circuit 23, and the output can be displayed on the time display 28. .

In the above embodiment, the transmitting device is installed on the fixed target side (fixed station) and the receiving device is installed on the moving target side (mobile station). A transmitting device may be installed on the target side. Additionally, a transmitting device is installed on the fixed target side.

A configuration may also be adopted in which receiving devices are individually installed on the sides of a plurality of moving targets and the moving speeds of each moving target are measured separately and simultaneously.

〔Effect of the invention〕

As described above, the present invention receives a measurement frequency signal from a fixed target transmitting device, synchronizes with this measurement frequency signal, and
A comparison frequency signal with a different frequency is transmitted, and a receiving device for a moving target detects the measurement frequency signal and the comparison frequency signal to determine the phase difference between the two, and the phase angle shift amount obtained from this phase difference. After finding the distance change from , we differentiated it with respect to time to find the speed of the moving target, so we can calculate the speed of many moving targets at the same time for one fixed target, and also calculate the speed of each moving target individually. It has the advantage of being able to be measured at a standard.

In addition, when using the conventional method, the fixed target side,
It was necessary to install a transmitting device and a receiving device on each side of the moving target, but according to the method according to the present invention, either one of the transmitting or receiving device is installed on the fixed target side or the moving target side.
This method has the advantage that the moving speed of a moving target can be measured by simply installing one device, and the device can be constructed at low cost.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a block diagram showing details of the second phase comparator and phase difference indicator in FIG. 1. In the figure, A is a fixed station, B is a mobile station, 1 is a measurement frequency generator, 2 is a comparison frequency generator, 3 is a carrier generator, 4 is a subcarrier generator, 5 is a subcarrier modulator, and 6 is a modulation wave generator,
7 is a first local oscillator, 8 is a first mixer, 9 is a second local oscillator, 1o is a second mixer, 11 is a first phase comparator, 12
is an amplifier, 13 is a first detector, 14 is a second detector, 15
is a second phase comparator, and 16 is a phase difference indicator.

Claims (1)

[Claims] A transmitting device is installed on the fixed target, a receiving device is installed on the moving target, and the transmitting device transmits a measurement frequency signal and a comparison frequency signal that is synchronized with the measurement frequency signal and has a different frequency, and A receiving device receives the two frequency signals, detects the measurement frequency signal and the comparison frequency signal, determines the phase difference between the detected two frequency signals, and calculates the phase angle obtained from the phase difference. The method is characterized in that the amount of change in distance between the fixed target and the moving target is determined by the amount of phase shift, and the relative speed of the moving target with respect to the fixed target is determined by differentiating the amount of change in distance with respect to time. A method for measuring the speed of a moving target.