JPH10206532A - Radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate object detection errors. SOLUTION: Oscillated waves from an oscillation antenna 3 are reflected by multiple reflective objects and received by a receiving antenna 4, and a mixed signal is generated by a mixing means 7. An FFT means 13 obtains multiple frequency components by Fourier transformation of a mixing signal for every preset cycle. An extraction means 14 discriminates frequency components and reference levels by levels and extracts frequencies corresponding to reflective objects. A constant operation means 15 obtains a reliability constant corresponding to multiple operation conditions individually to the frequency of reflective objects, and accumulates reliability constants for each frequency. A selection means 16 compares cumulative values of reliability constants of the frequency of each reflective object with predetermined reference cumulative values and selects frequencies whose cumulative values are higher than the reference cumulative values. A position operation means 17 computes a vehicle carrying an object of detection and a radar and a relative distance and a relative speed from the selected frequencies.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar device mounted on a vehicle or the like and for detecting an object around the radar device.

[0002]

2. Description of the Related Art In vehicles, for example, for detecting a collision object,
Alternatively, a radar device is mounted for detecting a following vehicle in auto cruise. In this type of radar device, when reflected waves from a plurality of objects such as other vehicles as objects are collectively received by an antenna to obtain a time-series signal, first, the radar wave is included in the time-series signal. Of a plurality of frequency components, a frequency component whose level is higher than a predetermined threshold level is
This is selected as the frequency component of the reflected wave from the object to be detected. Next, based on the frequency of the frequency component of the selected reflected wave, relative position information including a relative distance and a relative speed to the target is calculated.

[0003] As a prior art relating to such a radar apparatus, Japanese Patent Application Laid-Open No. 56-164971 and Japanese Patent Application Laid-Open
JP-A-313090 and JP-A-6-1944
No. 42 publication. JP-A-56-16497
In the FM-CW radar apparatus for an automobile disclosed in Japanese Unexamined Patent Application Publication No. 1-2003, the target frequency is determined by determining whether or not there is a part having a significantly higher level in the beat frequency spectrum distribution as compared with other frequencies. Is determined. In the vehicle obstacle detection device disclosed in Japanese Patent Application Laid-Open No. 4-313090, the shape of a detected object, which is a target, is identified from the shape of the power spectrum of the beat signal of the FM-CW radar device. In the radar apparatus disclosed in Japanese Patent Laid-Open Publication No. 6-194442, when this radar apparatus is used on the sea, clutter such as reflection from the sea surface is removed, and only the signal from the detected target is extracted.

[0004] The level of the frequency component obtained by the above-mentioned radar apparatus undergoes a level change such as fluctuation of the position of an object or multipath interference. In particular, when the radar apparatus is used on the ground, since there are many reflectors other than the target object such as a road surface, multipath interference often occurs. For this reason, the frequency component level may suddenly drop below the threshold level for a short period of time due to multipath interference despite the presence of an object. At this time, since the radar device removes the frequency component of the level lower than the threshold level, while the multipath interference occurs, the relative distance and the relative speed corresponding to the frequency component are not obtained, and it is erroneously recognized that there is no object. There are many.

Further, in order to eliminate the erroneous recognition of the presence or absence of an object due to the above-mentioned level change, the relative distance and the relative speed of the object are obtained, and the obtained relative distance and relative speed are obtained in the past. There is a method of determining reliability by comparing a relative distance and a relative speed with each other. In this method, the level change of the frequency component of the time-series signal and the reliability determination are rarely compared in parallel. When reliability is determined for a plurality of conditions, if the reliability of any one condition is determined to be lower than the reference, the frequency component of the frequency component is determined even if the reliability of the other condition is extremely high. Is not selected. For these reasons, it has been difficult to eliminate all misperceptions of the presence or absence of an object.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a radar apparatus which can eliminate erroneous detection of object detection.

[0007]

According to the present invention, there is provided an oscillating means for generating and oscillating a predetermined oscillating signal, and an oscillating signal from the oscillating means is obtained by being reflected by an object, and the level is obtained with time. Receiving means for receiving a changing time-series signal,
For each predetermined cycle, individually for a plurality of predetermined frequency components included in the time-series signal, the reliability constant corresponding to the plurality of calculation conditions, the value increases or decreases as the frequency component corresponding to the object. Constant calculating means for obtaining a cumulative value by accumulating a plurality of reliability constants for each frequency component, and for each frequency component, a frequency component whose cumulative value is equal to or greater than or less than a predetermined reference value. From the selecting means to select, and the frequency component selected by the selecting means,
And a position calculating means for obtaining relative position information including at least one of a relative distance to the target and a relative speed. According to the present invention,
The radar device uses the accumulated values of the plurality of reliability coefficients as a reference for selecting a frequency component for calculating relative position information with respect to the target from a time-series signal from the target. The reliability constant is determined based on, for example, the level of each frequency component or a frequency component calculated backward from past relative position information with respect to the target, and the value of the frequency component that reliably corresponds to the target is larger or smaller. . Thereby, when the frequency component corresponding to the position closer to the position of the target has a larger value of the reliability constant, the possibility that the frequency component corresponds to the position of the target increases as the cumulative value increases. This makes it possible to determine the presence / absence of an object by comparing the calculation conditions for the presence / absence of a plurality of objects in parallel. Also,
Since a plurality of calculation conditions having different standards are replaced with reliability constants, comparison is easy and weighting is easy.

In the present invention, one of the plurality of calculation conditions is an integrated value of the level of each frequency component of the time-series signal within a predetermined time, and the reliability constant is an integrated value. It is characterized in that it is larger or smaller as it is larger.
According to the present invention, the constant calculating means obtains a reliability constant with reference to a time integrated value of the level of the frequency component of the time-series signal. For example, even when a multipath disturbance that suddenly occurs in a short time and locally reduces the level of the frequency component occurs, the influence on the integrated value of the level is small. Therefore, it is possible to prevent erroneous recognition of the presence or absence of an object due to multipath interference.

Further, in the present invention, one of the plurality of calculation conditions is a specific position frequency corresponding to past relative position information with respect to the object, and the confidence constant is such that the frequency component is specified. It is characterized in that it is larger or smaller as it is closer to the position frequency. According to the present invention, the constant calculation means reversely calculates the frequency component from the relative position information including the relative distance and the relative speed of the object obtained in the past, and obtains the reliability constant based on the calculated frequency component. . Thereby, even when the level of the frequency component corresponding to the object temporarily decreases due to, for example, multipath interference, the reliability constant of the frequency component can be increased or decreased to facilitate selection by the selection unit. it can.

Further, according to the present invention, the radar apparatus further includes a processing unit mounted on a predetermined vehicle, for obtaining a specific object satisfying a predetermined specific condition based on position information from the position calculating unit. One of the plurality of calculation conditions is a specific object frequency corresponding to past relative position information between the vehicle and the specific object, and the confidence constant is:
The frequency component is larger or smaller the closer to the specific object frequency. According to the present invention, the above processing means is added to the radar device. The constant calculating means of the radar device calculates a frequency component related to the specific object relative position information determined in the past by the processing means, and obtains a reliability constant based on the calculated frequency component. With this, even when a plurality of objects are detected, the reliability constant of the object that is likely to be the specific object to be determined by the processing unit is increased or decreased, so that the selection unit can easily select the object. Can be.

Further, in the present invention, the specific object is an object to be followed by the vehicle, and the specific condition exists on a downstream side in a moving direction of the vehicle, and a relative speed between the vehicle and the specific object is small. The speed is lower than a predetermined reference speed.
According to the present invention, the processing device is a device for following a specific target object traveling ahead of the vehicle. In the radar device having such a device, the constant calculation means increases or decreases the reliability constant of an object whose relative speed is closer to 0 km / h on the downstream side in the moving direction of the vehicle.
Thereby, for example, in an auto cruise device,
The frequency component of the object to be followed can be easily selected by the selection means.

Further, according to the present invention, the specific object is an object that may collide with the vehicle, and the specific condition is that the specific object is stationary with respect to the ground surface or in the middle of stationary. Features. According to the invention, the processing device is a device for detecting an object colliding with a vehicle. In a radar device having such a processing device, the constant calculating means may be configured such that the absolute speed with respect to the ground surface is 0K / h.
The reliability constant increases or decreases for a stationary object close to m or an object that is in the middle of stationary. Thus, for example, in the collision detection device, the frequency component of the object that may collide with the vehicle can be easily selected by the selection unit.

Further, the present invention further comprises a detecting means for obtaining map data representing a plurality of roads on which the vehicle is to travel and fixed objects near the roads, and for obtaining data on the road on which the vehicle currently travels, The means selects the specific object from among the objects satisfying the specific condition and from the moving objects on the road where the vehicle currently runs. According to the present invention, the radar device further includes a detecting unit that grasps the position of the vehicle on the map data, such as a navigation device. The constant calculation means selects a specific object whose reliability constant should be increased or decreased from a plurality of objects on the same road as the road on which the vehicle obtained by the detection means is currently traveling. Thus, for example, when the vehicle travels in an urban area, it is possible to prevent a building facing the road from being mistaken as a specific target. Further, for example, when a vehicle travels near an intersection, it is possible to prevent another vehicle traveling on another intersecting road from being erroneously recognized as a specific target. Therefore, the reliability constant for the frequency component of the specific object to be detected can be reliably increased or decreased.

Further, the present invention further includes an obtaining means for obtaining traffic information of a road on which the vehicle currently travels, wherein the constant calculating means includes a moving object on a road on which the vehicle currently travels among objects satisfying a specific condition. It is characterized in that a specific target object is selected from the objects. According to the present invention, the radar device includes:
It further has a means for acquiring traffic information such as a VICS receiver. The constant calculating means determines, from the traffic information obtained by the obtaining means, the traffic condition of the road on which the vehicle is currently traveling, for example, the presence or absence of congestion, and calculates the reliability constant from among a plurality of objects on the same road. Choose specific objects to be larger or smaller. Thus, the reliability constant added to the frequency component of the specific object to be detected can be reliably increased or decreased in accordance with the traffic condition of the traveling road.

Further, in the present invention, the specific object is an object approaching the vehicle less than a predetermined distance, and the specific condition is that a relative distance to the vehicle is less than a predetermined distance. I do. According to the invention, the processing means mainly detects the presence or absence of an object around the vehicle. In a radar apparatus having such a processing device, the constant calculation means increases or decreases the reliability constant, for example, for an object having a shorter relative distance to the vehicle. Thus, for example, in the detection device for the approaching object, the frequency component of the object approaching the periphery of the vehicle can be easily selected by the selection unit.

Further, according to the present invention, the radar apparatus further includes an angle measuring means mounted on a vehicle for angularly displacing a radiation direction of an oscillation signal from the oscillation means at a predetermined cycle. Is an angular displacement amount in a radial direction, and the reliability constant is larger or smaller for an object present on the downstream side in the moving direction of the vehicle. According to the present invention, the radar apparatus has angle measuring means for periodically moving the emission direction of the oscillation signal within a predetermined angle range. The constant calculation means increases or decreases the reliability constant of the object located on the downstream side in the moving direction of the vehicle based on the angular displacement in the radial direction. Accordingly, in the so-called scan type radar device, the frequency component of the target object on the downstream side in the moving direction of the vehicle can be easily selected by the selection unit.

Further, according to the present invention, the radar device is mounted on a vehicle, and one of the plurality of calculation conditions includes a past relative distance between the vehicle and an object, a curvature of a road on which the vehicle travels, and the like. And the presence or absence of a vehicle on the same road, wherein the reliability constant is larger or smaller for an object existing on the same road as the vehicle. According to the present invention, the radar device determines whether or not the target is on the same road as the vehicle based on the relative distance to the target and the curvature of the road on which the vehicle travels, for example, based on a predetermined table. can do. A radar apparatus having such a means increases or decreases the reliability constant of an object on the same road. This makes it easier for the selecting means to select an object on the same road even when the running road curves. Further, when the vehicle travels on a curved road, it is possible to prevent another vehicle traveling in the opposite lane from being mistaken as an object on the same road.

[0018]

FIG. 1 is a block diagram showing an electrical configuration of a radar apparatus according to an embodiment of the present invention.
The radar device is a so-called FM-CW (Frequency Modula).
tion-Continuous Wave) radar device, for example, mounted on a vehicle. The radar device 1 detects an object existing around a mounted vehicle on which the radar device 1 is mounted as a detected object to be detected, and determines at least one of a relative distance and a relative speed between the detected object and the mounted vehicle. Get location information to include.

The radar device 1 comprises a transmitting antenna 3, a receiving antenna 4, an oscillating means 5, a receiving means 6, a mixing means 7, an analog / digital converting means 10, a signal processing means 11, an input / output means 19, an application means 21, Means 26, traffic information obtaining means 27, and vehicle sensor means 28. Antennas 3, 4, means 5
7 constitute the radar sensor means 9.

The oscillating antenna 3 radiates a transmission wave such as an electromagnetic wave whose frequency shifts with time, as will be described later, in response to an oscillating signal from the oscillating means 5. The oscillation signal is an AC power signal whose frequency shifts with time, for example, and its intensity is always constant. This transmission wave is radiated toward one or a plurality of reflection objects on the downstream side in the radiation direction of the transmission wave, is respectively reflected from the reflection objects, returns to the mounted vehicle, and is collectively received by the reception antenna 4 as a reflection wave. . The reflection object includes the detected object.

Specifically, the above-mentioned reflecting object which reflects the transmission wave from the oscillation antenna 3 includes, in advance, a preceding vehicle traveling on the same road as the traveling road on which the mounted vehicle is currently traveling, and a vehicle adjacent to the traveling road. Adjacent vehicles traveling on adjacent roads, buildings around the roads, and road surfaces and adjacent road surfaces. At least one of the reflective objects is a detected object whose relative position with respect to the mounted vehicle is to be detected by the radar device 1, and for example, a preceding vehicle corresponds to the detected object.

The receiving means 6 responds to the output from the receiving antenna 4 and represents a received electric field strength of the received reflected wave, and generates a time-series signal such that the signal level increases as the received electric field strength increases. , To the mixing means 8. The oscillating signal from the oscillating means 5 is supplied to the mixing means 8 in addition to the time-series signal. The mixing means 8 mixes the oscillation signal and the time-series signal to generate a mixed signal having a beat frequency of both signals. This mixed signal is converted to a digital signal by an analog / digital conversion circuit 10 (referred to as “A / D” in the drawing), and then supplied to a signal processing unit 11.

The signal processing means 11 includes an FFT means 13, an extracting means 14, a constant calculating means 15, a selecting means 16, and a position calculating means 17. FFT means 13
Then, the frequency component of the mixed signal within the unit time W2 is obtained by sampling and orthogonally transforming the mixed signal every predetermined unit time W2 (FIG. 2). Subsequently, the extraction unit 14 extracts a frequency corresponding to the reflection object from the frequency components of the mixed signal. Then, constant operation means 1
In step 5, for each frequency of the reflection object to be extracted, a reliability constant that individually conforms to a plurality of calculation conditions described later is individually calculated, and the calculated reliability constant is accumulated for each frequency. Further, the selecting means 16 selects only the frequency corresponding to the detected object based on the magnitude of the cumulative value of the reliability constant of each frequency of the reflecting object. Position calculation means 1
7 generates a position information signal representing position information including a relative distance and a relative speed between the detected object and the mounted vehicle from the frequency of the detected object selected by the selection unit 16. This position information signal is given to the application means 21 through the input / output means 19 such as an input / output interface circuit.

The application means 21 includes a following determination means 22, a collision determination means 23, and a short distance determination means 24. Each of the determination units 22 to 24 determines whether or not a predetermined condition is established between the detected object and the mounted vehicle using the position information signal from the position calculation unit 17. For example, the follow-up determination means 22 determines that the distance between the detected object such as the traveling vehicle preceding the mounted vehicle and the mounted vehicle is less than a predetermined distance, or that the relative speed between the two vehicles is equal to or higher than the predetermined speed. As a specific condition, it is determined whether the condition becomes larger. Also, the collision determination means 22
It is determined whether there is a possibility of collision based on the positional relationship between the detected object and the mounted vehicle and the relative speed. Further, the short distance determination means 24 determines whether or not the detected object is in an area within a predetermined distance from the mounted vehicle. When these specific conditions are satisfied, each determination unit generates a warning sound from, for example, a buzzer, and presents a warning to the driver of the vehicle.

The navigation means 26 corresponds to the detecting means of the present invention, for example, a GPS (Global Positioning System).
ng System) device and own-vehicle position detecting means such as a geomagnetic sensor, acquire the current position of the on-board vehicle on a map provided in advance in the navigation means 26, and construct a road structure and building around the on-board vehicle. It obtains peripheral information such as a situation around a mounted vehicle including an object. The traffic information acquisition means 27 is realized by a VICS receiver, for example.
Get the current traffic information around the onboard vehicle. The vehicle sensor means 28 includes, for example, means (not shown) for detecting an operation angle of a steering wheel, and a vehicle speed sensor (not shown) for detecting a traveling speed of the vehicle, and includes a current traveling direction of the mounted vehicle. And a behavior signal representing the behavior of the vehicle including the traveling speed. These peripheral information, traffic information, and behavior signal are given to the constant calculation means 15 and used for calculating a reliability constant as described later.

In the following, in order to explain the behavior of the FM-CW radar device, the behavior of the radar sensor means 9 and the behavior of the transmitted wave, the reflected wave, and the mixed signal will be described in detail.

The oscillation antenna 3 is installed, for example, so as to emit a transmission wave, which is an electromagnetic wave, on the downstream side in the traveling direction of the vehicle body. The receiving antenna 4 is installed so as to receive an electromagnetic wave from the downstream side in the traveling direction of the vehicle body, for example, a reflected wave described later. For this purpose, the oscillating and receiving antennas 3, 4 are installed, for example, in a front grille in front of the body of the vehicle. Oscillation and reception antenna 3,
Reference numeral 4 denotes a so-called highly directional antenna. For example, the beam width of the main lobe of the transmission wave from the oscillation antenna 3 is about 2 to 3 degrees. These antennas 3 and 4 may be realized by a single common antenna.

FIG. 2A is a graph for explaining the time-dependent shift of the frequency of the transmitted wave and the reflected wave. Solid line 31
Represents a shift with time of the frequency of the transmission wave, and a two-dot chain line 32
This represents a temporal shift of the frequency of the reflected wave corresponding to the transmission wave indicated by the solid line 31. The behavior of the frequency shift described below is that the object to be detected is single, there is no multipath interference, and the path length of the wireless transmission path between the transmitting and receiving antennas 3 and 4 and the object to be detected is limited. Is maintained at a certain length.

The frequency of the transmitted wave is swept so as to periodically increase and decrease by a predetermined displacement width δf around a predetermined center frequency f0 at a predetermined vibration cycle W1. Specifically, the frequency of the transmission wave is the time t
In the increasing period from 0 to time t2, it increases in proportion to time from a predetermined minimum frequency fmin to a predetermined maximum frequency fmax, and elapses from the maximum frequency fmax to the minimum frequency fmin in a decreasing period from time t2 to time t4. Decreases in proportion to

Maximum and minimum frequencies fmax, fmin
Are the frequencies respectively increased and decreased from the center frequency f0 by half the frequency of the displacement width δf. The center frequency f0 is, for example, 750 Hz, and the displacement width δf is, for example, 75 MHz. The vibration cycle W1 at this time is, for example, 1.3 msec. The increase and decrease periods are half the period of the oscillation cycle W1. Further, the absolute values of the time change rates of the frequency increase and decrease are equal. These maximum and minimum frequencies fmax, fmin and the oscillation period W
1 can be set as appropriate according to the usage state of the laser device 1 and the like.

The frequency of the reflected wave from each reflecting object, in other words, the frequency of the received wave received by the receiving antenna 4 is shifted with time, for example, like the transmitted wave, and the shift timing is set to be shorter than the shift timing of the transmitted wave. Is also an electromagnetic wave that is delayed. The delay time W3 from the transmission time of the above-described transmission wave to the reception time of the reflected wave corresponding to the transmission wave increases in proportion to the path length of the wireless transmission path of the electromagnetic wave. Therefore, the behavior of the frequency shift of the reflected wave differs only in the frequency shift timing, and the time change rate of the frequency shift, the center frequency f0, the change rate δf, and the oscillation period W1 are equal. Therefore, the reflected wave increases in proportion to the passage of time from the start time t1 of the frequency increase to the decrease start time t3 via the time t2, and in proportion to the passage of time from the decrease start time t3 to the decrease end time t5 via the time t4. Decrease. The times t1, t3, and t5 respectively correspond to times delayed by the delay time W3 from the times t0, t2, and t4 of the frequency shift of the transmission wave.

FIG. 2 (2) is a graph showing the temporal shift of the beat frequency of the mixed signal generated when the transmission wave and the reflected wave shown in FIG. 2 (1) are obtained. The beat frequency increases as the relative distance between the detected object and the radar device 1 increases. In the FM-CW radar device, the relative distance and the relative speed of the detected object can be obtained from a predetermined calculation formula described later using the beat frequency as a parameter.
When the above-described transmission wave is radiated while the path length is kept at a certain length, the beat frequency shifts at the same cycle as the oscillation cycle W1 of the transmission wave. Specifically, while the above-described delay time W3 elapses from the start time t0 of the frequency increase of the transmission wave,
The beat frequency increases in proportion to the passage of time, and maintains the maximum beat frequency fup from the start time t1 of the increase in the frequency of the reflected wave to the start time t2 of the decrease in the frequency of the transmitted wave. Further, it decreases in proportion to time from the start time t2 to the start time t3 of the frequency decrease of the reflected wave, and from the start time t3 to the end time t4 of the frequency decrease of the transmission wave, the minimum beat frequency fd
Keep n. Maximum and minimum beat frequencies fup, fdn
Are absolutely equal.

Further, since the signal level of the oscillation signal always keeps a predetermined level, the electric field strength of the oscillation wave always keeps a predetermined level. The received electric field strength of the individual reflected wave of each oscillating wave from each reflecting object varies depending on the reflectivity of the reflecting object's electromagnetic wave and the path length of the wireless transmission path between the antennas 3 and 4 and the reflecting object. However, if the reflection wave is a reflection wave from the same reflection object, it decreases in proportion to the fourth power of the length of the path length. At this time, when there are a plurality of reflective objects having similar reflectances and the path length of the wireless transmission path with each reflective object is an integral multiple of the wavelength of the reflected wave, multipath interference occurs. When multipath interference occurs, the signal level of the time-series signal sharply decreases. From these facts, the mixed signal is a pulsating signal whose signal level changes in response to the change over time of the received electric field strength of the reflected wave, and the fluctuation of the amplitude of the AC component of the signal level is caused by the change of the received electric field strength over time. Respond to change.

FIG. 3 is a flowchart for explaining the signal processing operation in the signal processing means 11. The detailed behavior of the signal processing unit 11 will be described below with reference to the flowchart of FIG.

The oscillation signal from the oscillating means 5 is transmitted to the transmitting antenna 3
, An oscillating wave is emitted. When the receiving antenna 4 receives the reflected wave from the reflecting object, the mixing means 7 starts generating a mixed signal, and steps a1 to a
Proceed to 2. In step a2, the analog / digital conversion means 10 converts the mixed signal from the mixing means 7 into a digital signal and supplies the digital signal to the FFT means 13.

Subsequently, at step a3, the FFT means 1
3 samples the signal level of the mixed signal at an observation point on the time axis for each predetermined sampling period.
The interval between the N observation points in this sampling is set to a length equal to or less than a unit time W2, which is a half of the oscillation period W1. For example, when the number of observation points is 128, the length is set to 1/128 of the unit time W2.

Subsequently, every time the signal level of the mixed signal is sampled, the FFT means 13 obtains a frequency component which is the signal level of the mixed signal at frequencies f1 to fN of N observation points on a predetermined frequency axis. When these reflection components are within a range that can be detected by the radar apparatus 1, only the levels of the frequency components of the beat frequencies fup and fdn corresponding to the relative distance between the reflection object and the mounted vehicle are reflected from the reflection object. The level corresponds to the received electric field strength of the reflected wave alone, and the frequency component of the remaining frequency is level 0
Alternatively, the level becomes a level corresponding to the received electric field strength of the noise signal superimposed on the time-series signal. When a plurality of reflective objects are present in a detectable range, the levels of the frequency components of a plurality of beat frequencies fup and fdn corresponding to the relative distances between the respective reflective objects and the mounted vehicle are respectively set to the respective reflective objects. The level corresponds to the received electric field strength of the reflected wave alone from. The level corresponding to the received electric field strength when there is a reflecting object is larger than the level corresponding to a noise signal when there is no multipath interference, for example.

The FFT means 13 is specifically realized by an arithmetic means for performing an orthogonal transform operation using, for example, a Fourier transform method. Each frequency component c1 (tn) to cN of the frequencies f1 to fN at an arbitrary sampling time tn
The value of (tn) is the value of N from the observation point on the time axis that is N points earlier than the sampling time tn to the sampling time tn.
Signal level values L1 to L of the mixed signal obtained at the observation points
It is obtained by Fourier transform using N. Specifically, the N-point fast Fourier transform method is used for this calculation. The number N of the Fourier transform is, for example, 128 points. Frequency f1 at any sampling time tn
The frequency component cn (t of any frequency fn of fN
The conversion formula of the fast Fourier transform method for obtaining n) is shown below.

[0039]

(Equation 1)

FIG. 4 is a graph showing frequency components obtained by the FFT means 13. In FIG. 3, the point N of the fast Fourier transform method is set to 8 points, and at points away from the mounted vehicle by relative distances respectively corresponding to the frequencies f1, f3, and f5,
Assume that there is a reflective object. FIG. 4A shows a frequency component obtained at a given sampling time tn, and FIG. 4B shows a frequency component obtained at the next sampling time tn + 1 after a lapse of a short time from the sampling time tn.

The level of the frequency component of the frequency corresponding to the reflection object often increases or decreases in a short time. This is because, for example, when the radar apparatus 1 is mounted on a vehicle and used, at least one of the detected object and the mounted vehicle often has a small vibration, the relative distance between the detected object and the mounted vehicle is frequently increased. Because it changes to Also, when the detected object is a vehicle, the reflectance of each part of the vehicle greatly differs due to the complicated appearance of the vehicle, and the reflectance of the reflected wave is changed only by a small change in the position where the transmission wave is irradiated. Because it changes. In addition, multipath disturbances occur frequently,
This is because the signal level of the time-series signal of the reflected wave from the reflecting object frequently decreases. Further, even if the frequency component is a frequency component having no corresponding reflection object, such as a frequency f7,
For example, the level of the corresponding reflection object may be close to the level of the frequency component of a certain frequency, depending on the noise component. The FFT means 13 calculates such a frequency component c1 (t
Signals representing n) to cN (tn) are supplied to the extracting means 14 to terminate the processing of step a3, and proceed to step a4.

Returning to FIG. 3 again, in step a4, the extracting means 14 sets the frequency components c1 of the frequencies f1 to fN to c1.
(Tn) to cN (tn) are set to a predetermined reference level Vr
The level is discriminated by ef1. By this level discrimination processing, the level of the frequency component is changed to the reference level Vref1.
The frequencies determined to be above are extracted as the frequencies corresponding to the reflection object. This reference level Vref1 is
For example, it is set to a level substantially equal to the signal level of the noise component included in the mixed signal. In this case, when the signal level increases or decreases as shown in FIG. 4, even if the frequency component is a frequency corresponding to the reflecting object, the signal level is less than the reference level Vref1 and the frequency is not extracted for the above-described plurality of reasons. Sometimes. Conversely, even if the reflection object has a frequency component that does not correspond to the frequency, the signal level may be higher than the reference level Vref1 and the frequency may be extracted. When the level of at least one frequency component is equal to or higher than the reference level Vref1, the extraction unit 14 gives the frequency component and the frequency of the frequency component to the constant calculation unit 15.

Subsequently, in step a5, the constant calculation means 15 obtains a plurality of types of reliability constants for one or a plurality of reflection object frequencies obtained from the extraction means 14,
The accumulated values S1 to SN are obtained. As described above, this reliability constant is used, for example, to exclude the frequency of the frequency component caused by the noise component from among the frequencies of the reflection object given from the extraction unit 14 from the calculation target of the position calculation unit 17, and It is used to add a frequency that is not extracted by the extraction means 14 due to path noise to a calculation target.
When the detected object is a vehicle running on the same road as the mounted vehicle, the detected object is used to remove a frequency corresponding to a building around the same road and a vehicle on another road.

More specifically, the above-mentioned reliability constants include, for example, a reliability constant K1 relating to the integrated value of the frequency component and a reliability constant K relating to the similarity with the past position information of the reflecting object.
2. Reliability constants K3 to K5 relating to the behavior of the reflecting object, reliability constants K6 relating to the road on which the mounted vehicle runs, and reliability constants K relating to the radiation direction of the transmission wave of the radar device 1.
7 are mentioned. The constant operation means 15 is provided by the FFT means 13
Has the cumulative variables S (f1) to S (fN) of the reliability constants for all the frequencies f1 to fN, respectively, and the above-mentioned reliability constants K1 to K7 are cumulative variables S (f1) for each of the frequencies f1 to fN. ) To S (fN), respectively, to obtain a cumulative value of the reliability constant. Details of the calculation method in the constant calculation means 15 will be described later.

Subsequently, at step a6, the selecting means 16
Then, among the above-mentioned frequencies f1 to fN, a frequency whose cumulative value S1 to SN of the reliability coefficient is equal to or higher than a predetermined reference cumulative value is extracted as the frequency of the detected object, and a signal representing the frequency is subjected to position calculation. To the means 17. This makes it possible to simultaneously determine whether or not the signal level of the mixed signal is equal to or higher than a predetermined reference level and detect a frequency corresponding to the detected object in the mixed signal. Also,
When the level of the frequency component increases or decreases due to multipath interference and superposition of an excessive noise signal, and when there is a reflected object other than the detected object around the vehicle, select the frequency corresponding to the detected object without fail. Can be.

Subsequently, in step a7, the position calculating means 17 generates position information between the detected object and the mounted vehicle.
The position calculation means 17 operates only when a signal representing the frequency is given from the selection means 16, and does not operate when the remaining signal is remaining. When the position calculating means 17 operates, the relative distance R and the relative speed v between the radar device 1 and the detected object are calculated from the given frequencies, that is, the maximum and minimum beat frequencies fup and fdn, using the following arithmetic expressions. I do. The relative speed v represents a speed in a direction in which the detected object approaches the radar device 1 by a positive value, and a speed in a direction away from the radar device 1 by a negative value.

[0047]

(Equation 2)

The coefficient Kr in the above equation is the center frequency f of the transmission wave.
A predetermined function F with 0 and displacement width δf as parameters
Required from.

Kr = F (f0, δf) (3) The coefficient Kv is defined by the following equation. c is the speed of light.

Kv = 2 · f0 / c (4) The above-mentioned maximum and minimum beat frequencies fup, fdn are:
The maximum and minimum frequencies fmax of the oscillation wave and the reflected wave,
It is sufficiently smaller than fmin. Therefore, the means for processing such a beat signal does not need to provide a processing configuration corresponding to a high frequency as compared with the means for directly handling the transmitted wave and the reflected wave, and thus the structure is simplified. Therefore, the structure of the entire radar device 1 can be simplified. The position information obtained by such a method is given to the application means 21 via the input / output means 19,
It is used for the above-described determination operation.

FIG. 5 is a flowchart for explaining in detail the method of calculating the accumulated values S1 to SN of the reliability constants K1 to K7 performed by the constant calculating means 15 in step a5 of the flowchart of FIG. The calculation method of each of the reliability constants K1 to K7 will be described with reference to this flowchart. When the frequency of the reflection object is given from the extraction means 14, the process proceeds from step b1 to step b2.

In step b2, a reliability coefficient K1 relating to the integrated value of the frequency component is calculated. In the constant calculation means 15, first, the frequency components c1 (tm) of the frequencies f1 to fN obtained by a plurality of samplings performed while going back by a predetermined detection period from the latest sampling time.
To cN (tm) for each of the frequencies f1 to fN to obtain integrated values Cf1 to CfN of the frequency components of each frequency within the detection period. The integrated value Cfn of an arbitrary frequency fn among the frequencies f1 to fN is represented by the following expression, and the frequency components cn (t1) to cn (t) of the frequency fn at the respective sampling times t1 to tM within the detection time are represented as follows.
M).

[0053]

(Equation 3)

The constant calculating means 15 determines whether or not these integrated values are equal to or larger than a predetermined reference integrated value for each frequency. From this determination result, as shown in the following equation, when the integrated value is equal to or greater than the reference integrated value, the reliability constant K1 is added to the cumulative variable S (fn) of the reliability constant of the frequency, and the frequency is less than the reference integrated value. For the remaining frequencies, the reliability constant K1 is subtracted from the cumulative variable S (fn). This cumulative variable S (fn)
For example, for each of the frequencies f1 to fn, the integration constant Sup (fn) for the maximum peak frequency fup obtained during the increase period of the transmission wave and the integration constant Sdn (fn) for the minimum peak frequency fdn obtained during the subtraction period are individually set. Required.

Sup (Pfupn) = Sup (fupn) + K1 Sdn (Pfdnn) = Sdn (fdnn) + K1 Except for Sup and Sdn other than the above, subtraction of K1 is performed. Each frequency represents an arbitrary frequency whose integrated value in the period is equal to or greater than the reference integrated value.

Table 1 shows that when a certain detection period including six samplings is set in the case where there are reflective objects corresponding to the frequencies f1, f3, and f5, each sampling time tm to tm + 5 in the detection period is set. F0 to f obtained by
7 and the integrated values Cf1 to Cf7 thereof.

[0057]

[Table 1]

As shown in Table 1, during the detection period, the frequency components of the frequencies f1, f3, and f5 corresponding to the reflecting object are continuously detected over the entire detection period even if the signal level fluctuates. . Also, even when multipath interference occurs, it is unlikely that detection is continuously performed over a plurality of sampling times.
Even when multipath interference occurs at the time of sampling that differs for each of F3 and F5, the integrated values Cf1, Cf3, and Cf5 are similar. Integrated value Cf of frequency f7 not corresponding to reflective object
7, a signal level equivalent to the corresponding frequency is temporarily detected, but is not detected continuously over the entire detection period, so that the absolute value of the integrated value is small. by this,
Integrated value C of frequencies f1, f3, f5 corresponding to the reflecting object
The integrated values of f1, Cf3, and Cf5 are significantly different from the remaining integrated value Cf7 that does not correspond to the reflecting object.

From these facts, it is understood that the integrated value of the frequency components of each frequency is not easily affected by the increase or decrease of the frequency components for the above-described reason. Therefore, rather than determining the level of the frequency component of each frequency at each sampling,
Judging the integrated value of the frequency components is less affected by the increase and decrease of the frequency components. Therefore, when the frequency component decreases for the above-described reason, it is erroneously determined that there is no reflective object corresponding to that frequency, and conversely, when the noise is excessive, it is erroneously determined that there is a reflective object corresponding to that frequency. Can be prevented.

Subsequently, at step b3, a reliability constant K2 relating to similarity with past position information is calculated. The constant calculating means 15 calculates a cumulative variable S (fn) of a frequency determined in the past to correspond to the detected object.
And the reliability constant K2 is subtracted from the remaining frequency cumulative variable.

Sup (Tfupn) = Sup (fupn) + K2 Sdn (Tfdnn) = Sdn (fdnn) + K2 Except for Sup and Sdn other than the above, only K1 is subtracted. In the above equation, Tfupn and Tfdnn are one cycle before In the increase period and the subtraction period of the signal processing operation, arbitrary frequencies fupn and fdnn, each of which is determined to have the detected object, are shown. The frequencies Tfupn and Tfdnn are obtained by, for example, calculating backward from the position information of the detected object obtained in the past signal processing operation one cycle before. Further, the frequency selected by the selection means 16 in the signal processing operation one cycle before may be directly stored.

As described above, the constant calculation means 15 increases the cumulative variable S (fn) of the reliability constant for the frequency at which the reflection object is expected to be continuously present. Since the reflecting object is another vehicle or building around the mounted vehicle, it rarely disappears or appears instantaneously. Therefore, in the latest detection period, it is considered that the reflection object is continuously present near the place where it is determined that the reflection object is present in the past detection period one cycle before. From this, by attaching the reliability constant K2 as described above, even if the signal level temporarily increases or decreases due to, for example, a noise component and multipath interference and is not erroneously extracted by the extracting means 14, the reflected object can be removed. It is possible to increase the cumulative value Sn of the frequency expected to be present.

Subsequently, in step b4, a reliability constant K3 for the detected object to be followed is calculated. Among the frequencies of the reflection object extracted by the extraction unit 14, the frequency to which the reliability constant K3 is added is, for example, a tracking specific frequency corresponding to the reflection object that satisfies the above-described specific condition of the determination by the tracking determination unit 22. To be elected. Specifically, the cumulative variable S (f of the frequency of the reflection object extracted by the extraction unit 14
In n), the reliability constant K3 is added only to the cumulative variable S (fn) whose frequency matches the tracking specific frequency, and the constant 0 is added to the cumulative variable of the remaining frequencies. The tracking specific frequency is, specifically, the frequency of the reflected wave from the reflecting object when the relative speed between the reflecting object and the mounted vehicle is 0 Km / hour, and is calculated from the above equation (2) and the hourly speed. can get. As a result, it is possible to increase the cumulative value of the reliability constant of the detected object as determined by the following determination unit 22 to be the preceding vehicle.

In the operation of determining the frequency to which the reliability constant K3 is to be added, the surrounding information and the traffic information from the navigation means 26 and the traffic information acquiring means 27 may be added as the criterion. For example, when it is possible to determine the position of a building around the vehicle from the surrounding information, regardless of the comparison result between the following specific frequency and the frequency,
The cumulative variable S (f of the frequency corresponding to the position of the building
A constant 0 is added to n). Further, for example, when the mounted vehicle travels near a crossroad, when the position of another road intersecting with the road on which the mounted vehicle is traveling can be determined, the frequency corresponding to the road is determined regardless of the comparison result described above. Is added to the accumulated variable S (fn). Thereby, for example, the cumulative variable S (f) of the remaining reflective objects other than the reflective objects running on the same road as the mounted vehicle is reflected.
n) becomes small, and it becomes difficult for the selection means 16 to select the image. Thereby, for example, when the detected object to be followed is to be detected, it is possible to prevent the remaining reflected objects from being erroneously detected as the detected object.

Subsequently, at step b5, a reliability constant K4 for the approaching detected object is calculated. Extraction means 1
Of the reflection object frequency extracted in step 4, the reliability constant K
As the frequency to which 4 is added, a frequency of the reflecting object that satisfies the specific condition of the determination by the short distance determination unit 24 is selected. Specifically, among the cumulative variables S (fn) of the frequency of the reflection object, the reliability constant K4 is added only to the cumulative variable S (fn) whose frequency coincides with the predetermined approaching specific frequency, and the remaining frequency is accumulated. A constant 0 is added to the variable. The approach specific frequency is, specifically, the frequency of the reflected wave from the reflective object when the relative distance between the reflective object and the mounted vehicle is less than a predetermined reference distance, and And is stored in the constant calculation means 15 in advance. Thus, the integrated value of the reliability constant of the detected object as detected by the short distance determination unit 24 can be increased.

In the operation of determining the frequency to which the reliability constant K4 is to be added, similarly to the operation of determining the reliability constant K3,
The surrounding information and the traffic information from the navigation means 26 and the traffic information obtaining means 27 described above may be added as a criterion, and the building on the side of the road and the vehicle on another road may be removed. Further, for example, road information acquisition means 2
When the on-board vehicle travels on a congested road using the traffic information from 7, the above-described reference distance may be shortened.
As a result, the cumulative variable S (fn) of a reflective object other than the reflective object that moves on the same road as the loading road is reduced, and is hardly selected by the selection unit 16. Therefore,
By the determination operation of the short distance determination means 23, it is possible to prevent such a reflected object from being erroneously detected as a detected object.

Subsequently, at step b6, a reliability constant K5 for the stationary object to be detected is calculated. Extraction means 1
Of the reflection object frequency extracted in step 4, the reliability constant K
As the frequency to which 5 is added, the frequency of a reflecting object that is stationary with respect to the ground surface is selected. Specifically, the reliability constant K5 is subtracted only from the cumulative variable S (fn) whose frequency coincides with the stationary specific frequency, out of the cumulative variable S (fn) of the frequency of the reflecting object as in the following equation, and the remaining constant is obtained. A constant 0 is added to the frequency cumulative variable. Alternatively, the reliability constant K5 is set to a negative value, and the reliability constant K5 is added to the cumulative variable S (fn). In the following equation, Tfupn and Tfdnn are frequencies fupn and f when the absolute speed of the reflecting object is 0 km / h.
dnn respectively.

Sup (Tfupn) = Sup (fupn) −K3 Sdn (Tfdn) = Sdn (fdnn) −K3 (8) Specifically, the stationary specific frequency is such that the absolute speed of the reflecting object with respect to the ground surface is 0 km / h. It is a certain frequency. Such a frequency is inversely calculated from, for example, the current traveling speed of the onboard vehicle obtained from the vehicle speed sensor and the above equation (2). As a result, the cumulative variable S (fn) of a stationary reflecting object such as a building adjacent to a road is reduced, and is hardly selected by the selecting unit 16. Thus, for example, when a detected object to be followed is to be detected, it is possible to prevent a building or the like from being erroneously detected as the detected object.

Next, at step b7, a reliability constant K6 relating to the shape of the road on which the vehicle travels is calculated. This reliability constant K6 is added to the cumulative variable S (fn) of the frequency extracted by the extracting means 14 when the vehicle travels on a curved road. The value of the reliability constant K6 varies depending on the combination of the curvature radius R of the road and the relative distance between the reflecting object and the detected object. The value of this reliability constant K6 is
For example, the constant calculating means 15 is associated with a combination of the radius of curvature R and the frequency calculated from the relative distance.
Is stored in advance as a table.

The constant calculating means 15 firstly outputs the vehicle sensor 2
8, a curvature radius R of the road is calculated from the operation angle and the traveling speed of the vehicle. The radius of curvature R may be calculated from the yaw angle and the traveling speed of the vehicle. Subsequently, the value of the reliability constant K6 corresponding to each combination of the frequency of one or a plurality of reflection objects extracted by the extraction means 14 and the calculated radius of curvature R of the road is read from the table, Cumulative variable S for each frequency
(Fn).

As described above, the transmission wave from the transmission antenna 3 of the radar device 1 has a strong directivity and is radiated linearly toward the downstream side in the current traveling direction of the mounted vehicle. When the vehicle travels on a curved road, the radiation direction of the transmission wave is different from the extension direction of the traveling road on which the vehicle is currently traveling, so that the radiation area of the transmission wave deviates from the traveling road and the adjacent road adjacent to the traveling road May protrude. The area of this protrusion becomes larger as the radius of curvature of the road becomes larger. In addition, the positional relationship of a portion of the adjacent road where the transmission wave emission regions overlap changes frequently as the traveling speed of the vehicle increases. From this, the reliability constant K6 corresponding to the radius of curvature R of the road and the traveling speed is added to the cumulative variable S (fn) of the frequency corresponding to the reflection object extracted by the extraction means 14 as described above. By doing so, when following a preceding vehicle traveling on the same road and following a curved road, it is possible to prevent a vehicle traveling on an adjacent road from being mistaken for a vehicle traveling on the traveling road. .

Subsequently, at step b8, the radar device 1
Is calculated. The reliability constant K7 is determined by the extraction means 14 when the vehicle travels on a curved road when the radar sensor means 9 of the radar device 1 has angle measuring means for angularly displacing the radiation direction of the transmission wave.
Is added to the cumulative variable S (fn) of the frequency extracted by This angle measuring means may be a device having a structure in which the direction of the transmitting antenna 3 is mechanically angularly displaced by using a motor, for example, or may be integrated with the transmitting antenna 3 like a so-called phased array and electrically connected. May be a device having a structure in which the radial direction is angularly displaced. Constant calculation means 15
For example, when the transmitting wave is angularly displaced horizontally on the ground centering on the traveling direction of the onboard vehicle, the reliability constant K7 is extracted when the transmitting wave coincides with the traveling direction.
4 is added to the cumulative variable S (fn) of the frequency extracted,
When the radiation direction and the traveling direction do not match, a constant 0 is added. Alternatively, the angle of the difference between the emission direction of the transmission wave and the traveling direction of the onboard vehicle is calculated, and the smaller the angle, the more the reliability constant K
The value of 7 may be increased and added to all the extracted frequencies.

When the radiation direction of the transmission wave is angularly displaced, the transmission wave may be radiated toward a place other than the road on which the mounted vehicle is traveling, for example, an adjacent road and a side of the road. In this case, as described above, by adding such a reliability constant according to the angle between the emission direction of the transmission wave and the traveling direction of the vehicle, when following a preceding vehicle traveling on the same road, The vehicle traveling on the road and the building on the side of the road can be prevented from being mistaken for the vehicle traveling on the traveling road.

As described above, each time the constant calculating means 15 obtains the frequency of the reflection object extracted by the extracting means 14,
The above-described reliability constants K1 to K7 are calculated and sequentially added to the cumulative variable S (fn). Table 2 shows the frequency f
It represents the integration constants K1 to K7 of the frequencies f0 to f7 obtained when there is a reflective object corresponding to 1, f3 and f5, and their accumulated values S1 to S7. In this case, it is determined that there is an object to be detected corresponding to the frequencies f1 and f5 at the time of past sampling one cycle before, and the frequency f3 is assumed to correspond to a reflective object at a place other than on the traveling road.

[0075]

[Table 2]

In Table 2, among the cumulative values S0 to S7 of the reliability constants of the frequencies f0 to f7, the cumulative values S1 and S5 of the frequencies f1 and f5 are large, and the cumulative value S3 of the frequency f3 is the integrated value of the frequency components. Is small although the reliability constant K1 is large. In this way, by adding a plurality of types of reliability constants, the above-described types of conditions can be quantitatively determined. In addition, by making the value of the reliability constant representing the condition to be emphasized larger than the values of the other reliability constants among the above-mentioned reliability constants K1 to K7, the conditions of the reliability constants K1 to K7 can be easily adjusted. Can be weighted. For example, in Table 2, the reliability constant K1 of the integrated value of the received electric field strength and the reliability constant K2 of the past position information are given larger values than the other reliability constants K3 to K7.

When the calculation and accumulation of the reliability constants K1 to K7 are completed, guard processing is performed in step b9. In the guard process, it is individually determined whether or not the final accumulated values S1 to S7 are equal to or larger than a predetermined upper limit value that can be calculated by the constant calculator 15, and if the final accumulated values S1 to S7 are equal to or larger than the upper limit value, the cumulative value is set to the upper limit. If the value is less than the upper limit, the value is kept as it is. This is because, when the constant calculation means 15 is a virtual circuit realized by the calculation processing of the microcomputer, it becomes difficult to calculate a numerical value exceeding the allowable number of digits of a variable set on the calculation processing program. It is implemented to prevent the inconvenience. Further, it is possible to prevent the accumulated value from becoming too large, and to prevent a response delay from occurring when the target actually comes off or disappears.

When such guard processing is completed, the process proceeds to step b10 to end the processing operation of the flowchart, and then proceeds to step a6 of the flowchart of FIG. Through such a series of operations, a plurality of types of reliability constants K1 to K7 can be calculated and their accumulated values can be obtained.

Each of the means 13 to 17 of the signal processing means 11 of the radar apparatus 1 performs the above-described arithmetic processing. Therefore, the signal processing means 11 can be realized by a microcomputer, and each of the means 13 to 17 can be realized by virtual means such as realized by arithmetic processing of the microcomputer. Thereby, the radar device 1
Can be reduced in the actual number of parts.

[0080]

As described above, according to the present invention, a radar device mounted on a vehicle calculates a frequency component for calculating a relative speed and a relative distance of an object by calculating a cumulative value of a plurality of reliability constants. Choose as a reference. This makes it possible to compare a plurality of calculation conditions in parallel and to easily weight each calculation condition.

Further, according to the present invention, the constant calculation means uses the integrated value of the level of the time series signal as the calculation condition. Furthermore, according to the present invention, the similarity to the relative distance and relative position of the object detected in the past is set as the calculation condition. As a result, a frequency component whose level temporarily decreases due to multipath interference can be reliably selected as a frequency component of the target object. Therefore, it is possible to prevent erroneous recognition of disappearance of the target object due to multipath interference.

Further, according to the present invention, the radar apparatus has processing means for estimating a future state of the vehicle from the obtained relative distance and relative speed and issuing a warning. The processing means includes a follow-up device of an auto-cruise device, a collision detection device, and a short-range monitoring device. The calculation condition is similar to the relative distance and relative speed of the specific object selected by the processing means. As a result, the frequency component of the specific object to be selected by each device can be reliably selected as the data for calculating the relative distance and the relative speed. Therefore, each processing means can execute a process based on the relative distance and the relative speed of the specific target object.

Further, according to the present invention, a radar apparatus having a follow-up device and a collision detecting device uses a map data and a vehicle position of a navigation device, and traffic information on a moving body on a road on which a vehicle is traveling. Only the target. Thus, it is possible to prevent a building near the road from being erroneously recognized as a specific target.

Further, according to the present invention, a so-called scan type radar apparatus determines the reliability constant based on the angular displacement of the radiation area and the detection area. Furthermore, according to the present invention, the radar device determines the reliability constant based on whether or not the object is on the same road as the vehicle. Thus, when the vehicle travels on a curved road, it is possible to prevent another vehicle traveling in the opposite lane from being mistaken as an object on the same road.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an electrical configuration of a radar device 1 according to an embodiment of the present invention.

FIG. 2 is a graph for explaining a temporal shift of the frequency of a transmission wave and a reflected wave, and a graph showing the temporal shift of a beat frequency of a mixed signal generated when the transmitted wave and the reflected wave are obtained. is there.

FIG. 3 is a flowchart for explaining a signal processing method in the signal processing circuit 11;

FIG. 4 is a graph for explaining a time-dependent shift of each frequency component obtained by the FFT means 13;

FIG. 5 is a table showing reliability constants K1 to K in a constant calculation unit 15.
7 is a graph for explaining the calculation method No. 7 in detail.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 radar apparatus 3 transmitting antenna 4 receiving antenna 5 oscillating means 6 receiving means 7 mixing means 12 FFT means 13 extracting means 15 constant calculating means 17 selecting means 18 position calculating means

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G01S 13/60 G01S 13/60 C 13/93 13/93 Z

Claims (11)

[Claims] An oscillation means for generating and oscillating a predetermined oscillation signal, and an oscillation signal from the oscillation means is obtained by being reflected by an object,
A receiving means for receiving a time-series signal whose level changes with time, and corresponding to a plurality of calculation conditions individually for a plurality of predetermined frequency components included in the time-series signal for each predetermined cycle A constant calculating means for obtaining a reliability constant to obtain a cumulative value by accumulating a plurality of reliability constants for each frequency component. Selecting means for selecting a frequency component whose cumulative value is equal to or greater than or less than a predetermined reference value, and a relative component including at least one of a relative distance to the object and a relative speed from the frequency component selected by the selecting means. A radar device comprising: position calculation means for respectively obtaining position information. 2. One of the plurality of calculation conditions is an integrated value of the level of each frequency component of the time-series signal within a predetermined time, and the reliability constant increases as the integrated value increases. The radar device according to claim 1, wherein the radar device is small. 3. One of the plurality of calculation conditions is a specific position frequency corresponding to past relative position information with respect to an object, and the confidence constant is that the frequency component is a specific position frequency. 2. The radar apparatus according to claim 1, wherein the closer to the radar, the larger or smaller the radar. 4. The radar device is mounted on a predetermined vehicle, and based on position information from the position calculation means,
The apparatus further includes processing means for obtaining a specific object satisfying a predetermined specific condition, wherein one of the plurality of calculation conditions is a specific object frequency corresponding to past relative position information between the vehicle and the specific object. The radar device according to claim 1, wherein the confidence constant is larger or smaller as the frequency component is closer to the specific target frequency. 5. The specific object is an object to be followed by the vehicle, and the specific condition is located on a downstream side in a moving direction of the vehicle, and a reference that defines a relative speed between the vehicle and the specific object in advance. The radar device according to claim 4, wherein the speed is lower than the speed. 6. The specific object is an object that has a possibility of colliding with the vehicle, and the specific condition is that the specific object is stationary with respect to the ground surface or is in the middle of stationary. The radar device according to claim 4. 7. A vehicle comprising: a plurality of roads on which the vehicle should travel; and map data representing a fixed object near the roads, further comprising: a detector for obtaining data of a road on which the vehicle currently travels; Of the objects that meet the specific conditions,
7. The radar apparatus according to claim 5, wherein a specific target object is selected from moving objects on a road on which the vehicle currently travels. 8. The vehicle according to claim 1, further comprising an obtaining unit configured to obtain traffic information of a road on which the vehicle is currently traveling, wherein the constant calculating unit is configured to output
7. The radar apparatus according to claim 5, wherein a specific target object is selected from moving objects on a road on which the vehicle currently travels. 9. The method according to claim 1, wherein the specific object is an object approaching the vehicle less than a predetermined distance, and the specific condition is that a relative distance to the vehicle is less than a predetermined distance. 5. The radar device according to 4. 10. The radar device, further comprising: an angle measuring unit mounted on a vehicle, for angularly displacing a radiation direction of an oscillation signal from an oscillating unit at a predetermined cycle, wherein one of the plurality of calculation conditions is included. Is the amount of angular displacement in the radial direction, and the reliability constant is larger or smaller for an object present on the downstream side in the moving direction of the vehicle.
The described radar device. 11. The radar device is mounted on a vehicle, and one of the plurality of calculation conditions includes a past relative distance between the vehicle and an object, a curvature of a road on which the vehicle travels,
2. The radar apparatus according to claim 1, wherein the relation is a relationship with the presence or absence of a vehicle on the same road, and the reliability constant is larger or smaller for an object existing on the same road as the vehicle.