Object detection sensor using phase difference sum method etc.

Abstract

To realize "discrimination between a mobile body and a stationary body" and "improvement of detection resolution" or the like by detecting an object using a spectrum obtained by converting a difference sum signal.SOLUTION: Provided is an object detection sensor 1 for detecting an object S within a detection region R. The object detection sensor includes: a transmission part 2 for transmitting an electric wave W; a reception part 3 for receiving a reflection wave H being the electric wave W reflected on the object S; and a detection part 4 for detecting the object S based on a signal B of the reflection wave H. The transmission part 2 transmits the electric wave W three times or more. The detection part 4 detects an object S by using a spectrum obtained by converting a difference sum signal ΔB+ to which a difference signal ΔB of a signal according to an n-th transmission and a signal according to an n+Z1-th transmission, and a difference signal ΔB of a signal according to an n-th transmission and a signal according to an n+Z2-th transmission, have been added. Further, Z1 and Z2 or the like may be selected according to speed of an object S'. Furthermore, an object detection method and an object detection program are provided for making the detection part 4 detect only an object S having a speed greater than 0 or the like, as a mobile body S'.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an object detection sensor, an object detection method, and an object detection program that detect an object within a detection area by a phase difference sum method or the like. [Background technology]

[0002] Conventionally, radar devices using the FMCW method and the like are known, and among them, for example, there is an FMCW radar device that detects multiple targets over a wide distance range and measures the distance and relative speed of the detected targets (see Patent Document 1). This FMCW radar device includes distance range observation period setting means for setting a plurality of distance range observation periods consisting of up-chirp periods and down-chirp periods by changing the measurable distance range, modulation frequency width setting means for setting a plurality of different modulation frequency widths for each distance range observation period, beat signal generation means for generating a beat signal for each distance range observation period from a transmission signal and a reception signal, passband width setting means for setting a passband width of the beat signal generated by the beat signal generation means for each distance range observation period, amplification means for amplifying the beat signal that passes through the passband width setting means, conversion means for converting the beat signal amplified by the amplification means into digital data, and switching means for switching between the passband width setting means and the amplification means for each distance range observation period. Furthermore, paragraph 0006 of Patent Document 1 describes measuring the relative velocity between targets in a situation where multiple targets are present, and paragraph 0019 etc. describes setting a distance range in which a frequency power spectrum can be obtained by FFT calculation for each distance range observation period. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-088273 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the FMCW radar device described in Patent Document 1, in a situation where moving and stationary objects are mixed as targets, the stationary objects and moving objects are superimposed in the set frequency power spectrum, making it difficult to distinguish between these moving and stationary objects. Even if a moving object is found based on the frequency spectrum obtained from the beat signal obtained by sweeping twice (transmitting twice) in order to distinguish between moving and stationary objects, detection may become impossible depending on the moving speed of the moving object. Furthermore, with the FMCW radar device of Patent Document 1, when multiple targets are close to each other, low power level peaks in the frequency power spectrum are masked by large peaks (for example, a person standing in front of a wall cannot be separated and cannot be detected), limiting detection resolution and making it difficult to capture minute movements of targets. Furthermore, the FMCW radar device of Patent Document 1 has the risk of detecting rainfall and the like as white noise.

[0005] In view of the above, an object of the present invention is to provide an object detection sensor, an object detection method, and an object detection program that can "distinguish between moving objects and stationary objects" and "improve detection resolution" by detecting an object using a spectrum converted from a differential sum signal. [Means for solving the problem]

[0006] The object detection sensor 1 according to the present invention is an object detection sensor that detects an object S within a detection area R, and includes a transmission unit 2 that transmits radio waves W to the detection area R, a reception unit 3 that receives a reflected wave H of the radio waves W from the transmission unit 2 reflected by the object S, and a detection unit 4 that detects the object S based on a signal B corresponding to the reflected wave H received by the reception unit 3, wherein the transmission unit 2 transmits the radio waves W three or more times, and the detection unit 4 outputs a differential sum signal ΔB obtained by adding at least a differential signal ΔB between a signal B corresponding to the reflected wave H due to the n-th transmission among the three or more transmissions of radio waves W by the transmission unit 2 and a signal B corresponding to the reflected wave H due to the n+Z1th transmission after the n-th transmission, and a differential signal ΔB between the signal B corresponding to the reflected wave H due to the n+Z2th transmission after the n+Z1th transmission, where n is a natural number, Z1 is a natural number greater than n, and Z2 is a natural number greater than Z1. + The first feature of the present invention is that the object S is detected based on a spectrum obtained by converting the above-mentioned signal.

[0007] A second feature of the object detection sensor 1 according to the present invention is that the object detection sensor detects an object S within a detection area R, and includes a transmission unit 2 that transmits radio waves W to the detection area R, a reception unit 3 that receives a reflected wave H of the radio waves W from the transmission unit 2 reflected by the object S, and a detection unit 4 that detects the object S based on a signal B corresponding to the reflected wave H received by the reception unit 3, wherein the transmission unit 2 transmits the radio waves W three or more times, and the detection unit 4 detects the object S based on a signal B corresponding to the reflected wave H received by the reception unit 3, where N is a natural number, j is a natural number from 1 to N, and Z1 j is a natural number greater than N, and Z2 j Z1 j In the case where the j-th transmission of the radio wave W by the transmitter 2 is a natural number larger than the j-th transmission, j Signal B corresponding to j and j+Z1 after the jth time. j Reflected wave H from the th transmission j Signal B corresponding to j Difference signal ΔB j and the reflected wave H j Signal B corresponding toj And the j+Z1 j j+Z2 after the first j Reflected wave H from the th transmission j Signal B corresponding to j Difference signal ΔB j The difference sum signal ΔB j + The object S is detected based on the spectrum obtained by converting the difference sum signal ΔB j + Each time detection of the object S based on the transformed spectrum is completed, 1 is added to the value of j, and detection of the object S is repeated.

[0008] The third feature of the object detection sensor 1 according to the present invention is, in addition to the first or second feature, that in the detection region R, moving objects S' and stationary objects S" are mixed as the object S, or only moving objects S' are present, and Z1 and Z2 as described in claim 1 or Z1 as described in claim 2 are selected according to the speed of the moving object S'. j and Z2 j is at least at a selected point.

[0009] others, Object Detection Sensor 1 is The object detection sensor detects an object S within a detection region R, and includes a transmitter 2 that transmits radio waves W to the detection region R, a receiver 3 that receives a reflected wave H of the radio waves W from the transmitter 2 reflected by the object S, and a detector 4 that detects the object S based on a signal B corresponding to the reflected wave H received by the receiver 3. In the detection region R, moving objects S' and stationary objects S" are mixed as the object S, or only moving objects S' are present, and the detector 4 detects only objects S within the detection region R whose speed is greater than 0 as the moving object S'. It's okay .

[0010] others, Object detection sensor 1 teeth The detection unit 4 detects only the object S whose speed is equal to or greater than a predetermined lower limit and / or equal to or less than a predetermined upper limit within the detection area R as the moving object S'. It's okay .

[0011] Due to these characteristics, a differential sum signal ΔB is obtained by adding at least a differential signal ΔB between a signal B corresponding to a reflected wave H due to the n-th transmission and a signal B corresponding to a reflected wave H due to the n+Z1-th transmission, and a differential signal ΔB between a signal B corresponding to a reflected wave H due to the n-th transmission and a signal B corresponding to a reflected wave H due to the n+Z2-th transmission. + By detecting the object S based on the spectrum converted from the spectrum, unlike Patent Document 1, it is possible to detect only the moving object S' even in a situation where moving objects S' and stationary objects S" are mixed, making it possible to distinguish between the moving object S' and the stationary object S" ("distinguishing between moving objects and stationary objects").Furthermore, it can be said that the moving object S' can be detected regardless of its moving speed. In addition, even for people standing in front of a wall or the like that could not be separated in Patent Document 1, the detection resolution is improved, making it easier to capture minute movements of the moving object S' ("improved detection resolution"), while also making it possible to increase the D / U ratio (Desired signal to Undesired signal ratio) of the moving object S' that is the detection target (someone wants to detect). It can also be said that white noise can be reduced even in conditions such as rain, making it possible to increase the D / U ratio of the moving object S' ("reduced white noise", etc.). Such an object detection sensor 1 can also be said to be an "object detection sensor using a phase difference sum method." In addition, the object detection sensor 1 may be configured so that the detection unit 4 detects only objects S within the detection area R whose speed is greater than 0 as moving bodies S', and such an object detection sensor 1 can also be said to be an "object detection sensor using a velocity pass filter."

[0012] Also, when N is a natural number and j is a natural number from 1 to N, etc., the difference sum signal ΔB j +By adding 1 to the value of j and sequentially repeating the detection of object S after each detection of object S based on the spectrum obtained by converting j, the possibility of capturing minute movements of object S in the detection of object S at any value of j increases, which can be said to reduce the risk of missing detection of a moving object S', thereby achieving a further "improvement in detection resolution."

[0013] Furthermore, by selecting Z1, Z2, etc. according to the speed of the moving object S', it is possible to further "distinguish between moving objects and stationary objects," "improve detection resolution," "reduce white noise," etc.

[0014] others, The object detection method is an object detection method using an object detection sensor 1 that detects an object S within a detection region R, the object detection sensor 1 having a transmission unit 2 that transmits radio waves W to the detection region R, a reception unit 3 that receives a reflected wave H of the radio waves W from the transmission unit 2 reflected by the object S, and a detection unit 4 that detects the object S based on a signal B corresponding to the reflected wave H received by the reception unit 3, the detection region R includes a mixture of moving objects S' and stationary objects S'', or only moving objects S', and the detection unit 4 is caused to detect only objects S within the detection region R whose speed is greater than 0 as the moving object S'. It is okay .

[0015] others, The object detection program is an object detection program used in an object detection sensor 1 that detects an object S within a detection region R, the object detection sensor 1 having a transmission unit 2 that transmits radio waves W to the detection region R, a reception unit 3 that receives a reflected wave H of the radio waves W from the transmission unit 2 reflected by the object S, and a detection unit 4 that detects the object S based on a signal B corresponding to the reflected wave H received by the reception unit 3, the object S being present within the detection region R as a mixture of moving objects S' and stationary objects S'', or only moving objects S' being present, and the detection unit 4 being caused to detect only objects S within the detection region R whose speed is greater than 0 as the moving object S'. It is okay .

[0016] These features allow the detection unit 4 to detect only objects S within the detection area R whose speed is greater than 0 (zero) as moving objects S'. This makes it possible to detect only the moving object S' even in a situation where moving objects S' and stationary objects S" are mixed, unlike Patent Document 1, and therefore makes it possible to distinguish between moving objects S' and stationary objects S" ("Distinguishing between moving objects and stationary objects"). In addition, it can be said that the detection resolution is improved even for people standing in front of a wall or the like, which could not be separated in Patent Document 1, and that it becomes easier to capture minute movements of the moving object S' ("Improvement of detection resolution"). Furthermore, such an object detection method or object detection program can also be said to be an "object detection method using the phase difference sum method" or an "object detection program using the phase difference sum method", or an "object detection method using a velocity pass filter" or an "object detection program using a velocity pass filter". Effect of the Invention

[0017] The object detection sensor, object detection method, and object detection program of the present invention can detect an object using a spectrum converted from a differential sum signal, thereby making it possible to "distinguish between moving and stationary objects" and "improve detection resolution," among other things. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic side view showing an object detection sensor according to the present invention; [Diagram 2] 2 is a block diagram showing an example configuration of a transmitter, a receiver, a detector, and the like in an object detection sensor. FIG. [Diagram 3]1 is a schematic graph showing a differential sum signal in an object detection sensor according to the present invention, in which (a) shows a differential sum signal ΔB+ based on 1 to 3 transmissions by adding "two": a differential signal ΔB between signal B due to the first transmission and signal B due to the second transmission, and a differential signal ΔB between signal B due to the first transmission and signal B due to the third transmission; (b) shows a differential sum signal ΔB+ based on 1 to 4 transmissions by adding "three" to (a) including a differential signal ΔB between signal B due to the first transmission and signal B due to the fourth transmission; and (c) shows the difference in (a). After an object is detected using the sum signal ΔB+, the "two" differential signal ΔB between signal B from the second transmission and signal B from the third transmission, and the differential signal ΔB between signal B from the second transmission and signal B from the fourth transmission are added, and the object is detected using the differential sum signal ΔB+ based on the second to fourth transmissions, and so on, successively showing differential sum signals ΔB+ based on the fourth to sixth, fifth to seventh, sixth to eighth, etc. transmissions, and (d) shows a case where the differential signal ΔB between signal B from the first transmission and signal B from the second transmission can be 0 (zero) on its own. [Figure 4] This is a photograph in lieu of a drawing that shows the situation when moving objects and stationary objects are mixed within the detection area and the moving object is moving at a position away from the stationary objects [1-1]. [Diagram 5] In the case of [1-1] in Figure 4, (a) is a waveform graph showing the radio waves transmitted four times and their reflected waves, (b) is a waveform graph showing each of the differential signals of each radio wave and each reflected wave in (a) and the differential sum signal obtained by adding each differential signal, and (c) is a spectrum obtained by FFT transforming each differential signal and the differential sum signal in (b). [Figure 6] This is a photograph in lieu of a drawing that shows the situation when moving objects and stationary objects are mixed within the detection area and a moving object is moving in close proximity to a stationary object [1-2]. [Figure 7] In the case of [1-2] in Figure 6, (a) is a waveform graph showing the radio waves transmitted four times and their reflected waves, (b) is a waveform graph showing each of the difference signals of each radio wave and each reflected wave in (a) and the difference sum signal obtained by adding each difference signal, and (c) is a spectrum obtained by FFT transforming each difference signal and the difference sum signal in (b). [Figure 8]This is a photograph in lieu of a drawing showing the situation in case of [2] during rainfall. [Figure 9] In the case of [2] in Figure 8, (a) is a waveform graph showing the radio waves transmitted four times and their reflected waves, (b) is a waveform graph showing each of the differential signals of each radio wave and each reflected wave in (a) and the differential sum signal obtained by adding each of the differential signals, and (c) is a spectrum obtained by FFT transforming each of the differential signals and the differential sum signal in (b). [Figure 10] 2 is a flowchart illustrating an object detection method and an object detection program according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to the drawings, embodiments of the present invention will be described in detail. <Overall configuration of object detection sensor 1> 1 to 9 show an object detection sensor 1 according to the present invention. The object detection sensor 1 is a sensor that detects an object S within a detection area R.

[0020] The object detection sensor 1 may be of any type or configuration as long as it can detect an object S within the detection area R, such as an FMCW (frequency modulated continuous wave) sensor (FMCW sensor device), a (multi-frequency CW) sensor that uses multiple (two or more) continuous waves of different frequencies simultaneously without modulation (particularly when continuous waves of two different frequencies are used simultaneously without modulation, it can also be called a two-frequency CW sensor), a (CW) sensor that uses only a continuous wave of a certain frequency without modulation, or other sensors that use radio waves, such as a Doppler sensor, a standing wave sensor, or other continuous wave sensors.

[0021] The object detection sensor 1 has a transmitting unit 2 that transmits radio waves W to a detection area R, a receiving unit 3 that receives (is capable of receiving) reflected waves H that are the radio waves W from the transmitting unit 2 reflected by an object S, and a detecting unit 4 that detects the object S based on the reflected waves H. The object detection sensor 1 may have one each of the above-mentioned units 2 to 4, but may also have at least one of the units 2 to 4 in plural. The detection area R and object S that are monitored by the object detection sensor 1 will be described below.

[0022] <Detection area R, object S> As shown in Figure 1, the "detection area R" detected by the object detection sensor 1 is an area into which radio waves W are transmitted (irradiated) from the transmitter 2, and is an area through which not only the radio waves W but also the reflected waves H that are reflected by the radio waves W on an object S pass. The detection area R is an area where the bundle of paths of radio waves W from the transmitter 2 and the path (or bundle of said paths) of the reflected waves H from the radio waves W reflected by the object S to the receiver 3 exist (the area occupied by the bundle of paths of radio waves W and the paths of the reflected waves H, etc.), and its shape can also be said to be approximately a truncated cone with a larger radius the further away from the transmitter 2 or the receiver 3. Moreover, it can be said that the object detection sensor 1 has the transmitter 2 and the receiver 3 disposed on one end side of the detection area R.

[0023] In other words, the transmitter 2 is installed at one end of an area assumed to be the detection area R and at a position where the transmitter 2 can transmit radio waves W to this area. Similarly, the receiver 3 is installed on the same side of the area assumed to be the detection area R and at a position where it can receive the reflected wave H that has passed through this area.

[0024] The location where the detection area R is expected (set) may be any location where it is necessary to measure the presence or absence of the object S itself within that location, the distance L between the object S and the object detection sensor 1, the speed V of the object S (moving body S'), etc., but it may be set, for example, at a thermal, hydroelectric, nuclear, solar, wind, geothermal, biomass, wave power, etc. power plant (such as an area surrounded by a fence), or it may be set at a substation, gas plant, water purification plant, airport, port facility, or other various facilities. Furthermore, in various facilities, the device may be installed not only outdoors where snowfall, vehicle traffic, building construction, etc. may occur, but also indoors where changes in the environment may occur due to changes in the layout of internal equipment such as the above-mentioned power plants, factories, warehouses, etc.

[0025] In such a detection region R, the objects S may include a mixture of moving objects S' and stationary objects S'', or may only include moving objects S'. Here, the "moving object S'" can be said to be an object whose speed V is greater than 0 (zero), or an object whose speed V is detected as equal to or greater than a predetermined value by a detection unit 4 described below, and will hereinafter be referred to as the moving object S'. Such a moving object S' may be a person (such as an intruder or suspicious person attempting to break into the various facilities mentioned above), a car such as a passenger car or a motorcycle, a light vehicle such as a bicycle or a cart, a motorbike, a car remotely operated (radio controlled) by radio, a drone, a helicopter, a ship, an airplane, or may also include a person (object) that has been hiding in the detection area R and has begun to move. Note that such a moving object S' may include raindrops during rainfall and snow (snowflakes) during snowfall, as well as sleet (a mixture of rain and snow), hail, freezing rain, fine ice (diamond dust), and debris that has entered the detection area R due to wind or the like.

[0026] Moreover, a "stationary body S" can be said to be an object whose velocity V is 0 (zero), or an object whose velocity V is detected by a detection unit 4 described below as being smaller than a predetermined value, and will hereinafter be referred to as a stationary body S". Such a stationary body S" may be, for example, a wall (exterior wall, etc.) of a building, a road cone (pylon, color cone (registered trademark)), a bar for a road cone, a tree, a flower bed, etc., a wall, fence, gate, service entrance, stairs, etc. that form the boundary between various facilities and the outside (outside world), or other protrusions or steps from the ground, signs, mirrors, guardrails installed on the ground, planted flowers or vegetation, hedges made of wood, bamboo, synthetic resin, etc.

[0027] Furthermore, "a mixture of moving objects S' and stationary objects S" exists within the detection area R" does not only mean that both stationary moving objects S' and stationary objects S" always exist within the detection area R, but also means that a moving object S' may enter (exist) within the detection area R where a stationary object S" exists. Furthermore, "only a moving object S' is present within the detection area R" does not only mean that only a moving object S' is always present within the detection area R, but also means that a moving object S' may enter (may be present) within a detection area R where neither a moving object S' nor a stationary object S'' is present. Note that a detection area R where a stationary object S" does not exist means that a stationary object S" such as a building does not exist in an area (an area occupied by the bundle of paths of radio waves W and the path of reflected waves H, etc.) in which the object detection sensor 1 can detect an object S due to factors such as the direction in which the transmitter 2 transmits radio waves W, which will be described later, but a stationary object S" may exist in the detection area R or in the vicinity of the object detection sensor 1.

[0028] Alternatively, the detection area R may be an area existing between the transmitter 2 and the receiver 3 (an area occupied by a bundle of paths of radio waves W passing between the transmitter 2 and the receiver 3), or an area existing between the transmitter 2 or the receiver 3 and a reflector that reflects the radio waves W from the transmitter 2 (an area occupied by a bundle of paths of radio waves W passing between the transmitter 2 and the reflector, or a bundle of paths of reflected waves passing between the reflector and the receiver 3). In these cases, the shape of the detection area R may be roughly rugby ball-shaped with a radius that increases as it approaches the midpoint between the transmitter 2 and the receiver 3, or roughly rugby ball-shaped with a radius that increases as it approaches the midpoint between the transmitter 2 or the receiver 3 and the reflector (the detection area R in these cases can also be called a Fresnel zone (first Fresnel zone)).

[0029] Multiple object detection sensors 1 may detect an object S within approximately the same detection area R, and one object detection sensor 1 may have one or more transmitting units 2 and one or more receiving units 3. First, the transmitter 2 will be explained in detail below.

[0030] <Transmitter 2> As shown in Figures 1 to 9, the transmitter 2 transmits radio waves W of a predetermined frequency f (wavelength λ = speed of light c ÷ frequency f) to the detection area R, and at least one transmitter 2 is provided for one detection area R (or for one sensor housing 5 of one object detection sensor 1). The transmitter 2 may transmit the radio wave W three or more times. For such a transmission unit 2, the frequency f of the transmitted radio waves W, whether or not it changes, the transmission timing, etc. are determined for each transmission method of the object detection sensor 1 described above. However, from here on, as an example, the transmission unit 2 when the object detection sensor 1 is an FMCW sensor will mainly be explained in detail.

[0031] The transmitter 2 transmits (irradiates) the radio waves W to the detection area R for a predetermined transmission time (sweep time) ΔT while modulating the frequency f of the radio waves W with a predetermined frequency fluctuation width Δf. The method (frequency sweep method) of modulating the frequency f of the radio wave W in one transmission by the transmitter 2 is not particularly limited, but may be, for example, a sawtooth wave method using an up-chirp (increasing the frequency f approximately linearly) or a down-chirp (decreasing the frequency f approximately linearly), or a triangular wave method using an up-chirp and a down-chirp.

[0032] When the transmitter 2 transmits the radio waves W three or more times with a gap therebetween as described above, a predetermined interval time K may be inserted between one transmission and the next transmission (or between each transmission). The interval time K is not particularly limited, but may be, for example, longer than the sweep time ΔT (particularly, the interval time K may be 10 times or more the sweep time ΔT), or may be 1 mSec or more and 100 mSec or less (e.g., 10 mSec). Incidentally, the interval time K may be 0 (zero) (that is, there may be no interval time K), and each interval time K may always have a constant value, or each interval time K may have a different value.

[0033] The transmitting unit 2 includes a modulated signal generator 21 capable of arbitrarily modulating the frequency f of a generated signal (basic signal G), a transmitting antenna 22 that transmits the basic signal G from the modulated signal generator 21 to the detection region R, and a basic output path (synchronous path) 23 that outputs the basic signal G to multiple receiving units 3. The transmitting unit 2 may be equipped with a transmitting amplifier that amplifies the signal from the modulating signal generator 21, or may be configured to be able to stop transmitting the radio waves W while outputting the base signal G to multiple receiving units 3.

[0034] In addition, multiple transmitters 2 may be provided for one detection area R (or for one sensor housing 5 of one object detection sensor 1), and each of the multiple transmitters 2 may transmit (irradiate) radio waves W (continuous waves) of different frequencies f to the same detection area R simultaneously, without modulation (or while modulating). In this case, each transmitting unit 2 may be configured to be able to stop transmitting the radio waves W while outputting the base signal G to each of the multiple receiving units 3.

[0035] <Radio Wave W> The radio waves W transmitted from the transmitter 2 described above refer to electromagnetic waves having a frequency f of 3 THz or less, and preferably microwaves having a frequency of 300 MHz or more and 300 GHz or less. Alternatively, the radio waves W may be, among the above-mentioned microwaves, millimeter waves having a frequency of 30 GHz or more and 300 GHz or less, or submillimeter waves having a frequency of 300 GHz or more and 3 THz or less.

[0036] In particular, the frequency f (wavelength λ) of the radio wave W may be, for example, 24.05 GHz or more and 24.25 GHz or less, in which case the object detection sensor 1 can be used as a sensor for a specific low-power radio station. In addition, the frequency f of the radio wave W may be 76 GHz or more and 77 GHz or less, or 77 GHz or more and 81 GHz or less. The transmission range and angle (directivity) of the radio waves W are not particularly limited, but for example, the transmission angle may be approximately 6° in the direction along the horizontal plane (left-right direction) and approximately 15° in the direction along the vertical plane (up-down direction), or the transmission angle may be approximately 20° in the left-right direction and approximately 20° in the up-down direction.

[0037] As described above, the transmission range of the radio waves W may be such that the transmission angle in the vertical direction is wider than that in the horizontal direction, or the transmission angles in the vertical and horizontal directions may be approximately the same, or alternatively, the transmission angle in the horizontal direction may be wider than that in the vertical direction.

[0038] In addition, the transmitting antenna 22 may be positioned so that the horizontal plane in the transmission range of the radio waves W becomes the E-plane (electric field plane) and the vertical plane becomes the H-plane (magnetic field plane) (horizontal polarization), or conversely, the horizontal plane may be positioned so that the H-plane and the vertical plane becomes the E-plane (vertical polarization). The radio wave W may be a circularly polarized wave (left-handed circularly polarized wave or right-handed circularly polarized wave) in which the electric field rotates left or right in the transmission (traveling) direction, or an elliptically polarized wave.

[0039] <Receiver 3> As shown in Figures 1 to 9, the receiving unit 3 receives reflected waves H that are reflected by an object S within the detection area R and pass through the detection area R, and at least one receiving unit 3 is provided for each detection area R (or for each sensor housing 5 of each object detection sensor 1). Here, when the above-mentioned transmitting unit 2 transmits radio waves W three or more times, if an object S (such as a moving object S') is present within the detection area R, each transmitted radio wave W will generate a reflected wave H reflected by the object S, etc. three or more times, and the receiving unit 3 will receive the reflected wave H three or more times.

[0040] Incidentally, when the object S is a moving object S', as described above, the moving object S' is an object S" whose speed V is greater than 0 (zero), and therefore the position of the moving object S' when the radio wave W is reflected (i.e., the reflection position, so to speak) shifts little by little (i.e., the distance L between the object detection sensor 1 and the moving object S' changes little by little), and the receiver 3 receives the reflected wave H three or more times. Furthermore, the faster the speed V of the moving body S', the greater the shift in the reflection position between one reception and the next (the change in distance L between the object detection sensor 1 and the moving body S'), and conversely, the slower the speed V of the moving body S', the smaller the change in distance L between the object detection sensor 1 and the moving body S' between one reception and the next. The configuration of such a receiving unit 3 also differs depending on the transmission method of the object detection sensor 1 described above, but from here on, as an example, we will mainly explain in detail the receiving unit 3 when the object detection sensor 1 is an FMCW sensor.

[0041] The receiving unit 3 is equipped with a receiving antenna 24 that receives reflected waves H, etc. and generates an electrical signal corresponding to the reflected waves H, and may also be equipped with a receiving amplifier that amplifies the signal from the receiving antenna 24. Generally, the transmitting antenna 22 and the receiving antenna 24 may not be separated, but may be simplified to a single antenna (such as a patch antenna).

[0042] In addition, multiple receiving units 3 may be provided for one detection area R (or for one sensor housing 5 of one object detection sensor 1), and multiple receiving units 3 may be arranged in the up-down direction (vertical direction), left-right direction (horizontal direction), approximately triangular shape, diagonal direction, etc. In addition, the receiving unit 3 may receive radio waves W transmitted from the transmitting unit 2 and passing through the detection area R, or may receive reflected waves that are reflected by a reflector provided opposite the transmitting unit 2 and pass through the detection area R. Furthermore, the sensor housing 5 of the object detection sensor 1 may be a sensor housing 5 in which the above-mentioned transmission unit 2 and reception unit 3 are both integrally attached.

[0043] <Detection unit 4> As shown in FIGS. 1 to 9, the detection unit 4 detects an object S within a detection region R. In particular, as shown in FIGS. 3(a) and 3(b), when the transmitter 2 transmits radio waves W three or more times, the detector 4 detects a difference sum signal ΔB obtained by adding at least a differential signal ΔB between a signal B corresponding to the reflected wave H due to the n-th transmission among the three or more transmissions of radio waves W by the transmitter 2 and a signal B corresponding to the reflected wave H due to the n+Z1-th transmission after the n-th transmission, and a differential signal ΔB between a signal B corresponding to the reflected wave H due to the n+Z2-th transmission after the n+Z1-th transmission. + The object S may be detected based on the transformed spectrum. In this case, in the present invention, "n is a natural number, Z1 is a natural number greater than n, and Z2 is a natural number greater than Z1."

[0044] As shown in FIG. 3C, when the transmitter 2 transmits the radio wave W three or more times, the detector 4 detects the reflected wave H j Signal B corresponding to j and j+Z1 after the jth iteration j Reflected wave H from the th transmission j Signal B corresponding to j Difference signal ΔB j and the reflected wave H j Signal B corresponding to j and j+Z1 j j+Z2 after the first j Reflected wave H from the th transmission j Signal B corresponding to j Difference signal ΔB j The difference sum signal ΔB j + The object S is detected based on the spectrum obtained by converting the difference sum signal ΔB j + After each detection of the object S based on the transformed spectrum is completed, the value of j may be incremented by 1 and the detection of the object S may be repeated. In this case, in the present invention, "N is a natural number, j is a natural number from 1 to N, and Z1 j is a natural number greater than N, and Z2 jis Z1 j It is a larger natural number."

[0045] Alternatively, the detection unit 4 may detect only objects S within the detection area R whose speed V is greater than 0 (zero) or whose speed V is equal to or greater than a predetermined value, and the detection unit 4 may output a transmission control signal (sweep control signal) X to the transmission unit 2, as described below. Regarding such a detection unit 4, the following mainly describes in detail an example of the detection unit 4 in the case where the object detection sensor 1 is an FMCW sensor.

[0046] The detection unit 4 also includes a mixer 4a that outputs a product (beat signal B) of a signal corresponding to the reflected wave H received by the reception unit 3 and a base signal G from the transmission unit 2 via the base output path 23. The detection unit 4 may include an A / D converter that performs A / D conversion on the analog data (analog waveform) of the beat signal B, a register that stores the A / D converted digital data (discrete numerical values), a cache memory, a main memory, a disk cache, a hard disk, or other storage device, and may also include a bandpass filter, a detector for determining waves (interference waves) that interfere with the calculation of the speed V and distance of the object S, and a configuration for outputting to the outside that an object S within the detection area R has been detected (output of an object detection signal).

[0047] The above-mentioned mixer 4a multiplies the fundamental signal G from the transmitter 2 and the signal from the receiver 3 by the following equation (1), and then extracts (demodulates or detects) only the component (beat signal B) of the difference (F1-F2) between the frequency F1 of the fundamental signal G (radio wave W) and the frequency F2 of the signal from the receiver 3 using a low-pass filter or the like, and outputs it to the detector 4. Incidentally, the detection by mixer 4a may be quadrature detection (IQ detection) or the like. In the case of IQ detection, the I channel waveform and the Q channel waveform have amplitude and phase information of the signal from the receiving unit 3 (the signal corresponding to the reflected wave H received by the receiving unit 3), and it can also be said that these I channel waveform and Q channel waveform are beat signal B.

[0048]

number

[0049] Based on the beat signal B output from the mixer 4a using this equation (1), the detector 4 detects an object S (presence or absence of a moving object S') within the detection region R from the reflected wave H.

[0050] <Detection contents of object S by detection unit 4> Here, the detection of the object S (particularly, the moving object S') by the detection unit 4 will be described. First, the detection unit 4 detects the distance L between the object S and the object detection sensor 1 based on the reflected wave H that is generated when the radio wave W transmitted once from the transmission unit 2 is reflected by the object S. The detection unit 4 can also detect the speed V of the object S and the approach / displacement of the object S (such as a moving object S') (whether the object S is approaching or moving away from the object detection sensor 1) based on the reflected wave H.

[0051] To more specifically show the detection of the distance L, for example, when the sweep time is ΔT, the frequency fluctuation width is Δf, the frequency of the beat signal B is (F1-F2), the calculated distance is L, and the speed of light is c, the detection is shown in the following equation (2).

[0052]

number

[0053] Using this equation (2) to calculate the distance L (the distance from the object detection sensor 1 to the object S), for example, if the sweep time ΔT = 1024 μSec, the frequency fluctuation range Δf = 180 MHz, and the frequency of the beat signal B (F1-F2) ≒ 176 kHz, then by substituting these into equation (2), the distance is calculated to be L ≒ 150 m. Alternatively, even if the sweep time and frequency fluctuation width are changed to, for example, ΔT = 512 μSec and frequency fluctuation width Δf = 90 MHz, if the frequency of beat signal B is (F1-F2) ≈ 117 kHz, the distance can be calculated as L ≈ 100 m. Also, the frequency fluctuation width Δf, which is related to the resolution described later, may be 200 MHz, 1 GHz, 4 GHz, 7 GHz, etc.

[0054] From the calculation of the distance L based on the beat signal B described above, it is possible to detect the velocity V of the object S (that is, the moving object S') based on the difference in the beat signal B. This will be explained in detail below. In the detailed explanation below, although the calculation of the distance L for each beat signal B is mentioned, in any case, taking into consideration the need to detect an object S (the presence or absence of a moving object S', etc.), it is not actually necessary to perform the Fourier transform formula described later or to calculate the distance L for each beat signal B.

[0055] As described above, when the transmitting unit 2 transmits radio waves W three or more times, if the receiving unit 3 receives the reflected wave H reflected by a moving body S' located within the detection area R three or more times, the reflection position by the moving body S' will shift slightly (the distance L between the object detection sensor 1 and the moving body S' will change slightly), and the faster the speed V of the moving body S', the greater the change in distance L will be, and the slower the speed V of the moving body S', the smaller the change in distance L will be. In other words, it can be said that the speed V of the moving object S' can be detected by observing the magnitude of change in distance L when the transmitting unit 2 transmits radio waves W three or more times. Also, if the detected speed V of an object S is 0 (zero) or less than a predetermined value, conversely, it can be said that the object S is a stationary object S". On the other hand, as described above, for each transmission of radio wave W, a beat signal B corresponding to the reflected wave H reflected by a moving body S', etc. is output from the mixer 4a, and the distance L between the moving body S', etc. and the object detection sensor 1 can be calculated.

[0056] Therefore, by transmitting a single radio wave W and then transmitting the next radio wave W' after an interval time K, beat signals B and B' corresponding to the reflected waves H and H' reflected by a moving body S', etc. are output, and the distances L and L' between a moving body S', etc. and the object detection sensor 1 are calculated, it can be said that the speed V of the moving body S', etc. (in other words, the relative speed V of the moving body S', etc. with respect to the object detection sensor 1) can be calculated by dividing the difference between the distance L and the distance L' by the interval time K, i.e., (L-L') / K. Furthermore, even if there is no interval time K between the transmission of each radio wave W, a single transmission of radio wave W, followed by a predetermined number of transmissions of radio wave W (for example, m times, where m is a natural number) and then a single transmission of radio wave W', will output beat signals B and B' corresponding to the reflected waves H and H' reflected by a moving body S', etc., and when the distances L and L' between a moving body S', etc. and the object detection sensor 1 are calculated, it can also be said that the speed V of the moving body S', etc. can be calculated by dividing the difference between the distance L and the distance L' by m times the sweep time ΔT, i.e., "(L-L') / (m×ΔT)".

[0057] Furthermore, since the reception of the reflected wave H and the output of the beat signal B due to each transmission of radio waves W are performed using the same receiving unit 3 and the same mixer 4a in one object detection sensor 1, each time the transmitting unit 2 transmits a radio wave W and the receiving unit 3 receives a reflected wave H, a beat signal B is output from the mixer 4a (in other words, each time a beat signal B is output, it is overwritten, and it can be said that when a beat signal B has been output for a certain time, the beat signal B from before that time no longer remains in the receiving unit 3 or mixer 4a). Therefore, each time beat signal B is output from mixer 4a, it may be converted into digital data by an A / D converter in detector 4, and a predetermined number of such digital data may be stored in a storage device in detector 4.

[0058] <Beat differential signal ΔB> In this way, by storing a predetermined number of beat signals B, the detection unit 4 can obtain a differential signal ΔB (so-called a "beat differential signal ΔB") by subtracting the beat signal B' corresponding to the reflected wave H' resulting from a subsequent (such as the next) transmission of radio wave W' (so-called "beat signal B corresponding to the reflected wave H resulting from the (n+Z1)th transmission after the nth transmission") from the beat signal B corresponding to the reflected wave H resulting from a single transmission of radio wave W (so-called "beat signal B corresponding to the reflected wave H resulting from the nth transmission"). Similarly, the detection unit 4 can also obtain a beat difference signal ΔB by subtracting the beat signal B' corresponding to the reflected wave H' due to one transmission of radio wave W' after the (n+Z1)th transmission (in other words, the "beat signal B corresponding to the reflected wave H due to the (n+Z2)th transmission after the (n+Z1)th transmission") from the beat signal B corresponding to the reflected wave H due to the nth transmission.

[0059] By repeating this process, the detection unit 4 can obtain a beat difference signal ΔB by subtracting the beat signal B' corresponding to the reflected wave H' due to one transmission of radio wave W' after the n+Z2nd transmission from the beat signal B corresponding to the reflected wave H due to the nth transmission ("beat signal B corresponding to the reflected wave H due to the n+Z3rd transmission after the n+Z2nd transmission"), or can obtain a beat difference signal ΔB by subtracting the beat signal B corresponding to the reflected wave H due to the n+Z4th transmission after the n+Z3rd transmission from the beat signal B corresponding to the reflected wave H due to the nth transmission, or a beat difference signal ΔB... by subtracting the beat signal B corresponding to the reflected wave H due to the n+Z5th transmission after the n+Z4th transmission from the beat signal B corresponding to the reflected wave H due to the nth transmission. In the present invention, "Z3 is a natural number greater than Z2, Z4 is a natural number greater than Z4, and Z5 is a natural number greater than Z4, . . . ".

[0060] Here, the beat difference signal ΔB, which is the difference between a certain (n-th) beat signal B and a subsequent (n+Z1) beat signal B′, is calculated as follows: Beat signal B (analog waveform output from mixer 4a) corresponding to the reflected wave H from the nth transmission is A / D converted and then stored in a storage device as digital data. When beat signal B (which is an analog waveform) corresponding to the reflected wave H from the n+Z1th transmission is A / D converted, subtraction is performed between the amplitudes of beat signal B corresponding to the reflected wave H from the n+Z1th transmission and beat signal B corresponding to the reflected wave H from the nth transmission at the same time from the start of the sweep (subtraction process between digital data), and a beat differential signal ΔB is obtained. As the beat difference signal ΔB, the difference between the waveforms of the I channel and the difference between the waveforms of the Q channel may be obtained.

[0061] Similarly, the difference between the beat signal B corresponding to the reflected wave H from the nth transmission and the beat signal B corresponding to the reflected wave H from the n+Z2th transmission and subsequent transmissions after n+Z1 is calculated by subtracting the amplitudes of the beat signal B corresponding to the reflected wave H from the n+Z2th transmission, etc., at the same time from the start of the sweep, from the beat signal B corresponding to the reflected wave H from the n+Z2th transmission, etc., when the beat signal B (which is an analog waveform) corresponding to the reflected wave H from the n+Z2th transmission, etc., is A / D converted, to obtain a beat difference signal ΔB. Additionally, in the above description, each time the beat signal B (which is an analog waveform) corresponding to the reflected wave H from the (n+Z1)th transmission or later is A / D converted, subtraction is performed between the beat signals B. However, the beat signals B corresponding to the reflected wave H from the (n+Z1)th transmission or later may also be A / D converted and then stored in a storage device. If stored in this manner, a beat difference signal ΔB between the beat signals B corresponding to the reflected wave H from any number of transmissions can also be obtained, such as the difference between the beat signal B corresponding to the reflected wave H from the (n+Z1)th transmission and the beat signal B corresponding to the reflected wave H from the (n+Z2)th transmission.

[0062] As described above, each of the multiple beat difference signals ΔB obtained in this manner is the difference between a certain beat signal B and a subsequent beat signal B'. Considering that there is only a very short time difference (e.g., m times the interval time K or the sweep time ΔT) between the certain beat signal B and the subsequent beat signal B', it can be said that the certain beat signal B and the subsequent beat signal B' may have almost the same waveform (sine wave signal). Explaining this in detail with reference to FIG. 3(d) etc., it can be said that the one beat signal B and the subsequent one beat signal B' are radio waves W and W' transmitted from the same transmitting unit 2 with the same sweep time ΔT and the same frequency fluctuation width Δf (because the transmission of the radio waves W and W' is a short time such as interval time K), and are reflected by the same moving body S' etc., to become reflected waves H and H'.

[0063] The beat signals B and B' corresponding to the reflected waves H and H' reflected from the same moving object S', etc. are sine wave signals, and it can be said that their amplitudes and periods T are almost the same. It can also be said that the only difference between beat signals B and B' is their phase. In this way, when taking the difference between two beat signals B and B' which have almost the same amplitude and period T but differ only in phase, the resulting beat difference signal ΔB can be said to only reflect the phase difference. In addition, the beat difference signal ΔB which only reflects the phase difference can be said to be a so-called "phase difference signal."

[0064] Here, depending on the value of the speed V of the moving body S' (for example, when the speed V (m / Sec) is approximately the same as the wavelength λ of the radio wave W divided by the period T of the radio wave W, i.e., λ / T (m / Sec)), beat signals B and B' will be sinusoidal signals with approximately the same amplitude and period T but with a phase difference of one period T, and it can be said that beat signals B and B' are almost the same signals as sinusoidal signals. In other words, as shown in FIG. 3(d), the beat difference signal ΔB between a certain beat signal B and a subsequent beat signal B', which are almost similar, may be a signal of almost 0 (zero) (a signal with almost 0 amplitude) or a signal with a very low level (amplitude or energy peak), and the D / U ratio may also be low.

[0065] <Beat difference sum signal ΔB + > Therefore, among these multiple beat difference signals ΔB, at least two beat difference signals ΔB are added together to form a beat difference sum signal ΔB + is calculated as follows: As shown in FIG. 3(a), the amplitudes of the beat signal B corresponding to the reflected wave H from at least the nth transmission and the beat signal B corresponding to the reflected wave H from the n+Z1th transmission (which is digital data) are added together at the same time from the start of the sweep (addition processing of digital data), and the beat difference signal ΔB is generated. + is required.

[0066] In addition, the beat difference sum signal ΔB + Alternatively, the difference between the waveforms of the I channel and the difference between the waveforms of the Q channel may be calculated by adding at least two of them together. Furthermore, when beat signal B corresponding to reflected wave H from the (n+Z)th transmission is A / D converted, the digital data of beat signal B corresponding to reflected wave H from the previous nth transmission and beat signal B corresponding to reflected wave H from the (n+Z)th transmission will be stored in the storage device.

[0067] Here, this beat difference sum signal ΔB + Since each of the difference signals ΔB, which reflect only the phase difference, is added, the beat difference sum signal ΔB + The method for obtaining this can be called the "phase difference sum method." Beat difference sum signal ΔB using the "phase difference sum method" + By calculating (a), it can be said that even if one of the two beat difference signals ΔB and ΔB' is a signal that is almost 0 (zero), both of the two beat difference signals ΔB and ΔB' will not be signals that are almost 0 (zero) at the same time (see Figure 3(a) etc.).

[0068] The above-mentioned FIG. 3(a) can also be said to be the case where n=1, Z1=2, and Z2=3 (1, 2, and 3 are selected as the values ​​of n, Z1, and Z2, respectively), and the values ​​of n, Z1, and Z2 in this case can also be expressed as (n, Z1, Z2)=(1, 2, 3). In this case, the difference between n and Z1 is (Z1-n)=1 and the difference between Z1 and Z2 is (Z2-Z1)=1. Other cases where (Z1-n)=1 and (Z2-Z1)=1 include, for example, (n, Z1, Z2)=(2, 3, 4), (3, 4, 5), (4, 5, 6), etc. In addition, (Z1-n) = 2 and (Z2-Z1) = 2 are also acceptable; for example, it can be said that there are (n, Z1, Z2) = (1, 3, 5), (2, 4, 6), (3, 5, 7), etc.; (Z1-n) = 3, 4, 5... and (Z2-Z1) = 3 or 4, 5...; or (Z1-n) = 1 and (Z2-Z1) = 2, or (Z1-n) = 2 and (Z2-Z1) = 1, (Z1-n) = 2 and (Z2-Z1) = 3, (Z1-n) = 3 and (Z2-Z1) = 2..., etc. are also acceptable.

[0069] Also, as shown in FIG. 3(b), the number of beat difference signals ΔB to be added may be increased to three or more. In this case, in addition to the beat difference signal ΔB (which is digital data) between the beat signal B corresponding to the reflected wave H due to the n-th transmission and the beat signal B corresponding to the reflected wave H due to the n+Z1st transmission described above, and the beat difference signal ΔB (which is digital data) between the beat signal B corresponding to the reflected wave H due to the n-th transmission and the beat signal B corresponding to the reflected wave H due to the n+Z2nd transmission, the beat difference signal ΔB (which is digital data) between the beat signal B corresponding to the reflected wave H due to the n-th transmission and the beat signal B corresponding to the reflected wave H due to the n+Z3rd transmission, etc., are also added together, and the amplitudes at the same time from the start of the sweep are added together to generate a beat difference sum signal ΔB in which the number of beat difference signals ΔB to be added is increased to three or more. + is required. In this way, by increasing the number of beat difference signals ΔB to be added to three, it is possible to increase the possibility that all of the three beat difference signals ΔB will not simultaneously become approximately 0 (zero) signals. Furthermore, by increasing the number of beat difference signals ΔB to be added to four or more, it is possible to further increase the possibility that all of the beat difference signals ΔB will not simultaneously become approximately 0 (zero) signals. When the beat signal B corresponding to the reflected wave H from the (n+Z)th transmission is A / D converted, the digital data of the beat signal B corresponding to the reflected wave H from the previous (n)th transmission, the beat signal B corresponding to the reflected wave H from the (n+Z)th transmission, and the beat signal B corresponding to the reflected wave H from the (n+Z)th transmission are stored in the storage device. This is the same even when the number of added beat difference signals ΔB is four or more (for example, When beat signal B corresponding to reflected wave H due to the (n+Z)th transmission is A / D converted, the digital data of each of beat signals B corresponding to reflected wave H due to the previous (n)th to (n+Z)th transmissions will have been stored in the storage device.

[0070] The above Figure 3(b) can also be said to be the case where n = 1, Z1 = 2, Z2 = 3, and Z3 = 4 (where 1, 2, 3, and 4 are selected as the values of n, Z1, Z2, and Z3 respectively). In this case, the values of n, Z1, Z2, and Z3 can also be expressed as (n, Z1, Z2, Z3) = (1, 2, 3, 4). In this case, the difference between n and Z1 is (Z1 - n) = 1, the difference between Z1 and Z2 is (Z2 - Z1) = 1, and the difference between Z2 and Z3 is also (Z3 - Z2) = 1. In addition, other cases where (Z1 - n) = 1 and (Z2 - Z1) = 1 and (Z3 - Z2) = 1 include, for example, (n, Z1, Z2, Z3) = (2, 3, 4, 5), (3, 4, 5, 6), (4, 5, 6, 7), and so on.

[0071] In addition, (Z1 - n) = 2 and (Z2 - Z1) = 2 and (Z3 - Z2) = 2 may also hold. For example, it can be said that there are cases such as (n, Z1, Z2, Z3) = (1, 3, 5, 7), (2, 4, 6, 8), (3, 5, 7, 9), and so on. (Z1 - n) = 3, 4, 5,... and (Z2 - Z1) = 3, 4, 5,... and (Z3 - Z2) = 3, 4, 5,... may also occur, or (Z1 - n) = 1 and (Z2 - Z1) = 1 and (Z3 - Z2) = 2, or (Z1 - n) = 1 and (Z2 - Z1) = 2 and (Z3 - Z2) = 1, (Z1 - n) = 2 and (Z2 - Z1) = 1 and (Z3 - Z2) = 1, (Z1 - n) = 1 and (Z2 - Z1) = 2 and (Z3 - Z2) = 2, (Z1 - n) = 1 and (Z2 - Z1) = 2 and (Z3 - Z2) = 2, or (Z1 - n) = 2 and (Z2 - Z1) = 2 and (Z3 - Z2) = 3, (Z1 - n) = 2 and (Z2 - Z1) = 3 and (Z3 - Z2) = 2, (Z1 - n) = 3 and (Z2 - Z1) = 2 and (Z3 - Z2) = 2, and so on. Furthermore, for (n, Z1, Z2, Z3, Z4), (n, Z1, Z2, Z3, Z4, Z5), and so on, the same applies. As long as n, Z1, Z2, Z3, Z4, Z5,... are all natural numbers and the magnitude relationship is n < Z1 < Z2 < Z3 < Z4 < Z5 <..., any values can be selected.

[0072] Furthermore, as shown in FIG. 3(c), when N is a natural number and j is a natural number from 1 to N, the difference sum signal ΔB j + After each detection of the object S based on the transformed spectrum is completed, the value of j may be incremented by 1, and the detection of the object S may be sequentially repeated. In this case, when j=1, the reflected wave H 1 Beat signal B corresponding to 1 and the reflected wave H from the second transmission 1 Beat signal B corresponding to 1 Beat difference signal ΔB 1 and the reflected wave H from the first transmission 1 Beat signal B corresponding to 1 and the reflected wave H from the third transmission 1 Beat signal B corresponding to 1 Beat difference signal ΔB 1 The beat difference sum signal ΔB 1 + When j=2, the reflected wave H 2 Beat signal B corresponding to 2 and the reflected wave H from the third transmission 2 Beat signal B corresponding to 2 Beat difference signal ΔB 2 and the reflected wave H from the second transmission 2 Beat signal B corresponding to 2 and the reflected wave H from the fourth transmission 2 Beat signal B corresponding to 2 Beat difference signal ΔB 2 The beat difference sum signal ΔB 2 + When j=3, the reflected wave H 3 Beat signal B corresponding to 3 and the reflected wave H from the fourth transmission 3 Beat signal B corresponding to 3 Beat difference signal ΔB 3 And the reflected wave H from the third transmission 3 Beat signal B corresponding to 3 and the reflected wave H from the fifth transmission 3 Beat signal B corresponding to 3Beat difference signal ΔB 3 The beat difference sum signal ΔB 3 + When j=4, the reflected wave H 4 Beat signal B corresponding to 4 and the reflected wave H from the fifth transmission 4 Beat signal B corresponding to 4 Beat difference signal ΔB 4 And the reflected wave H from the fourth transmission 4 Beat signal B corresponding to 4 and the reflected wave H from the sixth transmission 4 Beat signal B corresponding to 4 Beat difference signal ΔB 4 The beat difference sum signal ΔB 4 + Similarly, when j=5, 6, 7, etc., the beat difference sum signal ΔB j + Request. When detecting an object S at any of these values ​​of j, even if the object S is a person or the like of a moving object S' standing in front of a stationary object S" such as a wall, the possibility of capturing minute movements of the object S (especially the moving object S') increases, which can be said to reduce missed detections of the moving object S', thereby achieving further "improvements in detection resolution" and increasing the D / U ratio of the moving object S' that is the object of detection.

[0073] In the above-mentioned FIG. 3(c), when j=1, Z1 1 = 2, and Z2 1 = 3 (j and Z1 1 and Z2 1 In this case, j, Z1 1 , Z2 1 Each value of (j,Z1 1 ,Z2 1 )=(1,2,3), in which case j and Z1 1 The difference between (Z1 1 -1)=1, and Z1 1 and Z2 1 The difference is (Z2 1 -Z1 1 )=1, and in summary, (Z1 1-1) = 1, 2, 3... and (and) / or (Z2 1 -Z1 1 ) = 1, 2, 3, etc., for example, in addition to the above, (1, Z1 1 ,Z2 1 )=(1,2,4), (1,3,4), (1,3,5), (1,3,6), (1,4,6), (1,4,7), etc. Similarly, when j=2, (Z1 2 -2) = 1, 2, 3... and / or (Z2 2 -Z1 2 ) = 1, 2, 3, etc. For example, (2,Z1 2 ,Z2 2 )=(2,3,4), (2,3,5), (2,4,5), (2,4,6), (2,4,7), (2,5,7), etc., and when j=3, (Z1 3 -3) = 1, 2, 3... and (and) / or (Z2 3 -Z1 3 ) = 1, 2, 3... For example, (3,Z1 3 ,Z2 3 )=(3,4,5), (3,4,6), (3,5,6), (3,5,7), (3,5,8), (3,6,8), etc., and when j=4, (Z1 4 -4) = 1, 2, 3... and (and) / or (Z2 4 -Z1 4 ) = 1, 2, 3, etc. For example, (4,Z1 4 ,Z2 4 )=(4,5,6), (4,5,7), (4,6,7), (4,6,8), (4,6,9), (4,7,9)...etc., and when j=5, (Z1 5 -5) = 1, 2, 3... and (and) / or (Z2 5 -Z1 5 ) = 1, 2, 3, etc. For example, (5, Z1 5 ,Z2 5 )=(5,6,7), (5,6,8), (5,7,8), (5,7,9), (5,7,10), (5,8,10) etc. are also acceptable.

[0074] Furthermore, in FIG. 3(c), when j=1, (1,Z1 1 ,Z2 1 ,Z3 1 ,Z4 1 ) or (1,Z1 1 ,Z2 1 ,Z3 1 ,Z4 1 ,Z5 1 )···, similarly, Z1 1 , Z2 1 ,Z3 1 , Z4 1 , Z5 1 Each is a natural number, and the relationship between them is 1. <Z1 1 <Z2 1 <Z3 1 <Z4 1 <Z5 1 <..., any value may be selected. Similarly, when j=2, Z1 2 , Z2 2 ,Z3 2 , Z4 2 , Z5 2 Each is a natural number, and the relationship between them is 2. <Z1 2 <Z2 2 <Z3 2 <Z4 2 <Z5 2 <..., any value may be selected, and when j=3, Z1 3 , Z2 3 ,Z3 3 , Z4 3 , Z5 3 Each is a natural number, and the relationship between them is 3. <Z1 3 <Z2 3 <Z3 3 <Z4 3 <Z5 3 <..., any value may be selected, and when j=4, Z1 4 , Z2 4 ,Z3 4 , Z4 4 , Z5 4 Each is a natural number, and the relationship between them is 4. <Z1 4<Z2 4 <Z3 4 <Z4 4 <Z5 4 <..., any value may be selected, and when j=5, Z1 5 , Z2 5 ,Z3 5 , Z4 5 , Z5 5 Each is a natural number, and the relationship between them is 5. <Z1 5 <Z2 5 <Z3 5 <Z4 5 <Z5 5 <..., any value may be chosen, and similarly for subsequent values ​​of j. Also, for each value of j, (j,Z1 j ,Z2 j ,Z3 j ,Z4 j ,Z5 j The difference between the values ​​of (1,Z1 1 ,Z2 1 ,Z3 1 ,Z4 1 ,Z5 1 )=(1,2,3,4,5,6 ) and (Z1 1 -1)=(Z2 1 -Z1 1 )=(Z3 1 -Z2 1 )=(Z4 1 -Z3 1 )=(Z5 1 -Z4 1 ) = 1, so the difference between each value was 1, but when j = 2, (2,Z1 1 ,Z2 1 ,Z3 1 ,Z4 1 ,Z5 1 )=(2,4,6,8,10,12 ) and (Z1 1 -1)=(Z2 1 -Z1 1 )=(Z3 1 -Z2 1 )=(Z4 1 -Z3 1 )=(Z5 1 -Z41 ) = 2, where the difference between the values ​​is 2.

[0075] <Difference sum spectrum> Here, the actual beat difference sum signal ΔB + Since is a waveform with various frequency components, it is necessary to find the value of the frequency that is most prevalent among those frequency components. Therefore, in general, the beat difference sum signal ΔB is obtained by applying the Fourier transform formula shown in the following equation (3). + A spectrum of frequencies at (so to speak, a difference sum spectrum) is obtained, and frequency components showing amplitude or energy peaks in the difference sum spectrum are obtained.

[0076]

number

[0077] The actual transformation according to equation (3) may be performed by a fast Fourier transform (FFT), which is an algorithm for performing a discretized Fourier transform at high speed. Up to this point, first, the beat signals B and B are generated based on the digital data stored in the storage device. j The waveforms are subtracted to obtain the beat difference signals ΔB and ΔB j and calculate the difference signals ΔB and ΔB j The beat difference sum signal ΔB + , ΔB j + Finally, the Fourier transform is performed on each of the beat difference signals ΔB to obtain each spectrum (so to speak, a difference spectrum) (each of these difference spectra may also be stored in a storage device), and the waveform graphs of each difference spectrum after the Fourier transform are added together to obtain the beat difference sum signal ΔB + , ΔB j + Alternatively, the difference sum spectrum may be calculated. In addition, based on the digital data stored in the memory device, each beat signal B, B j Each of the distance spectra is Fourier-transformed to obtain each spectrum (so to speak, distance spectrum). (Each of these distance spectra may also be stored in a storage device.) Then, the waveform graphs of the distance spectra after the Fourier transform are subjected to subtraction processing to obtain beat difference signals ΔB, ΔB j The difference spectrum of each of the difference spectra is calculated (each of these difference spectra may be stored in a storage device), and finally, the waveform graphs of each difference spectrum are added to obtain a beat difference sum signal ΔB + , ΔB j + Alternatively, the difference sum spectrum may be calculated.

[0078] <Processing to determine the presence or absence of object S (moving object S')> In this way, the detection unit 4 may perform any type of determination processing as long as it can detect an object S (particularly a moving body S') within the detection area R using the difference sum spectrum obtained by performing the Fourier transform, and may, for example, perform the processing as shown in Figures 3(a) and (b) described above only once to determine only the presence or absence of a moving body S' (see Figure 10(a)), or may perform the processing as shown in Figures 3(a), (b), and (c) described above at regular intervals (for example, 1 sec, 3 sec, etc.) to determine only the presence or absence of a moving body S' at regular intervals (see Figures 10(b) and (c)). Alternatively, the detection unit 4 may perform the process shown in Fig. 3(c) continuously and sequentially, rather than at fixed time intervals, to constantly determine the presence or absence of a moving object S' (see Fig. 10(c)). As will be described later, if the detection unit 4 determines that a moving object S'U is present as a result of the determination of the presence or absence of the moving object S', it may output a moving object detection signal Y to the outside (e.g., the user).

[0079] These processes make it possible to make the most necessary determination as to whether or not a moving object S' is present within the detection area R, and since there is no need to calculate the speed V of the moving object S' or the distance L between the moving object S' and the object detection sensor 1 each time, it can be said that this reduces the processing burden and improves the processing speed. Here, the detection unit 4 may detect the object S within the detection region R by determining whether the amplitude or energy in the frequency component indicating the peak in the differential sum spectrum or the like exceeds a predetermined threshold value to determine the presence or absence of the moving object S'.

[0080] On the other hand, the detection unit 4 may not only determine the presence or absence of the moving object S', but also detect the speed V, distance L, approach / departure of the moving object S', etc. In addition, the detection unit 4 may also detect the presence or absence of the stationary object S'' within the detection region R and the distance L between the stationary object S'' and the object detection sensor 1 based on the digital data of each beat signal B, B j stored in the storage device. In this way, the detection unit 4 may detect only the presence or absence of the moving object S' within the detection region R, but may also detect the object S including not only the presence or absence of the moving object S' but also the speed V etc. of the moving object S' and other stationary objects S''. Also, when the detection unit 4 determines that there is a moving object S' within the detection region R, it may be configured to output to the outside (such as the user) that there is a moving object S'. In addition, the detection unit 4 may also be configured to output to the outside the detected speed V, distance L, approach / departure of the moving object S', etc.

[0081] <Selection of Z1, Z2, Z3 ··· etc. and speed V of moving object S'> The selection of Z1, Z2, Z3 ··· etc. in FIGS. 3(a), (b) etc. described above and Z1 in FIG. 3(c) described above j , Z2 j , Z3 j ··· etc. may be selected according to the speed V of the moving object S' to be detected (or to be detected) within the detection region R. Therefore, the speed V of the moving object S' to be detected will be explained in detail below.

[0082] <Speed V etc. of moving object S'> If the moving object S' is a person (an intruder, a pedestrian, etc.), when a person starts moving from a stationary position, the speed per second can be said to be greater than 0 m / Sec, while the walking speed per second can be said to be approximately 1 m / Sec, and the fastest speed a person can run (the fastest running speed) can be said to be approximately 12 m / Sec, so it can be said that the person's speed V should be greater than 0 m / Sec (or 1 m / Sec or more) and 13 m / Sec or less. Also, if the moving object S' to be detected is an automobile such as a passenger car or motorcycle, when a stopped automobile starts to move, the speed in terms of speed per second can be said to be greater than 0 m / sec., whereas if the automobile is moving slowly, the speed can naturally be said to be 1 m / sec., and since the legal maximum speed on general roads is 30 to 60 km / h in terms of speed per hour (approximately 8 to 17 m / sec. in terms of speed per second), and the maximum speed in terms of automobile performance can be said to be approximately 200 km / h or more in terms of speed per hour (approximately 56 m / sec or more), it can also be said that the automobile's speed V in terms of speed per second should be greater than 0 m / sec (or 1 m / sec or more) and 60 m / sec or less.

[0083] Furthermore, in the case where the moving object S' to be detected is a light vehicle such as a bicycle, when a stopped light vehicle starts to move, the speed per second can be said to be greater than 0 m / sec., while if a light vehicle moves slowly, the speed per second can be said to be 1 m / sec., etc., and light vehicles also follow the legal maximum speed on general roads, for example, 30 to 60 km / h (approximately 8 to 17 m / sec.), while the maximum speed of bicycles (keirin) and the like can be said to be approximately 70 km / h or more (approximately 19 m / sec or more) per hour. Therefore, the speed V of a light vehicle, in terms of speed per second, can be said to be greater than 0 m / sec (or 1 m / sec. or more) and 20 m / sec or less. Furthermore, in the case where the moving object S' to be detected is a moped (Type 1 or Type 2), when a stopped moped starts to move, the speed per second can be said to be greater than 0 m / Sec, while if the moped is moving slowly, the speed per second can be said to be 1 m / Sec, etc., and according to the legal maximum speed for mopeds on public roads, the speed is 30 km / h per hour (about 8 m / Sec per second, but Type 2 is 60 km / h (about 17 m / Sec)), and the maximum speed in terms of the performance of a moped can be said to be approximately 80 km / h or more per hour (approximately 22 m / Sec or more). Therefore, it can be said that the speed V of a car, in terms of seconds, should be greater than 0 m / Sec (or 1 m / Sec or more) and 25 m / Sec or less.

[0084] In addition, if the moving object S' to be detected is a car, drone, helicopter, ship, etc. that is remotely controlled by radio, etc., it is possible for these to be stopped (stationary in the air, moored on water), and when a stopped car, drone, etc. starts to move, it can be said that its speed in terms of speed per second is greater than 0 m / sec. However, if it is moved slowly, it can naturally be said that its speed in terms of speed per second is 1 m / sec, etc., and since the maximum speed in terms of the performance of the car, drone, etc. can be said to be approximately 100 km / h or more (approximately 28 m / sec or more) in terms of speed per hour, it can be said that the speed V of the car, drone, etc., in terms of speed per second, should be greater than 0 m / sec (or 1 m / sec or more) and 30 m / sec or less. Furthermore, if the moving object S' to be detected is an airplane remotely controlled by radio or the like, when the airplane, which is stopped on a runway, etc., begins to take off (starts to move on the runway, etc.), it can be said that the speed V of the airplane, in terms of speed per second, is greater than 0 m / Sec. However, since the airplane cannot stop in the air, the minimum flight speed can be said to be approximately 14 km / h or more in terms of speed per hour (approximately 4 m / Sec. in terms of speed per second), and the maximum speed, which is an indication of the airplane's performance, can be said to be approximately 300 km / h or more in terms of speed per hour (approximately 83 m / Sec. or more). Therefore, it can be said that the speed V of the airplane, in terms of speed per second, should be greater than 0 m / Sec (or 1 m / Sec or more) and less than 90 m / Sec.

[0085] As described above, the moving object S' includes raindrops, snowflakes, sleet, hail, sleet, icy rain, and fine ice. However, it can be said that raindrops are not the detection target. Regarding the speed (fall speed) of raindrops, the fall speed of raindrops, etc., depends on the size, etc., but it can be said that it is about 2 m / sec to 10 m / sec per second, and the fall speed of snowflakes, depends on the size, shape, etc., but it can be said that it is about 1 m / sec to 2 m / sec per second, and other falling objects such as sleet (a mixture of raindrops and snowflakes) are not detected. The falling speed of large objects (graupel, hailstones, etc.) can be said to be between about 3 m / sec and about 9 m / sec per second, depending on the size and shape, the falling speed of graupel and hailstones can be said to be between about 5 m / sec and about 30 m / sec per second, depending on the size and shape, the falling speed of icy raindrops can be said to be between about 2 m / sec and about 10 m / sec per second, depending on the size and shape, and the falling speed of fine ice can be said to be between about 1 m / sec and about 2 m / sec per second, depending on the size and shape. Furthermore, the falling speed of raindrops, etc. can be said to be a terminal velocity determined by the gravity acting on the raindrops, etc. and the resistance force of the air. Such raindrops, etc. suddenly enter the detection area R (detection area R having an approximately truncated cone shape whose radius increases the further it is from the transmitting unit 2 or the receiving unit 3) at that terminal velocity, and it can be said that the terminal velocity does not decrease within the detection area R. As described above, the moving object S' also includes dust and other particles that have entered the detection area R due to wind or other factors. However, this dust and other particles can also be said to not be subject to detection. Since the speed at which the dust and other particles move is approximately the same as the wind speed, it can also be said to be greater than 0 m / sec (or 1 m / sec or more) and less than 50 m / sec per second.

[0086] <The speed V of the moving object S' and the minimum distance resolution L min > Since it can be said that the speed V of the moving object S' to be detected is related to the minimum resolution of the object detection sensor 1, the minimum resolution (the minimum distance that can be resolved into two objects S) will also be described. As shown in the above equation (2), the distance L between the object detection sensor 1 and the object S (the moving object S' at a certain moment) is determined by the sweep time ΔT and frequency fluctuation range Δf in the above-mentioned transmission unit 2, and the frequency (F1-F2) of the beat signal B corresponding to the reflected wave H reflected by the moving object S' at a certain moment. The graph waveform of the distance spectrum obtained by Fourier transforming the beat signal B shows the frequency (F1-F2) on the horizontal axis, the sweep time ΔT in μSec, the frequency fluctuation width Δf in MHz, and the speed of light c approximately 3×10 8 Since the frequency is measured in m / Sec, the frequency (F1-F2) value on the horizontal axis of the distance spectrum is in kHz.

[0087] The horizontal axis of each spectrum graph shown in FIG. 5(c), FIG. 7(c), and FIG. 9(c) is the beat difference signal ΔB or the beat difference sum signal ΔB. + It represents the frequency (F1-F2) at and its unit is also kHZ. That is, the beat difference sum signal ΔB + The frequency (F1-F2) in the frequency range can be determined in increments of 1KHz (in other words, the minimum resolution of the frequency (F1-F2) is (F1-F2) min is 1kHz).

[0088] Minimum resolution of this frequency (F1-F2) (F1-F2) min Substituting this into the above equation (2), the minimum distance resolution L min is expressed by the following equation (4). Furthermore, the minimum resolution of frequency (F1-F2) is min is the beat difference sum signal ΔB + Of course, depending on the spectrum, etc., the value may be other than 1 kHz.

[0089]

number

[0090] Using this formula (4), the minimum distance resolution L minFor example, as described above, the sweep time ΔT = 1024 μSec, the frequency fluctuation width Δf = 180 MHz, and the minimum resolution of the frequency (F1-F2) are min If we substitute this value into equation (4), the minimum resolution of the distance is L min This is calculated to be approximately 0.75m. In addition, even if the sweep time and frequency fluctuation width are changed to, for example, ΔT = 512 μSec and frequency fluctuation width Δf = 90 MHz, the minimum resolution of the frequency (F1-F2) min is 1kHz, so the minimum distance resolution is L min This is calculated to be approximately 0.75m.

[0091] < Minimum velocity resolution V min and selection of Z1, Z2, Z3, etc. First, the minimum resolution of this distance L min From the minimum resolution of the velocity, V min Request. An interval time K is inserted between each transmission of radio waves W, and (Z1-n)=(Z2-Z1)=(Z3-Z2)===1 (or (Z1 1 -1)=(Z2 1 -Z1 1 )=(Z3 1 -Z2 1 )==1,...,(Z1 j -j)=(Z2 j -Z1 j )=(Z3 j -Z2 j ) = 1, if the interval time K is sufficiently larger than the sweep time ΔT (K>>ΔT), then the minimum velocity resolution V min is the minimum distance resolution L min divided by the interval time K, "V min =L min It can also be calculated as "K / (1×K)".

[0092] This "V min =L min / (1×K)" to find the minimum velocity resolution V minFor example, as described above, the sweep time ΔT = 1024 μSec, the frequency fluctuation width Δf = 180 MHz, and the minimum resolution of the frequency (F1-F2) are min = 1kHz, interval time K = 10mSec, "V min =L min / (1×K)」, the minimum resolution of the velocity is V min 75 m / sec, which is a very large value calculated based on the speed V of the moving body S' described above. Therefore, the following will discuss the case where the values ​​of Z1, Z2, Z3, etc. are variously changed.

[0093] If an interval time K is inserted between each transmission of radio wave W, and (Z1-n)=(Z2-Z1)=(Z3-Z2)=···=2 (i.e., one transmission is skipped to obtain the beat difference signal ΔB), then if K>>ΔT, then the minimum resolution of the velocity V min is the minimum distance resolution L min Divide by twice the interval time K to get "V min =L min / (2×K)". This "V min =L min / (2×K)" with the same sweep time ΔT = 1024 μSec, frequency fluctuation width Δf = 180 MHz, and minimum resolution of frequency (F1-F2) as above. min = 1kHz, and the interval time K = 10mSec, the minimum velocity resolution V min It is halved to ≒37.5 m / Sec.

[0094] Similarly, if an interval time K is inserted between each transmission of radio wave W, and (Z1-n)=(Z2-Z1)=(Z3-Z2)=···=3, etc. (in other words, the beat difference signal ΔB is obtained by skipping two transmissions between them), then if K>>ΔT, then the minimum resolution of the velocity V min "V min =L min / (3×K)" .... By repeating this, for example, if an interval time K is inserted between each transmission of radio wave W, and (Z1-n) = (Z2-Z1) = (Z3-Z2) =... = 50 (so to speak, 49 transmissions are skipped to find the beat difference signal ΔB), then if K >> ΔT, then the minimum resolution of the velocity V min "V min =L min / (50×K)". So, this "V min =L min / (50×K)" with the same sweep time ΔT = 1024 μSec, frequency fluctuation width Δf = 180 MHz, and minimum resolution of frequency (F1-F2) as above. min = 1kHz, and the interval time K = 10mSec, the minimum velocity resolution V min It can also be said that this value corresponds to a moving object S' whose speed V is 1 m / sec or more, i.e., ≈1.5 m / sec.

[0095] Here, when (Z1-n)=(Z2-Z1)=(Z3-Z2)=...=2, 3...50 or a greater value (in other words, when the beat difference signal ΔB is obtained by skipping 1, 2...49 or more transmissions), at least one (or all) of the analog waveforms of the beat signal B in the skipped transmissions need not be A / D converted or the A / D converted digital data need not be stored in a storage device, but rather the A / D conversion may be performed or the A / D converted digital data may be stored in a storage device every second, every third...50 or more transmissions in which the difference is actually obtained. If we skip even more times, for example, (Z1-n) = (Z2-Z1) = (Z3-Z2) = . . . = 100 (so to speak, 99 transmissions are skipped to obtain the beat difference signal ΔB), then if K >> ΔT, the minimum resolution of the velocity V min "V min =L min / (100×K)" and this "V min =L min / (100×K)" with the same sweep time ΔT = 1024 μSec, frequency fluctuation width Δf = 180 MHz, and minimum resolution of frequency (F1-F2) as above. min = 1kHz, and the interval time K = 10mSec, the minimum velocity resolution V min ≒0.75 m / Sec (less than 1 m / Sec), and it can be said that the start of movement of any moving object S' can be captured.

[0096] Furthermore, if ΔT is 10 mSec, even if (Z1-n) = (Z2-Z1) = (Z3-Z2) = ··· = 100, detection will occur approximately once per sec, and it can be said that there will be no missed detections for a moving object S' that actually moves within the detection area R. In addition, the sweep time ΔT, the frequency fluctuation width Δf, and the minimum resolution of the frequency (F1-F2) min Even if the value of the interval time K is different, the minimum resolution of the velocity V can be obtained by selecting the corresponding value of (Z1-n) = (Z2-Z1) = (Z3-Z2) = . min It can also be said that it is possible to make it even smaller (for example, 0.50 m / Sec or 0.25 m / Sec).

[0097] Therefore, the sweep time ΔT, frequency fluctuation width Δf, and minimum resolution of frequency (F1-F2) min Although the value of the interval time K is not changed at all, the minimum resolution of the velocity V can be changed by changing the values ​​selected for Z1, Z2, Z3, etc. min It can be said that it is possible to appropriately set In other words, Z1, Z2, Z3, etc. can be selected depending on the speed V of the moving object S' to be detected (or to be detected), and the object detection sensor 1 can also be said to be an "object detection sensor with a speed pass filter." Furthermore, with regard to the selection of Z1, Z2, Z3, etc., as described above, Z1, Z2, Z3, etc. may be selected so that the slower the speed V of the moving body S' to be detected, the larger (Z1-n) = (Z2-Z1) = (Z3-Z2) = ··· etc. (or at least one of Z1-n), (Z2-n), and (Z2-Z1) becomes larger), and the faster the speed V of the moving body S' to be detected, the smaller (Z1-n) = (Z2-Z1) = (Z3-Z2) = ··· etc. (or at least one of (Z1-n), (Z2-n), and (Z2-Z1) becomes smaller).

[0098] In addition, if the interval time K is not sufficiently larger than the sweep time ΔT (K>>ΔT), and (Z1-n)=(Z2-Z1)=(Z3-Z2)===2, the minimum velocity resolution V min "V min =L min / {(2×K)+(1×ΔT)}" and similarly, if (Z1-n)=(Z2-Z1)=(Z3-Z2)=...=3, the minimum resolution of the velocity V min "V min =L min / {(3×K)+(2×ΔT)}", if (Z1-n)=(Z2-Z1)=(Z3-Z2)=···=4, the minimum velocity resolution V min "V min =L min / {(4×K)+(3×ΔT)}". In addition, even if there is no interval time K between the transmissions of each radio wave W, if (Z1-n)=(Z2-Z1)=(Z3-Z2)===2, the minimum resolution of the velocity V min "V min =L min / (1×ΔT)” and similarly, if (Z1-n)=(Z2-Z1)=(Z3-Z2)=···=3, the minimum resolution of the velocity V min "V min =L min / (2×ΔT)”, if (Z1-n)=(Z2-Z1)=(Z3-Z2)=···=4, the minimum velocity resolution Vmin "V min =L min / (3×ΔT)” can also be calculated.

[0099] <Lower limit V' and upper limit V” of speed V> The minimum resolution of the speeds mentioned so far is V min Taking into consideration the relationship between the selection of Z1, Z2, Z3, etc., the detection unit 4 may detect only an object S within the detection area R whose speed V is equal to or greater than a predetermined lower limit V' and / or whose speed V is equal to or less than a predetermined upper limit V'', as a moving body S'. First, the lower limit V' is the minimum resolution V min However, since the lower limit V' can be 0.50 m / Sec, 0.25 m / Sec, etc. depending on the selection of Z1, Z2, Z3, etc., the lower limit V' can be 0.50 m / Sec, 0.75 m / Sec, 1.00 m / Sec, etc.

[0100] It can be said that by setting such a lower limit value V', the start of movement of any moving object S' can be captured. On the other hand, with regard to the upper limit value V", among the moving objects S' within the detection area R, raindrops and the like that are not targets for detection have a speed V of approximately 2.0 m / sec or more, and since raindrops and the like suddenly enter the detection area R at terminal velocity, the lower limit value V' may be 3.0 m / sec, 2.5 m / sec, 2.0 m / sec, etc., and the upper limit value V" does not necessarily have to be set. In this way, by setting the lower limit value V' and the upper limit value V'', it is possible to better "distinguish between moving and stationary objects" and "improve detection resolution", and it becomes possible to detect objects S other than the target that may be present within the detection area R, whose speed can be known in advance (for example, the falling speed of raindrops during rainfall), separately from non-targets, which can be said to achieve further "reduction of white noise", etc.

[0101] <Example> As described above, by selecting Z1, Z2, Z3, etc., the speed of the moving object S' is corresponded to, and the beat difference sum signal ΔB is obtained by the "phase difference sum method" as described above. + An embodiment of the object detection sensor 1 for determining the above will be described below. Here, the embodiment of the object detection sensor 1 shown in FIGS. 4 to 9 shows a simulation example for the case of FIG. 3(a) where (Z1-n)=(Z2-Z1)=(Z3-Z2)=1.

[0102] Figures 4 and 5 show the same embodiment in the case where moving object S' is moving at a position away from stationary object S" when moving objects S' and stationary objects S" are mixed within the detection area R [1-1], Figures 6 and 7 show the case where moving object S' is moving at a position close to stationary object S" when moving objects S' and stationary objects S" are mixed within the detection area R [1-2], and Figures 8 and 9 show the case [2] during rainfall. In the graphs shown in Figs. 5(a), 7(a) and 9(a), the horizontal axis represents time t (Sec) and the vertical axis represents the voltage output as beat signal B (more precisely, the IQ-detected I-channel waveform and Q-channel waveform). Similarly, in the graphs shown in Figs. 5(b), 7(b) and 9(b), the horizontal axis represents time t (Sec), but the vertical axis represents the voltage output as beat difference signal ΔB (more precisely, the difference between the IQ-detected I-channel waveform and the Q-channel waveform) (since it is a difference, it can take a negative value). In the graphs shown in Figs. 5(c), 7(c) and 9(c), the horizontal axis represents each beat difference signal ΔB and the beat difference sum signal ΔB. + The vertical axis represents frequency (F1-F2) at the frequency of 100 Hz, and the vertical axis represents power (energy).

[0103] In particular, in the graphs shown in Figures 5(a), 7(a), and 9(a), "A / D(1)" indicates digital data obtained by A / D conversion of beat signal B corresponding to reflected wave H due to the first transmission of radio waves W, and similarly, "A / D(2)" indicates digital data obtained by A / D conversion of beat signal B corresponding to reflected wave H due to the second, third, and fourth transmission of radio waves W, "I1, Q1" indicate the I-channel waveform and Q-channel waveform (digital data) of beat signal B corresponding to reflected wave H due to the first transmission of radio waves W, and similarly, "I2, Q2" indicates the second, "I3, Q3" indicates the third, and "I4, Q4" indicates the I- and Q-channel waveforms of beat signal B corresponding to reflected wave H due to the fourth transmission of radio waves W. In the graphs shown in Figs. 5(b), 7(b), and 9(b), "phase difference (1-2)" indicates the beat difference signal ΔB between the digital data obtained by A / D converting the beat signal B from the first transmission and the digital data obtained by A / D converting the beat signal B from the second transmission. Similarly, "phase difference (2-3)" indicates the beat difference signal ΔB between the second and third transmissions, "phase difference (3-4)" indicates the beat difference signal ΔB between the digital data obtained by A / D converting the beat signal B from the third and fourth transmissions, and "phase difference sum (1-2)+(2-3)+(3-4)" indicates the beat difference sum signal ΔB between the beat difference signal ΔB between the first and second transmissions, the beat difference signal ΔB between the beat difference signal ΔB between the second and third transmissions, and the beat difference signal ΔB between the beat difference signal ΔB between the third and fourth transmissions. + "I1-I2, Q1-Q2" indicate the differential waveform between the first I and Q channels and the second I and Q channels, and similarly, "I2-I3, Q2-Q3" indicate the differential waveform between the second and third, "I3-I4, Q3-Q4" indicate the differential waveform between the third and fourth I and Q channels, and "I, Q" indicates the sum of the differential waveform between the first and second I and Q channels, the differential waveform between the second and third I and Q channels, and the differential waveform between the third and fourth I and Q channels. Furthermore, in the graphs shown in Fig. 5(c), Fig. 7(c), and Fig. 9(c), "phase difference peak (1-2)" indicates the peak of the spectrum obtained by FFT-transforming the beat difference signal ΔB between the first and second beat signals B, and similarly, "phase difference peak (2-3)" indicates the peak of the spectrum obtained by FFT-transforming the beat difference signal ΔB between the second and third beat signals B, "phase difference peak (3-4)" indicates the peak of the spectrum obtained by FFT-transforming the beat difference signal ΔB between the third and fourth beat signals B, and "phase difference sum peak (1-2)+(2-3)+(3-4)" indicates the peak of the spectrum obtained by FFT-transforming the beat difference signal ΔB between the first and second beat signals ΔB, the beat difference signal ΔB between the second and third beat signals ΔB, and the beat difference signal ΔB between the third and fourth beat signals. + The spectrum peaks obtained by FFT transformation are shown. Below, we will explain the cases [1-1], [1-2], and [2] respectively.

[0104] <[1-1] case where moving object S' is moving away from stationary object S"> To explain the case of [1-1] shown in Figures 4 and 5 in detail, the moving object S' is a person, and the stationary object S" is multiple road cones and bars (or fences). Since the person is moving at a position away from the road cones and bars, peaks can be confirmed in the spectra of "phase difference peak (1-2)", "phase difference peak (2-3)", and "phase difference peak (3-4)" which show each beat difference signal ΔB in Figure 5(c), and the sum of these, the beat difference sum signal ΔB + In the spectrum of the "phase difference sum peak (1-2)+(2-3)+(3-4)" which shows This higher peak (i.e., the beat difference sum signal ΔB + ), the detection unit 4 can more accurately determine whether the energy in the frequency component showing the peak has exceeded a predetermined threshold, and it can be said that the accuracy of the detection unit 4 in detecting the speed V and distance L of the moving object S', and the approach / departure of the moving object S', etc. is improved. Incidentally, the white thing seen behind the road cone and the bar in Fig. 4 can be said to be sunlight reflected off a glass building.

[0105] <[1-2] Case where a moving object S' is moving close to a stationary object S"> In the case of [1-2] shown in Figures 6 and 7, the moving object S' is a person and the stationary object S" is multiple road cones and bars. Unlike the case of [1-1] described above, the person is moving in close proximity to the road cones and bars. Therefore, although the presence or absence of peaks can be confirmed in the spectra of "phase difference peak (1-2)," "phase difference peak (2-3)," and "phase difference peak (3-4)" which indicate each beat difference signal ΔB in Figure 7(c), the height of these peaks is not sufficient. This is because, as described above, multiple objects S, namely, a moving object S' (a person) and a stationary object S" (a road cone and a bar), are close to each other within the detection area R of the object detection sensor 1. Therefore, in the spectrum representing each beat difference signal ΔB, peaks with small energy levels are masked by large peaks. As a result, it is not possible to separate a person moving near the road cone and the bar using only the spectrum of the beat difference signal ΔB, and it can be said that it becomes difficult to detect a moving object S' moving in a position close to the stationary object S". However, the beat difference sum signal ΔB in Fig. 7(c) + In the spectrum of the “phase difference sum peak (1-2)+(2-3)+(3-4)” which indicates the phase difference signal ΔB, a higher peak is observed when the lower peaks of the “phase difference peak (1-2),” “phase difference peak (2-3),” and “phase difference peak (3-4)” which indicate the beat difference signal ΔB are added together. This higher peak (i.e., the beat difference sum signal ΔB + ), the detection unit 4 can more accurately determine whether or not the energy in the frequency component indicating a peak has exceeded a predetermined threshold even if the spectrum of each beat difference signal ΔB does not have a sufficient peak height. In other words, even in the case where a moving object S' is moving in a position close to a stationary object S" [1-2], in which a small peak in the energy level is masked by a large peak in the beat difference signal ΔB alone, it is easier to capture minute movements of the moving object S' to be detected by increasing the D / U ratio of the moving object S' that is the detection target (desired to be detected). In the case of [1-2], the accuracy of the detection unit 4 in detecting the speed V, distance L, and approach / departure of the moving object S' is also improved. In addition, the white thing seen behind the road cone and the bar in Figure 6 can also be said to be sunlight reflected off a glass building.

[0106] <In the case of [2] during rainfall> In the case of [2] shown in Figures 8 and 9, the stationary objects S" are multiple road cones, etc., and the raindrops are moving objects S', but there are no moving objects S' (people, etc.) to be detected. In this case, no peaks can be clearly confirmed in the spectra of "phase difference peak (1-2)", "phase difference peak (2-3)", and "phase difference peak (3-4)" which show each beat difference signal ΔB in Figure 9(c). + In the spectrum of the "phase difference sum peak (1-2) + (2-3) + (3-4)" which shows the above, even though each beat difference signal ΔB is added, no high peak appears (because each raindrop is small and the energy of the reflected wave H by that small raindrop is small, etc.). In other words, although raindrops that are not the detection target exist as moving objects S' within the detection area R, the beat difference sum signal ΔB + Since no high peaks are observed in the frequency components corresponding to raindrops that are not the detection target, the energy of the frequency components corresponding to the peaks is unlikely to exceed a predetermined threshold value, and the beat difference sum signal ΔB obtained by adding up each beat difference signal ΔB is generated. + It can also be said that the occurrence of false positives can be reduced by using Also, as shown by the spectrum of the phase difference sum peak (1-2)+(2-3)+(3-4) in FIG. 9(c), even in a rainy situation, if there is a moving object S' other than the raindrops, the beat difference sum signal ΔB obtained by adding each beat difference signal ΔB will be generated as in the above-mentioned cases [1-1] and [1-2]. + By using this, a higher peak is produced, which means that white noise can be reduced, and it can be said that the D / U ratio of the mobile unit S' can be increased ("reducing white noise", etc.). As a result, it can be said that even during rainfall, the detection unit 4 has no trouble detecting the speed V and distance L of the moving object S', as well as the approach and separation of the moving object S'. Next, the object detection method used in the object detection sensor 1 will be described first, and then the object detection program will be described.

[0107] <Object detection method> 10(a) to (c) show a flowchart of an object detection method according to the present invention. The object detection method is a method using the object detection sensor 1 that detects an object S within the detection area R described above.

[0108] The object detection method may be such that the above-mentioned detection unit 4 detects only the object S within the detection area R whose speed V is greater than 0 as the moving object S'. In this case, the object detection method may cause the detection unit 4 described above to detect as moving bodies S' only those objects S within the detection area R whose speed V is equal to or greater than a predetermined lower limit V' and / or whose speed V is equal to or less than a predetermined upper limit V".

[0109] In addition, as shown in FIG. 3(a) and (b), the object detection method includes, in the detection unit 4, generating a beat difference sum signal ΔB obtained by adding at least a beat signal B corresponding to a reflected wave H due to an n-th transmission among three or more transmissions of radio waves W by the transmission unit 2 described above, a beat difference signal ΔB between a beat signal B corresponding to a reflected wave H due to an n+Z1-th transmission after the n-th transmission, and a beat difference signal ΔB between a beat signal B corresponding to a reflected wave H due to an n+Z2-th transmission after the n+Z1-th transmission. + The object S may be detected based on the transformed spectrum. In this case, also in the object detection method according to the present invention, "n is a natural number, Z1 is a natural number greater than n, and Z2 is a natural number greater than Z1."

[0110] As shown in FIG. 3(c), the object detection method includes transmitting, to the detection unit 4, a reflected wave H from the j-th transmission of the radio wave W from the transmission unit 2 described above, which is one of three or more transmissions of the radio wave W. j Beat signal B corresponding to j and j+Z1 after the jth iteration j Reflected wave H from the th transmission j Beat signal B corresponding to j Beat difference signal ΔB j and the reflected wave H j Beat signal B corresponding to j and j+Z1 j j+Z2 after the first j Reflected wave H from the th transmission j Beat signal B corresponding to j Beat difference signal ΔB j The beat difference sum signal ΔB j + Based on the spectrum obtained by converting the above, the object S is detected, and the beat difference sum signal ΔB j + After each detection of the object S based on the transformed spectrum is completed, the value of j may be incremented by 1 and the detection of the object S may be repeated. In this case, in the object detection method according to the present invention, "N is a natural number, j is a natural number from 1 to N, and Z1 j is a natural number greater than N, and Z2 j is Z1 j It is a larger natural number."

[0111] Furthermore, the object detection method may select Z1, Z2, Z3, etc. according to the speed V of the moving body S' to be detected before the above-mentioned detection unit 4 detects the object S, or the above-mentioned detection unit 4 may be made to select Z1, Z2, Z3, etc. according to the speed V of the moving body S' to be detected. Each of the object detection methods shown in FIGS. 10(a) to (c) will be described in detail below.

[0112] In the case of the object detection method shown in the flowchart of Figure 10(a), the above-mentioned detection unit 4 performs the processing as shown in Figures 3(a) and (b) only once to determine only the presence or absence of a moving object S', and has the following steps. In the object detection method of FIG. 10(a), after starting the process of detecting an object S (moving object S') (step S0), the detection unit 4 outputs a transmission control signal (sweep control signal) X to the transmission unit 2 (step S1), and then determines whether or not a moving object S' is present (step S2). If it is determined that a moving object S'U is present, a moving object detection signal Y is output to the outside (user, etc.) (step S3), and the process ends (step S4). If it is determined that a moving object S'U is not present, the process ends (step S4) without going through step S3. 10(a), the object detection method does not need to include the above-mentioned step 3, and other information such as the speed V and distance L of the detected moving body S', and the approach / departure of the moving body S' may be output to the outside. Also, in the object detection method of Fig. 10(a), in one step 1, the detection unit 4 may output the transmission control signal X to the transmission unit 2 three or more times, and the transmission unit 2 may transmit the radio wave W three or more times.

[0113] In the case of the object detection method shown in the flowchart of Figure 10(b), the above-mentioned detection unit 4 performs the processing as shown in Figures 3(a) and (b) at regular intervals to determine only the presence or absence of a moving object S' at regular intervals, and has the following steps. In the object detection method of FIG. 10(b), similarly, the process of detecting an object S (moving object S') begins (step S0), and then the detection unit 4 outputs a transmission control signal (sweep control signal) X to the transmission unit 2 (step S1). Next, the presence or absence of a moving object S' is determined (step S2). If it is determined that a moving object S'U is present, a moving object detection signal Y is output to the outside (user, etc.) (step S3). However, what follows differs from FIG. 10(a) in that after a certain time T, the process returns to step S1 of outputting the transmission control signal X, and if it is determined that no moving object S'U is present, the process returns to step S1 of outputting the transmission control signal X after a certain time T without going through step S3. 10(b) does not necessarily have to include step 3, and the detection unit 4 may output to the outside the detected speed V and distance L of the moving body S', the approach and separation of the moving body S', etc. Also, in the object detection method of Fig. 10(b), the detection unit 4 may output the transmission control signal X to the transmission unit 2 three or more times in one step 1, and the transmission unit 2 may transmit the radio wave W three or more times.

[0114] In the case of the object detection method shown in the flowchart of FIG. 10(c), the reflected wave H j Beat signal B corresponding to j and the beat difference signal ΔB j and the beat difference sum signal ΔB j + This method detects an object S based on a spectrum obtained by converting j, and after each detection is completed, increments the value of j by 1 and repeats the detection of the object S. This method has the following steps: In the object detection method of FIG. 10(c), similarly, the process of detecting an object S (moving object S') begins (step S0), and then the detection unit 4 outputs a transmission control signal (sweep control signal) X to the transmission unit 2 (step S1). Next, the presence or absence of a moving object S' is determined (step S2). If it is determined that a moving object S'U is present, a moving object detection signal Y is output to the outside (user, etc.) (step S3). However, what follows differs from FIG. 10(a) in that 1 is added to the value of j (step S4'), and after a certain time T, the process returns to step S1 where the transmission control signal X is output, and if it is determined that a moving object S'U is not present, the process skips step S3, and returns to step S1 where 1 is added to the value of j (step S4'), and after a certain time T, the process returns to step S1 where the transmission control signal X is output. 10(c) does not necessarily have to include step 3, and the detection unit 4 may output to the outside the detected speed V and distance L of the moving body S', the approach and separation of the moving body S', etc. Also, in the object detection method of Fig. 10(c), the detection unit 4 may output the transmission control signal X to the transmission unit 2 three or more times in one step 1, and the transmission unit 2 may transmit the radio wave W three or more times.

[0115] <Object detection program> FIG. 10 can also be said to show a flowchart of an object detection program according to the present invention. The object detection program is a program executed by the object detection sensor 1 for detecting an object S within the detection area R described above.

[0116] In the object detection program, the above-mentioned detection unit 4 may be caused to detect only the object S within the detection area R whose speed V is greater than 0 as a moving object S'. In this case, the object detection program may cause the detection unit 4 to detect only those objects S within the detection area R whose speed V is equal to or greater than a predetermined lower limit V' and / or whose speed V is equal to or less than a predetermined upper limit V" as moving bodies S'.

[0117] In addition, as shown in FIGS. 3(a) and 3(b), the object detection program controls the detection unit 4 to generate a beat difference signal ΔB obtained by adding at least a beat signal B corresponding to the reflected wave H due to the n-th transmission among the three or more transmissions of the radio wave W by the transmission unit 2 described above, a beat difference signal ΔB between the beat signal B corresponding to the reflected wave H due to the n+Z1th transmission after the n-th transmission, and a beat difference signal ΔB between the beat signal B corresponding to the reflected wave H due to the n-th transmission and the beat signal B corresponding to the reflected wave H due to the n+Z2th transmission after the n+Z1st transmission, + The object S may be detected based on the transformed spectrum. In this case, also in the object detection program according to the present invention, "n is a natural number, Z1 is a natural number greater than n, and Z2 is a natural number greater than Z1."

[0118] Also, as shown in FIG. 3(c), the object detection program causes the detection unit 4 to receive a reflected wave H from the j-th transmission of the radio wave W from the transmission unit 2 described above, out of three or more transmissions of the radio wave W. j Beat signal B corresponding to j and j+Z1 after the jth iteration j Reflected wave H from the th transmission j Beat signal B corresponding to jBeat difference signal ΔB j and the reflected wave H j Beat signal B corresponding to j and j+Z1 j j+Z2 after the first j Reflected wave H from the th transmission j Beat signal B corresponding to j Beat difference signal ΔB j The beat difference sum signal ΔB j + Based on the spectrum obtained by converting the above, the object S is detected, and the beat difference sum signal ΔB j + After each detection of the object S based on the transformed spectrum is completed, the value of j may be incremented by 1 and the detection of the object S may be repeated. In this case, in the object detection program according to the present invention, "N is a natural number, j is a natural number from 1 to N, and Z1 j is a natural number greater than N, and Z2 j is Z1 j It is a larger natural number."

[0119] Furthermore, the object detection program may select Z1, Z2, Z3, etc., according to the speed V of the moving body S' to be detected before the above-mentioned detection unit 4 detects the object S, or may cause the above-mentioned detection unit 4 to select Z1, Z2, Z3, etc., according to the speed V of the moving body S' to be detected. Each of the object detection programs shown in FIGS. 10(a) to (c) will be explained in detail below.

[0120] In the case of the object detection program shown in the flowchart of Figure 10(a), the above-mentioned detection unit 4 performs the processing as shown in Figures 3(a) and (b) only once to determine only the presence or absence of a moving object S', and the program has the following steps. In the object detection program of FIG. 10(a), after the process of detecting an object S (moving object S') is started (step S0), a transmission control signal (sweep control signal) X is output from the detection unit 4 to the transmission unit 2 (step S1), and then a determination is made as to whether or not a moving object S' is present (step S2). If the determination results in the presence of a moving object S'U, a moving object detection signal Y is output to the outside (user, etc.) (step S3), and the process is terminated (step S4). If the determination results in the absence of a moving object S'U, the process is terminated (step S4) without going through step S3. Incidentally, the object detection program in FIG. 10(a) does not need to include step 3 described above, and other information such as the speed V and distance L of the detected moving body S', and the approach / departure of the moving body S' may be output to the outside.

[0121] In the case of the object detection program shown in the flowchart of Figure 10(b), the above-mentioned detection unit 4 performs the processing as shown in Figures 3(a) and (b) at regular intervals to determine only the presence or absence of a moving object S' at regular intervals, and has the following steps. Similarly, in the object detection program in FIG. 10(b), the process of detecting an object S (moving object S') begins (step S0), and then the detection unit 4 outputs a transmission control signal (sweep control signal) X to the transmission unit 2 (step S1). Next, the presence or absence of a moving object S' is determined (step S2). If it is determined that a moving object S'U is present, a moving object detection signal Y is output to the outside (user, etc.) (step S3). However, what follows differs from FIG. 10(a) in that after a certain time T, the process returns to step S1 of outputting the transmission control signal X, and if it is determined that no moving object S'U is present, the process returns to step S1 of outputting the transmission control signal X after a certain time T without going through step S3. Incidentally, the object detection program in FIG. 10(b) does not necessarily have to include step 3 described above, and the detection unit 4 may output to the outside the detected speed V and distance L of the moving object S', as well as the approach and separation of the moving object S'.

[0122] In the case of the object detection program shown in the flowchart of FIG. 10(c), the reflected wave Hj Beat signal B corresponding to j and the beat difference signal ΔB j and the beat difference sum signal ΔB j + This is a program that detects an object S based on a spectrum obtained by converting j, and adds 1 to the value of j each time the detection is completed, and repeats the detection of the object S. The program has the following steps: Similarly, in the object detection program in FIG. 10(c), the process of detecting an object S (moving object S') begins (step S0), and then the detection unit 4 outputs a transmission control signal (sweep control signal) X to the transmission unit 2 (step S1). Next, the presence or absence of a moving object S' is determined (step S2). If it is determined that a moving object S'U is present, a moving object detection signal Y is output to the outside (user, etc.) (step S3). However, what follows differs from FIG. 10(a) in that 1 is added to the value of j (step S4'), and after a certain time T, the process returns to step S1 where the transmission control signal X is output. If it is determined that no moving object S'U is present, then 1 is added to the value of j (step S4') without going through step S3, and after a certain time T, the process returns to step S1 where the transmission control signal X is output. Incidentally, the object detection program in FIG. 10(c) does not necessarily have to include step 3 described above, and the detection unit 4 may output to the outside the detected speed V and distance L of the moving body S', as well as the approach and separation of the moving body S'.

[0123] <Other> The present invention is not limited to the above-described embodiment. The configurations or overall structure, design, shape, dimensions, weight, etc. of the object detection sensor 1, the object detection method, and the object detection program can be appropriately changed in accordance with the spirit of the present invention. Up to this point, the object detection sensor 1, the object detection method, and the object detection program have been described in the case where the object detection sensor 1 is an FMCW sensor, but below, a description will be given of the case where the object detection sensor 1 is a sensor other than an FMCW sensor.

[0124] When the object detection sensor 1 is a multi-frequency CW sensor, a CW sensor, or a Doppler sensor, the signal B or B corresponding to the reflected wave H due to the transmission of the above-mentioned radio wave W isj As with the FMCW sensor, the above-mentioned beat signal is generated, and the differential signals ΔB and ΔB j Also, the beat difference signal is the same as above, and the difference sum signal ΔB + or ΔB j + The above-mentioned beat difference sum signal is also obtained. In addition, when the object detection sensor 1 is a standing wave sensor, the signal B or B corresponding to the reflected wave H due to the transmission of the radio wave W described above is generated. j is a signal with frequency on the horizontal axis and amplitude on the vertical axis (a distance spectrum, so to speak), and the difference signals ΔB and ΔB j is the difference signal of the distance spectrum, and the difference sum signal ΔB + or ΔB j + is the difference sum signal of the distance spectrum. Note that a standing wave is a wave that occurs when waves with the same frequency but different traveling directions overlap. In addition, when the object detection sensor 1 is a standing wave sensor, a wave detector (diode mixer, etc.) may be used instead of the mixer 4a in the configuration example of FIG. 2.

[0125] Furthermore, the object detection sensor 1, the object detection method, and the object detection program may use the MUSIC (MUltiple SIgnal Classification) method. The MUSIC method is a technique (algorithm) for estimating the number and directions of the transmitters 2 that transmit radio waves W using an array antenna (an antenna in which multiple antenna elements are regularly arranged and power is supplied under certain excitation conditions). The object detection sensor 1, the object detection method, and the object detection program may use a MIMO (Multiple-Input and Multiple-Output) method. The MIMO method is a method in which multiple antennas are used for both the transmission unit 2 and the reception unit 3.

[0126] In the object detection sensor 1, object detection method, and object detection program, if the object detection sensor 1 is a Doppler sensor, when detecting only objects S whose velocity V in the detection area R is greater than 0 as moving objects S', or detecting only objects S whose velocity V in the detection area R is equal to or greater than a predetermined lower limit V' and / or equal to or less than a predetermined upper limit V", the velocity V may be calculated directly from the beat signal B to detect the moving object S', rather than by subtracting the beat signal B as in the above-mentioned FMCW sensor. Incidentally, even in the case of processing such as that shown in FIGS. 3(a) and (b), if the detection of the object S is repeated with n=j, it can be said that the processing includes FIG. 3(c) (in other words, claim 1 includes claim 2). In addition, in the above description of the process shown in FIG. 3(c), the difference sum signal ΔB j + After each detection of object S based on the transformed spectrum, 1 was added to the value of j and the detection of object S was repeated. However, after each detection, the value of j was increased to 2, 3, or 4 or more. The number added to j was different each time, or the number added to j was (Z1 j -j)=(Z2 j -Z1 j )=(Z3 j -Z2 j ) = .

[0127] <Sensor housing 5> As shown in FIGS. 1 to 9 and described above, the sensor housing 5 is a housing in which at least one of the above-mentioned transmitting unit 2 and receiving unit 3 is attached. Furthermore, as long as at least one of the transmitting unit 2 and the receiving unit 3 is attached to one sensor housing 5, there is no limit to the number of each. For example, one sensor housing 5 may have one transmitting unit 2 and one receiving unit 3 attached thereto. The shape of sensor housing 5 is not particularly limited, and may be, for example, substantially flat plate-like or substantially rectangular parallelepiped, and the shape of sensor housing 5 as viewed from the front may be substantially square or circular. The sensor housing 5 may be attached to a support member such as a pillar so that the transmitter 2 and the receiver 3 face sideways (approximately horizontally, see FIG. 1, etc.) or downward (FIGS. 4, 6, 8, etc.). [Industrial Applicability]

[0128] In the object detection sensor, the object detection method, and the object detection program according to the present invention, there is no limitation on the location where the detection area R is assumed (set), and the object detection sensor, the object detection method, and the object detection program can be used in any location. [Explanation of symbols]

[0129] 1. Object detection sensor 2. Transmitter 3. Receiving section 4. Detection section R Detection area S object S' Mobile S” stationary body W Radio H reflected wave B Signal corresponding to the reflected wave ΔB difference signal ΔB + difference sum signal H j Reflected wave from j-th transmission B j Signal corresponding to the reflected wave from the jth transmission ΔB j Difference signal from j-th transmission ΔB j + Difference sum signal from j-th transmission

Claims

1. An object detection sensor that detects an object (S) within a detection region (R), The device has a transmitting unit (2) that transmits radio waves (W) to the detection area (R), a receiving unit (3) that receives a reflected wave (H) of the radio waves (W) from the transmitting unit (2) that is reflected by the object (S), and a detecting unit (4) that detects the object (S) based on a signal (B) corresponding to the reflected wave (H) received by the receiving unit (3), The transmission unit (2) transmits the radio wave (W) three or more times, When n is a natural number, Z1 is a natural number greater than n, and Z2 is a natural number greater than Z1, the detection unit (4) detects that, among three or more transmissions of the radio wave (W) by the transmission unit (2), A differential signal (ΔB) between a signal (B) corresponding to a reflected wave (H) due to the n-th transmission and a signal (B) corresponding to a reflected wave (H) due to the n+Z1-th transmission after the n-th transmission; A differential signal (ΔB) between a signal (B) corresponding to the reflected wave (H) due to the n-th transmission and a signal (B) corresponding to the reflected wave (H) due to the n+Z2nd transmission after the n+Z1st transmission is At least the added differential sum signal (ΔB ＋ ) is converted into a spectrum to detect the object (S).

2. An object detection sensor that detects an object (S) within a detection region (R), The device has a transmitting unit (2) that transmits radio waves (W) to the detection area (R), a receiving unit (3) that receives a reflected wave (H) of the radio waves (W) from the transmitting unit (2) that is reflected by the object (S), and a detecting unit (4) that detects the object (S) based on a signal (B) corresponding to the reflected wave (H) received by the receiving unit (3), The transmission unit (2) transmits the radio wave (W) three or more times, The detection unit (4) is a detector in which N is a natural number, j is a natural number from 1 to N, and Z ｊ is a natural number greater than N, and Z2 ｊ Z1 ｊ In the case where the number of transmissions is a natural number larger than the number of transmissions of the radio wave (W) by the transmission unit (2), The reflected wave from the jth transmission (H ｊ ) corresponding to the signal (B ｊ ) and j+Z1 after the jth time ｊ The reflected wave from the th transmission (H ｊ ) corresponding to the signal (B ｊ ) and the difference signal (ΔB ｊ )and, The reflected wave (H ｊ ) corresponding to the signal (B ｊ ) and j + Z1 ｊ j+Z2 after the first time ｊ The reflected wave from the th transmission (H ｊ ) corresponding to the signal (B ｊ ) and the difference signal (ΔB ｊ ) and At least the added differential sum signal (ΔB ｊ ＋ Detecting the object (S) based on a spectrum obtained by converting the The detection unit (4) detects the difference sum signal (ΔB ｊ ＋ ) is converted into a spectrum, and the object detection sensor adds 1 to the value of j and repeats the detection of the object (S).

3. In the detection region (R), the object (S) may be a mixture of moving objects (S') and stationary objects (S''), or only moving objects (S') may be present; Depending on the speed of the moving body (S'), Z1 and Z2 as described in claim 1 or Z1 as described in claim 2 are selected. ｊ and Z2 ｊ 3. The object detection sensor according to claim 1, wherein at least one of the following is selected.

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