JP2007225410A - Pulse radar obstacle detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulse radar obstacle detection device which can measure the distance to an object even in an environment in which there exist radio wave leakage and fluctuations in the transmission timing of a pulse control section. <P>SOLUTION: The pulse radar obstacle detection device 1 comprises a transmitting section 2 for transmitting a pulsed radio wave, the pulse control section 3 for controlling the transmitting section 2, a receiving section 4 for receiving a reflected wave, a storage device 5 for storing an output signal, a correlation calculation section 8 for calculating the degree of correlation and outputting time delay information having the highest degree of correlation, a delay processing section 9 for providing an output to a comparator 6 with the addition of a time delay, the comparator 6 for performing difference processing between the output signal and a signal of the storage device 5, and a distance measuring section 7 for calculating the distance to the object. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention transmits a radio wave toward an object, receives a reflected wave from the object, and calculates a distance to the object from a time delay between a time when the radio wave is transmitted and a time when the radio wave is received. The present invention relates to a pulse type radar apparatus.

  Conventionally, as disclosed in Japanese Patent Laid-Open No. 7-72237 (Patent Document 1), a pulse radar type obstacle detection device that identifies a weak reflected signal and improves distance measurement capability is known.

As shown in FIG. 11, the pulse radar type obstacle detection device is roughly divided into a radar head 101 having a pulse signal transmitting unit 101a for transmitting a pulse signal and a reflected pulse signal receiving unit 101b for receiving a reflected pulse. An arithmetic storage unit 102 having a sampling unit 102a that samples a signal received by the signal receiving unit 101b, an addition storage unit 102b that sequentially adds and stores the sampling results for each sampling point, and data stored mainly in the addition storage unit 102b The determination unit 103 having a function of determining the presence or absence of a reflected pulse from the contents of the signal, the function of controlling the driving of the radar device in general, that is, the pulse signal transmission unit 101a, the activation of the sampling unit 102a and the addition storage unit 102b of the arithmetic storage unit 102 That controls the activation of the determination unit 103 And it is configured to include a pulse control unit 104 having a function, a. The pulse radar type obstacle detection device 100 configured as described above periodically outputs a pulse signal by the pulse signal transmission unit 101a. The reflected pulse from the target is continuously received by the reflected pulse signal receiving unit 101b and binarized by the binarizing means. Then, the sampling unit 102a samples the binarized signal at a certain sampling point or a plurality of sampling points after the transmission timing of the pulse signal transmission unit 101a to obtain a sampling value of 0 or 1, and sets this to each sampling point. The result is given to the corresponding addition storage unit 102b. Therefore, the addition storage unit 102b adds the sampling values of 0 or 1 for each predetermined number of times of transmission of the signal by the pulse signal transmission unit 101a. When the addition processing for the predetermined number of times is completed, the determination unit 103 compares the normalized addition value obtained by dividing the addition value for each addition storage unit 102b by the number of additions with a predetermined threshold value. It is determined whether or not there is a reflection signal from the target, and based on this, the presence or absence of an external target is determined.
JP-A-7-72237

  However, this pulse radar type obstacle detection device 100 uses so-called leaked radio waves such as a signal received in the radar circuit that is not a reflected signal from the pulse signal transmission unit 101a or a signal received in the radar redom. In some cases, the reflected wave from the object cannot be detected. Further, the waveform of the leaked radio wave changes due to fluctuations in the transmission timing time of the pulse control unit 104, etc., and the leaked radio wave may not be removed with one stored waveform.

  The present invention has been invented in view of the above-mentioned background art, and its problem is that it can measure the distance of an object even in an environment where there are fluctuations in leaked radio waves and transmission timing time of a pulse control unit. Is to provide.

  In order to solve the above-described problem, the invention according to claim 1 of the present application includes a transmission unit that transmits a pulsed radio wave toward an object, a pulse control unit that controls the transmission unit, and a reception antenna. A receiving unit that receives a reflected wave from an object and branches and inputs an output signal received by a correlation calculation unit and a comparator; a storage device that stores an output signal from a receiving unit in an environment without an object in advance; The output signal of the receiving unit is branched and input, the degree of correlation between this output signal and the signal of the storage device is calculated based on the pulse transmission timing of the pulse control unit, and the time delay information with the highest calculated degree of correlation is the delay processing unit A time calculating unit that adds a time delay to the output signal of the storage device based on the time delay information, and a delay processing unit that outputs the comparator to the comparator. It provided a comparator for differential processing an output signal from the signal receiving unit, a distance measuring unit which comparator a pulse control unit calculates the distance to the object than the time delay between the difference processed signal.

  Further, in the invention according to claim 2 of the present application, in the pulse radar type obstacle detection device according to claim 1, a temperature measurement unit is provided that causes the storage device to select an output signal in accordance with the temperature measurement result around the reception unit. The storage device stores in advance the output signal from the receiving unit in an environment where there is no object for each temperature measured by the temperature measuring unit, and according to the result of the temperature measurement around the receiving unit by the temperature measuring unit The output signal is selected.

  Further, in the invention according to claim 3 of the present application, in the pulse radar type obstacle detection device according to claim 1 or 2, the first low-pass that performs frequency filtering at a predetermined frequency or less with respect to the branch input from the receiving unit to the correlation calculating unit. A filter and a second low-pass filter that performs frequency filtering on a signal of the storage device with a frequency equal to or lower than a predetermined frequency and passes the result to the correlation calculation unit are provided.

  In the pulse radar type obstacle detection device according to the first aspect of the present invention, it is possible to extract only the signal received by the receiving antenna while reducing the influence of the time fluctuation by the pulse control unit or the like. It is possible to reduce false detection of an object due to leaked radio waves from the internal circuit of the type obstacle detection device.

  In the pulse radar type obstacle detection device according to the second aspect of the present invention, in particular, only the signal received by the receiving antenna can be extracted while reducing the influence of the time fluctuation due to the temperature change. It is possible to further reduce false detection of an object due to leaked radio waves from the internal circuit of the type obstacle detection device.

  In the pulse radar type obstacle detection device according to the third aspect of the present invention, in particular, since the correlation calculation is performed after removing the noise component, a higher correlation value can be obtained. Thereby, a highly accurate correlation calculation can be performed.

  Hereinafter, the present invention will be described based on embodiments shown in the accompanying drawings.

  1 to 3 show a pulse radar type obstacle detection apparatus which is a first embodiment corresponding to claim 1 of the present application.

  As shown in FIG. 1, the pulse radar type obstacle detection apparatus includes a transmission unit 2 that transmits a pulsed radio wave toward an object, a pulse control unit 3 that controls the transmission unit 2, and a reception antenna 4a. And receiving a reflected wave from the object, branching and inputting the output signal received by the correlation calculation unit 8 and the comparator 6, and an output from the receiving unit 4 in an environment without the object in advance The storage device 5 for storing the signal and the output signal of the receiving unit 4 are branched and input, and the degree of correlation between the output signal and the signal of the storage device 5 is calculated based on the pulse transmission timing of the pulse control unit 3 and calculated. A correlation calculation unit 8 that outputs time delay information having the highest degree of correlation; a delay processing unit 9 that adds a time delay to the signal in the storage device 5 based on information from the correlation calculation unit 8 and outputs the signal to the comparator 6; Time delay processing by part 9 The comparator 6 that performs differential processing on the output signal of the storage device 5 and the output signal from the receiving unit 4 and the signal that is differentially processed by the pulse control unit 3 and the comparator 6 cause a target to be obtained. And a distance measuring unit 7 for calculating the distance.

  Next, the operation of this embodiment will be described based on the waveforms shown in FIG.

  FIG. 2A shows an output signal of the receiving unit 4. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude, which is an output signal when there is an object. This output signal also includes a signal received by the receiving antenna 4a of radio waves other than the reflected wave from the object, for example, leaked radio waves of a circuit in the transmission unit 2.

  FIGS. 2B1 to 2B5 are leaked radio wave signals shifted by a certain amount in the time direction. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude. This figure shows, for example, a state in which there is no object at the time of manufacturing the pulse radar type obstacle detection device 1, or a receiving antenna by means such as installing an appropriate radio wave absorber on the front surface of the pulse radar type obstacle detection device 1. The waveform obtained by storing the output signal from the receiving unit 4 in a state where the radio wave input to 4a is blocked in the storage device 5 is shifted by the correlation calculating unit 8 by a certain time value.

  FIG. 2C shows that the correlation calculation unit 8 compares the output signal branched from the reception unit 4 with the output of the delay processing unit 9 obtained by adding a delay to the output signal stored in the storage device 5. The signal is input to the comparator 6 and processed by the comparator 6. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude. This signal is obtained by removing leaked radio waves from the circuit in the transmitter 2 from the signal shown in FIG.

  The operation of this embodiment will be described based on the flowchart shown in FIG.

  First, when the power source (not shown) of the pulse radar type obstacle detection device 1 is turned on, the operation is started (S1). When the operation of the pulse radar type obstacle detection device 1 is started, the correlation calculation unit 8 correlates the output signal of the reception unit 4 and the output signal of the storage device 5 (S2). Specifically, the output signal of the storage device 5 is shifted by a certain time value, and the correlation between each waveform and the output signal is calculated, and the time value with the highest degree of correlation is output (S3). According to the time delay value information output from the correlation calculation unit 8, the delay processing unit 9 adds a delay to the output signal of the storage device 5 (S4). In this state, the comparator 6 compares the output signal of the receiving unit 4 with the output of the delay processing unit 9 obtained by adding a delay to the output signal stored in the storage device 5 (S5). And the presence determination of a target object is performed from the result (S6). Next, the distance measuring unit 7 calculates the distance to the object from the time delay between the pulse control unit 3 and the signal compared by the comparator 6.

  Therefore, in the pulse radar type obstacle detection device 1 of this embodiment, it is possible to extract only the signal received by the receiving antenna 4a while reducing the influence of the time fluctuation by the pulse control unit 3 or the like. It is possible to reduce erroneous detection of an object due to leaked radio waves from the internal circuit of the radar obstacle detection device 1.

  4 and 5 show a pulse radar type obstacle detection apparatus according to a second embodiment corresponding to claims 1 and 3 of the present application.

  Here, only matters different from those in the first embodiment will be described, and other matters are the same as those in the first embodiment, and thus description thereof will be omitted.

  As shown in FIG. 4, the pulse radar type obstacle detection device 1 is less than a predetermined frequency with respect to the branch input from the reception unit 4 to the correlation calculation unit 8 in order to remove the noise component in the first embodiment described above. The first low-pass filter 10 that performs the frequency filtering and the second low-pass filter 11 that performs frequency filtering below a predetermined frequency on the signal of the storage device 5 and passes the signal to the correlation calculation unit 8 are added.

  Next, the operation of this embodiment will be described based on the waveforms shown in FIG.

  FIG. 5 (a <b> 1) is an output signal of the receiving unit 4. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude, which is an output signal when there is an object. This output signal also includes a signal received by the receiving antenna 4a of radio waves other than the reflected wave from the object, for example, leaked radio waves of a circuit in the transmission unit 2.

  FIG. 5 (a 2) shows the branched received signal passed through the first low-pass filter 10. The noise component superimposed on the waveform is removed by the first low-pass filter 10.

  FIG. 5 (b <b> 0) is a signal stored in the storage device 5. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude. This figure shows, for example, a state in which there is no object at the time of manufacturing the pulse radar type obstacle detection device 1, or a receiving antenna by means such as installing an appropriate radio wave absorber on the front surface of the pulse radar type obstacle detection device 1. The output signal from the receiving unit 4 in a state where the radio wave input to 4a is cut off is stored in the storage device 5. That is, this signal is a signal including a leaked radio wave from the circuit in the transmitter 2.

  FIGS. 5B1 to 5B5 are leaked radio wave signals obtained by shifting the signal after passing through the second low-pass filter 11 by a certain amount in the time direction. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude. This figure shows, for example, a state in which there is no object at the time of manufacturing the pulse radar type obstacle detection device 1, or a receiving antenna by means such as installing an appropriate radio wave absorber on the front surface of the pulse radar type obstacle detection device 1. The waveform obtained by storing the output signal from the receiving unit 4 in a state where the radio wave input to 4a is blocked in the storage device 5 is shifted by the correlation calculating unit 8 by a certain time value.

  FIG. 5 (c) shows a comparison between the output signal branched from the receiving unit 4 and the output of the delay processing unit 9 obtained by adding a delay to the output signal stored in the storage device 5 in the correlation calculation unit 8. The signal is input to the comparator 6 and processed by the comparator 6. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude. This signal is obtained by removing leaked radio waves from the circuit in the transmitter 2 from the signal shown in FIG.

  Therefore, in the pulse radar type obstacle detection device 1 of this embodiment, since the correlation calculation is performed after removing the noise component, a higher correlation value can be obtained. That is, highly accurate correlation calculation can be performed.

  6 to 8 show a pulse radar type obstacle detection apparatus according to a third embodiment corresponding to claims 1 and 2 of the present application.

  Here, only matters different from those in the first embodiment will be described, and other matters are the same as those in the first embodiment, and thus description thereof will be omitted.

  As shown in FIG. 6, the pulse radar type obstacle detection device includes a temperature measurement unit 12 that causes the storage device 5 to select an output signal in accordance with the temperature measurement result around the reception unit 4. An output signal from the receiving unit 4 in an environment where there is no object is stored in advance for each temperature measured by the temperature measuring unit 12, and according to a result of temperature measurement around the receiving unit 4 by the temperature measuring unit 12 Select the output signal.

  Next, the operation of this embodiment will be described based on the waveforms shown in FIG.

  FIG. 7A shows an output signal of the receiving unit 4. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude, which is an output signal when there is an object. This output signal also includes a signal received by the receiving antenna 4a of radio waves other than the reflected wave from the object, for example, leaked radio waves of a circuit in the transmission unit 2.

  7 (b1) and (b2) are signals stored in the storage device 5, respectively. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude. This figure shows, for example, a state in which there is no object at the time of manufacturing the pulse radar type obstacle detection device 1, or a receiving antenna by means such as installing an appropriate radio wave absorber on the front surface of the pulse radar type obstacle detection device 1. The output signal from the receiving unit 4 in a state where the radio wave input to 4a is cut off is stored in the storage device 5 in two waveforms under conditions where the temperature of the device is different. That is, this signal is a signal including the leaked radio wave of the circuit in the transmitter 2 at each temperature.

  7 (c1) to (c5) are leaked radio wave signals that are selected according to temperature information from the temperature measuring unit 12 and that are shifted from the waveform signal output from the storage device 5 by a certain amount in the time direction. . In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude. This figure shows, for example, a state in which there is no object at the time of manufacturing the pulse radar type obstacle detection device 1, or a receiving antenna by means such as installing an appropriate radio wave absorber on the front surface of the pulse radar type obstacle detection device 1. The waveform obtained by storing the output signal from the receiving unit 4 in a state where the radio wave input to 4a is blocked in the storage device 5 is shifted by the correlation calculating unit 8 by a certain time value.

  FIG. 7D shows that the correlation calculation unit 8 compares the output signal branched from the reception unit 4 with the output of the delay processing unit 9 obtained by adding a delay to the output signal stored in the storage device 5. The signal is input to the comparator 6 and processed by the comparator 6. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude. This signal is obtained by removing leaked radio waves from the circuit in the transmitter 2 from the signal shown in FIG.

  The operation of this embodiment will be described based on the flowchart shown in FIG.

  First, when the power source (not shown) of the pulse radar type obstacle detection device 1 is turned on, the operation is started (S1). When the operation of the pulse radar type obstacle detection device 1 is started, the temperature measurement unit 12 measures the temperature around the reception unit 4 and selects the output signal of the storage device 5 according to the temperature measurement result (S2). . A correlation calculation unit 8 performs a correlation calculation on the output signal from the reception unit 4 and the output signal of the selected storage device 5 (S3). Specifically, the output signal of the storage device 5 is shifted by a certain time value and the correlation between each waveform and the output signal is calculated, and the time value with the highest degree of correlation is output (S4). In accordance with the time delay value information output from the correlation calculation unit 8, a delay is added to the output signal of the storage device 5 selected by the delay processing unit 9 (S5). In this state, the comparator 6 compares the output signal of the receiving unit 4 and the output of the delay processing unit 9 obtained by adding a delay to the output signal of the storage device 5 (S6). Then, the presence of the object is determined based on the result (S7). Next, the distance measuring unit 7 calculates the distance to the object from the time delay between the pulse control unit 3 and the signal compared by the comparator 6.

  Therefore, in the pulse radar type obstacle detection device 1 of this embodiment, it is possible to extract only the signal received by the receiving antenna 4a while reducing the influence of time variation due to temperature change and the pulse control unit 3 or the like. Therefore, it is possible to reduce false detection of an object due to leaked radio waves from the internal circuit of the pulse radar type obstacle detection device 1.

  9 and 10 show a pulse radar type obstacle detection apparatus according to a fourth embodiment corresponding to all claims 1 to 3 of the present application.

  Here, only matters different from those in the first embodiment will be described, and other matters are the same as those in the first embodiment, and thus description thereof will be omitted.

  As shown in FIG. 9, the pulse radar type obstacle detection device 1 is less than a predetermined frequency with respect to the branch input from the reception unit 4 to the correlation calculation unit 8 in order to remove a noise component in the third embodiment described above. The first low-pass filter 10 that performs the frequency filtering and the second low-pass filter 11 that performs frequency filtering below a predetermined frequency on the signal of the storage device 5 and passes the signal to the correlation calculation unit 8 are added.

  Next, the operation of this embodiment will be described based on the waveforms shown in FIG.

  FIG. 10A shows an output signal of the receiving unit 4. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude, which is an output signal when there is an object. This output signal also includes a signal received by the receiving antenna 4a of radio waves other than the reflected wave from the object, for example, leaked radio waves of a circuit in the transmission unit 2.

  10B1 and 10B2 are signals stored in the storage device 5, respectively. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude. This figure shows, for example, a state in which there is no object at the time of manufacturing the pulse radar type obstacle detection device 1, or a receiving antenna by means such as installing an appropriate radio wave absorber on the front surface of the pulse radar type obstacle detection device 1. The output signal from the receiving unit 4 in a state where the radio wave input to 4a is cut off is stored in the storage device 5 in two waveforms under conditions where the temperature of the device is different. That is, this signal is a signal including the leaked radio wave of the circuit in the transmitter 2 at each temperature.

  10 (c1) to (c5) are selected according to the temperature information from the temperature measurement unit 12, and the signal output from the storage device 5 is passed through the second low-pass filter 11 as time. It is a leaked radio wave signal shifted by a certain amount in the direction. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude. This figure shows, for example, a state in which there is no object at the time of manufacturing the pulse radar type obstacle detection device 1, or a receiving antenna by means such as installing an appropriate radio wave absorber on the front surface of the pulse radar type obstacle detection device 1. The waveform obtained by storing the output signal from the receiving unit 4 in a state where the radio wave input to 4a is blocked in the storage device 5 is shifted by the correlation calculating unit 8 by a certain time value.

  FIG. 10D shows a comparison between the output signal branched from the receiving unit 4 and the output of the delay processing unit 9 obtained by adding a delay to the output signal stored in the storage device 5 in the correlation calculation unit 8. The signal is input to the comparator 6 and processed by the comparator 6. In this figure, the horizontal axis indicates time, and the vertical axis indicates the signal magnitude. This signal is obtained by removing leaked radio waves from the circuit in the transmitter 2 from the signal shown in FIG.

  Therefore, in the pulse radar type obstacle detection device 1 of this embodiment, since the correlation calculation is performed after removing the noise component, a higher correlation value can be obtained. That is, highly accurate correlation calculation can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows the pulse radar type obstruction detection apparatus which is 1st embodiment of this invention. (A) is an output waveform of the receiving unit of the pulse radar type obstacle detection device, (b1) to (b5) are waveforms obtained by shifting the waveform of the signal stored in the storage device by a certain time by the correlation calculation unit, (C) is the output waveform of the comparator. The flowchart which shows operation | movement of the pulse radar type obstruction detection apparatus. The block diagram which shows the pulse radar type obstruction detection apparatus which is 2nd embodiment of this invention. (A1) is the output waveform of the receiver of the pulse radar type obstacle detection device, (a2) is the output waveform of the first low-pass filter, (b0) is the signal stored in the storage device, and (b1) to (b5) Is a waveform obtained by shifting the waveform of a signal stored in the storage device by a predetermined time by the correlation calculation unit, and (c) is an output waveform of the comparator. The block diagram which shows the pulse radar type obstruction detection apparatus which is 3rd embodiment of this invention. (A) is an output waveform of the receiving unit of the pulse radar type obstacle detection device, (b1) to (b5) are waveforms obtained by shifting the waveform of the signal stored in the storage device by a certain time by the correlation calculation unit, (C) is the output waveform of the comparator. The flowchart which shows operation | movement of the pulse radar type obstruction detection apparatus. The block diagram which shows the pulse radar type obstruction detection apparatus which is 4th embodiment of this invention. (A1) is the output waveform of the receiver of the pulse radar type obstacle detection device, (a2) is the output waveform of the first low-pass filter, (b0) is the signal stored in the storage device, and (b1) to (b5) Is a waveform obtained by shifting the waveform of a signal stored in the storage device by a predetermined time by the correlation calculation unit, and (c) is an output waveform of the comparator. The block diagram which shows the pulse radar type obstacle detection apparatus which is a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pulse radar type obstruction detection device 2 Transmitter 3 Pulse control unit 4 Receiving unit 4a Receiving antenna 5 Storage device 6 Comparator 7 Distance measuring unit 8 Correlation calculating unit 9 Delay processing unit 10 First low-pass filter 11 Second low-pass filter 12 Temperature measurement unit

Claims (3)

  A transmitter that transmits pulsed radio waves toward the target, a pulse controller that controls the transmitter, and an output signal obtained by receiving a reflected wave from the target with the receiving antenna is compared with the correlation calculator. A receiving unit for branching input to the receiver, a storage device for storing an output signal from the receiving unit in an environment where there is no object in advance, and an output signal of the receiving unit is branched and input, and the output signal and the signal of the storage device are The correlation calculation unit calculates the correlation degree based on the pulse transmission timing of the pulse control unit, outputs the time delay information with the highest calculated correlation degree to the delay processing unit, and the time delay information outputs the time delay to the output signal of the storage device. A delay processing unit that adds a delay and outputs to the comparator, a comparator that performs differential processing on the output signal of the storage device output by the delay processing unit and the output signal from the reception unit, and pulse control And comparator differential processed signal and the time-delayed pulse radar type obstacle detection device formed by providing a distance measuring unit for calculating a distance to the object, the more.   A temperature measurement unit is provided that causes the storage device to select an output signal according to the temperature measurement result around the reception unit, and the storage device measures an output signal from the reception unit in an environment where there is no object by the temperature measurement unit. 2. The pulse radar type obstacle detection device according to claim 1, wherein the pulse radar type obstacle detection device is stored in advance for each temperature, and an output signal is selected according to a result of temperature measurement around the receiving unit by the temperature measuring unit.   A first low-pass filter that performs frequency filtering below a predetermined frequency for a branch input from the reception unit to the correlation calculation unit; a second low-pass filter that performs frequency filtering below a predetermined frequency for a signal in the storage device; The pulse radar type obstacle detection device according to claim 1 or 2, characterized by comprising:

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