JP3973047B2 - Pulse radar equipment - Google Patents

Description

  The present invention relates to a radar system for detecting a target by emitting a radio wave and receiving a reflected wave, and more specifically, a pulse for emitting a high-frequency transmission radio wave in the form of pulses generally divided at equal intervals. The present invention relates to a pulse radar apparatus which is a radar and can be used for short-distance measurement and has high resolution.

Most of the radars currently used are pulse radars. In general, a pulse radar can detect a target having a long distance and measure the distance to the target. Various signal processing techniques used in such a pulse radar are described in Non-Patent Document 1 below.
Matsuo Sekine Radar signal processing technology IEICE

  Further, as conventional techniques for detecting a target at a relatively short distance, there are the following non-patent document 2 and patent documents 1 and 2. Non-Patent Document 2 proposes a method of measuring the distance and speed of a moving object within a distance of 125 m using a 9.5 GHz band microwave that is amplitude-modulated by a sine wave signal.

  Patent Document 1 discloses a small-sized, low-cost, low-power-consumption microwave pulse transmitter / receiver suitable for applications such as data communication, sensors, and measuring instruments using microwave band weak radio. Although a gate is used here, this is for suppressing oscillation and has a different purpose from the present invention.

Patent Document 2 discloses a high-resolution short-range radar that can be used with a simple license application, can be used outdoors without worrying about radio interference, and is expected to be used for various applications by non-contact distance measurement outdoors. ing.
Morikami, Nakaji, “A method for measuring the distance and speed of short-distance moving objects” The Institute of Electronics, Information and Communication Engineers General Conference '00 B-2-2 215 Japanese Patent Application Laid-Open No. 2001-116822 “Microwave Pulse Transceiver” JP 2000-241535 A “Short Range Radar Device”

  As described above, the conventional pulse radar has been used at a relatively long distance of several tens of meters or more to the target. In order to use the pulse radar for short-distance measurement, it is necessary to make a sharp pulse, the use frequency band is widened, and the band of elements to be used in the apparatus needs to be widened, which is difficult to realize.

  FIG. 25 and FIG. 26 are explanatory diagrams of bands in this pulse radar. FIG. 25 is an explanatory diagram of bands used for general AM and FM signals. In AM and FM signals, the use band is limited to a narrow band centering on the frequency of the carrier wave, so that the influence of noise can be reduced.

  FIG. 26 is an explanatory diagram of the band of the pulse radar. The narrower the width of the pulse of the pulse radar, the wider the band used. Even if the signal power S is the same, the total noise power N of the band increases, the S / N (signal to noise ratio) deteriorates, and the influence of noise is reduced. It becomes easy to receive. In particular, S / N deteriorates at 1 GHz or more, and various problems occur. Increasing the pulse width to reduce S / N reduces the band and reduces the noise N, but increases the minimum distance to the detectable object.

  In order to reduce the short distance limit of detection to about 15 cm by the conventional technique of pulse radar as described above, the pulse width needs to be about 1 nsec. For this purpose, a bandwidth of about 1 GHz is required, the noise bandwidth is extremely wide as 1 GHz, the S / N becomes very bad, and the target detection becomes very difficult.

  Furthermore, in order to handle signals with a pulse width of about 1 nsec and a frequency bandwidth of about 1 GHz, a general-purpose digital LSI such as a DSP cannot be used, and it is necessary to construct a circuit with a specially developed semiconductor for high speed. There is a problem that the cost is very high and mass production is difficult due to variation in characteristics.

  Further, as a different problem, the conventional technique has a problem that a malfunction other than a target to be detected due to interference from a plurality of radars, that is, an erroneous target is detected.

  In view of the above-described problems, an object of the present invention is to provide a pulse radar device that has a short distance detection limit and a high distance resolution without using a specially developed semiconductor. Another object of the present invention is to provide a pulse radar device that can prevent malfunctions such as detecting an erroneous target by applying spread spectrum technology to pulse radar.

  FIG. 1 is a block diagram showing the configuration of the receiving unit of the pulse radar apparatus according to the present invention. FIG. 1 shows the principle configuration of a pulse radar apparatus 1 that detects a target by transmitting a pulse signal. The apparatus 1 includes at least a control pulse generation means 2 and a gate means 3.

  The control pulse generating means 2 generates a control pulse signal by delaying a signal that is a basis for generating a transmission pulse, for example, an AM rectangular wave signal, and the gate means 3 is reflected from the target using the control pulse signal. The gate operation is performed on the received signal.

  In the embodiment of the invention, as shown in FIG. 1, the detection means 4 for detecting the output of the gate means 3, for example, phase detection (I-Q detection), and the control pulse generating means 2 have the above-mentioned delay amount. When changing the distance, the distance to the target is calculated by using the output of the detection means 4 in correspondence with the delay corresponding to the component corresponding to the amplitude of the received signal, for example, the sum of squares of the I component and the Q component. The calculation means 5 may be further provided, or the phase difference between the signal that is the basis of the transmission pulse generation and the reception signal using the detection means 4 and the output of the detection means 4, for example, the I component and the Q component. Further, distance calculation means 5 for calculating the distance to the object can be further provided.

  In the embodiment, a pulse, for example, a pulse having the width of the actual transmission pulse is generated from the signal used as a basis for generating the transmission pulse, and the transmission pulse generation modulation signal is generated by limiting the spectrum range of the pulse. For example, it may further include a modulation signal generating means for supplying an amplitude modulator that amplitude-modulates a sine wave as a carrier wave.

  The pulse radar device according to the present invention includes a first signal that is a basis for generating a transmission pulse, a second signal for phase modulation having a frequency lower than that of the first signal, and an intermediate frequency between the first and second signals. Control pulse generation means for generating a control pulse signal by delaying a signal generated using the pseudo-random signal for modulation generated in step 1 and a gate for performing a gate operation on the received signal using the control pulse signal Means.

  In the embodiment of the invention, the modulation pseudo-random signal may be an amplitude modulation signal for the first signal. Alternatively, it may be a signal for phase modulation with respect to the first signal, and the generated signal may be a signal in which a pulse exists even in a section where the pseudo random signal is Low.

  In the embodiment of the invention, as described above, the detection means for detecting the output of the gate means and the output of the detection means when the control pulse generation means changes the delay amount correspond to the amplitude of the received signal. It may further comprise distance calculation means for calculating the distance to the object in correspondence with the delay amount at which the component is maximized or the phase difference between the above-mentioned base signal and the received signal.

  Further, in the embodiment, a pulse is generated from a signal generated by using the first signal, the second signal, and the pseudo-random signal, and the spectrum range of the pulse is band-limited to transmit a pulse. Modulation signal generation means for generating a generation modulation signal may be further provided.

  As described above, according to the present invention, for example, a signal serving as a basis for generating a transmission pulse is delayed, and a gate operation is performed on the received signal using the signal.

  As described above in detail, according to the present invention, for example, a radar apparatus capable of performing accurate short-range measurement by delaying a signal that is a basis for generating a transmission pulse and performing a gate operation on the received signal is realized. Is done. Further, as an advantage of AM, it is possible to limit a noise band by cutting with a narrow band filter, and to prevent malfunction such as detecting an erroneous target object due to interference from other radars by using spread spectrum. it can.

  FIG. 2 is a block diagram showing the configuration of the first embodiment of the pulse radar device according to the present invention. In the embodiment of the present invention, a pulse radar based on an ASK (amplitude shift keying) system that performs amplitude modulation on a sine wave signal as a carrier wave will be described.

  The operation of the pulse radar apparatus of FIG. 2 will be described using the waveforms of the respective parts shown in FIGS. First, the rectangular wave oscillator 11 of FIG. 2 oscillates a rectangular wave as shown in FIG. The duty ratio of this rectangular wave is 50%, for example, and the frequency is 10 MHz.

  The pulse generation circuit and the band limiting unit 12 have the same frequency and a small duty ratio in synchronization with the rising of the rectangular wave generated by the rectangular wave oscillator 11, for example, a narrow width as shown in FIG. A pulse is generated, and the band is limited so as to meet the regulations as shown in FIG.

  The pulse width of (a) is basically determined by the distance resolution required for the pulse radar. If the required resolution (minimum distance) is a and the pulse width is pW, the round-trip distance of the radio wave is 2 × a. If the speed of light is c, the pulse width pW is given by the following equation.

pW = 2 × a / c (1)
For example, when a = 0.3 m, pW is 2 ns.
For example, an in-vehicle radar for domestic use uses a band near 76 GHz. According to the regulations, in the 76-77 GHz band, it is possible to occupy 500 MHz per channel. When the pulse width is 2 ns, the width of the main lobe is 500 MHz, but the side lobe is larger than that and needs to be attenuated. Therefore, it is necessary to limit the bandwidth.

  The programmable delay line 13 of FIG. 2 corresponds to a signal from a computer, for example, a signal capable of shifting the rectangular wave generated by the rectangular wave oscillator 11 every 1 ns in the range of 0 to 100 ns, as shown in FIG. It is something that delays. This delay range and shift amount differ depending on the requirements. Also, the direction of delay shift varies depending on the request. For example, if you don't know what is there, you need to sweep the delay time, but if you want to track a car whose location has been detected in advance, only the vicinity of the delay time corresponding to that distance The amount of delay can be controlled in accordance with the content of the request.

  The pulse generation circuit 14 generates, for example, a pulse with a same duty and a small duty ratio and matching rising edges corresponding to a rectangular wave having a delay of 10 MHz and a duty ratio of 50%, which is delayed by the programmable delay line 13. Is. As shown in FIG. 6, this pulse is a pulse delayed by the delay time by the programmable delay line 13 with respect to the output of the pulse generation circuit and the band limiting unit 12.

The output of the carrier wave oscillator 15 is shown in FIG. This carrier wave is a continuous wave (sine wave) as shown in (a), and the frequency is only a single component as shown in (b).
The output of the carrier wave oscillator 15 is amplitude-modulated by the amplitude modulator 16 using the pulse output from the pulse generation circuit and the band limiting unit 12. The output is conceptually shown in FIG.

  FIG. 8A shows the output of the amplitude modulator 16, which is an image in which the carrier wave of FIG. 7 is output only while the pulse as the waveform of FIG. 4A is HIGH. (B) is a frequency domain waveform of this output, and has a limited bandwidth around the frequency of the carrier wave.

  The output of the amplitude modulator 16 is sent to the object to be detected by the radar by the transmitting antenna 17, here reflected from each of the two vehicles and received by the receiving antenna 18 of the pulse radar device.

  FIG. 9 (a) shows the input waveform to the receiving antenna 18. Among these, a waveform with a small amplitude is from a small vehicle in front, and a waveform with a large amplitude is from a large vehicle farther away. A reflected wave is shown.

  The received pulse received by the receiving antenna 18 is envelope-detected by the detector 19. FIG. 9B is an explanatory diagram of the output waveform of the detector 19. As shown in the figure, the reflected signals from the two vehicles received by the receiving antenna 18 are output as two sets of pulses having different amplitudes as shown below by envelope detection. The interval between the output pulses is drawn wider than the interval between the signals received by the receiving antenna 18.

  The output of the detector 19 is amplified by the amplifier 20 and then given to the gate circuit 21. The gate circuit 21 receives the output of the pulse generation circuit 14, that is, the pulse delayed by the programmable delay line 13 described in FIG. 6, and the gate circuit 21 uses the output of the pulse generation circuit 14 as a control signal. The gate operation for the output of the amplifier 20 is executed.

  By this gate operation, even when the width of the transmission pulse is small and the influence of noise is large, it is possible to correctly detect the target by cutting the portion other than the corresponding reception pulse.

  FIG. 10 is an explanatory diagram of the operation of the gate circuit 21. In FIG. In FIG. 5A, a solid line waveform indicating the output of the amplifier 20 as an input to the gate circuit 21 and a dotted line waveform indicating the output of the pulse generation circuit 14 as a gate signal for control are drawn. (B) shows the output of the gate circuit 21.

  In (i), the delay amount of the gate signal is small, the gate pulse does not coincide with any of the input pulses in time, and the output of the gate circuit 21 is basically zero. In (ii), the time t1 of the pulse of the gate signal coincides with the pulse corresponding to the waveform reflected from the vehicle (front vehicle) close in FIG. 2, and this pulse is obtained as an output. In (iii), the delay amount is intermediate, and the output is 0 as in (i). In (iv), the delay amount t2 coincides with the time of a pulse reflected from a distant vehicle (rear vehicle), and this pulse is output.

  FIG. 11 is an explanatory diagram of input and output to the low-pass filter 22. This filter allows a frequency component of 10 MHz or less as a fundamental wave of the output of the rectangular wave oscillator 11 to pass, and the outputs corresponding to (i) and (iii) in FIG. 10 are basically zero, and (ii) The output corresponding to (iv) is a sine wave, and the amplitude and phase of the sine wave correspond to the magnitude and position of the input pulse.

  The output of the low-pass filter 22 is given to the IQ detector 23. The output of the rectangular wave oscillator 11 is also input to the IQ detector 23 via the low pass filter 24. As described above, these two low-pass filters 22 and 24 are for passing the fundamental wave as the output of the rectangular wave oscillator 11, that is, 10 MHz, and the IQ detector 23 is the output of the low-pass filter 24. That is, IQ detection is performed on the output of the low-pass filter 22 based on the sine wave as the fundamental wave of the output of the rectangular wave oscillator 11, and an I (synchronous) component and a Q (orthogonal) component are output, respectively.

  FIG. 12 is an explanatory diagram of the operation of the IQ detector 23. In the figure, the top waveform is an output of the low-pass filter 24, that is, a reference waveform. (I) corresponds to (i) in FIG. 11, and since the output of the low-pass filter 22 is 0, the outputs of I and Q are also 0. (Ii) is an output corresponding to the reflected wave from the above-mentioned nearby vehicle, the phase difference θ1 with respect to the reference signal of the I and Q signals corresponds to the distance from the nearby vehicle, and the amplitude corresponds to the reception intensity of the reflected wave. .

  (Iii) corresponds to the case where the delay amount is intermediate, and the outputs of I and Q are also zero. (Iv) corresponds to the reflected wave from the far vehicle, the phase difference θ2 with respect to the reference signals of the I and Q outputs corresponds to the distance to the far vehicle, and the amplitude corresponds to the received intensity of the reflected wave. larger than ii).

  In this embodiment, two types of methods are used in order to obtain the distance from the object using the I component and the Q component as the output of the IQ detector. This distance calculation is executed by the A / D converter and the microcomputer (MC) 27 using the I component and the Q component as the output of the IQ detector 23 via the two low-pass filters 25 and 26. Is done. Here, the two low-pass filters 25 and 26 are low-pass filters that are inserted in front of the A / D converter and generally correspond to half the sampling frequency.

In the first method for obtaining the distance to the object, the value of (I ² + Q ² ) corresponding to the amplitude is obtained from the I and Q components as the outputs of the low-pass filters 25 and 26.
By changing the delay time by the programmable delay line 13 in FIG. 2, the time when the value of (I ² + Q ² ) becomes maximum is the time until the radio wave is reflected from the object, and the object is calculated from that time. Distance to is required. This first method is used, for example, when the pulse width is short and the signal power is small.

  FIG. 13 is an explanatory diagram of the relationship between the delay time and the amplitude. In the figure, the amplitude is maximized at t1 corresponding to the round trip time of the radio wave to the near vehicle described in FIG. 2 and at time t2 when the radio wave goes back and forth between the large vehicle.

  In the second method for obtaining the distance to the object, the distance to the object is obtained using the phase difference obtained from the I component and the Q component, that is, the phase differences θ1 and θ2 described in FIG. This second method is used, for example, when the signal power is relatively large.

  Using the repetition period T (100 ns) of the same transmission pulse as the output of the rectangular wave oscillator 11 with respect to the I and Q components, and the speed of light c, the phase difference θ, the delay time τ, and the distance D to the object are It is given by

θ = tan ⁻¹ (Q / I) (2)
τ = θT / 2π (3)
D = τ × c / 2 = θTc / 4π (4)
FIG. 14 shows the relationship between the delay time by the programmable delay line 13 and the phase difference as in FIG. The delay times t1 and t2 correspond to the phase differences θ1 and θ2 described in FIG.

  Here, in order to obtain the distance to the object, the I and Q components output from the IQ detector are digitized and then processed by software using a microcomputer. However, by using an analog circuit, However, it is natural that the phase and distance can be calculated. As described above, since the signal is 10 MHz or less by the low-pass filter, a general LSI or the like can be used.

  FIG. 15 is a block diagram showing the configuration of the second embodiment of the pulse radar apparatus of the present invention. In the second embodiment, in order to prevent a malfunction such as detecting an erroneous target object due to the interference from the plurality of radars described above, a spread spectrum (SS) method is applied and a signal is transmitted using a pseudo-random sequence. It is characterized by the fact that it is spread and transmitted, and despreading is performed at the time of reception, and is called the ASK-SS system.

  That is, comparing FIG. 15 with FIG. 2, in FIG. 2, instead of directly giving the output of the rectangular wave oscillator 11 to the pulse generation circuit and the band limiting unit 12 and the programmable delay line 13, a spreading result using a pseudo-random sequence is given. There is a basic difference.

  15, the output (S21 signal) of the rectangular wave transmitter 11 described in FIG. 3 is given to the frequency divider 31, and the frequency divider 31 outputs the S22 signal having a frequency corresponding to the PN sequence chip section. . The signal is further supplied to another frequency divider 32, and an S23 signal having a frequency lower than that of the S22 signal, for example, a frequency corresponding to a half cycle of the PN sequence repetition, is output.

FIG. 16 shows the output of the PN (sequence) generator 33. As described above, the repetition period of the PN sequence corresponds to, for example, a bit interval, and is set to, for example, ½ of the period of the S23 signal.
Next, an exclusive OR (EXOR) of the output of the PN (sequence) generator 33 and the S23 signal as the output of the frequency divider 32 is taken by the EXOR gate 34. As the output, as shown in FIG. 17A, the PN sequence waveform is output in the interval where the S23 signal is H, and the PN sequence is inverted and output in the interval where the S23 signal is L.

  The output of the EXOR gate 34 corresponds to the result of the phase modulation by the PN series S23 signal. As described above, the PN sequence is used in order to prevent interference from many other radars, for example, in an on-vehicle radar. However, this phase modulation is considered to make the interference prevention more effective.

  Finally, the AND gate 35 takes the logical product of the output of the EXOR gate 34 and the S21 signal output from the rectangular wave oscillator 11, and the output is the same as the pulse generation circuit and band limiter 12 shown in FIG. To line 13.

  FIG. 18 is an explanatory diagram of the output of the AND gate 35. FIG. 4A shows a waveform in the time domain. In the upper waveform, for example, the pulse of the S21 signal (10 MHz) as the output of the rectangular wave oscillator 11 is repeated many times inside the first H section corresponding to one chip section. Since the above waveform cannot be expressed correctly, the enlarged waveform is shown below in the form of the output of the pulse generation circuit and band limiter 12.

FIG. 18B shows a waveform in the frequency domain, and it is shown that more frequency components exist around the frequency of the S21 signal.
In the second embodiment of FIG. 15, a transmission pulse is sent based on the output of the AND gate 35, and the reception pulse is detected by the IQ detector 23 via the gate circuit 21 and the like, and from the low-pass filters 25 and 26. Until output, the operation is basically the same as in the first embodiment of FIG. However, since the transmission signal is spread using a pseudo-random sequence, an operation such as despreading is required, and processing by the A / D converter and the microcomputer 27, particularly the microcomputer, is different.

Explaining the difference, the output of the EXOR gate 34 is given to the microcomputer for despreading, despreading is performed, the value of (I ² + Q ² ) is obtained, and Fourier transform is performed. , The power in only the frequency region of the S23 signal is extracted, and the distance is obtained as the round-trip time of the radio wave to the target when the value becomes maximum.

  In the second method described above, similarly, the I and Q signals after despreading are each subjected to Fourier transform, and the power in only the frequency domain of the signal of S23 is extracted. ) To (4), the phase difference and the distance to the object are obtained.

  FIG. 19 is a block diagram showing the configuration of the pulse radar device according to the third embodiment of the present invention. In the third embodiment, similarly to the second embodiment, an operation using a spread spectrum system is performed. However, the gate circuit 21 arranged in the subsequent stage of the amplifier 20 in FIG. The difference is that it is placed with the detector 19.

  As a result, even when there is a leak to the pulse signal that controls the gate operation, it can be separated from the high-frequency signal by the high pulse filter, the leak component can be cut off, and a malfunction can be prevented.

  FIG. 20 is a block diagram showing the configuration of the fourth embodiment of the pulse radar apparatus according to the present invention. In the fourth embodiment, as in the second and third embodiments, an operation using a spread spectrum system is performed. For example, instead of the AND gate 35 in FIG. 15 as the second embodiment, FIG. 20 is different in that the EXNOR gate 40 is used. This fourth embodiment is called an improved ASK-SS system.

  In the second embodiment, as described with reference to FIG. 18, in the interval where the pseudo-random sequence is L, there is no pulse in the output of the pulse generation circuit and the band limiting unit 12, and no signal is transmitted from the transmission antenna 17. There are sections, and the amplitude of the received signal also decreases correspondingly. Therefore, in the fourth embodiment, the use of the EXNOR gate 40 reduces the period in which no pulse is output, and doubles the amplitude of the signal at the time of reception, as will be described later, thereby making signal processing more reliable. can do.

FIG. 21 is an explanatory diagram of an output signal of the EXNOR gate 40 in FIG.
This figure corresponds to FIG. 18 for the second embodiment. FIG. 18 illustrates that the pulse generation is performed only for the section in which the PN sequence is H. However, in FIG. 21, the AM-OSC rectangular wave signal, that is, the falling point of the S21 signal also in the section in which the PN sequence is L. It is shown that a pulse that rises in accordance with is generated.

  In FIG. 15, since the AND gate 35 is used, a pulse is generated only when the S21 signal is H, that is, amplitude modulation is performed, whereas in FIG. 20, the EXNOR gate is used. Therefore, the phase is shifted by 180 degrees, indicating that a pulse is generated in synchronization with the falling edge of the S21 signal, that is, a phase modulation operation is performed.

  The difference between the operation on the received signal in the fourth embodiment and the operation in the second embodiment will be described with reference to FIGS. FIG. 22 is a conceptual explanatory diagram of the output of the low-pass filter 22. The left side shows the output in the fourth embodiment, and the right side shows the output in the second embodiment.

  Assuming that the received signal, ie, the output of the gate circuit 21, has the same waveform as the generated pulse described in FIGS. 18 and 21, in the fourth embodiment on the left side, the rectangular shape from the low-pass filter 22 even in the interval where the PN sequence is L. An output frequency of the wave oscillator 11, for example, a sine wave waveform of 10 MHz is output. Although the phase changes abruptly when the PN sequence changes from H to L, a sine wave having the same frequency is output even when the PN sequence is L.

On the other hand, in the second embodiment, that is, in the second embodiment, the sine wave is not output in the interval where the PN sequence is L, and the output of the low-pass filter 22 is zero.
FIG. 23 is an explanatory diagram of the output operation of the IQ detector 23 in the fourth embodiment, and FIG. 24 is an explanatory diagram of the output operation of the IQ detector 23 in the second embodiment. In this IQ detection, detection is performed using a local signal as a sine wave having the same frequency as the input signal.

  In FIG. 23, positive values are output for both the I component and the Q component for the interval where the PN sequence is H, and the phase of the input signal from the low-pass filter 22 is substantially inverted in the interval where the PN sequence is L. Negative values are output for both the I component and the Q component.

On the other hand, in the second embodiment shown in FIG. 24, since the value of the input signal is 0 in the interval where the PN sequence is L, the values of both the I component and the Q component are 0.
As described above, in the fourth embodiment, the amplitude of the output signal of the IQ detector can be almost doubled compared to the second embodiment, and the interval in which the amplitude is 0 can be reduced. it can. Thereby, for example, signal processing by the A-D converter and the microcomputer 27 can be made more reliable.

  That is, in the second embodiment, it is necessary to select data only in the section where the PN sequence is H. However, for example, if the signal processing speeds up, it is troublesome to check the sections of H and L due to time lag. turn into. In addition, since there is no positive or negative interval in the signal value, it is impossible to detect a DC offset. On the other hand, in the fourth embodiment, for example, it is possible to cancel the DC offset by taking an average, and to use the entire section as data.

(Supplementary note 1) In a radar device that detects a target by transmitting a pulse signal, a control pulse generating means that generates a control pulse signal by delaying a signal that is a basis for generating a transmission pulse;
A pulse radar device comprising: gate means for performing a gate operation on a received signal using the control pulse signal.

(Appendix 2) Detection means for detecting the output of the gate means;
When the control pulse generating means changes the amount of delay, the distance to the target is calculated using the output of the detecting means so as to correspond to the delay amount at which the component corresponding to the amplitude of the received signal is maximized The pulse radar device according to appendix 1, further comprising a calculation unit.

(Supplementary Note 3) Detection means for detecting the output of the gate means;
When the control pulse generating unit changes the amount of delay, the distance calculating unit calculates the distance to the target in accordance with the phase difference between the base signal and the received signal using the output of the detecting unit The pulse radar device according to appendix 1, further comprising:

  (Additional remark 4) It is further provided with the modulation signal production | generation means which produces | generates a pulse from the signal used as the basis of the said transmission pulse production, and produces | generates the modulation signal for transmission pulse production | generation by restrict | limiting the spectrum range of this pulse. The pulse radar device according to appendix 1.

(Additional remark 5) In the radar apparatus which transmits a pulse signal and detects a target, the 1st signal used as the basis of transmission pulse creation, the 2nd signal for phase modulation of a frequency lower than the 1st signal, Control pulse generating means for generating a control pulse signal by delaying a signal created using a pseudo-random signal for amplitude modulation generated at an intermediate frequency between the first and second signals;
A pulse radar device comprising: gate means for performing a gate operation on a received signal using the control pulse signal.

(Supplementary note 6) The pulse radar device according to supplementary note 5, wherein the pseudo-random signal is a signal for amplitude modulation with respect to the first signal.
(Supplementary note 7) The pseudo-random signal is a signal for phase modulation with respect to the first signal, and the generated signal is a signal in which a pulse is present even when the pseudo-random signal is Low. The pulse radar device according to appendix 5.

(Appendix 8) Detection means for detecting the output of the gate means;
When the control pulse generating means changes the amount of the delay, despreading is performed on the output of the detecting means using the pseudo-random signal, the power in the frequency band is extracted, and the power value is maximum. The pulse radar device according to appendix 5, further comprising distance calculation means for calculating the distance to the target in correspondence with the delay amount.

(Supplementary note 9) Detection means for detecting the output of the gate means;
When the control pulse generating means changes the amount of the delay, despreading is performed on the output of the detecting means using the pseudo-random signal, and the power in the frequency band is extracted to obtain the first base The pulse radar device according to appendix 5, further comprising distance calculating means for calculating a distance to the target in correspondence with a phase difference between the received signal and the received signal.

  (Supplementary Note 10) A modulated signal for generating a transmission pulse by generating a pulse from a signal created using the first signal, the second signal, and a pseudo-random signal, and band-limiting the spectrum range of the pulse. The pulse radar apparatus according to appendix 5, further comprising modulation signal generation means for generating

It is a principle block diagram of the radar device receiver of the present invention. 1 is a configuration block diagram of an ASK pulse radar device as a first embodiment of the present invention. It is a figure which shows the output of the rectangular wave oscillator in 1st Embodiment. It is a figure which shows the output of a pulse generation circuit and a band limiting part. It is a figure which shows the output of a programmable delay line. It is a figure which shows the output of the pulse generation circuit to which the output of a programmable delay line is given. It is a figure which shows the output of a carrier wave oscillator. It is a figure which shows the output of an amplitude modulator. It is a figure which shows the output of an envelope detector. It is a figure explaining operation | movement of a gate circuit. It is a figure which shows the output of the low pass filter into which the output of a gate circuit is input. It is a figure explaining the output of an IQ detector. It is a figure which shows the relationship between the amplitude corresponding to the output of an IQ detector, and the delay time of a delay line. It is a figure which shows the relationship between the phase difference calculated | required from the output of a detector, and the delay time of a delay line. It is a block diagram of the configuration of an ASK-SS radar apparatus as a second embodiment. It is a figure which shows the example of a PN series. It is a figure explaining the output of an EXOR gate. It is a figure explaining the output of an AND gate, a pulse generation circuit, and a band limiting part. It is a block diagram of the configuration of the third embodiment of the pulse radar device of the present invention. It is a block diagram of the configuration of an improved ASK-SS radar apparatus as a fourth embodiment. It is explanatory drawing of the pulse produced | generated in 4th Embodiment. It is a figure which shows the comparison of the output of the gate circuit in 4th Embodiment and 2nd Embodiment, and the low-pass filter of the latter stage. It is a figure which shows the output of the IQ detector in 4th Embodiment. It is a figure which shows the output of the IQ detector in 2nd Embodiment. It is FIG. (1) explaining the influence of the noise in a prior art. It is FIG. (2) explaining the influence of the noise in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pulse radar apparatus 2 Control pulse generation means 3 Gate means 4 Detection means 5 Distance calculation means 11 Rectangular wave oscillator 12 Pulse generation circuit and band control part 13 Programmable delay line 14 Pulse generation circuit 15 Carrier oscillator 16 Amplitude modulator 19 Envelope detection Device 21 Gate circuit 22, 24, 25, 26 Low-pass filter 23 IQ detector 27 A / D converter and microcomputer 31, 32 Frequency divider 33 PN (series) generator 34 EXOR gate 35 AND gate 40 EXNOR gate

Claims (5)

In a radar device that detects a target by transmitting a pulse signal,
A first signal that is a basis for creating a transmission pulse, a second signal for phase modulation having a frequency lower than that of the first signal, and a modulation signal that is generated at an intermediate frequency between the first and second signals Pulse generation signal generating means for generating a signal for pulse generation using the pseudo-random signal of
Modulation signal generation means for generating a pulse from the signal generated in the pulse generation signal generation means, band-limiting the spectrum range of the pulse, and generating a transmission pulse generation modulation signal;
Said first signal in said pulse generation signal producing means, said second signal, said pseudo random signal and delaying the signal generated by using the control pulse generating means for generating a control pulse signal When,
Gate means for performing a gate operation on the received signal using the control pulse signal;
A pulse radar device comprising:   The pulse radar apparatus according to claim 1, wherein the pseudo-random signal is an amplitude modulation signal for the first signal.   The pseudo-random signal is a signal for phase modulation with respect to the first signal, and the generated signal is a signal in which a pulse is present even when the pseudo-random signal is low. The pulse radar device according to 1. Detection means for detecting the output of the gate means;
When said control pulse generating means to vary the amount of the delay, performs despreading with the pseudo-random signal to the output of the detection wave unit, extracts the power of the frequency band of the second signal, 2. The pulse radar device according to claim 1, further comprising distance calculation means for calculating a distance to the target in correspondence with a delay amount at which the power value is maximized. Detection means for detecting the output of the gate means;
When said control pulse generating means to vary the amount of the delay, performs despreading with the pseudo-random signal to the output of the detection wave unit, extracts the power of the frequency band of the second signal, 2. The pulse radar device according to claim 1, further comprising distance calculating means for calculating a distance to the target in correspondence with a phase difference between the first signal serving as the base and a received signal.

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