1. A ranging module apparatus comprising:

a signal transmitter unit (10) that transmits electromagnetic waves;

a scanner unit (30) that scans the electromagnetic wave emitted by the signal emitter unit into space to generate a projected electromagnetic wave;

a signal receiver unit (40) that receives a reflected electromagnetic wave from an object and outputs a received signal; and

a signal processor unit (50) which calculates a distance to the object based on the received signal of the signal receiver unit, wherein

The signal receiver unit includes:

a first receiver unit designed to receive a reflected electromagnetic wave generated by a main lobe and two grating lobes of the projected electromagnetic wave;

a second receiver unit designed to receive a reflected electromagnetic wave generated by the main lobe and one grating lobe of the projected electromagnetic wave; and

a third receiver unit designed to receive a reflected electromagnetic wave generated by the main lobe and another grating lobe of the projected electromagnetic wave, wherein

The signal processor unit determines which of the reflected electromagnetic waves generated by the main lobe or the one or the other grating lobe of the projected electromagnetic wave corresponds to the electromagnetic wave received by the signal receiver unit based on a combination of the received signals of the first, second and third receiver units and calculates a distance to the object.

2. A ranging module apparatus as claimed in claim 1 wherein

The signal processor unit is configured to perform:

obtaining a first added signal by adding the received signal of the first receiver unit and the received signal of the second receiver unit;

obtaining a second added signal by adding the received signal of the first receiver unit and the received signal of the third receiver unit;

obtaining a third added signal by adding the received signal of the first receiver unit, the received signal of the second receiver unit, and the received signal of the third receiver unit;

determining a main signal, of a plurality of signals occurring among the first, second, and third addition signals, at which one of the first, second, and third addition signals is collectively maximum in signal strength, as a reception signal output by the signal receiver unit that receives the reflected electromagnetic wave of the main lobe of the projected electromagnetic wave;

determining a signal greater than the second added signal present in the first added signal in a remaining signal excluding the primary signal as a received signal output by the signal receiver unit receiving the reflected electromagnetic wave of the one grating lobe of the projected electromagnetic wave; and

determining a signal present in the second added signal that is greater than the first added signal as a received signal output by the signal receiver unit that receives the reflected electromagnetic wave of the other grating lobe of the projected electromagnetic wave.

3. A ranging module apparatus according to claim 1 or 2, wherein

The signal receiver unit comprises two of the first receiver units, wherein

The signal processor unit determines which of the reflected electromagnetic waves generated by the main lobe or the one or the other grating lobe of the projected electromagnetic wave corresponds to the electromagnetic wave received by the signal receiver unit based on a combination of the received signals of two of the first receiver units, the second receiver unit and the third receiver unit.

4. An apparatus for processing an output signal from a ranging module,

the ranging module comprises at least three receiver units (41a, 41b, 41c) comprising:

a first receiver unit designed to receive a reflected electromagnetic wave generated by a main lobe and two grating lobes of a projected electromagnetic wave;

a second receiver unit designed to receive a reflected electromagnetic wave generated by the main lobe and one grating lobe of the projected electromagnetic wave; and

a third receiver unit designed to receive a reflected electromagnetic wave generated by the main lobe and another grating lobe of the projected electromagnetic wave,

the device comprises:

an electrical conversion circuit (43) that converts the reflected electromagnetic waves from the first, second, and third receiver units into electrical reception signals; and

a signal processor circuit (50) receiving the electrical receive signal, the signal processor circuit configured to perform:

identifying which lobe, the main lobe or one grating lobe or the other grating lobe, produces a reflected electromagnetic wave corresponding to the electrical received signal output from the receiver unit; and

at least a distance to the object is calculated based on the identified lobes.

5. The apparatus of claim 4, wherein the signal processor circuit is configured to further perform:

summing the electrical received signals in different combinations to obtain a plurality of summed signals; and

the summed signals are compared to identify a lobe.

6. The apparatus of claim 5, wherein the signal processor circuit is configured to further perform:

determining a lobe based on signals occurring at different times on the plurality of summed signals.

7. A method for processing an output signal from a ranging module, the method comprising:

identifying, by the circuitry, which lobe, main lobe or one grating lobe or the other grating lobe, produces a reflected electromagnetic wave corresponding to the electrical received signal output from the receiver unit (40); and

based on the identified lobes, at least a distance to the object is calculated by a circuit (50).

8. The method of claim 7, further comprising the steps of:

adding, by circuitry, the two electrical received signals from the at least three receiver units to obtain at least two added signals; and

the summed signals are compared by circuitry to identify lobes.

9. The method of claim 8, further comprising the steps of:

determining, by circuitry, a lobe based on signal strengths occurring at different times on a plurality of signals obtained by combining, in different combinations, signals corresponding to the reflected electromagnetic wave produced by the main lobe or the one or the other grating lobe.

Background

LiDAR (light detection and ranging) with OPA (optical phased array) architecture is known. LiDAR is also known as a ranging module device. In the range module arrangement, in addition to the main lobe, from which light is projected, at least one grating lobe light is present, which is projected at an angle different from the main lobe light.

In the ranging module apparatus, the light-projecting OPA is designed such that the angle between the main lobe light and the grating lobe light is at least three times the scanning angle, so that the grating lobe light does not fall within the scanning range of the main lobe light. In the light reception OPA, the light reception angle is designed so that light from the main lobe light projection direction is received in synchronization with projection, and the grating lobe light is outside the light reception range.

U.S. patent application publication 2009/0129008A discloses a LiDAR system that uses grating lobe light in addition to main lobe light to measure distance to an object.

Disclosure of Invention

However, the LiDAR system described in U.S. patent application publication 2009/0129008A is provided with separate light receiving portions for each of the main lobe light and the grating lobe light. In this configuration, the number of light receiving elements required is large, and thus the size of the device is large.

In view of the above, an object of the present disclosure is to provide a ranging module capable of suppressing an increase in body shape.

According to an aspect of the disclosure, an apparatus comprises: a signal transmitter unit that transmits electromagnetic waves; a scanner unit that scans the electromagnetic wave emitted by the signal emitter unit into a space to generate a projected electromagnetic wave; a signal receiver which receives a reflected electromagnetic wave from an object and outputs a received signal; and a signal processor unit that calculates a distance to the object based on the reception signal of the signal receiver unit. The signal receiver unit includes: a first receiver unit designed to receive a reflected electromagnetic wave generated by a main lobe and two grating lobes of a projected electromagnetic wave; a second receiver unit designed to receive the reflected electromagnetic wave generated by the main lobe and one grating lobe of the projected electromagnetic wave; and a third receiver unit designed to receive the reflected electromagnetic wave generated by the main lobe of the projected electromagnetic wave and the further grating lobe. The signal processor unit determines which of the main lobe of the projected electromagnetic wave or the reflected electromagnetic wave generated by one or the other grating lobe corresponds to the electromagnetic wave received by the signal receiver unit, based on a combination of the signals received by the first, second and third receiver units, and calculates the distance to the object.

According to this configuration, the signal receiver unit includes: a first receiver unit receiving a main lobe and two grating lobes; a second receiver unit receiving the main lobe and one of the grating lobes; and a third receiver unit receiving the main lobe and the further grating lobe. The signal processor unit calculates the distance using a combination of the three received signals. As a result, the total signal strength can be kept high even if the strength of each received signal is low. As a result, an increase in the number of light receiving elements can be suppressed and an increase in body shape can be suppressed.

Drawings

The disclosure is further described with reference to the accompanying drawings, in which:

fig. 1 is a block diagram of a ranging module apparatus according to a first embodiment;

FIG. 2 is a diagram illustrating a main lobe and grating lobes projecting an electromagnetic wave;

fig. 3 is a diagram showing a configuration of the signal receiver unit shown in fig. 1;

FIG. 4 is a block diagram of the signal processor unit shown in FIG. 1;

FIG. 5 is a block diagram of a direction encoding unit shown in FIG. 4;

FIG. 6 is a block diagram of the direction determination unit shown in FIG. 4;

fig. 7 is a diagram showing a state in which reflected electromagnetic waves are received by three antenna elements;

fig. 8 is a diagram showing a received signal and an added signal;

fig. 9 is a diagram showing a configuration of a signal receiving unit according to the second embodiment;

fig. 10 is a diagram showing a state in which reflected electromagnetic waves are received by four antenna elements;

fig. 11 is a diagram showing a received signal and an added signal in the second embodiment;

fig. 12 is a block diagram of a ranging module apparatus according to a third embodiment; and

fig. 13 is a block diagram of the signal processor unit shown in fig. 12.

Detailed Description

Hereinafter, embodiments are described with reference to the drawings. In the various embodiments described herein, identical or equivalent components are given the same reference numerals.

First embodiment

The first embodiment is described below. The ranging module shown in fig. 1 is mounted on a vehicle, and is configured to measure at least a distance between the vehicle and an object (TG) by transmitting and receiving electromagnetic waves. The ranging module is composed of an integrated chip formed on an SOI (silicon on insulator) substrate by silicon photons. Light or millimeter waves are used as electromagnetic waves.

As shown in fig. 1, the ranging module apparatus includes a signal transmitter unit 10(SGTR), a transmission driving unit 20(DRV), and a scanner unit 30 (SCN). The signal transmitter unit 10 generates and outputs an electromagnetic wave as a transmission signal. The transmission driving unit 20 drives the signal transmitter unit 10. The scanner unit 30 scans a space using the electromagnetic wave output by the signal transmitter unit 10. In this embodiment, the space may be a three-dimensional range around the vehicle. Electromagnetic waves are emitted and projected so as to scan a space. The electromagnetic waves that scan the space are also known as the projection electromagnetic waves (PEMW).

The signal transmitter unit 10 and the transmission driving unit 20 are connected by a metal wiring such as Al formed on the SOI substrate. The signal transmitter unit 10 and the scanner unit 30 are connected by at least one waveguide including a core layer made of Si or the like and a core layer made of SiO₂Etc. to form a clad. The signal transmitter unit 10 comprises for example a laser diode. The signal emitter unit 10 generates light by supplying current from the emission driving unit 20.

The scanner unit 30 includes a projection unit 31(PRJT) and a phase control unit 32 (PHCN). The projection unit 31 projects the electromagnetic wave emitted from the signal emitter unit 10 into space. The phase control unit 32 drives the projection unit 31. The projection unit 31 is composed of an OPA in which waveguides are branched and arranged in parallel, and electromagnetic waves are emitted from the ends of a plurality of waveguides arranged in parallel.

The phase control unit 32 is configured to change the phase of the electromagnetic wave emitted from the projection unit 31 according to an electric signal input from a control circuit (not shown). The projection unit 31 includes a plurality of waveguides as components. The phase of the electromagnetic wave passing through each of the plurality of waveguides is periodically changed by the phase control unit 32. As a result, the phase of the electromagnetic wave emitted from the plurality of waveguides is periodically changed. As a result, the directivity of the electromagnetic wave emitted from the entire projection unit 31 changes. As a result, electromagnetic waves are emitted in an arbitrary direction, and the space is scanned by changing the direction.

The ranging module device includes a configuration for receiving a reflected electromagnetic wave (REMW) from an object, in addition to the signal transmitter unit 10 and the like. The ranging module apparatus includes a signal receiver unit 40(SGRV), a signal processor unit 50(SGPR), and a communication unit 60 (COM). The signal receiver unit 40 receives the reflected electromagnetic wave and outputs the received signal. The signal processor unit 50 calculates a distance to the object, etc., based on the signal received by the signal receiver unit 40. The communication unit 60 transmits the distance and the like calculated by the signal processor unit 50 to the ECU of the vehicle and the like. The signals transmitted by the communication unit 60 may include a distance signal DS, a velocity signal VE and an angle signal AG.

The signal receiver unit 40 includes an antenna unit 41(ANT), a multiplexer unit 42(MX), and an electrical conversion unit 43 (CV). The antenna unit 41 is configured to receive electromagnetic waves from the outside. The antenna unit 41 has a phased array structure including a plurality of waveguides arranged in parallel. The antenna unit 41 is configured to introduce an electromagnetic wave from an end of each waveguide. A phase shifter (not shown) is disposed in each waveguide. The antenna unit 41 controls the phase of the electromagnetic wave introduced into each waveguide by a phase shifter. As a result, the antenna unit 41 can control the introduction direction of the electromagnetic wave in the entire antenna unit 41.

The plurality of waveguides constituting the antenna unit 41 are combined into one and connected to the multiplexer unit 42. The multiplexer unit 42 multiplexes the electromagnetic waves received by the antenna unit 41 and the electromagnetic waves output by the signal transmitter unit 10. As a result, a beat signal is generated. This is because the distance to the object is measured by the FMCW (frequency modulated continuous wave) method.

The multiplexer unit 42 is connected to the electrical conversion unit 43 through a waveguide. The electromagnetic waves multiplexed by the multiplexer unit 42 are transmitted to the electric conversion unit 43. The electric conversion unit 43 includes a plurality of components (e.g., a photoelectric conversion unit), a current-voltage conversion unit, and an analog-to-digital conversion unit (not shown). The photoelectric conversion unit is constituted by a photodiode or the like. The current-voltage conversion unit is constituted by a transimpedance amplifier or the like. The analog-to-digital converter converts the analog signal into a digital signal. The electric conversion unit 43 is connected to the signal processor unit 50 through a metal wiring. The electromagnetic wave transmitted to the electric conversion unit 43 is converted into a digital signal and transmitted to the signal processor unit 50.

In the ranging module provided with the projection unit having the phased array structure, as shown in fig. 2, the electromagnetic wave is projected into three parts. That is, the projected electromagnetic wave is divided into a main lobe ML controlled in a desired direction by the phase control unit 32, and two grating lobes GL1 and GL2 projected on both sides of the main lobe ML. Then, when the main lobe ML is scanned as indicated by arrow AR1, the grating lobes GL1 and GL2 are also scanned as indicated by arrows AR2 and AR 2. As a result, reflected electromagnetic waves of grating lobes GL1 and GL2 and reflected electromagnetic waves of main lobe ML are generated. As a result, both the reflected electromagnetic wave of the main lobe ML and the reflected electromagnetic waves of the grating lobes GL1 and GL2 are introduced into the ranging module.

The ranging module of the present embodiment has a configuration that measures a spatial index such as a distance from an object reflecting each of a plurality of lobes based on a received electromagnetic wave. The ranging module determines which of the reflected electromagnetic waves generated by the main lobe ML or grating lobe GL1 or grating lobe GL2 of the projected electromagnetic wave corresponds to the received electromagnetic wave. The ranging module determines which of the reflected electromagnetic waves generated by the main lobe ML or grating lobe GL1 or grating lobe GL2 corresponds to the received electromagnetic wave. The ranging module has a configuration that measures a distance to an object according to a lobe that generates a reflected electromagnetic wave based on a determination result.

Specifically, as shown in fig. 3, the antenna unit 41 includes an antenna unit 41a, an antenna unit 41b, and an antenna unit 41 c. Each of the antenna elements 41a, 41b, and 41c is composed of a plurality of waveguides. The phase shifters are arranged in the plurality of waveguides. The antenna elements 41a, 41b and 41c are arranged to receive electromagnetic waves from different directions.

The antenna element 41a is arranged to receive the reflected electromagnetic wave of the main lobe ML and the two grating lobes GL1 and GL2 of the projected electromagnetic wave. The antenna element 41b is arranged to receive the reflected electromagnetic wave of the main lobe ML and one grating lobe GL1 of the projected electromagnetic wave. The antenna element 41c is arranged to receive the reflected electromagnetic wave of the main lobe ML and the further grating lobe GL2 of the projected electromagnetic wave.

The multiplexer unit 42 and the electrical conversion unit 43 have an array structure corresponding to the antenna unit 41. Specifically, multiplexer unit 42 includes multiplexer unit 42a, multiplexer unit 42b, and multiplexer unit 42 c. The electric conversion unit 43 includes an electric conversion unit 43a, an electric conversion unit 43b, and an electric conversion unit 43 c. The electromagnetic waves received by the antenna units 41a, 41b, and 41c are multiplexed by the multiplexer units 42a, 42b, and 42c separately from the electromagnetic waves output by the signal transmitter unit 10. Each of the multiplexed electromagnetic waves is converted into a reception signal by the electrical conversion units 43a, 43b, and 43 c.

A part of the signal receiver unit 40 constituted by the antenna unit 41a, the multiplexer unit 42a and the electrical conversion unit 43a is also referred to as a first receiver unit 40 a. A part of the signal receiver unit 40 constituted by the antenna unit 41b, the multiplexer unit 42b and the electrical conversion unit 43b is also referred to as a second receiver unit 40 b. A part of the signal receiver unit 40 constituted by the antenna unit 41c, the multiplexer unit 42c and the electrical conversion unit 43c is also referred to as a third receiver unit 40 c.

The signal processor unit 50 determines one of the lobes based on a combination of the received signals of the three receiver units. The signal processor unit 50 determines which of the reflected electromagnetic waves caused by the main lobe ML, one grating lobe GL1 or the other grating lobe GL2 of the projected electromagnetic wave corresponds to the electromagnetic wave received by the signal receiver unit 40. The signal processor unit 50 calculates the distance to the object for the main lobe ML and each of the two grating lobes GL1 and GL 2.

As shown in fig. 4, the signal processor unit 50 includes a data holding unit 51(DTHD), a direction encoder unit 52(DREN), an FFT processor unit 53(FFT), a direction determination unit 54(DRDT), and a distance calculation unit 55 (DSCL). The signal processor unit 50 is composed of, for example, a DSP (digital signal processor). The data holding unit 51 holds the reception signal output by the electrical conversion unit 43. The direction encoder unit 52 encodes the received signal held by the data holding unit 51.

As shown in fig. 5, the direction encoder unit 52 includes a combination addition unit 521(COAD) and a division unit 522 (DIVD). The reception signals of the electromagnetic waves received by the antenna units 41a, 41b, and 41c are added by the combination addition unit 521, and then divided by the number of the added signals by the division unit 522, thereby being averaged.

In the following description, the reception signal of the first receiver unit 40a is referred to as a first reception signal (#1 RSSG). The reception signal of the second receiver unit 40b is referred to as a second reception signal (#2 RSSG). The reception signal of the third receiver unit 40c is referred to as a third reception signal (#3 RSSG). The direction encoder unit 52 adds the first received signal and the second received signal, and then averages them to obtain a first added signal (#1 ADSG). The direction encoder unit 52 adds the first received signal and the third received signal, and then averages them to obtain a second added signal (#2 ADSG). The direction encoder unit 52 adds the first received signal, the second received signal, and the third received signal, and then averages them to obtain a third added signal (#3 ADSG). These plural added signals are transmitted to the FFT processor unit 53.

The FFT processor unit 53 performs FFT processing on the added signal transmitted from the direction encoder unit 52, and detects a frequency. The FFT processor unit 53 transmits the frequency detection result and the signal transmitted from the direction encoder unit 52 to the direction determination unit 54.

As shown in fig. 6, the direction determining unit 54 comprises a main lobe determining unit 541(MLDT) and a grating lobe determining unit 542 (GLDT). The main lobe determination unit 541 is configured to determine whether the electromagnetic wave received by the signal receiver unit 40 corresponds to a reflected electromagnetic wave caused by the main lobe ML of the projected electromagnetic wave. The grating lobe determination unit 542 is configured for determining whether the electromagnetic wave received by the signal receiver unit 40 corresponds to a reflected electromagnetic wave caused by the grating lobes GL1 and GL2 of the projected electromagnetic wave.

The main lobe determining unit 541 determines, among the plurality of signals appearing on the plurality of added signals, a signal at which the signal intensities among the plurality of added signals are collectively maximized, as a received signal, which is output by the signal receiver unit 40 upon receiving the reflected electromagnetic wave caused by the main lobe ML that projects the electromagnetic wave. The plurality of addition signals include a first addition signal, a second addition signal, and a third addition signal. The signal at which the signal strength is maximized in common among the plurality of added signals is also referred to as a main signal or a maximum strength signal.

The grating lobe determination unit 542 determines, among the remaining signals excluding the main signal, a signal larger than the plurality of second addition signals appearing on the plurality of first addition signals as a reception signal output by the signal receiver unit 40 upon reception of the reflected electromagnetic wave caused by one grating lobe GL1 of the projected electromagnetic wave. The signal which is present in the first addition signal and is greater than in the second addition signal is referred to as the first relative intensity signal.

The grating lobe determination unit 542 determines a signal appearing on the plurality of second added signals that is larger than the plurality of first added signals as a reception signal that is output by the signal receiver unit 40 upon receiving the reflected electromagnetic wave caused by the other grating lobe GL2 of the projected electromagnetic wave. The direction determining unit 54 transmits the determination result of the main lobe ML, the grating lobes GL1 and GL2, and the frequency detection result transmitted from the FFT processor unit 53 to the distance calculating unit 55. The signal present in the second summed signal that is greater than in the first summed signal is referred to as a second relative intensity signal.

The distance calculation unit 55 is configured to calculate the distance to the object and the speed of the object based on the information transmitted from the direction determination unit 54. In the present embodiment, the distance calculation unit 55 calculates the distance and velocity of two objects, which are an object that reflects the main lobe ML of the projected electromagnetic wave and objects that reflect the grating lobes GL1 and GL 2. The distance and speed of the object and the relative movement direction (direction or angle) calculated by the signal processor unit 50 are transmitted to the ECU and the like by the communication unit 60 as a distance signal DS, a speed signal VE, and an angle signal AG.

For example, when the main lobe ML and the two grating lobes GL1 and GL2, which project electromagnetic waves, are reflected by the three objects 100a, 100b, and 100c at the positions shown in fig. 7, the received signals are output as shown in fig. 8. That is, the signal strength of the first received signal output from the first receiver unit 40a including the antenna unit 41a becomes high at three times t1, t2, and t 3. Further, the signal strength of the second reception signal output from the second receiver unit 40b including the antenna unit 41b becomes high at times t2 and t 3. Further, the signal strength of the third received signal output from the third receiver unit 40c including the antenna unit 41c becomes high at times t1 and t 3. In fig. 8 and fig. 11 described later, different hatchings are applied to the first, second, and third reception signals and the first, second, and third reception signals included in the added signal.

When these received signals are processed by the direction encoder unit 52, the first, second and third summed signals are converted as shown in fig. 8. At times t2 and t3, the signal strength of the first addition signal takes a maximum value. At times t1 and t3, the signal strength of the second addition signal takes a maximum value. At time t3, the signal strength of the third phase added signal takes a maximum value.

The main lobe determination unit 541 determines a signal at time t3, at which the signal strength becomes maximum in common among the first, second, and third addition signals, as a received signal corresponding to the reflected electromagnetic wave caused by the main lobe ML. This signal is called the main signal.

The grating lobe determination unit 542 identifies the reflected electromagnetic wave generated by the grating lobe GL1 or the reflected electromagnetic wave generated by the grating lobe GL2 from the signals at the remaining times t1 and t 2. The grating lobe determination unit 542 determines a signal at time t2 (when the signal strength of the first addition signal is greater than the signal strength of the second addition signal) as a reception signal corresponding to the reflected electromagnetic wave caused by the grating lobe GL 1.

The grating lobe determining unit 542 determines a signal at time t1 (when the signal strength of the second addition signal is greater than the signal strength of the first addition signal) as a reception signal corresponding to the reflected electromagnetic wave caused by the grating lobe GL 2.

The distance calculation unit 55 calculates the distances to the objects 100a, 100b, and 100c and the velocities of the objects 100a, 100b, and 100c from the beat signals generated by the multiplexer units 42a, 42b, and 42 c. Further, since the differential angle between the main lobe ML and the grating lobes GL1 and GL2 is determined by the design of the projection unit 31, the distance calculation unit 55 calculates the directions of the objects 100a, 100b, and 100c based on the projection direction of the main lobe ML and the differential angle.

The effects of the present embodiment are explained. To increase the scanning angle in the ranging module, methods such as reducing the number of ranging points and/or shortening the ranging period may be considered. However, if the number of ranging points is reduced, the spatial resolution is reduced, and if the ranging period is shortened, the signal-to-noise ratio of the received signal is reduced. Therefore, ranging performance may be degraded. In addition, it is conceivable to increase the number of systems such as the light receiving OPA, but if the number of systems is increased, the build and cost may be increased.

On the other hand, the present embodiment utilizes a configuration of simultaneously receiving the reflected electromagnetic wave of the main lobe and the grating lobe of the projected electromagnetic wave, and detects an object based on the three received signals. As a result, the scan angle can be increased without reducing the number of ranging points and the ranging period. Further, the antenna unit 41 is composed of a plurality of units. By averaging and encoding each received signal, the effect of noise is reduced. Even in the present embodiment including a plurality of antenna elements, the SN ratio can be maintained. In addition, the present embodiment utilizes a plurality of antenna elements provided by dividing a single antenna element 41. As a result, an increase in body shape due to an increase in the area of the antenna element is suppressed. In addition, an increase in cost can be suppressed by changing the combination of electromagnetic waves received by each of the plurality of antenna elements.

Second embodiment

The second embodiment is described below. The present embodiment is a modification in which the configuration of the signal receiver unit 40 is modified from the first embodiment. Since the present embodiment is similar to the first embodiment in other respects, only the aspects different from the first embodiment will be described.

As shown in fig. 9, the antenna unit 41 includes four antenna units 41a, 41b, and 41 c. The antenna unit 41 is divided into two antenna portions 41a and 41a, an antenna portion 41b, and an antenna portion 41 c. The signal receiver unit 40 includes two first receiver units 40a and 40 a. The signal processor unit 50 determines which lobe is the origin of the reflected electromagnetic wave based on a combination of the received signals received by the two first 40a and 40a, second 40b and third 40c receiver units. The signal processor unit 50 determines whether the electromagnetic wave received by the signal receiver unit 40 corresponds to a reflected electromagnetic wave of the main lobe ML of the projected electromagnetic wave, whether the electromagnetic wave received by the signal receiver unit 40 corresponds to a reflected electromagnetic wave of the grating lobe GL1, or whether the electromagnetic wave received by the signal receiver unit 40 corresponds to a reflected electromagnetic wave of the grating lobe GL 2.

The direction encoder unit 52 adds the received signals of the two first receiver units 40a and the received signal of the second receiver unit 40b and then averages them to obtain a first added signal. The direction encoder unit 52 adds the received signals of the two first receiver units 40a and the received signal of the third receiver unit 40c and then averages them to obtain a second added signal. The direction encoder unit 52 adds the received signal of one of the first receiver units 40a, the received signal of the second receiver unit 40b and the received signal of the third receiver unit 40c and then averages them to obtain a third added signal. The direction determining unit 54 and the distance calculating unit 55 calculate the distance to the object, the velocity of the object and the direction of the object, identifying the main lobe ML, the grating lobe GL1 and the grating lobe GL2, similarly to the first embodiment.

For example, when the main lobe ML and the two grating lobes GL1 and GL2, which project electromagnetic waves, are reflected by the three objects 100a, 100b, and 100c at the positions shown in fig. 10, the received signals are output as shown in fig. 11. That is, the signal strengths of the first reception signals output from the two first receiver units 40a and 40a become high at three times t1, t2, and t 3. Further, the signal strength of the second reception signal output from the second receiver unit 40b becomes high at times t2 and t 3. Further, the signal strength of the third received signal output from the third receiver unit 40c becomes high at times t1 and t 3.

When these received signals are processed by the direction encoder unit 52, the first, second and third summed signals are converted as shown in fig. 11. The signal strength of the first addition signal at times t2 and t3 reaches a maximum value. The signal strength of the second addition signal reaches the maximum at times t1 and t 3. The signal strength of the third phase added signal reaches a maximum at time t 3.

Based on the above, similarly to the first embodiment, it is determined that the signal at time t3 is a received signal corresponding to the reflected electromagnetic wave generated by the main lobe ML. Further, it is determined that the signal at time t2 is a received signal corresponding to a reflected electromagnetic wave generated by one grating lobe GL1, and the signal at time t1 is a received signal corresponding to a reflected electromagnetic wave generated by the other grating lobe GL 2.

Then, the distances to the objects 100a, 100b, and 100c and the velocities of the objects 100a, 100b, and 100c are calculated from the beat signals generated by the multiplexer units 42a, 42b, and 42 c. Further, the directions of the objects 100a, 100b, and 100c are calculated based on the projection direction of the main lobe ML or the like.

Also in the present embodiment, the same effects as those of the first embodiment are achieved. Further, the signal strength of the first and second added signals is increased by configuring the system to include two antenna units 41a and to include the received signals from the two first receiver units 40a and 40a in the first and second added signals. As a result, the detection and ranging accuracy of the object can be improved.

Third embodiment

The third embodiment is described below. The present embodiment is a modification, and the method of measuring the distance to the object is modified from the first embodiment. Since the present embodiment is similar to the first embodiment in other respects, only the aspects different from the first embodiment will be described.

The ranging module apparatus of this embodiment measures the distance to the object by a TOF (time of flight) method. Specifically, as shown in fig. 12, the signal receiver unit 40 does not include the multiplexer unit 42, and is configured to transmit the electromagnetic wave received by the antenna unit 41 to the electrical conversion unit 43 as it is. Further, as shown in fig. 13, the signal processor unit 50 does not include the FFT processor unit 53, and is configured to transmit the signal from the direction encoder unit 52 to the direction determination unit 54.

The distance calculation unit 55 calculates the distance to the object based on the time from when the electromagnetic wave is transmitted from the signal transmitter unit 10 to when the reflected electromagnetic wave is received by the signal receiver unit 40. The communication unit 60 transmits the distance and the object direction calculated by the signal processor unit 50 to the ECU and the like.

Also in the case where the distance is measured in this manner by the TOF method in the present embodiment, the same effect as that of the first embodiment is obtained.

Other embodiments

The present disclosure is not limited to the above-described embodiments, and may be appropriately modified within the scope described in the claims.

For example, in the third embodiment, the method of measuring the distance to the object is modified from the first embodiment, but in the second embodiment, the distance may be measured by the TOF method.

The ranging module apparatus in the present disclosure includes a plurality of circuit elements. For example, the plurality of circuit elements in the first embodiment provide the transmission driving unit 20, the phase control unit 32, the electrical conversion unit 43, the signal processor unit 50, and the communication unit 60. The transmission drive unit 20, the phase control unit 32, the electrical conversion unit 43, the signal processor unit 50, and the communication unit 60 may also be referred to as a transmission drive circuit 20, a phase control circuit 32, an electrical conversion circuit 43, a signal processor circuit 50, and a communication circuit 60, respectively. The plurality of circuit elements is provided by analog circuitry, digital circuitry, computer circuitry, or a combination thereof. The analog circuits are provided by elements such as comparator circuits, amplifier circuits, and power conversion circuits. The digital circuit includes a plurality of logic circuits. The digital circuitry may be provided by an array of logic circuits, for example, an ASIC: an application specific integrated circuit; FPGA: a field programmable gate array; SoC: a system on a chip; PGA: a programmable gate array; or a CPLD: a complex programmable logic device. The computer circuitry includes at least one processor circuit and at least one memory circuit. The memory circuit is a non-transitory tangible storage medium that non-temporarily stores programs and/or data that can be read by the processor. The storage medium may be a semiconductor memory, a magnetic disk, an optical disk, or the like. The program is a collection of instructions. The program may be distributed as a single item or as a storage medium storing the program.