JP2006343286A - Receiving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiving device capable of detecting accurately the position of a transmission source by correcting a received output corresponding to an obstacle existing between the transmission source of a radio wave and an antenna. <P>SOLUTION: In this receiving device 1 having the antenna 4 capable of switching a reception orientation direction, for receiving a radio wave by switching the reception orientation direction, and detecting the position of the transmission source of the radio wave based on the received output, the received output is corrected based on a variation of the received output by the antenna 4, and the position of a pedestrian 90 is detected based on the corrected received output. Since the received output is corrected based on the variation of the received output by the antenna 4, the received output attenuated by an obstacle existing between the pedestrian 90 and the antenna 4 can be corrected properly, and the position of the pedestrian 90 can be detected accurately based on the corrected received output. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a receiving apparatus that receives radio waves transmitted from a transmission source and detects the position of the transmission source.

Conventionally, as a device for receiving radio waves transmitted from a transmission source and detecting the position of the transmission source, it has a plurality of directional antennas arranged in different directions, and switches and receives them. One that estimates the direction of arrival of radio waves based on the received signal is known (see Patent Document 1).
JP 2002-107439 A

  However, in such a device, when an obstacle exists between the radio wave transmission source and the antenna, the reception output is reduced due to the radio wave attenuation, and the position of the transmission source is accurately determined based on the reception output. It is difficult to detect.

  Therefore, an object of the present invention is to provide a receiving apparatus that can accurately detect the position of a transmission source by correcting the reception output according to an obstacle existing between the transmission source of the radio wave and the antenna.

  That is, the receiving apparatus according to the present invention has an antenna that can switch the reception directivity direction, receives the radio wave by switching the reception directivity direction, and detects the position of the radio wave transmission source based on the reception output. The apparatus includes detection means for detecting a fluctuation amount of the reception output of the antenna and a correction means for correcting the reception output based on the fluctuation amount.

  According to the present invention, by correcting the reception output based on the amount of fluctuation in the reception output of the antenna, the reception output attenuated by the obstacle existing between the transmission source and the antenna can be appropriately corrected and corrected. The distance to the transmission source can be accurately detected based on the reception output. Therefore, the position of the transmission source can be detected with high accuracy.

  In the receiving apparatus according to the present invention, it is preferable that the correction unit performs correction by adding a larger correction value to the reception output of the antenna as the fluctuation amount is larger. In the receiver according to the present invention, it is preferable that the transmission source is a transmitter carried by a pedestrian, is mounted on a vehicle, and detects the position of the pedestrian from the vehicle. Furthermore, the receiving device according to the present invention preferably includes notifying means for notifying the fact that the pedestrian is present in an area where the vehicle is to travel.

  According to the present invention, the position of the transmission source can be detected with high accuracy by correcting the reception output according to the obstacle present between the radio wave transmission source and the antenna.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic configuration diagram of a receiving apparatus according to an embodiment of the present invention. The receiving device 1 according to the present embodiment is applied to a pedestrian presence information providing system that provides pedestrian presence information. As shown in FIG. 1, the receiving device 1 is mounted on a vehicle, receives a radio wave transmitted from a transmitter 91 possessed by a pedestrian 90, and based on the received value, a pedestrian 90 that is a radio wave transmission source. Detect the direction and distance. And the position of the pedestrian 90 is detected based on the direction and distance. In addition, the pedestrian 90 here includes not only a pedestrian but also a person who moves on a sidewalk, for example, a person who rides a bicycle.

  The receiving device 1 includes an antenna 4 that receives radio waves. The antenna 4 is an antenna that can switch the reception directivity direction. Here, the reception directing direction means a direction in which reception sensitivity is maximized. As the antenna 4, for example, a plurality of directional antenna elements 4 a to 4 e arranged in different directions are provided, and one of the antenna elements 4 a to 4 e used for reception is switched and selected by the switch 40. The switchable directivity direction is used. This makes it possible to receive radio waves by switching the reception directing direction of the antenna 4. The antenna elements 4a to 4e are parts that convert received radio waves into electrical signals.

  In FIG. 1, for convenience of explanation, the directional antenna elements 4 a to 4 e are illustrated in the same direction, but in actuality, they are disposed in different directions. For example, the receivable area is arranged so as to expand radially. Further, the case where the antenna 4 includes five directional antenna elements 4a to 4e has been described. However, the antenna 4 includes four or less or six or more directional antenna elements as long as the reception directivity direction can be switched. It may be. In addition, as the antenna 4, for example, a single directional antenna may be used and the direction of the directional antenna may be mechanically switched as long as the reception directional direction can be switched. It may be one that switches electronically like an antenna.

  A receiver 5 is connected to the antenna 4. The receiving unit 5 is for detecting a desired received signal such as detection processing or noise removal processing. A reception level detection unit 6 is connected to the output side of the reception unit 5. The reception level detection unit 6 receives the reception signal detected by the reception unit 5 and detects the reception level of the reception signal. Reception signals received by the antenna elements 4 a to 4 e are sequentially input to the reception level detection unit 6. And the reception level detection part 6 detects a reception level about each of those reception signals.

  A reception level attenuation correction unit 7 is connected to the output side of the reception level detection unit 6. The reception level attenuation amount correction unit 7 is a correction unit that corrects the reception output according to the attenuation amount of the reception level due to an obstacle between the pedestrian 90 and the antenna 4. The reception level attenuation correction unit 7 corrects the reception level based on the amount of fluctuation of the reception level (reception output). This detailed operation will be described later.

  A direction distance estimation unit 8 is connected to the output side of the reception level attenuation correction unit 7. The direction distance estimation unit 8 is based on the corrected reception level output from the reception level attenuation correction unit 7, and the distance to the radio wave arrival direction and radio wave transmission source, that is, the direction where the pedestrian 90 is located and the pedestrian 90. It functions as an estimation means for estimating the distance. The direction distance estimation unit 8 is connected to the estimated direction correction table 9 and the reception level correction table 10. The estimated direction correction table 9 is a table in which a direction estimation correction value is recorded, and provides direction estimation correction information to the direction distance estimation unit 8. The reception level correction table 10 is a table in which reception level estimation correction values are recorded, and provides reception level estimation correction information to the direction distance estimation unit 8.

  In addition, the direction distance estimation unit 8 is connected to the antenna switching unit 11. The antenna switching unit 11 switches the reception directivity direction of the antenna 4, receives a control signal from the direction distance estimation unit 8, and outputs a switching signal to the antenna 4. In addition, the direction distance estimation unit 8 is connected to the information provision determination unit 12. The information provision determination unit 12 determines whether or not to provide information that the pedestrian 90 is present in the vehicle traveling direction to the driver of the vehicle. For example, the information provision determination unit 12 acquires vehicle speed information and turn signal information, refers to the pedestrian presence information provision area table 13 corresponding to these information, and determines whether there is a pedestrian in the information provision area.

  And the information provision determination part 12 judges that the information that there is a pedestrian in the vehicle traveling direction should be provided when the area where the vehicle is about to travel and the pedestrian location overlap, and to that effect The signal is output to the information providing unit 14. The information providing unit 14 is an informing means for informing the driver of the vehicle that the pedestrian 90 is in an area to be traveled. As the information providing unit 14, for example, information providing information to the driver through hearing, such as a buzzer, a speaker, information providing information to the driver through vision such as a lamp, LED, liquid crystal display, or information to the driver through tactile sense such as a vibrator. What you provide is used.

  FIG. 2 is an explanatory diagram of a reception area in the reception apparatus according to the present embodiment.

  As shown in FIG. 2, when the vehicle is traveling in the straight direction, the information providing area 60 is formed so as to extend long in front of the vehicle 50. The information providing area 60 changes depending on the state of the vehicle such as the vehicle speed of the vehicle 50. Here, when the pedestrian 90 having the transmitter 91 is behind the truck 51 to be stopped, the truck 51 becomes an obstacle, the radio wave transmitted from the transmitter 91 is attenuated, and the reception output of the receiver 1 is reduced. To do. In this case, the radio wave transmitted from the transmitter 91 is received by the receiver 1 only as propagated around the track 51, such as W1 and W2 in FIG.

  For this reason, when the direction of the pedestrian 90 and the distance to the pedestrian are obtained based on the received output as it is, it is detected that the distance is longer than the actual distance, and the information is present in the information providing area 60. If it is outside the provision area 60, it will be erroneously determined. Therefore, in the receiving device 1 according to the present embodiment, the direction and distance of the pedestrian 90 are accurately detected by correcting the reception output in consideration of the presence or absence of an obstacle, and the position of the pedestrian 90 is accurately detected. It is something to be detected.

  FIG. 3 is a flowchart of the reception output correction process in the reception apparatus according to this embodiment.

  The control process in FIG. 3 is repeatedly executed at a predetermined cycle by, for example, the reception level attenuation correction unit 7. First, as shown in S10 of FIG. 3, a replacement process for the maximum value of the reception level is performed. This process is performed in order to acquire a predetermined set number n of the maximum value of the reception level, and is a process of performing array replacement of the acquired reception level maximum value Lmax. For example, when Lmax [0], Lmax [1], Lmax [2], and Lmax [3] are recorded as the maximum value data, the arrays are moved up to Lmax [1] and Lmax [2], respectively. , Lmax [3], and Lmax [4].

  And it transfers to S12 and the acquisition process of reception level La-Le in each of the directional antenna elements 4a-4e is performed. And the selection process of the reception level maximum value Lmax is performed (S14). This process is a process of selecting the reception level La to Le acquired in S12 having the highest reception level as the maximum value Lmax [0].

  Then, the process proceeds to S16, and it is determined whether or not the number of recorded maximum values Lmax has exceeded a predetermined set number n. If not, the process returns to S10. If it exceeds, the average value Lav for n Lmax and the standard deviation σ for n Lmax are calculated (S18). The standard deviation σ of the reception level maximum value corresponds to a variation in reception output, that is, a variation in reception output.

  Then, the process proceeds to S20, and the reception level correction value Lh is calculated. This calculation process is performed by calculating the correction value Lh based on the average value Lav and the standard deviation σ. For example, the correction value Lh is calculated using the following equations (1) and (2).

Lh = Lav + A · σ ^c · (B−Lav) (1)
Lh = Lav (2)
When the average value Lav is smaller than B, the correction value Lh is calculated using equation (1). When the average value Lav is equal to or greater than B, the correction value Lh is calculated using Equation (2). In the expressions (1) and (2), A, B and C are predetermined constants. In equation (1), the larger the variation (variation) in the reception level, the larger the value (A · σ ^c · (B−Lav)) is added to the average value Lav, and the correction value Lh is set to a larger value. .

  Then, the process proceeds to S 22, and the reception level correction value Lh calculated in S 20 is output to the direction distance estimation unit 8. The direction distance estimation unit 8 uses the correction value Lh as a reception output, and estimates the distance to the pedestrian 90 based on the reception output.

  FIG. 4 is an explanatory diagram of the reception output in the reception apparatus according to this embodiment.

FIG. 4 is a graph with the horizontal axis representing the distance to the pedestrian 90 and the horizontal axis representing the reception output. As shown in FIG. 2, the vehicle 50 equipped with the receiving device 1 in the state where there is an obstacle (truck 51) is shown. It shows a change in the reception output (reception level maximum value) when the pedestrian 90 runs and approaches.
The solid line in FIG. 4 indicates the reception output before correction, and the broken line in FIG. 4 indicates the outline of the reception output after correction. Also, the setting number n in FIG. 4 means the reception output range for the reception level maximum value of the setting number n.

  In FIG. 4, when the distance to the pedestrian 90 having the transmitter 91 is far (distance range of Sa in FIG. 4), the reception output is small and the fluctuation amount is large. In this distance range Sa, the pedestrian 90 (transmitter 91) is behind the truck 51 and cannot be seen from the vehicle 50 at all.

  When the distance to the pedestrian 90 approaches and becomes the distance range Sb, the reception output increases accordingly, and the fluctuation amount decreases. This distance range Sb is a state in which the vehicle 50 moves forward and the pedestrian 90 can be seen from behind the track 51. When the distance to the pedestrian 90 is further reduced and the distance range Sc is reached, the reception output increases accordingly, and the variation amount further decreases. This distance range Sc is a state in which the pedestrian 90 completely sees from the vehicle 50. Such reception output (solid line in FIG. 4) is corrected in accordance with the amount of variation, whereby reception output corresponding to the distance to the pedestrian 90 is obtained (broken line in FIG. 4).

  As described above, when the obstacle exists, the fluctuation amount of the reception output becomes large. For this reason, as described above, it is possible to accurately detect the distance and position of the pedestrian 90 by correcting the reception output by adding a larger correction value as the fluctuation amount of the reception output is larger.

  As described above, according to the receiving apparatus according to the present embodiment, by correcting the reception output based on the amount of fluctuation of the reception output of the antenna 4, the obstacle present between the transmitter 91 and the antenna 4 is corrected. The attenuated received output can be corrected appropriately. For this reason, the distance and position to the pedestrian 90 can be detected with high accuracy.

  Moreover, when using for the pedestrian presence information provision system which provides pedestrian presence information, the position of the pedestrian 90 can be detected accurately and it can be judged appropriately whether the pedestrian 90 exists in a vehicle running direction.

  In addition, although this embodiment demonstrated the case where the receiving device which concerns on this invention is applied to a pedestrian presence information provision system, the receiving device which concerns on this invention is not restricted to such a thing, Transmission of an electromagnetic wave Any other system that detects the position of the source may be used. Further, the above-described embodiment shows an example of a receiving apparatus according to the present invention, and the receiving apparatus according to the present invention may be modified so as not to change the gist described in each claim.

It is a structure schematic diagram of the receiver which concerns on embodiment of this invention. It is explanatory drawing of the receiving range in the receiver of FIG. It is a flowchart of the control processing in the receiver of FIG. It is explanatory drawing of the reception output in the receiver of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Receiving device, 4 ... Antenna, 50 ... Vehicle, 90 ... Pedestrian, 91 ... Transmitter.

Claims (4)

In a receiving apparatus that has an antenna capable of switching the reception directivity direction, receives the radio wave by switching the reception directivity direction, and detects the position of the radio wave transmission source based on the reception output,
Detecting means for detecting a fluctuation amount of the reception output of the antenna;
Correction means for correcting the reception output based on the variation amount;
A receiving device.   The receiving apparatus according to claim 1, wherein the correction unit performs correction by adding a larger correction value to the reception output of the antenna as the fluctuation amount is larger. The transmission source is a transmitter possessed by a pedestrian,
Mounted on a vehicle and detecting the position of the pedestrian from the vehicle;
The receiving apparatus according to claim 1 or 2. The receiving apparatus according to claim 3, further comprising a notifying unit that notifies that the pedestrian is present in an area where the vehicle is to travel.

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