JP4895880B2 - Speed detection device and speed detection notification system provided with speed detection device - Google Patents

Description

  The present invention relates to a speed detection device that measures the moving speed of a moving body such as a vehicle traveling on a road using the Doppler effect, a speed detection notification system including the speed detection device, and a speed detection method. .

  Conventionally, in a speed detection device that measures the moving speed of a moving body such as a vehicle traveling on a road, a transmission wave is transmitted to the moving path, and the reflected wave generated by the transmission wave and the passage of the moving body is detected. It is known that the speed is calculated by using the Doppler effect generated between the speed detection device and the object by receiving and detecting the frequency change of the received reflected wave (see, for example, Patent Document 1). . Specifically, the speed detection device is disposed above or to the side of the moving path of the moving body, and transmits a transmission wave toward the moving body located on the rear side in the traveling direction from directly below or from the side to the side. The transmission unit includes a transmission unit, a reception unit that receives a reflected wave from the moving body, and a control unit that includes a speed calculation unit that calculates a speed based on a reception signal from the reception unit. For example, as shown in FIG. 3, the transmission wave transmitted from the transmission unit of the speed detection device is arranged at a predetermined height above the moving route of the road and is formed on the rear side in the traveling direction of the moving body and with the ground. It is transmitted at an angle θ °. Since the transmission wave spreads by θ ° with respect to the angle α ° (that is, the antenna angle) formed by the central axis of the wave and the ground, the transmission wave that reaches the ground changes from the angle α-θ ° formed by the ground to α + θ °. Thus, the traveling direction side has an elliptical region with a long side. When a moving body enters this radio wave region, the transmission wave is reflected by the moving body to become a reflected wave, and the reflected wave is detected by the receiving unit. Then, the receiving unit sends a received signal based on the reflected wave to the speed calculating unit, and the speed calculating unit calculates the speed based on the received signal.

Moreover, as a speed detection notification system using a speed detection device, there is a system including a speed detection device and a notification device that performs predetermined notification based on the detection result (see, for example, Patent Document 2). For example, when a vehicle traveling on a road enters the detection area of the speed detection device, and the vehicle speed is equal to or higher than a speed threshold set in advance in the speed detection device, the sound, voice, light There are some which notify the driver of an overspeed warning by lighting / blinking display, display of characters and images, and the like.
JP 2004-271298 A JP2005-182256

  In any of the speed detection devices used in the conventional speed detection notification system, the transmission wave transmitted from the transmission unit is generally predetermined with respect to the central axis (also referred to as a beam axis) of the wave. Since it spreads with the width of the angle, when it reaches the moving body by the spread angle, the radio wave area will be larger than that at the time of transmission. Since the center axis of the wave is transmitted obliquely with respect to the moving body in order to use the Doppler effect as described above, the angle formed by the moving body and the wave also affects the movement of the moving body. It will change with it. Although the angle changes depending on the position of the moving body in this way, the correction value obtained from the single angle formed by the central axis of the transmission wave transmitted from the transmitting unit installed in the inclined posture and the moving body is The speed of the moving object is calculated in advance based on the correction value. For this reason, when a reflected wave reflected near the center axis of the transmission wave is received, an accurate velocity of the moving body can be calculated with the set correction value, but it deviates from the center axis of the transmission wave. Position, especially at the start of speed detection and at the end of speed detection, a large calculation error occurs in the correction value set for the central axis, even if the moving speed of the moving object is constant. However, depending on the position of the moving body in the moving direction, there is an inconvenience that a speed significantly different from the actual speed is detected. For example, as shown in FIG. 3, when the moving body passes through the radio wave region of the transmission wave, the reflected wave at the point P and the reflected wave at the point Q have the frequency even if the moving body is at a constant velocity. Different. However, the angle correction performed at the time of speed calculation only gives the same coefficient for the reflected wave at the point P and the reflected wave at the point Q, usually a coefficient based on the antenna angle α. That is, the angle between the transmission wave and the reflected wave at the point P and the ground is α−θ, but the angle correction is not a coefficient based on α−θ °, but a coefficient based on α ° of a preset antenna angle. Is given. The same applies to the point Q and the points in the radio wave area of other transmission waves. Therefore, the farther away from the antenna angle α of the transmission section, the reflected wave at that point has a significantly different frequency, but since a constant coefficient is always given for the angle correction, there is a large variation in the calculated value after the angle correction. As a result, the accuracy of the speed detection device is lowered. In addition, if a highly directional antenna is used in the speed detection device to prevent the spread of transmission waves, which is the cause of the decrease in detection accuracy, the transmission of transmission waves transmitted to the ground is prevented and the detection accuracy of the speed detection device However, there is a problem that the entire apparatus becomes very large and the burden on the cost increases. Further, when the correction value is changed according to the position of the moving body, it is difficult to implement the correction value because it is necessary to improve the control device with a large capacity.

  Therefore, the present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a high-accuracy speed detection device that can accurately detect a speed without using a large and expensive antenna with high directivity. .

The present invention has been made to solve the above-described problems, and the speed detection device according to the present invention is arranged above the movement path of the moving body, and is located on the rear side in the traveling direction from directly below. A transmission unit that transmits a transmission wave toward the body, a reception unit that receives a reflected wave from the moving body, and a control unit that includes a speed calculation unit that calculates a speed based on a reception signal from the reception unit. in the speed detection apparatus of the Doppler system, wherein, among the reflected waves reflected from the moving body over time, a plurality of reflections from the reflected wave reception start to the first specific-th receiving later than this range and waves, the remaining range was divided and a plurality of reflected wave to the second specific th received at the front side than this from the reflected wave of the reception end, which is set around the central axis of the transmission wave received from only Characterized in that only the signal of the reflected wave is a means for sending said velocity calculating means.

  In the speed detection device having the above configuration, when the reception unit receives the reflected wave generated when the moving body passes through the radio wave region of the transmission wave, the control unit includes a part of the received reflected wave. Since only the above signal is sent to the speed calculation means, the reflected wave signal that does not calculate the speed is not sent to the speed calculation section, and the number of signals to be calculated is reduced, so the circuit scale of the speed calculation means is reduced and the circuit consumption Electric power may be small. In addition, the control means includes a first specific number of reflected waves received after the reception start reflected wave among the reflected waves reflected from the moving body over time, and a reception end reflection. Since only the reflected wave signals received in the remaining range excluding the plurality of reflected waves from the wave to the second specific side received on the near side are sent to the speed calculation means, the control means sends a speed calculation unit. The signal to be sent to is only a reflected wave signal generated when the mobile body passes only a specific area within the radio wave area of the transmission wave, that is, a range set around the central axis of the transmission wave. Thus, a signal having a small variation in the frequency of the reflected wave among the reflected waves reflected from the moving body over time is calculated. Therefore, since the variation of the calculated value of the speed calculation unit is reduced, the detection accuracy of the speed detection device is increased.

In addition, the above-described feature is that the speed detection device is disposed on the side of the moving path of the moving body, and transmits a transmission wave from the side toward the moving body located on the rear side in the traveling direction from the side. The speed detection device according to the present invention is arranged on the side of the moving path of the moving body, and transmits from the side toward the moving body located on the rear side in the traveling direction from the side. Speed detection using a Doppler method, comprising: a transmitting means for transmitting a wave; a receiving means for receiving a reflected wave from a moving body; and a control means having a speed calculating means for calculating a speed based on a received signal from the receiving means. in the device, wherein, among the reflected waves reflected from the moving body over time, a first plurality of reflected waves to a specific numbered receiving later than this from the reflected wave of the reception start, the receiving ends This from the reflected wave of The remaining range plurality of the reflected wave was divided up second specific th received at remote front side, only the signal of the reflected wave received only from the range set around the central axis of the transmission wave It may be a means for sending to the speed calculating means.

  In particular, it is preferable to include conversion means for converting the reflected wave received by the receiving means, and pulse number measurement means for counting the pulses converted by the conversion means. In order to specify the number of the reflected wave reflected from the moving body over time from the start of reception, the conversion means for converting the pulse of the reflected wave, and the pulse for counting the pulses converted by the conversion means By providing the number measuring means, it is possible to specify the number of the pulse wave input to the pulse number measuring means having a simple configuration from the start of reception of the reflected wave. Therefore, it is not necessary to perform a complicated calculation for specifying the number of the reflected wave from the start of reception, and the reflected wave can be specified by a pulse number measuring means having a simple circuit configuration, and the apparatus is compact. It can be configured with a circuit.

  In particular, it is preferable that the speed calculation means is activated to process the reflected wave signal sent from the processing means. Since the speed calculation means is activated to process the reflected wave signal sent from the processing means, the speed calculation unit when the reflected wave signal is not sent is in a dormant state, and the speed calculation is performed. The power consumption of the part can be reduced.

  Furthermore, it is preferable that the speed calculation means calculates the speed of the moving body by detecting a time per predetermined wavelength of the reflected wave received and pulse-converted by the reception signal means. The reflected wave is detected by the receiving means, and the speed of the moving body is calculated by detecting the time per predetermined wavelength of the pulse wave pulse-converted by the receiving means by the speed calculating means. Since the speed is calculated using the reflected wave in this way, there is no need for a circuit for generating an electromagnetic wave having a plurality of frequencies, and the speed can be calculated using a single frequency radio wave. A simpler configuration.

  Further, the transmission wave transmitted from the transmission means arranged above the moving body is transmitted toward the rear side in the traveling direction from directly below the transmission means, and the angle formed with the ground can be set to 30 °. preferable. When the moving body enters the area where the speed of the transmitted wave is detected from behind, the angle of the transmitted wave and the ground is set to 30 °, so that the reflected wave can reliably receive the Doppler effect. . Therefore, a difference due to the Doppler effect between the transmitted wave and the reflected wave appears remarkably, and the accuracy of the speed-calculated value increases.

  Furthermore, it is preferable that only a specific pulse corresponding to the reflected wave signal received in the remaining range is extracted from the pulses measured by the pulse measuring means. Since only the pulse corresponding to the signal received in the remaining range is extracted from the received reflected wave signal, the reflected wave signal can be specified by the pulse measured by the pulse measuring means having a simple circuit configuration. Thus, the circuit of the speed detection device has a simpler configuration.

  In addition, the speed detection notification system according to the present invention includes a speed detection device and notification means for performing notification based on a value detected by the speed detection device. Since the speed detection notification system performs notification based on the value detected by the speed detection device according to the present invention, the detection accuracy becomes high and more detailed values can be detected. Therefore, the notification from the notification means is highly reliable, and abundant types of notification according to the detected value can be performed.

Still further, in the speed detection method according to the present invention, the transmission wave is transmitted backward and downward in the traveling direction to receive the reflected wave from the moving body in order to transmit the transmission wave obliquely to the moving body. In this case, among the reflected waves reflected from the moving body with the passage of time, a plurality of reflected waves from the reflected wave at the start of reception to the first specific number of reflected waves received after this, and the reflected wave at the end of reception from the remaining range plurality of the reflected wave was divided up second specific th received in than this front side, the reflected wave of the signal received only from the setting range about the central axis of the transmitted wave Only the speed is calculated.

  In the speed detection method of the method, when the reception unit receives the reflected wave generated by the moving body passing through the radio wave region of the reflected wave, the processing unit is configured to receive a part of the received reflected wave. Since only the above signal is sent to the speed calculation means, the signal of the reflected wave not speed-calculated is not sent to the speed calculator, the number of signals to be calculated is reduced, and the speed calculation can be performed in a short time. In addition, in order to identify the reflected wave generated when the moving body passes through the radio wave area of the transmitted wave, the received wave of the reflected waves reflected from the moving body with the passage of time is received. The first specific number of reflected waves received after this from the start reflected wave and the plurality of reflected waves from the reflected end wave received to the second specific number received before this are excluded. Since only the reflected wave signal received in the remaining range is speed-calculated, the speed-calculating signal is only the reflected wave signal generated when the mobile body passes a specific area within the radio wave area of the transmitted wave, A speed of a signal with less variation among the frequencies of the reflected waves reflected from the moving body with time is calculated. Accordingly, the variation in the calculation value for calculating the speed is reduced, and the detection accuracy of the speed detection device is increased.

  As described above, in the speed detection device according to the present invention, the processing means receives the first of the reflected waves reflected from the moving body over time from the reflected wave at the start of reception. The speed calculation is performed only on the reflected wave signals received in the remaining range, excluding the plurality of specific reflected waves and the reflected waves from the end of reception up to the second reflected wave received on the near side. Since it is a means for sending to the means, there is an effect of providing a high-accuracy speed detection device that can accurately detect the speed without using a large and expensive antenna with high directivity.

  Moreover, in the speed detection method according to the present invention, among the reflected waves reflected from the moving body over time, the first specific number of reflected waves received after the reflected wave at the start of reception is received. Since only the reflected wave signal received in the remaining range is calculated from the reflected wave at the end of reception, excluding a plurality of reflected waves received up to the second side before this, the directivity of the antenna is reduced. Even if it is not increased, the speed detection accuracy is improved.

  Hereinafter, an embodiment of a speed detection device according to the present invention will be described with reference to the drawings.

  The speed detection device in the present embodiment detects the speed of the moving body 9 by the Doppler method, and is used to detect the speed of a vehicle or the like traveling on the road. As shown in the block diagram of FIG. 1, the speed detection device 1 includes a transmission / reception antenna 2 that transmits and receives microwaves (frequency 3G to 30 GHz, wavelength 1 to 10 cm) that is a transmission wave f and a reflected wave S. A transmission unit 3 that generates a transmission wave f, a reception unit 4 that detects a reflected wave S and transmits a signal c of the reflected wave S to the control unit 5, and a transmission / reception of a signal c and a microwave transmitted from the reception unit 4 And a control unit 5 for controlling This will be specifically described below.

  The transmission unit 3 includes a microwave generation unit 31 that generates a microwave and an amplification unit 32 that amplifies the microwave. The microwave generator 31 receives a signal from the controller 5, generates a microwave signal, and outputs it to the amplifier 32. The output microwave signal is amplified by the amplifying unit 32 and transmitted from the transmission / reception antenna 2 as a transmission wave f. The transmission / reception antenna 2 of the present embodiment is installed in the vicinity of 5 m above the moving path of the moving body 9 such as a vehicle, and the antenna angle is not directly below but directed to the rear side in the traveling direction of the moving body 9. Is tilted downward by 30 °. That is, the moving body 9 receives the transmission wave f from the transmitting / receiving antenna 2 in front of the moving path (moving direction) and above.

  Since the transmission unit 3 includes the amplifier 32, even if the signal from the microwave generation unit 31 has a weak electric field strength, the transmission unit 3 amplifies the weak signal and reliably reaches the moving body 9. Can generate radio waves.

  The receiving unit 4 includes an amplifying unit 41 that amplifies the reflected wave S received by the transmission / reception antenna 2 and a converting unit 42 that detects the amplified reflected wave S and performs pulse conversion. The amplifying unit 41 receives the reflected wave S generated by the transmission wave f transmitted from the transmitting / receiving antenna 2 and hits the moving body 9 by the transmitting / receiving antenna 2, amplifies the received reflected wave S, and outputs the amplified reflected wave S to the converting unit 42. To do. The converting unit 42 includes a waveform generating unit 42a and a pulse measuring unit 42b. The waveform generating unit 42a detects the signal of the reflected wave S input from the amplifying unit 41, and the reflected wave S shown in FIG. Create a waveform. Further, the pulse measuring unit 42b shapes the waveform of the reflected wave S created by the waveform creating unit 42a into a rectangular pulse wave signal c shown in FIG. 5B.

  Since the receiving unit 4 includes the amplifying unit 41, the reflected wave S from the moving body 9 received by the transmission / reception antenna 2 has a weak electric field intensity simply by using the amplifying unit 41 of a simple circuit. However, the weak signal can be amplified to an electric field intensity that can be reliably detected by the waveform creation unit 42a.

  The control unit 5 is constituted by, for example, a central processing unit (hereinafter referred to as “CPU”), and includes a counter 51 as a pulse number measuring unit and a speed calculation unit 52 that calculates the speed of the signal c sent from the counter 51. With. In addition, the control unit 5 includes an adjustment unit 53 that outputs a signal for starting the microwave generation unit 31 of the transmission unit 3 described above. The counter 51 counts the number of pulses of the rectangular pulse signal c shaped by the pulse measuring unit 42b. That is, when the pulse signal c from the pulse measuring unit 42b is input, the number of wavelengths is counted. When the pulse signal is input for the first time, the count value becomes “1”. Until the initialization, the pulse signal c is counted once every time one wavelength is input. The counter 51 has a predetermined lower limit value and upper limit value set in advance. The counter 51 outputs the pulse signal c to the speed calculation unit 52 only when the input pulse signal c is a value between the lower limit and the upper limit of the counter 51. Upon receiving the rectangular pulse signal c from the counter 51, the speed calculation unit 52 calculates the speed based on the signal c. When the rectangular pulse signal c from the counter 51 is not received, the speed calculation unit 52 is in a resting state, reducing the calculation load on the control unit 5 and saving power.

  Next, a flowchart of an operation example of the speed detection device in the present embodiment is shown in FIG.

  First, when the speed detection device 1 is activated (START), the transmission unit 2 transmits a microwave as a transmission wave from the transmission / reception antenna 2 to the movement path of the moving body 9 based on a signal from the control unit 5 (step 201). ). When starting the speed detection, the value of the counter 51 is once initialized together with the transmission of the microwave and becomes a count value “0” (step 202). When the mobile body 9 passes through the transmission area of the transmission wave f in a state where the transmission wave f is transmitted to the movement path of the mobile body 9, the transmission wave f hits the mobile body 9 and a reflected wave S is generated. Is received by the transmitting / receiving antenna 2 (step 203). The received reflected wave S is amplified by the amplifying unit 41 of the receiving unit 4, and the amplified reflected wave signal is detected by the waveform creating unit 42a to create a waveform of the reflected wave S and output to the pulse measuring unit 42b. . Further, the pulse measuring unit 42b shapes the rectangular pulse signal c based on the waveform output by the waveform forming unit 42a (step 204).

  The rectangular pulse signal c is sent from the pulse measuring unit 42b to the counter 51 of the control unit 5, and the counter 51 counts the number of pulses, that is, the number of wavelengths of the pulse signal c (step 205). A lower limit value N and an upper limit value K are predetermined for the counter 51. If the count value of the counter 51 (that is, the total number of pulses input to the counter 51) is less than the lower limit value N, the next operation is performed. The process returns to the count of the number of pulses in step 205 again. If the count value of the counter 51 is equal to or greater than the lower limit N, the process proceeds to the next operation (step 206). Next, in step 206, if the count value of the counter 51 is equal to or greater than the lower limit value N, it is determined whether the value is less than the upper limit value K predetermined for the counter 51. If it is less than the upper limit K, the counter 51 sends the pulse signal c to the speed calculation unit 52 while continuing to count the pulse signal c (step 207). The speed calculation unit 52 receives the rectangular pulse waveform signal c, and calculates the speed of the vehicle by detecting the time around the predetermined wavelength of the signal c. The counter 51 continues to send the pulse signal c to the speed calculation unit 52 until the count value of the pulse signal c input to the counter 51 becomes equal to or higher than the upper limit set value K. Upon receiving the signal c, the speed calculation unit 52 continues the speed calculation while receiving the pulse signal c from the counter 51 (step 208). The counter 51 stops sending the pulse signal c to the speed calculation unit 52 when the count value reaches the upper limit value K or more, and the speed calculation unit 52 thereby stops the calculation (step 209). With the operations from step 201 to step 209, the speed calculation when one mobile body 9 passes through the radio wave region of the transmission wave is completed. Further, when it is necessary to detect the speed of the moving body 9 in the rearward direction, for example, the following vehicle, the counter value of the counter 51a is initialized and the operation from step 202 is repeated again (step 210). Further, when it is not necessary to perform speed detection, the speed detection device 1 is stopped (END).

The frequency of the reflected wave S received in step 203 differs depending on the position of the moving body 9 even if the moving body 9 is at a constant speed. This difference in the frequency of the reflected wave S is one of the causes of a decrease in detection accuracy of the conventional speed detection device 1. The speed detection device of the present embodiment reduces the difference in the frequency of the reflected wave S by reducing the variation in the frequency of the reflected wave S, thereby improving the detection accuracy.
First, the reflected wave S received in step 203 will be described with reference to FIG.

  FIG. 3 shows that the speed detection device 1 according to the present embodiment is installed above the moving path of the road, and the angle formed between the transmission antenna 2 and the ground is obliquely downward (backward downward tilt direction) as the set angle α °, that is, the moving body. 9 illustrates a state in which a microwave is transmitted backward in the traveling direction of 9. The microwave, which is the transmission wave f, is transmitted from the transmission / reception antenna 2 with an angle α ° between the central axis A and the ground, that is, the antenna angle α °, and is transmitted to the antenna angle α ° by a radio wave diffusion action. On the other hand, the case of propagating in the air while spreading by ± θ ° is shown. The transmission wave region is formed by the diffusion of the radio wave, and the microwave reflected by the vehicle when the traveling vehicle enters the region is received by the transmission / reception antenna 2 as the reflected wave S (see FIG. 5). The reflected wave S has a different frequency depending on the position of the vehicle where the reflected wave S is generated even if the vehicle is traveling in the transmission region of the transmitted wave f at a constant speed, and the difference in the frequency of the reflected wave S is a speed calculation. Causes variations in value.

  Next, the cause of the variation in the speed calculation value will be described in more detail. When the reflected wave S is received by the transmission / reception antenna 2, the reflected wave S is incident at an angle γ (not shown) with respect to the traveling direction of the moving body 9. Is done. Therefore, the speed detection device 1 performs angle correction by the speed calculation unit 52 in order to observe the apparent speed of the moving body 9. The relationship between the speed of the moving object and the apparent speed is as follows.

V = v / cosγ ......... Formula 1

  Here, V is a speed at which the moving body 9 passes through the moving path, v is an apparent speed observed by the speed detecting device 1, γ is an incident angle of the reflected wave S received by the transmitting / receiving antenna 2, and cos γ is an angle correction coefficient. is there.

  From Equation 1, the speed V at which the moving body 9 passes through the moving path depends on the incident angle γ of the reflected wave S received by the transmitting / receiving antenna 2. Usually, in the speed calculation of the speed detection device, the incident angle γ is a fixed value, and a constant is always given. However, the transmission wave f of the actual speed detection device 1 has a radio wave region by diffusion, and the region spreads at an angle of ± θ ° with respect to the antenna angle α ° of the transmission / reception antenna 2 as shown in FIG. ing. Furthermore, although the incident angle γ of the reflected wave S varies depending on the position of the vehicle, the incident angle γ is calculated as a constant as in Equation 1. For example, the incident angle of the reflected wave S generated when the moving body 9 passes the point P shown in FIG. 3 is α−θ °, and the incident angle of the reflected wave S generated when it passes the point Q is α + θ °. is there. However, the angle correction performed by the speed calculation unit 52 is always calculated by cos α from α ° that is the antenna angle of the transmission / reception antenna 2, and at each position that is outside α ° that is the antenna angle of the moving body 9. The value calculated by the speed calculation unit 52 varies (including a calculation error due to cos α).

  In the present embodiment, in order to increase the detection accuracy of the speed detection device, the variation in the incident angle γ of the reflected wave S to the transmission / reception antenna 2 is suppressed by the operation from step 205 to step 208. Hereinafter, a description will be given with reference to FIG.

  As shown in FIG. 4, the transmission wave f is transmitted at the antenna angle α of the transmission / reception antenna 2 and spreads by ± θ °. Until the vehicle enters the radio wave region of the transmission wave f and deviates from the radio wave region, the incident angle α ° of the reflected wave S to the transmission / reception antenna 2 varies within an angular range of ± θ °. The speed detection device 1 according to the present embodiment does not calculate the speed of the reflected wave S in the entire range of the incident angle α ± θ ° to the transmission / reception antenna 2 but includes the reflected wave S with the antenna angle α ° before and after the reflected wave S. Variations in the calculated values are suppressed by calculating the speed limited to a specific angle range with respect to some reflected waves S and the central axis A, for example, within a range of −3 to +3 degrees with respect to the antenna angle α °. That is, the velocity calculation is not performed for all the reflected waves S from the incident angle α−θ ° to the incident angle α + θ ° received by the transmission / reception antenna 2, but the angle correction coefficient cosα of Equation 1 including the incident angle α ° is calculated. Only the reflected wave S generated when the vehicle passes within a specific range in which the value is less likely to affect is speed-calculated. Therefore, the speed calculation unit 52 calculates the speed of only the reflected wave S near the antenna angle α, so that variation (variation) due to the value of the angle correction coefficient cos α is small, and the speed calculated value is also a value with small variation (variation). Thus, the detection accuracy of the speed detection device 1 is increased.

  Note that the velocity of the reflected wave S may be calculated only for the reflected wave S of the transmission wave f at the antenna angle α °. However, in the actual use state, the reflection timing differs depending on the vehicle width, vehicle height, etc. of the moving body 9 such as a vehicle, and the reflection timing differs depending on rainy weather or other road conditions. Therefore, if a certain range is provided for limiting the reflected wave S, a biased value depending on the use state is not calculated. In the present embodiment, the transmission / reception antenna 2 is 5 m above the ground, and the antenna angle is inclined by 30 ° with respect to the ground toward the rear in the traveling direction. Since the transmission wave f is diffused in an angle range of 30 ° ± 10 °, the incident angle of the reflected wave S, which is hard to be influenced by the value of the angle correction coefficient cos α, to the transmission / reception antenna 2 is in the range of 27 ° to 32 °. Only when there is a speed calculation. A value obtained by averaging all the speed-calculated values may be used as a speed value, or only a specific value selected from all the speed-calculated values may be averaged or the speed may be averaged. One selected value of all the calculated values may be used as the speed value.

  Furthermore, for the limitation by the incident angle of the reflected wave S described above, pulses input to the counter 51 are counted using the counter 51 provided in the control unit 5 of FIG. The counting is performed in step 205 and step 206 in FIG. 2 in which the pulse signal c is input from the pulse measuring unit 42b of the receiving unit 4. Hereinafter, the operation of steps 205 and 206 will be described in detail.

  First, as shown in FIG. 5A, the reflected wave S is a quarter wavelength of the microwave that is the transmission wave f from the transmission / reception antenna 2, and the standing wave Sf and the node Sf are repeated. It is a wave. That is, when the antinode Sh and the node Sf are repeated twice, one wavelength is obtained. The amplitude of the reflected wave S is not obtained if the moving body 9 is stopped, and an amplitude in which the belly Sh and the node Sf are repeated is obtained if the moving body 9 is moving. Since the wavelength λ of the reflected wave S represents the distance through which the wave propagates, the speed of the moving body 9 can be measured by measuring the time during which the wavelength λ propagates. In the speed detection device 1 of the present embodiment, when the signal of the reflected wave S is input to the receiving unit 4 after being received by the transmission / reception antenna 2, the reflected wave S is received by the pulse measuring unit 42b of the receiving unit 4 as shown in FIG. To a rectangular pulse waveform signal c shown in FIG. The counter 51 counts the number of pulse waveforms with the rise of two times of the pulse waveform as the count number “1”.

  As described above, the wavelength λ that is the wavelength of the reflected wave S is the distance traveled by the moving body 9. Therefore, the distance traveled by the moving body 9 in the radio wave area of the transmission wave f is converted from the count value at the count 51. That is, the value counted by the counter 51 up to that position is calculated by dividing the distance traveled by the moving body 9 in the radio wave region of the transmission wave f by the wavelength λ of the pulse waveform. For example, as shown in FIG. 4, a case where the moving body 9 passes through the range from the radio wave area point A to the point D of the transmission wave f will be described. A point A to a point D is a region where the transmission wave f transmitted from the transmission / reception antenna 2 is diffused, and an angle with the ground is α ± θ °. The region where the speed is calculated is α−θ1 ° to α + θ2 °, and is a range from point B to point D. When the mobile body 9 enters the transmission area of the transmission wave f, the reception unit 4 receives the signal from the point A to the point B, but the speed calculation is not performed. In other words, although it is counted by the counter 51, the pulse signal c is not input to the speed calculation unit 52. The count value at the point B is a value X obtained by dividing the distance L1 from the point A to the point B by the wavelength λ of the pulse waveform signal c of the reflected wave S. With this X as the lower limit of the count value of the counter 51, speed calculation is not performed when the value is less than the value X. Then, the speed calculation is performed from the reflected wave S until the moving body 9 passes through the point B and reaches the point C. The count value up to the point C is a value Y obtained by dividing the distance L2 from the point A to the point C by the wavelength λ of the pulse waveform signal c of the reflected wave S. Accordingly, when the count value of the counter 51 is in the range from X to less than Y, the pulse waveform signal c input to the counter 51 is output to the speed calculator 52, and the speed calculator 52 calculates the speed. . Further, when the moving body 9 passes after the point C, the counter value of the counter 51 exceeds the upper limit value Y, so the pulse waveform signal c input to the counter 51 is output to the speed calculation unit 52. No speed calculation is performed. As a result, for the speed calculation, the speed when the moving body 9 passes from the point B to the point C, that is, the incident angle of the reflected wave S to the transmission / reception antenna 2 is in the range of α−θ1 ° to α + θ2 °. Only the speed can be calculated, and a value with small variation (fluctuation) due to a difference in angle can be calculated at the time of speed calculation. Further, since the calculation range is designated simply by changing the setting value of the counter 51, the calculation range according to the road condition can be designated with a simple operation, and the installation of the counter 51 after the speed detection device 1 is installed. The value can be changed easily.

  FIG. 6 is a diagram illustrating an embodiment of a speed detection notification system including a notification unit 7 that notifies the speed detection device 1 based on the detected value, and detects the speed of a vehicle 8 traveling on a road. The apparatus 1 detects the speed, sends the detection result to the operation unit 6 via the communication cable, and wirelessly communicates to the overspeed determination processing device 71 of the notification unit 7 when the speed threshold preset in the operation unit 6 is exceeded. The overspeed determination processing device 71 controls the information board 72 via the communication cable based on the value, and displays the information board 72. The speed detection device 1 is installed at a point of 5 m in the center of the lane where speed detection is performed, and the antenna angle of the speed detection device 1 is inclined by 30 ° with respect to the vehicle coming from the rear. The operation unit 6 and the overspeed determination processing device 71 are installed in the vicinity of 1.5 m above the roadside so that the operator can easily perform maintenance even after the speed detection notification system is installed. The information board 72 is installed beside the road. The information board 72 may be anywhere as long as the driver of the vehicle 8 can easily recognize the information on the information board 72.

  The operation unit 6 compares the speed detected value with a preset threshold value, and if the speed detected value is equal to or greater than the threshold value, not only outputs the value to the overspeed determination device 71 but also the speed This is for changing the setting of the upper limit value and the lower limit value of the counter 51 of the detection device 1 or changing the threshold value to be compared with the value of the speed detected. Further, the overspeed determination processing device 71 displays warning information on the information board 72 based on the input signal and warns the driver. For example, in the case of a road with a speed limit of 50 km / h, the threshold value of the operation unit 6 is set to 40 km / h, and when the vehicle 8 at 45 km / h enters the detection area of the speed detection device 1, the speed detection device 1 uses the vehicle 8. Speed detection calculates a value of 45 km, and the operation unit 6 receives the value and compares it with a threshold speed of 40 km of the operation unit 6. Since the vehicle speed of the vehicle 8 is 40 km / h or more, the detection result is output to the overspeed determination processing device 71. The overspeed determination device 71 has a first threshold of 40 km / h and a second speed of 50 km, and if the speed of the vehicle 8 is in the range of 40 km / h to 50 km / h, the information board 72 will read “speed attention”. If the speed of the vehicle 8 is 50 km / h or more, the information board 72 is displayed with a text “Overspeed” to warn the driver of the vehicle 8. In addition, the display board 72 can not only notify the driver of the vehicle 8 using characters, but also can use various notification means such as sound, sound, light lighting / flashing display, image display, and the like. .

  As described above, in the speed detection notification system using the speed detection device 1 of the present embodiment, the speed detection portion, the setting of the counter 51 and the operation unit 6 for setting the threshold value for the speed detection value are the same as the speed detection device 1. Since it is arranged at a position where another worker on the roadside can operate, it is possible to easily change the threshold value of the speed detection value sent to the overspeed determination device 71 even after the speed detection notification system is installed. In addition, since the setting of the counter 51 of the speed detection device 1 can be performed by the operation unit 6, even after the installation of the speed detection notification system, the operator can change the setting value according to the road condition by changing the setting of the operation unit. Can be done easily. Further, since the speed detection device 1 and the operation unit 6 are not integrated, it is only necessary to install the small speed detection device 1 when installing on the road, and the operation unit 6 may be provided separately from the road. . Further, the overspeed determination device 71 and the display plate 72 are not integrated, and the overspeed determination device 71 is disposed at a position that can be operated by a worker on the roadside different from the display plate 72. The setting can be easily changed after installation.

  In the above-described embodiment, the speed detection device 1 is used for speed detection of the vehicle 8 traveling on a single lane road. However, the speed detection device 1 is not limited to speed detection and can be used as a device for detecting the presence of the vehicle 8. For example, there is a notification system in which the detection device is installed on the side line road side of the junction where the main line road and the side line road meet to notify the vehicle 8 traveling on the main line that there is a vehicle 8 traveling on the side line road. . When the vehicle 8 enters the side road, the detection device detects the presence of the vehicle 8 and alerts the vehicle traveling on the main road.

  In the above embodiment, the speed detection device 1 is installed 5 m above the movement route, and the transmission wave f is transmitted toward the rear side in the traveling direction of the road, and is set to an angle of 30 ° between the central axis A and the ground. However, the speed detection device 1 may be installed on the side of the road, and the transmission wave f may be transmitted toward the rear side in the traveling direction of the road and set to an angle of 30 ° with respect to the traveling direction from the side of the road. In any case, the Doppler effect between the transmission wave f and the reflected wave S by the moving body may be remarkably exhibited, and the moving body may be installed so as not to be hindered. Moreover, although the angle (antenna angle) between the central axis A and the ground is set to 30 °, the angle is not limited to 30 °, and may be in the range of 30 to 45 degrees. In any case, the angle formed between the center axis A and the ground may be an angle at which the speed detection of the moving body can be detected with high accuracy by the Doppler effect.

  Furthermore, in the speed detection device 1 of the above embodiment, the angle between the central axis A and the ground is set to 30 °, and the incident angle of the reflected wave S received in the radio wave region of the transmission wave f is 27 ° to 32 °. The velocity of only the reflected wave within the range was calculated, but the limitation of the range of the incident angle of the reflected wave S depends on the set range of the speed detection accuracy of the speed detection device, and the angle between the central axis A and the ground On the other hand, it is not limited to −3 ° to + 2 °. In any case, it may be in a range that is not easily affected by the angle correction coefficient when performing angle correction in speed calculation.

  The reflected wave S received by the receiving unit 4 is converted into a pulse and the pulse is counted by the counter 51. However, the counter 51 is not provided, but software that counts in the CPU of the control unit may be built. However, if the counter 51 is provided as hardware separate from the CPU, the processing speed increases and reliable speed detection becomes possible.

  Furthermore, if the number of pulses of the pulse signal c sent from the receiving unit 4 is between the lower limit value and the upper limit value set in the counter 51, the counter 51 may send the pulse signal c to the speed calculation unit 52 as needed. However, the counter 51 once captures all the pulse signals c, deletes the pulse signals c that are less than the lower limit value and greater than or equal to the upper limit value, and sends the remaining signals to the speed calculation unit 52. You may send it.

It is a block diagram which shows the structure of the speed detection apparatus which concerns on this embodiment. It is a flowchart which shows operation | movement of the speed detection apparatus which concerns on this embodiment. It is a side view which shows the electromagnetic wave area | region of the transmission wave f transmitted from a transmission / reception antenna. It is a side view which shows the calculation area | region of the reflected wave S of the speed detection apparatus which concerns on this embodiment. (A) It is a wave form diagram which shows the state of reflected wave S. FIG. (B) It is a wave form diagram which shows the state of the pulse waveform which carried out the pulse conversion of the reflected wave S. FIG. It is a figure which shows schematic structure of the speed detection alerting | reporting system provided with the speed detection apparatus which concerns on this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Speed detection apparatus, 2 ... Transmission / reception antenna, 3 ... Transmission part, 4 ... Reception part, 5 ... Control part, 6 ... Operation part, 7 ... Notification part, DESCRIPTION OF SYMBOLS 8 ... Vehicle, 9 ... Moving body, 31 ... Microwave generation part, 32 ... Amplification part, 41 ... Amplification part, 42 ... Conversion part, 51 ... Counter, 52 ... speed calculation part, 53 ... adjustment part, 71 ... overspeed determination device, 72 ... information board, 42a ... waveform generation part, 42b ... pulse measurement part, c ... Pulse signal, f ... transmitted wave, A ... central axis (antenna angle), S ... reflected wave, X, Y ... count value, L1, L2 ... distance

Claims (9)

Transmitting means for transmitting the transmission wave (f) to the moving body (8, 9) located above the moving path of the moving body (8, 9) and positioned from above to the moving body (8, 9) located behind the traveling direction. 3), receiving means (4) for receiving the reflected wave (f) from the moving body (8, 9), and speed calculation for calculating the speed based on the received signal (c) from the receiving means (4) In a Doppler type speed detection device comprising control means (5) having means (52),
Of the reflected waves (S) reflected from the moving body (8, 9) with the passage of time, the control means (5) receives a first identification received after the reflected wave (S) at the start of reception. the remaining range plurality of reflected wave (S), was divided and a plurality of reflected waves (S) from the end of reception of the reflected wave (S) to a second specific th received at the front side than this to th And means for sending only the signal (c) of the reflected wave (S) received from only the range set around the central axis (A) of the transmitted wave (f) to the speed calculating means (52). A speed detector characterized by the following. Transmission that is arranged on the side of the moving path of the moving body (8, 9) and transmits the transmission wave (f) from the side toward the moving body (8, 9) located on the rear side in the traveling direction from the side. The speed is calculated based on the means (3), the receiving means (4) for receiving the reflected wave (f) from the moving body (8, 9), and the received signal (c) from the receiving means (4). In a Doppler type speed detection device comprising a control means (5) having a speed calculation means (52),
Of the reflected waves (S) reflected from the moving body (8, 9) with the passage of time, the control means (5) receives a first identification received after the reflected wave (S) at the start of reception. the remaining range plurality of reflected wave (S), was divided and a plurality of reflected waves (S) from the end of reception of the reflected wave (S) to a second specific th received at the front side than this to th And means for sending only the signal (c) of the reflected wave (S) received from only the range set around the central axis (A) of the transmitted wave (f) to the speed calculating means (52). A speed detector characterized by the following.   A conversion means (42) for converting the reflected wave (S) received by the reception means (4), and a pulse number measurement means (51) for counting the pulses converted by the conversion means (42). The speed detection device according to claim 1 or 2, further comprising:   The speed according to claim 3, wherein the speed calculation means (52) is activated to process the signal (c) of the reflected wave (S) sent from the pulse number measurement means (51). Detection device.   The speed calculating means (52) calculates the speed of the moving body (8, 9) by detecting the time per predetermined wavelength of the reflected wave (S) received and pulse-converted by the receiving means (4). The speed detection device according to claim 3 or 4, wherein   The transmission wave (f) transmitted from the transmission means (3) disposed above the mobile body (9) is transmitted toward the rear side in the traveling direction from directly below the transmission means (3), and The speed detection device according to claim 1, wherein the angle formed is set to 30 °.   4. Only a specific pulse corresponding to the signal (c) of the reflected wave (S) received in the remaining range is extracted from the pulses measured by the pulse measuring means (51). The speed detection device described.   A speed detection notification system comprising: the speed detection device according to any one of claims 1 to 7; and notification means (7) for performing notification based on a value detected by the speed detection device. When the transmission wave (f) is transmitted obliquely to the mobile body (8, 9) and the reflected wave (S) from the mobile body (8, 9) is received, the mobile body (8, 9) with time elapses. the reflected wave reflected (S) from a plurality of reflected waves from the start of reception of the reflected wave (S) to the first specific-th receiving later than this and (S), the reception end the reflected wave (S than this from) the remaining range plurality of reflected waves and (S) were divided in to a second specific th received at the front side, is set around the central axis (a) of the transmitted wave (f) A speed detection method characterized by calculating a speed of only the signal (c) of the reflected wave (S) received from only a range .

Images