(19) Japanese Patent Office (JP)
`(12) Kokai Unexamined Patent Application Bulletin (A)
`(11) Laid Open Patent Application No.
`
`4-348293
`(43) Publication Date
`
`December 3, 1992
`Number of Claims
`
`
`5
`Number of Pages
`
`5
`
`Examination Request
`
`
`not yet made
`Identification Code
`FI
`
`
`(51)
`
`
`Int. Cl.5
`G01S 13/60
` 7/295
`(21) Application No.:
`
`3-197521
`
`D
`Z
`
`
`Internal File No.
`8940-5J
`8940-5J
`
`(71) Applicant:
`
`Tech. Indic.
`
`
`000005326
`Honda Motor Co., Ltd.
`2-1-1 Minamiaoyama,
`Minato-ku, Tokyo-to
`KAWAI, Takayuki
`Honda Motor Co., Ltd.
`1-4-1 Chuo, Wako-shi,
`Saittama-ken
`ASHIHARA, Atsushi
`Honda Motor Co., Ltd.
`1-4-1 Chuo, Wako-shi,
`Saittama-ken
`Patent Attorney, TORII,
`Kiyoshi
`
`(22) Application Date:
`
`May 7, 1991
`
`(72)
`
`Inventor:
`
`
`
`
`
`
`
`
`
`
`
`
`
`(72)
`
`Inventor:
`
`(74) Agent:
`
`
` (54) [Title of the invention] Onboard Radar Device
` (57) [Abstract]
`[Purpose] To be able to eliminate noise components
`when the radar detection signal suddenly changes
`greatly due to, for example, detection loss of an object
`such as a vehicle
`traveling
`in
`front, which
`is
`characteristic of onboard radar devices.
`[Constitution] A constitution is adopted with which,
`when the radar detection signal changes in excess of a
`threshold value within a fixed time, it is possible to use
`a nonlinear filter processing means that holds the value
`from
`immediately before
`the change, and
`to
`continuously hold the value from immediately before the
`change, for a prescribed time span.
`
`
`
`
`
`
`Translation by Patent Translations Inc. 206-357-8508 mail@PatentTranslations.com
`
`1
`
`

`
`JP-04-348293-A (2)
`[0004] Heretofore, to eliminate noise in the signal, linear
`[Claims]
`[Claim 1] In an onboard radar device that continuously
`filtering has been done using a FIR filter or the like. But
`with such linear filter processing, the sudden change in
`detects the relative distance to an object or the relative
`the signal is only suppressed to some extent, so it is
`speed or the like, an onboard radar device characterized
`impossible to effectively eliminate the noise of large
`by using a nonlinear processing means that, when the
`sudden changes, such as detection loss, that occur in
`detection signal of the radar device changes in excess of
`the detection signal of an onboard radar device as
`a preset threshold value within a fixed time, holds the
`described above.
`value of the detection signal from immediately before the
`[0005] For example, if the detection signal of an onboard
`change.
`[Claim 2] An onboard radar device as recited in claim 1
`radar device changes as shown in FIG. 2, then if the
`detection signal is processed using a FIR filter, a signal
`above, characterized by continuously holding the value
`such as shown in FIG. 5 will result, and in particular,
`of the detection signal from immediately before the
`effects such as detection loss will largely remain, and
`change, limited to a prescribed time span.
`[Claim 3] An onboard radar device as recited in claim 2
`desirable processing results will not be obtained.
`[0006] In FIG. 2, A shows a detection loss portion in one
`above, characterized by variably setting the prescribed
`sampling period, B shows a misdetection portion, C
`time for holding the value of the detection signal from
`shows a detection loss portion that continues over
`immediately before the change, in accordance with the
`multiple sampling periods, and D shows a detection
`amount of change when the detection signal changes in
`signal change portion when a new object comes in
`excess of a threshold value, or the magnitude of the
`between one's own vehicle and the previous detection
`detection signal at that time.
`[Claim 4] An onboard radar device as recited in claim 2
`object. And A3, B3, C3, and D3 in FIG. 5 show,
`respectively, the FIR filter processing portions that
`above, characterized by variably setting the prescribed
`correspond to portions A to D in FIG. 2.
`time for holding the value of the detection signal from
`[0007]
`immediately before the change, in accordance with the
`[Problems to Be Solved by the Invention] The
`reception level of the detection signal when the detection
`problem to be solved is that it is impossible to effectively
`signal changes in excess of a threshold value.
`[Claim 5] An onboard radar device as recited in claim 1
`eliminate the noise of sudden large changes such as
`detection loss, which is characteristic of onboard radar
`above, characterized by variably setting the threshold
`devices.
`value for the change in the detection signal when the
`[0008]
`value of the detection signal from immediately before the
`[Means for Solving the Problems] The present
`change is to be held, in accordance with the travel speed
`invention is made so as to eliminate the noise in the
`on the vehicle.
`[Detailed Description of the Invention]
`detection signal, by using a nonlinear filter processing
`[0001]
`means to hold the value of the detection signal as it was
`[Field of Industrial Application] The present invention
`immediately before the change, when the detection
`signal of an onboard radar device changes suddenly.
`relates to an onboard radar device that takes a vehicle
`[0009]
`traveling in front or the like as an object, and detects the
`[Operation] The present invention makes it possible to
`relative distance to the object or the relative speed or the
`effectively eliminate the noise of sudden large changes
`like.
`[0002]
`such as detection loss, which is characteristic of onboard
`[Prior art] In recent years systems have been developed
`radar devices, such that when the travel speed of one's
`own vehicle is controlled in accordance with such noise-
`in which a Doppler radar, FM-CW radar, pulse radar, or
`eliminated detection signals, so as to maintain the proper
`such a radar device is put aboard an automobile or other
`inter-vehicle distance between one's own vehicle and the
`traveling vehicle, and for example a vehicle traveling in
`vehicle traveling in front at all times, the controllability will
`front is taken as an object, the relative distance to the
`no longer be degraded.
`object and relative speed are continuously detected, and
`[0010]
`according to the detection results, the travel speed of
`[Working examples] FIG. 1 shows an example of the
`one's own vehicle is controlled so as to keep the spacing
`composition of an onboard radar device when FM-CW
`between one's own vehicle and the vehicle traveling in
`radar is used.
`front to an appropriate inter-vehicle distance at all times.
`[0011] In the configuration of this drawing, after a signal
`[0003] With such an onboard radar device, due to effects
`at the transmission frequency that is emitted from the
`such as relative wavering left and right or pitching of the
`oscillator 1 is modulated at a fixed frequency by the
`vehicle body in the space between one's own vehicle and
`modulator 2, the modulated transmission signal goes
`the vehicle traveling in front, sometimes the detection of
`through the directional coupler 3 and the circulator 4 and
`the object gets lost, or misdetection occurs, and the
`is emitted as an electromagnetic wave from the antenna
`detection signal changes greatly in a short time span.
`5, the reflected waves from the object are received by
`Such sudden changes in the detection signal become a
`the antenna 5, the received signal goes through the
`source of noise for control when controlling the travel
`circulator 4 and is sent to the mixer 6, where a beat
`speed of one's own vehicle so as to maintain a proper
`frequency is generated with the transmission signal that
`inter-vehicle distance between one's own vehicle and the
`is sent from the directional coupler 3, the beat frequency
`vehicle traveling in front at all times.
`Translation by Patent Translations Inc. 206-357-8508 mail@PatentTranslations.com
`
`2
`
`

`
`JP-04-348293-A (3)
`FIG. 2, the period during which there is detection loss or
`signal is amplified by the amplifier 7 to a fixed level and
`the like is prolonged and continues over the sampling
`is made into a radar detection signal, the radar detection
`periods for multiple times (in FIG. 2, the sampling periods
`signal is converted to a digital signal in the AD converter
`for two times are shown), then the value of the detection
`8, then it is temporarily accumulated in the buffer
`signal from immediately before, which should be held
`memory 9, and the digitized radar detection signal that is
`during ε filter processing for the second and subsequent
`read from the memory 9 undergoes nonlinear digital filter
`times no longer exists, and processing cannot be
`processing by the ε filter processing unit 10. In the
`completely done, and the detection loss or the like at the
`drawing, RD represents the radar detection signal that
`second and subsequent times gets output as-is.
`has undergone this filter processing.
`[0020] Because of this, the present invention is further
`[0012] The beat frequency that arises between the
`characterized in that, in order to make it possible to deal
`transmission signal and
`the
`reception signal
`is
`with detection loss and the like that continues for a
`proportional to the distance to the object, so the relative
`certain extent, a means is adopted that continuously
`distance to the object can be directly determined by the
`holds the value of the detection signal from immediately
`radar detection signal. And the relative speed with the
`before, limited to a prescribed time span, when the radar
`object can be determined indirectly by calculating the
`detection signal changes in excess of a preset threshold
`time change of the distance to the detected object.
`[0013] Here, the ε filter processing unit 10 is set so that
`value and the value of the detection signal from
`immediately before the change is to be held.
`when the radar detection signal changes greatly and
`[0021] Specifically, if ε filter processing is to be done for
`exceeds a preset threshold value within a fixed time, the
`each sampling of the radar detection signal, in the ε filter
`value of the detection signal from just before the change
`processing unit 10, when the radar detection signal has
`is held. And the ε filter processing unit 10 is actually
`greatly changed continuously over a relatively long
`constituted by a microprocessor, so that the content of
`period due to detection loss or the like, the value from
`the ε
`filter processing
`is executed by arithmetic
`immediately before the first time is held continuously
`processing that follows a prescribed algorithm.
`[0014] Now, if for example the radar detection signal
`during an interval of sampling periods from the first
`sampling time when the radar detection signal changed
`changes as shown in FIG. 2, then if the detection signal
`greatly to a preset nth sampling time.
`is processed by the ε filter processing unit 10, it becomes
`[0022] And by adopting such a means, if, for example,
`the signal that is shown in FIG. 3, and it is possible to
`the radar detection signal changes as shown in FIG. 2, a
`almost completely eliminate the effect when the radar
`portion such as portion C, in which the period of detection
`detection signal suddenly changes greatly due to
`loss or the like is prolonged and continues to within the
`detection loss, misdetection, or the like. In FIG. 3, A1, B1,
`nth sampling period, is processed to an optimum state as
`C1, and D1 represent, respectively, the ε filter processing
`shown in portion C2 in FIG. 4, with almost none of the
`portions that correspond to the portions A to D in FIG. 2.
`[0015] Thus, with
`the present
`invention, ε
`filter
`effect remaining.
`[0023] Furthermore, in a detection signal change portion
`processing is done limited to only the portion in which
`when, as shown in portion D in FIG. 2, a new object
`there is a great change exceeding the preset threshold
`comes in between one's own vehicle and the previous
`value, so with respect to the portion where the change is
`detection object, as shown in portion D2 in FIG. 4, from
`small, being no greater than the threshold value, by way
`the time the radar detection signal first changes greatly,
`of ε filter processing, the value from immediately before
`the value from immediately before the change is held
`the change is held, and filter processing for optimum
`continuously for interval period of a prescribed number
`noise-elimination can be done without causing any
`of times (n times), and then a switchover is made to the
`degradation in the properties of the radar detection
`detection signal of the new object, which is output as the
`signal.
`[0016] Shown in FIG. 6 are the properties of the
`radar detection signal.
`[0024] Also, if FIR filter processing is done after the
`threshold values (TH1, TH2) that correspond to the
`above-described ε filter processing has been carried out,
`amount of change in the radar detection signal in order
`processing is done to further smooth out the portions A2,
`to put the ε filter processing unit 10 in the operational
`B2, C2, and D2 in FIG. 4, and it becomes possible to
`state (ON) or in the non-operational state (OFF).
`[0017] And with the present invention, means are
`obtain a radar detection signal in which the noise
`components are more effectively eliminated.
`adopted whereby, in the ε filter processing unit 10, the
`[0025] In addition, in the present invention, a means is
`signal of the travel speed of one's own vehicle is read
`adopted that variably sets the prescribed time for holding
`and the threshold value for when to hold the value from
`the value from immediately before the change, according
`immediately before the change in the radar detection
`to the amount of change when the radar detection signal
`signal is variably set in accordance with the travel speed
`changes in excess of a threshold value.
`of one's own vehicle, according to a pre-registered table.
`[0026] Specifically, in the ε filter processing unit 10, when
`[0018] And by adopting such a means, it is made
`the value as it was immediately before the change at the
`possible to selectively detect only an object that has the
`first time is to be held continuously for the interval from
`speed, acceleration, or the like that should be watched.
`[0019] Also, in performing the ε filter processing,
`the first-time to the nth time sampling period, when the
`radar detection signal changes in excess of a threshold
`because this to be done for each sampling of the radar
`value, the amount of change in the radar detection signal
`detection signal, if, for example, as shown in portion C in
`Translation by Patent Translations Inc. 206-357-8508 mail@PatentTranslations.com
`
`3
`
`

`
`JP-04-348293-A (4)
`detected stepwise, and the value of n is set optimally
`according to the reception level of radar detection signal
`detected at that time, so that the weaker the reception
`level of the radar detection signal is, the greater the value
`of n is, such that the holding time is prolonged, and the
`stronger the reception level is, the smaller the value of n
`is, such that the holding time is shortened.
`[Effects of the invention] Thus, because the onboard
`radar device according to the present invention uses a
`nonlinear filter processing means that holds the value
`from immediately before the change when, within a fixed
`time, the radar detection signal changes in excess of a
`threshold value, it has the advantage of being able to
`effectively eliminate, with no degradation
`in
`the
`characteristic properties of the radar detection signal, the
`noise components when the radar detection signal
`suddenly changes greatly due to detection loss of the
`object or the like, which is characteristic of onboard radar
`devices.
`[Brief Description of the Drawings]
`[FIG. 1] This is a block diagram showing a configuration
`example of an onboard radar device according to the
`present invention.
`[FIG. 2] This is a characteristics diagram showing an
`example of a radar detection signal in which noise is
`mixed in due to detection loss of the object or the like.
`[FIG. 3] This is a characteristics diagram when nonlinear
`filter processing is done on the radar detection signal in
`FIG. 2 according to a working example of the present
`invention.
`[FIG. 4] This is a characteristics diagram for when
`nonlinear filter processing is done on the radar detection
`signal in FIG. 2 according to another working example of
`the present invention.
`[FIG. 5] This is a characteristics diagram for when
`conventional FIR filter processing is done on the radar
`detection signal in FIG. 2.
`[FIG. 6] This is a diagram showing the characteristics of
`threshold values according to the amount of change in
`the radar detection signal that determines whether or not
`to perform nonlinear filter processing according to the
`present invention.
`[Explanation of the symbols]
`1 … oscillator
`2 … modulator
`3 … directional coupler
`4 … circulator
`5 … antenna
`6 … mixer
`7 … amplifier
`8 … AD converter
`9 … buffer memory
`10 … ε filter processing unit
`
`is detected stepwise, and the value of n is optimally set
`according to the amount of change detected at that time,
`so that the greater the amount of change is, the greater
`the value of n is, according to a pre-registered table.
`[0027] And by adopting such a means, in the ε filter
`processing unit 10, it becomes possible to carry out ideal
`processing to fit the state of change of the radar
`detection signal, for example as follows.
`[0028] That is, if the amount of change in the radar
`detection signal is large, then with many sampling times
`that can adequately compensate for the interval during
`which the radar detection signal has changed such as to
`exceed the threshold value, the value from immediately
`before the change can be held continuously. If the
`amount of change in the radar detection signal is
`moderate, for example if a new object has come in, then
`after continuously holding, for a moderate number of
`sampling times, the value of the radar detection signal
`from immediately before the change, the detection signal
`for the new object can be output. And if the amount of
`change in the radar detection [signal1] is small, then n=0
`applies, and the radar detection signal can be output as-
`is, without holding any value as it was immediately before
`the change.
`[0029] And with the present invention, it is also possible
`to use a means that variably sets the prescribed time for
`holding the value from immediately before the change,
`according to the magnitude (absolute value) of the radar
`detection signal when the radar detection signal changes
`in excess of a threshold value.
`[0030] Specifically, in the ε filter processing unit 10, when
`the value as it was immediately before the change at the
`first time is to be held continuously for the interval from
`the first-time to the nth time sampling period, when the
`radar detection signal changes in excess of a threshold
`value, the magnitude of the radar detection signal is
`detected stepwise, and the value of n is optimally set
`according to the magnitude of radar detection signal
`detected at that time, so that the greater (smaller) the
`value of the radar detection signal, which is to say, the
`nearer (farther) the detected object is, the greater the
`value of n is, according to a pre-registered table.
`[0031] And by adopting such a means, in the ε filter
`processing unit 10, it becomes possible to carry out ideal
`processing to fit the state of change of the radar
`detection signal, as in the aforementioned case.
`[0032] And with the present invention, it is also possible
`to use a means that variably sets the prescribed time for
`holding the value from immediately before the change,
`according to the reception level of the radar detection
`signal when the radar detection signal changes in excess
`of a threshold value.
`[0033] Specifically, in the ε filter processing unit 10, when
`the value as it was immediately before the change at the
`first time is to be held continuously for the interval from
`the first-time to the nth time sampling period, when the
`radar detection signal changes in excess of a threshold
`value, the reception level of the radar detection signal is
`
`1 There is a typographical error in the original Japanese
`text. -- trans.
`Translation by Patent Translations Inc. 206-357-8508 mail@PatentTranslations.com
`
`4
`
`

`
`[FIG. 1]
`
`[FIG. 2]
`
`JP-04-348293-A (2)
`[FIG. 3]
`
`[FIG. 4]
`
`[FIG. 5]
`
`
`
`[FIG. 6]
`
`
`
`
`
`
`
`
`
`
`
`
`
`Translation by Patent Translations Inc. 206-357-8508 mail@PatentTranslations.com
`
`5
`
`

`
`FROM :
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`FAX NO.
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`No•'· 30 2015 03:32PM Pl
`Patent iranslations From: Men:!r C:·<:)·~
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`Certification of Translation
`
`Translator's Declaration: November 30, 2015
`
`I, Mark Spahn, hereby declare:
`
`That I possess advanced knowledge of the Japanese and English languages. My
`qualifications are as follows:
`• over 35 years as a Japanese-English translator, focusing primarily on technical
`and legal documents. including four years in-house at the law offices of Baker &
`McKenzie in Tokyo
`• Master's degree in Electrical Engineering/Computer Science from the University of
`Utah
`computer programmer at Computer Task Group
`co-author of • Japanese Kanji & Kana: A Complete Guide to the Japanese Writing
`System," Tuttle Publishing, 1981, 1997,2011,2012
`co-author of ''The Kanji Dictionary• (a 47,000-entry bilingual dictionary, well known
`as the Spahn-Hadamitzky dictionary) Tuttle Publishing 1996, 1998, 2002.
`
`•
`•
`
`•
`
`I hereby certify that I translated Japanese Unexamined Patent Application Number JP-04-
`348293-A, from Japanese to English and that, to the best of my ability, my English
`translation, attached hereto, is a true and correct translation_
`
`I further certify that I am competent in both English and Japanese to render and certify
`such translation. I understand that willful false statements and the like are punishable by
`a fine or imprisonment, or both (18 U.S.C. 1001 ). I declare under penalty of perjury under
`the laws of the United States of America that all statements made herein of my own
`knowledge are true, and all statements made on information and belief are believed to be
`true.
`
`Mark Spahn
`
`6