JPH07306262A - Radar - Google Patents

Abstract

PURPOSE:To provide a radar which can perform tracking while suppressing the influence of eclipsing. CONSTITUTION:Outputs from a SIGMAch multiplier 8, an Ech multiplier 9, and an Lch multiplier 10 are fed to an error calculating means 11. Error calculation results are then fed to a PRF(Pulse Repetition Frequency) modifying means 12a in order to predict the influence of eclipse. When such a decision is made that the eclipse has an effect, the PRF is modified thus realizing the radar having an enhanced target tracking performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar device for searching and tracking a target.

[0002]

2. Description of the Related Art FIG. 12 is a block diagram of a conventional radar apparatus. In FIG. 12, 1 is a transmitter that generates a transmission wave and supplies a reference signal to each component, and 2 is a receiver that directly transmits the transmission wave. 4 is a transmission / reception switcher for preventing sneaking around to the input, 3 is an antenna for irradiating a target with a transmission wave and receiving a reflected wave from the target, 4 is a reception gate signal output from a reception gate generator 6. A receiver which detects and amplifies a reflected wave received by the inter-antenna 3 and outputs a received signal, 5 is a spectrum analysis means for separating the target from the received signal and obtaining a relative speed with the target, and 6 for tracking the transmitted wave. A reception gate generator that generates a reception gate signal for cutting off the input of the receiver during irradiation.

The conventional radar device is constructed as described above, irradiates the transmission wave output from the transmitter 1 from the antenna 3 toward the target, receives the reflected wave from the target at the antenna 3, and receives the reflected wave. The wave is detected and amplified by the receiver 4,
The spectrum of the received signal which is the output of the receiver 4 is analyzed by the spectrum analysis means 5.
The target tracking is performed by separating the target signal and calculating the target speed at.

[0004]

Since the conventional radar device is constructed as described above, all or part of the reflected wave from the target is received during irradiation of the transmitted wave as shown in FIG. Since the input of the receiver 4 is sometimes blocked by the reception gate signal, the reflected wave is lost only in the shaded area in FIG.
g) occurs. Therefore, the S / N is deteriorated, and it becomes difficult to separate the target signal by the spectrum analysis means 5, so that there is a problem that stable tracking cannot be performed.

[0005]

A radar apparatus according to the present invention uses a Σch multiplier, an Ech multiplier, and a received signal for a received signal.
And a divider for distributing to Lch multipliers, a reception gate generator for generating a Σ gate signal, an E gate signal, and an L gate signal in synchronization with a reference signal, and Σc
An error calculation unit that calculates an error from the outputs of the h multiplier, the Ech multiplier, and the Lch multiplier, and outputs an error signal, and a PRF (Pulse Repeateti).
on Frequency is checked and PR is performed.
PRF switching means for outputting an F switching command is provided. Further, for each PRF, distance-to-error data indicating the relationship between the distance to the target and the error signal, target-distance prediction means for predicting the distance to the error data and the distance from the error signal to the target, and the distance-to-error data and the target. Distance tracking means for predicting the distance to the current target from the distance between the relative speed with respect to and the previously predicted target, and PRF selection means for selecting the optimum PRF from the predicted distance and distance-to-error data Is.

[0006]

In the radar device according to the present invention, since the PRF is switched by predicting that the received signal from the target is affected by the eclipse, the effect of the eclipse is reduced. Therefore, the target tracking can be performed stably.

[0007]

【Example】

Example 1. FIG. 1 is a block diagram showing a first embodiment of the present invention. 1 to 5 are the same as FIG. 10 and 6a is a Σ gate signal, an E gate signal, and an L gate signal in synchronization with a reference signal from a transmitter.
Reference numeral 7 denotes a reception gate generator that generates each of the gate signals, and 7 denotes a reception signal for a Σch multiplier, an Ech multiplier,
And Lch multipliers, and 8, 9 and 10 are Σch multipliers for multiplying the received signals distributed by the distributor 7 by Σ gate signals and E gate signals, respectively. 11 is a multiplier for Ech, and a multiplier for Lch for multiplying the L gate signal. Reference numeral 11 is a spectrum analysis unit 5 for spectrum analysis of outputs from the multiplier 8 for Σch, the multiplier 9 for Ech, and the multiplier 10 for Lch. The error calculation means performs error calculation from the result and outputs an error signal Δ, and 12a is a PRF switching means that outputs a PRF switching command according to the error signal and the PRF switching reference value V. The above is new to FIG. It is added to.

In the radar device configured as described above, when the reception signal from the target is output from the receiver 4 during the i-th sampling time, the distributor 7 causes the Σch multiplier 8 and the Ech multiplier. 9, and Lch multiplier 10
Will be distributed to. Also, the reception gate generator 6a outputs the Σ gate signal to the Σch multiplier 8, the E gate signal to the Ech multiplier 9, and the L gate signal to the Lch multiplier 10, respectively. FIG. 2 shows the relationship among the transmitted wave, the Σ gate signal, the E gate signal, the L gate signal, and the reflected wave and the error signal Δ. The Σch multiplier 8 multiplies the distributed reception signal by the Σ gate signal, and as a result, outputs the Σch multiplier 8 Σ
get i. Similarly, the output Ei of the Ech multiplier 9 is obtained from the received signal and the E gate signal, and the output Li of the Lch multiplier 10 is obtained from the received signal and the L gate signal. By performing spectrum analysis in the spectrum analysis means 5, Σi,
SΣi, SEi, S from which unnecessary signals have been removed from Ei, Li
Li is obtained. The error calculation means 11 executes error calculation from SΣi, SEi, and SLi, and outputs an error signal Δ. The error calculation is as shown in Equation 1.

[0009]

[Equation 1]

The error signal Δ calculated by the error calculation of the above equation 1 indicates the position of the received signal. As shown in FIG. 2, when the reflected wave is at the position with respect to the transmitted wave, the error signal Δ is-. When the position is 1 and the error signal Δ is 0
The error signal Δ is 1 in the case of the position. Figure 3
Is a flowchart showing the operation of the PRF switching determination means 12a. The PRF switching determination means 12a compares the error signal Δ with the PRF switching reference value V to determine whether or not to switch the PRF, and the PRF switching is performed based on the result. It outputs a command. The PRF switching reference value V is a positive number of 1 or less, and the smaller the value is set, the less the influence of Eclipse becomes, but the more the PRF is changed. In FIG. 3, in steps 31 and 32, it is judged from the error signal Δ and the PRF switching reference value V whether or not there is an influence of eclipse.
If it is determined that there is an influence of Eclipse as a result of steps 32 and 32, a PRF switching command is output in step 33.

FIG. 4 is the same as FIG. 1 from 1 to 11. In order to execute the PRF switching judgment, the PRF switching judging means 12a of FIG.
The switching determination means 12b is newly added. Figure 5
Indicates the operation of the PRF switching determination means 12b,
The steps 51 and 52 for performing the PRF switching determination based on the target speed v are newly added to FIG. PRF
The switching determination means 12b determines the error signal Δ and the PRF switching reference value V.
And whether or not to switch the PRF from the relative speed v is determined, and a PRF switching command is output according to the result.
When it is determined that there is an influence of eclipse as a result of step 31 or 32 in FIG. 5, the increase or decrease of the influence of eclipse in the future is predicted from the target relative speed in steps 51 and 52, and it is predicted that eclipse will increase. 33 outputs a PRF switching command. 6 is the same as FIG. 1 from 1 to 11, and in order to execute the PRF switching determination, the PRF switching determination means 12 of FIG.
a whose operation is different from that of the a and PRF switching determination means 12b
The F switching determination means 12c is newly added. FIG. 7 shows the operation of the PRF switching determination means 12c, which is different from FIG. 3 in that the error signal Δ, the PRF switching reference value V, the relative speed v, and the reception signal SΣ of the i-th sampling time.
A step of determining whether or not to switch the PRF from the N received signals SΣ (i−N) before the i-th and i-th sampling times is added. Here, N is an arbitrary positive integer. FIG. 7 shows the operation of the PRF switching judging means 12c, and steps 31, 32, 51 and 52 are shown.
In the case where eclipse has occurred, it is predicted that the influence will decrease in the future. In step 71, the eclipse degree calculation is executed. The calculation of the degree of eclipse is as shown in Formula 2, and predicts the degree of eclipse.

[0012]

[Equation 2]

When it is judged in step 72 that the eclipse degree X, which is the result of the eclipse degree calculation of the above-mentioned equation 2, is larger than SΣi, the PRF switching command is output in step 33. 8 is different from FIG. 1 in that the distance-to-error data 13 showing the relationship between the target distance and the error signal Δ, and the PRF with the smallest influence of Eclipse when the distance to the target is unknown and the distance to the target are selected. The target distance predicting means 14 for predicting is added. The target distance prediction means 14 is
If the distance to the target is unknown when the PRF switching command is output from the PRF switching means 12a, the PRFs are switched in order, the error is calculated in each PRF, and the PRF with the smallest error signal Δ is selected. Further, the error signal Δ and the distance-to-error data 1 obtained at each PRF
The target distance prediction operation is performed from 3 to predict the distance to the target. In the target distance prediction operation, the predicted value of the target distance is narrowed down to a range corresponding to the error signal Δ by referring to the distance-to-error data 15 based on the error signal Δ obtained in a certain PRF, and then the PRF is changed. By carrying out similarly, the predicted value of the target distance is further narrowed down. The distance to the target is predicted by repeating the above.
For example, when the distance-to-error data 13 is as shown in FIG. 9 and the distance to the target is R1, the PRF is PRF1.
Error signal Δ is 0 when PRF2 is −0.
5, it is assumed that the error signal Δ at PRF3 is 0.3.
Since the error signal Δ is 0 at PRF1, the distance R to the target is calculated from the distance-to-error data 13 by searching the distance range where the error signal Δ is 0 ± k at PRF1. , A3, A4. Here, k is a threshold coefficient. Similarly PR
Since the error signal Δ is −0.5 at F2, the target distance range is limited to B4 and B5 where the error signal Δ is −0.5 ± k at PRF2 among A1, A2, A3 and A4. Since the error signal Δ is 0.3 at PRF3, the distance R1 to the target is predicted to be within the range of C5.
FIG. 8 shows a distance-to-error data 13 showing the relationship between the target distance and the error signal Δ, and a target for predicting the distance to the target by selecting the PRF with the smallest Eclipse when the distance to the target is unknown. The distance predicting means 14, the distance tracking means 15 for outputting a new target distance Rn from the distance-to-error data 13, the target distance Rp and the relative speed v when the target distance Rp is known, the new target distance Rn and the distance. Error data 1
Optimal P that selects the PRF with the smallest Eclipse from 3
The RF selection means 16 is added. First, the target distance tracking means 15 will be described with reference to FIG. For example, when the currently used PRF is PRF1 and the previously predicted distance is Rp, the PRF switching means 12a to PRF
The new target distance Rn when the switching command is output is shown in FIG.
It is predicted to be the upper limit value Ru or the lower limit value Rd of the range A of 1. Further, if the target is approaching from the relative speed v with respect to the target, Rn is predicted to be Rd because Rn is smaller than Rp. Conversely, if the target is moving away, Rn
Is higher than Rp, so Rn is predicted to be Ru. The optimum PRF selection means 16 obtains the error signal Δ for each PRF by referring to the distance-to-error data 13 from the distance Rn, and selects the PRF that is predicted to have the smallest error signal Δ. For example, as shown in FIG. 9, when the predicted distance is R2, PRF2 having the smallest error signal Δ in R2 is selected.

[0014]

As described above, according to the present invention, the means for predicting the influence of the eclipse is provided, and the optimum PRF is selected based on the result of the prediction. Therefore, the received signal loss due to the eclipse is lost. It is possible to obtain a radar device in which the target tracking performance is improved.

[Brief description of drawings]

FIG. 1 is a configuration block diagram showing a first embodiment of the present invention.

FIG. 2 is a waveform diagram for explaining the operation according to the present invention.

FIG. 3 is a flowchart showing the operation of the radar device according to the present invention.

FIG. 4 is a configuration block diagram showing a first embodiment of the present invention.

FIG. 5 is a flowchart showing the operation of the radar device according to the present invention.

FIG. 6 is a configuration block diagram showing a first embodiment of the present invention.

FIG. 7 is a flowchart showing the operation of the radar device according to the present invention.

FIG. 8 is a configuration block diagram showing a first embodiment of the present invention.

FIG. 9 is a diagram for explaining the operation according to the present invention.

FIG. 10 is a configuration block diagram showing a first embodiment of the present invention.

FIG. 11 is a diagram for explaining the operation according to the present invention.

FIG. 12 is a block diagram showing a configuration of a conventional radar device.

FIG. 13 is a waveform diagram for explaining the operation of the conventional radar device.

[Explanation of symbols]

 1 transmitter 2 transmission / reception switch 3 antenna 4 receiver 5 spectrum analysis means 6 reception gate generator 6a reception gate generator 7 distributor 8 Σch multiplier 9 Ech multiplier 10 Lch multiplier 11 error calculation means 12a PRF Switching means 12b PRF switching means 12c PRF switching means 13 Distance-to-error data 14 Distance prediction means 15 Distance tracking means 16 Optimal PRF selection means

Front page continuation (72) Inventor Yukinori Shiozaki 325 Kamimachiya, Kamakura City Mitsubishi Electric Corporation Kamakura Factory

Claims (5)

[Claims] 1. A transmitter that outputs a transmission wave for irradiating a target and a reference signal to each component, a transmission / reception switcher for switching between transmission and reception, and an antenna for transmission / reception.
A receiver connected to the antenna, and a distributor for distributing the reception signal obtained by the receiver to the Σch multiplier, the Ech multiplier, and the Lch multiplier,
A reception gate generator that generates a Σ gate signal corresponding to a Σch multiplier, an E gate signal corresponding to an Ech multiplier, and an L gate signal corresponding to an Lch multiplier in synchronization with the reference signal; A Σch multiplier that multiplies the signal distributed by the distributor with the Σ gate signal, an Ech multiplier that multiplies the similarly distributed signal with the E gate signal, and a similarly distributed signal with the above Lch multiplier for multiplying the L gate signal, and Σch, Ech
And Lch each output of the multiplier is input to perform spectrum analysis, error calculation means to perform error calculation on the result of the spectrum analysis means and output an error signal, and PRF (Pulse by error signal).
A radar device comprising PRF switching means for determining whether or not to change the repetition frequency and outputting a PRF switching command. 2. The radar device according to claim 1, wherein the determination of PRF switching is made based on the relative speed between the error signal and the target. 3. An eclipse degree predicting means for predicting an eclipse degree, which is a degree of eclipse, from a received signal from a target and an average of past received signals is provided, and a judgment of PRF switching is made by a relative speed between the error signal and the target. The radar device according to claim 1, wherein the radar device is operated according to an eclipse degree. 4. The distance-to-error data showing the relationship between the distance to the target and the error signal for each PRF, and the optimum PRF when the distance to the target is unknown, and selecting the distance-to-error data and the error signal. A target distance predicting means for predicting a distance from the target to the target is provided.
The described radar device. 5. A distance tracking means for performing distance tracking from the distance, distance-to-error data, and relative speed predicted when the PRF was previously switched, and a PRF selection means for selecting an optimum PRF according to the distance to the target. Claim 1 characterized by
The described radar device.