Ultrasonic sensing for measuring objects in spatial environments

Abstract

A first receiver, adjacent to a second receiver, is used to locate the acoustic receiver for sensing the incident sound wave. The first and second receivers have a center point along a first axis. A third receiver is adjacent to the first receiver. The center point of the third receiver is along a second axis perpendicular to the first axis. A third axis, perpendicular to the second axis, intersects the center point of the third receiver. A fourth axis intersects the center point of the second receiver and is perpendicular to the third axis. A fourth receiver is adjacent to both the second and third receivers. The center point of the fourth receiver is offset from both the third and fourth axes by a distance greater than zero but less than half the wavelength of the incident sound wave.

Description

Ultrasonic sensing for measuring objects in space environments The present disclosure relates generally to ultrasonic sensors and, more particularly, to ultrasonic sensing for measuring objects in a space environment. Ultrasonic sensors for sensing and measuring objects in two- and / or three-dimensional space have existed for decades and are used in robotics, unmanned aerial vehicles (UAVs), and several other applications. The accuracy of the measurement depends in part on how the ultrasonic sensor is able to receive the ultrasonic waveform. For example, for both time-of-flight (TOF) and pitch-catch acoustic sensing, the arrival time of the transmitted ultrasonic wave can be correlated with the phase information on the incident wave. Various methods for capturing this information, as well as ultrasonic sensor configurations for optimally capturing this information, are proposed in the following patent and non-patent literature. Jimenez JA et al. published "Characterization of ultrasonic sensors designed to identify reflectors in 3D environments" Characterisation of An ultrasonic sensor designed to identify reflectors in 3D environments” discusses the use of a single transmitter and multiple receivers to receive additional data from incident ultrasound. Figure 1 is a diagram of an ultrasonic sensor array 1 according to the prior art, in which a single transmitter 7 transmits an ultrasonic signal to be received by nine receiving transducers 5 to locate objects in a three-dimensional environment. Jimenez envisioned using nine receivers to locate objects in a three-dimensional environment, but further noted that only three transducers are typically required to classify three-dimensional objects. Here Jimenez used nine diamond-shaped transducers to distinguish between edges, planes, and corners of an object. The transducers were configured using a diamond shape due to the symmetry of the shape, which allowed for simplified measurement calculations. Using three transducers in this configuration would not produce measurements that could be used to determine the location of an object in a three-dimensional environment. Rudoy's US 2018 / 0074177 A1 utilizes Jimenez's configuration. The primary difference between Rudoy and Jimenez is the reduction in the number of emitters. However, this reduction is insignificant, as Jimenez uses more emitters than are required to locate objects in a 3D environment. Furthermore, Rudoy differs from Jiménez in that it states that it is not possible to use more emitters than shown in Figure 1. Bogdan Kreczmer published “Estimation of the azimuth of the direction of arrival of an ultrasonic signal by using indirect determination of the phase shift” Estimation of the Azimuth Angle of the Arrival Direction for an Ultrasonic Signal by using Indirect Determination of the Phase Shift" discusses configurations operating in one or two planes, but fails to reduce the number of transducers required, thus making the system impractical in practice. Kreczmer points out that since the receivers are spaced more than 1 / 2 wavelength apart, incident phase information on the incident ultrasonic wave cannot be directly obtained. Kreczmer therefore indirectly addresses this problem by introducing mathematical concepts for closely spaced transducers and applying them to the configuration proposed by Kreczmer. FIG2 illustrates an ultrasonic sensor array 2 according to the prior art. An incident wave 9 on a transducer 5 is shown, where the transducers 5 are separated by more than 1 / 2 wavelength and the incident wave 9 approaches the transducer 5 at various angles of incidence. KR20220107169A, assigned to Topsoens, proposes the use of miniature transducers, allowing them to be placed closer than the half-wavelength required to directly measure the phase of the incident ultrasonic wave. Phase ambiguity elimination in KR20220107169 requires transducers to be spaced no closer than half a wavelength relative to the input signal. This solution has been known for many years, but microphones or receivers of this size are not readily available. KR20220107169 requires transducers to be spaced no closer than half a wavelength, allowing for direct measurement of the incident phase and direct calculation of azimuth and elevation angles. Additional known disclosures use polarized electrostatic transducers to solve this problem. The use of polarized electrostatic transducers does not involve the problems associated with the 1 / 2 wavelength spacing required for the above-mentioned transducers. However, when using piezoelectric transducers, the use of this method is impractical due to the limited field of view of approximately 17 degrees. Other existing methods for measuring objects in both two and three dimensions require the use of ultrasonic arrays. In the case of ultrasonic arrays, triangulation and trilateration are used to determine three-dimensional measurements, such as distance, azimuth, and elevation. However, even in this case, direct measurement is not possible. Therefore, there exists a heretofore unaddressed need in the industry to address the aforementioned deficiencies and inadequacies. Embodiments of the present disclosure provide a method for positioning an acoustic receiver for sensing an incident sound wave. Briefly described, in architecture, among other things, one embodiment of the method can be broadly summarized as the following steps. Providing a first acoustic receiver having a center point; positioning a second acoustic receiver adjacent to the first acoustic receiver, wherein the second acoustic receiver has a center point, wherein the center point of each of the first acoustic receiver and the second acoustic receiver is positioned along a first axis; positioning a third acoustic receiver adjacent to the first acoustic receiver, wherein the third acoustic receiver has a center point, wherein the center point of each of the first acoustic receiver and the third acoustic receiver is positioned along a second axis, wherein the second axis is perpendicular to the first axis, and wherein the third axis intersects the center point of the third acoustic receiver and a fourth axis intersects the center point of the second acoustic receiver, wherein the third axis and the fourth axis are different from the first axis and the second axis, respectively, and are perpendicular; positioning a fourth acoustic receiver adjacent to the second acoustic receiver and the third acoustic receiver, wherein the center point of the fourth acoustic receiver is positioned an offset distance from each of the third axis and the fourth axis; and receiving an incident sound wave having a wavelength, wherein the offset distance is greater than zero but less than one-half of the wavelength of the incident sound wave. In one embodiment, a step includes: using a control device to compare parallel incident sound waves received at each of a first group of acoustic receivers and a second group of acoustic receivers; and using a control device to compare parallel incident sound waves received at each of a third group of acoustic receivers and a fourth group of acoustic receivers, wherein each group of acoustic receivers is unique and has at least two acoustic receivers. In another aspect, the method further includes determining the location of the object in the spatial environment by calculating: calculating the elevation angle of the object by comparing parallel measurements between the first set of acoustic receivers and the second set of acoustic receivers; and determining the azimuth angle of the object by comparing parallel measurements between the third set of acoustic receivers and the fourth set of acoustic receivers. In this aspect, the method further includes calculating the location of the object in the spatial environment using at least one of the following: a distance of the object from at least one of the first, second, third, or fourth acoustic receivers; an elevation angle of the location of the object relative to at least one of the first, second, third, or fourth acoustic receivers; and an azimuth angle of the location of the object relative to at least one of the first, second, third, or fourth acoustic receivers. In this aspect, the method further includes positioning a transducer adjacent to at least one of the acoustic receivers; and radiating at least one sound wave using the transducer. In this aspect, the method further includes positioning an additional acoustic receiver adjacent to the second acoustic receiver, wherein the additional acoustic receiver has a center point positioned along the first axis. In another aspect, the method further includes positioning an additional acoustic receiver adjacent to the third acoustic receiver, wherein the additional acoustic receiver has a center point positioned along the second axis. In this aspect, the method further includes positioning a fifth acoustic receiver adjacent to the third acoustic receiver, wherein a center point of the fifth acoustic receiver is positioned along the second axis; and positioning a sixth acoustic receiver adjacent to the third acoustic receiver, wherein a center point of the sixth acoustic receiver is positioned along the first axis. In another aspect, the method further includes positioning a seventh acoustic receiver adjacent to the fifth acoustic receiver, wherein a center point of the seventh acoustic receiver is offset from a fifth axis, wherein the fifth axis is perpendicular to the second axis and the third axis, and wherein the offset distance of the seventh acoustic receiver is greater than zero but less than one-half of a wavelength of the incident sound wave. In yet another aspect, the method further includes positioning an eighth acoustic receiver adjacent to the sixth acoustic receiver, wherein a center point of the eighth acoustic receiver is offset from a sixth axis, wherein the sixth axis is perpendicular to the first and fourth axes, and wherein the offset distance of the eighth acoustic receiver is greater than zero but less than one-half of a wavelength of the incident sound wave. The present disclosure may also be viewed as providing an acoustic sensor array. In this regard, one embodiment of such a device may be implemented as follows, among other things. A first acoustic receiver has a center point positioned adjacent to a second acoustic receiver, wherein the second acoustic receiver has a center point, and wherein the center point of each of the first and second acoustic receivers is positioned along a first axis. A third acoustic receiver is positioned adjacent to the first acoustic receiver, wherein the third acoustic receiver has a center point, and wherein the center point of each of the first and third acoustic receivers is positioned along a second axis. The second axis is perpendicular to the first axis. The third axis intersects the center point of the third acoustic receiver, and the fourth axis intersects the center point of the second acoustic receiver, wherein the third and fourth axes are different from the first and second axes, respectively, and are perpendicular. A fourth acoustic receiver is positioned adjacent to the second and third acoustic receivers. The center point of the fourth acoustic receiver is positioned at an offset distance from each of the third and fourth axes. An incident sound wave has a wavelength, and the offset distance of the fourth acoustic receiver is greater than one but less than one-half of the wavelength of the incident sound wave. In one aspect, a controller is added, wherein the controller compares incident sound waves received at a first set of acoustic receivers parallel to incident sound waves received at a second set of acoustic receivers, and compares incident sound waves received at a third set of acoustic receivers parallel to incident sound waves received at a fourth set of acoustic receivers, wherein each set of acoustic receivers is unique and has at least two acoustic receivers. In another aspect, each of the acoustic receivers comprises a transducer. In another aspect, a transducer is positioned adjacent to at least one of the acoustic receivers, wherein the transducer is configured to radiate at least one sound wave. In another aspect, an additional acoustic receiver is positioned adjacent to the second acoustic receiver, wherein the additional acoustic receiver has a center point positioned along the first axis. In another aspect, an additional acoustic receiver is positioned adjacent to the third acoustic receiver, wherein the additional acoustic receiver has a center point positioned along the second axis. In another aspect, a fifth acoustic receiver is positioned adjacent to the third acoustic receiver, wherein the fifth acoustic receiver has a center point positioned along the second axis; and a sixth acoustic receiver is positioned adjacent to the second acoustic receiver, wherein the sixth acoustic receiver has a center point positioned along the first axis. In this aspect, the seventh acoustic receiver is positioned adjacent to the fifth acoustic receiver, wherein a center point of the seventh acoustic receiver is positioned at an offset distance from a fifth axis, wherein the fifth axis is perpendicular to the second axis and the third axis, and wherein the offset distance is greater than zero but less than half the wavelength of the incident sound wave. In yet another aspect, the eighth acoustic receiver is positioned adjacent to the sixth acoustic receiver, wherein a center point of the eighth acoustic receiver is positioned at an offset distance from a sixth axis, wherein the sixth axis is perpendicular to the first axis and the fourth axis, and wherein the offset distance is greater than zero but less than one-half of the wavelength of the incident sound wave. The present disclosure may also be viewed as providing a multi-array acoustic sensor configuration. In this regard, one embodiment of such a device may be implemented as follows, among other things. A housing has a first sensor array and a second sensor array. The second sensor array is positioned adjacent to the first sensor array. Each of the first and second sensor arrays has a first acoustic receiver having a center point; a second acoustic receiver positioned adjacent to the first acoustic receiver, wherein the second acoustic receiver has a center point, wherein the center point of each of the first and second acoustic receivers is positioned along a first axis; a third acoustic receiver positioned adjacent to the first acoustic receiver, wherein the third acoustic receiver has a center point, wherein the center point of each of the first and third acoustic receivers is positioned along a second axis, the second axis being perpendicular to the first axis, wherein the third axis intersects the center point of the third acoustic receiver, and a fourth axis intersects the center point of the second acoustic receiver, wherein the third and fourth axes are different from the first and second axes, respectively, and are perpendicular; and a fourth acoustic receiver positioned adjacent to the second and third acoustic receivers, wherein the center point of the fourth acoustic receiver is positioned an offset distance from each of the third and fourth axes. An incident sound wave has a wavelength, and the offset distance of the fourth acoustic receiver is greater than one but less than one-half of the wavelength of the incident sound wave. Other systems, methods, features, and advantages of the present disclosure will become apparent to those skilled in the art upon examination of the following figures and embodiments. All such additional systems, methods, features, and advantages are intended to be included within this specification, be within the scope of the present disclosure, and be protected by the accompanying patent claims. The acoustic receiver described herein (also referred to as a sensor, a sensor with a transducer, or simply a transducer) provides the detected direction of an object relative to the sensor as range, azimuth, and elevation data within the sensor's field of view, wherein the sensor has transducers positioned therein and wherein the transducers are spaced farther apart than half the wavelength of an incident sound wave. Methods for sensing the distance, azimuth, and elevation of an object relative to the sensor (sensing objects in three-dimensional space) are discussed herein. Furthermore, the use of the sensor for two-dimensional object detection is discussed. Detection of two-dimensional objects reduces the detection directions to two directions: range and azimuth, azimuth and elevation, and range and azimuth. All sensors or transducers can provide robust range, azimuth, and elevation data within the sensor's field of view, where the transducers are spaced farther apart than half the wavelength of a sound wave, which can be referred to as a sonic wavelength. This disclosure proposes three separation methods for three-dimensional sensors. This disclosure also provides certain variations of the above. By removing one of the detection directions, the sensor can be used as a two-dimensional sensor to sense range as well as azimuth or elevation. The sensor can also be simplified to detect only time of arrival, azimuth, and elevation without detecting range, which is desirable when there is detection from another sensor or beacon. The sensor can also be simplified to detect only azimuth and elevation without detecting range, which is desirable when there is detection from another sensor or beacon. The sensor can also be simplified to detect only time of arrival, azimuth, or only elevation. The sensor can also be simplified to detect only azimuth or elevation. Since these are all sub-variants of three-dimensional sensors, this disclosure primarily discusses the design and operation of three-dimensional sensors. It will be appreciated that similar concepts can be used to design and operate two-dimensional sensors. Described herein are certain terms, structures, and definitions that apply to all methods and designs. Some of these terms and structures include: receiver, transducer, transmit burst, resonance decay, transmit burst time, received echo, time of arrival, time of flight, speed of sound at current temperature, distance, time, azimuth, elevation, 3D math, transducer layout, optional additional transducers, angular resolution, incident echo. The following is an explanation of these terms. These methods and designs have variations in some areas, which will be generally described here but will be discussed in detail later in this specification. A receiver can receive sound waves. The receiver can be an acoustic receiver, a sensor, or a transducer. In some examples, the receiver can be a piezoelectric receiver. A transducer is a device used to transmit and receive sound waves. The transducer can be located within the sensor or be part of the sensor itself. A transmit burst is a short burst of sound sent by the sensor, typically 4 to 13 single-frequency ultrasonic waves. The transmit burst can be any ultrasonic frequency, but has a single frequency, typically 23 kHz, 25 kHz, 32 kHz, 40 kHz, or 50 kHz, with a range from 20 kHz to 100 kHz or higher. For simplicity of disclosure, a frequency of 40 kHz will be used as an example. It should be understood that any single frequency will work well. Using lower frequencies (such as 23 kHz or 25 kHz) can produce a long-range sensor for detecting the distance and direction of an object relative to the sensor because the air does not absorb lower frequencies as quickly as higher frequencies. When the transducer initiates a burst of sound, the resonance decay on the transducer may cause the transducer to be unable to detect a certain distance (typically around 30cm) and may not allow reliable phase measurement during this time. Some transducers may resonate faster, but at the expense of receiver sensitivity. The effects of resonance damping can be mitigated by alternating transmit bursts between at least two transducers for each range axis (e.g., azimuth and elevation). This allows for phase measurements of azimuth and elevation to be taken on the other range axis every other measurement cycle during the resonance damping period. In this example, the azimuth and elevation of targets or objects farther than approximately 30 cm from the transducer can be consistently evaluated, while the azimuth and elevation of targets or objects closer than 30 cm from the transducer can be measured every other cycle. Additional transducers or transmitters can be used to remove burst transmissions from transducers used to measure distance directions (such as azimuth and elevation). This can allow the phase of nearby targets (e.g., less than 30 cm from the target) to be measured even during the transmission burst and resonance decay. The transmit burst time is the time from the start of the transmit burst by the transducer. Although for most piezoelectric transducers the amplitude increases as the transducer transmits the sound wave, the burst start time is the time used to transmit the burst. The received echo includes the burst waveform (composed of sound waves) and the resonance decay left by it on the transducer. The time of arrival is obtained when an echo is received, where the sound wave reflects from an object in the sensor's field of view and then returns to the sensor. Alternatively, the sound wave can be transmitted from another sensor, transmitter, beacon, or object. Time of flight is used to estimate distance based on the time elapsed from the time of the transmit burst, along with the speed of sound at the device's operating temperature and the time of arrival. Sensors with accurate distance measurement can use this information to calculate azimuth and elevation using the calculations described herein. Time of flight is the time between the transmission burst and the reception of the echo. Time of flight can be determined by taking the time elapsed between the transmission time and the arrival time. Time of flight can be calculated as follows: Where ToF is time of flight; ToT is time of transmission; and ToA is the time of arrival of the incident sound wave received at the sensor. Because the speed of sound in air changes based on temperature, it is necessary to determine the speed of sound at the current operating temperature. This is usually done using a temperature sensor and is calculated as follows: Among them SOS t is the speed of sound in air, in millimeters per second; T is the temperature of air, in degrees Celsius; 331,300 is the speed of sound at 0°C, in mm / s. The distance of an object or beacon relative to a sensor can be measured using the transmit burst and arrival time in the following equation: ToF is the time of flight, which is the time it takes for a sound wave to travel from the time the transducer emits a burst of transmission to the time the transducer or sensor receives the transmission burst; SOS t The speed of sound at a given or measured air temperature. Alternatively, the distance to a beacon or other external sensor relative to the sensor can be calculated using the following equation: ToF is the time of flight, which is the time it takes for a sound wave to be emitted from a transducer, beacon, or other external sensor until it is received by the sensor. t The speed of sound at a given or measured air temperature. Time is used in calculations instead of distance because time is measured by the microcontroller. Therefore, no conversion to distance is required for all real-time mathematical operations. However, SOS can be used for all equations. tConverting time to distance can be inefficient. The goal of converting distance to time is to find the temporal distance between the transducers. This is done only when the temperature changes. The microcontroller operates by measuring time. This allows the microcontroller or microcontroller within the sensor to use the time measurement directly (without conversion) without requiring extensive computation during the receive portion of the measurement cycle, which can result in better real-time operation. Regarding range, azimuth is measured side-to-side or right-to-left, while elevation is measured up and down. The three-dimensional mathematics of azimuth and elevation are based on the principles of right-angle trigonometry. This is further described in detail with respect to the method and design proposed in this article. All methods and designs described herein can use various layouts of sensors and transducers. In some examples, additional transducers or dedicated transmitters can be used, the benefits of which are described in detail with respect to each method and design presented herein. In industrial environments, where off-axis targets or beacons may be present, it may be necessary to sense the object, azimuth, and elevation at 180 degrees. The sensor's angular resolution is best when directly in front of the sensor and degrades as the object moves to the side. This is due to the physics of sound, measurement noise, and the resolution / accuracy of the phase (zero-crossing) information provided by the sensor. Even so, the sensor can measure the center region very accurately and still obtain reliable estimates within the -90 to +90 degree range, albeit with reduced accuracy. The incident echo can be considered a plane wave. Sound is a spherical wavefront propagating from a source. This is true for reflections (echoes) from objects in the sensor's field of view, or for signals received by the sensor from a beacon or another sensor. This article describes the calculations for determining the direction of arrival of the incident ultrasonic wavefront. Using the calculations shown, the incident wavefront can be considered a plane wave for any two receivers simultaneously. All zero crossings corresponding to the phase of the incident wave occur in the same plane because they correspond to the angle of incidence of the incident echo. That is, because the incident wave can be modeled as a plane, all zero crossings also lie on this plane. For a frequency of 40 kHz, zero crossings repeat every 25 μs (1 / 40 kHz), corresponding to the phase of the incident wave. Figures 3A and 3B are top views of an acoustic sensor array 8 according to an exemplary embodiment of the present disclosure. Figures 3A and 3B illustrate a minimum configuration of acoustic receivers 22 used to determine / calculate the range, elevation, and azimuth of an object. In some examples, at least one of the acoustic receivers 22 may be a transceiver or a sensor having a transducer positioned therein. In some examples, the acoustic receivers 22 may be referred to as receivers, transceivers, sensors, or transducers. It should be understood that these refer to acoustic receivers 22 configured as transceivers or having transducers positioned therein. To determine / calculate range, elevation, and azimuth, a nonlinear configuration of the acoustic receivers 22 relative to one another is preferred. In one example, this can be an L-shaped configuration of the acoustic receivers 22. In some examples, when more than one acoustic receiver 22 is a transceiver, or when each of the acoustic receivers 22 is a transceiver, the transceivers in the acoustic receivers 22 can alternately transmit sound waves. In some examples, additional acoustic receivers 22 can be placed in a vertical or horizontal configuration to provide greater accuracy or coverage when detecting objects. Furthermore, the spacing between the acoustic receivers 22 can vary depending on environmental conditions. For example, while close spacing between the acoustic receivers 22 is not required in this example, close spacing of the acoustic receivers 22 may be advantageous in cluttered environments. FIG. 3B provides an additional example of a nonlinear configuration of the acoustic receivers 22, where at least one acoustic receiver 22 is a transceiver. In some examples, a control circuit 26, such as a microcontroller, processing circuit, or analog-to-digital converter, may be used to evaluate incident sound waves. The control circuit 26 may be a separate circuit from the acoustic receiver 22 or may be integrated within the acoustic receiver 22. Further discussion of the function of the control circuit is discussed below. The first working example presented focuses on 40 kHz sound. If a different frequency is used, the proposed understanding must be used to recalculate the spacing of the sensors (which can be called transducers) and the calculation used to determine the distance direction of the object. Figures 3A and 3B illustrate a suggested transducer configuration. The transducers are aligned vertically (elevation) and horizontally (azimuth) relative to the first transducer A and lie in the same plane. The sensor typically initiates a sound burst of sound waves from either the second transmitter B or the third transmitter C. The transducers transmit short bursts of sound, typically 4 to 13 ultrasonic waves at a single frequency. When the second transducer B activates a sound burst, the resonance decay of the second transducer B will cause the second transducer B to be unable to detect a certain distance (typically about 30 cm), and will not allow azimuth measurement during this period. When the third transducer C activates a sound burst, the resonance decay of the third transducer C will cause this transducer to be unable to detect a certain distance (typically about 30 cm), and will not allow elevation measurement during this period. Alternating the transmission of sound bursts between the second transducer B and the third transducer C allows distance measurement every other measurement period during the resonance decay period. The received echo comprises a burst waveform, which further comprises a sound wave and the resonant decay left on the receiving transducer. For the purposes of this example, a frequency of 40 kHz will be used; however, it should be noted that any wavelength can be used. Specifically, for long distances, lower frequencies may be preferred because they are not absorbed as quickly by air and allow the use of long-range sensors. In this example, the transducers have a diameter of 16 mm and are spaced 17.5 mm from center to center. This spacing allows one wave to fall on the receiving transducer while the other wave falls on a nearby transducer. The following is a set of equations and calculations that can be used to accurately measure the distance direction of an object's position relative to the transducer. The time interval of a 40KHz wave is 25uS. This can be calculated using the following equation: This means that the 40kHz sine wave occurs every 25µS during the echo duration. Because the speed of sound in air changes based on temperature, the speed of sound at the current operating temperature must be determined. This is typically done using a temperature sensor and is calculated as follows: Among them SOS t is the speed of sound in air, in millimeters per second; T is the temperature of air, in degrees Celsius; 331,300 is the speed of sound at 0°C, in mm / s. For the speed of sound in air at 20°C: The following provides an example of calculating the wavelength in millimeters. If the speed of sound at a given or sensed temperature is calculated and the time interval of the waves at a frequency of 40 KHz is known, the following equation can be used to calculate the wavelength in millimeters: Among them SOS t is the speed of sound in air in millimeters per second; time spacing is the known time interval at a given wavelength; wavelength mm is the wavelength of sound at a given frequency in millimeters. In the example where the sensor operates at 40 kHz and the speed of sound in air at 20°C calculated previously is: It will be appreciated that this calculation requires some unit conversions. Next, the time interval between the two transducers can be calculated. Given the center-to-center transducer spacing, the time interval can be calculated. The general equation for the time interval is as follows: Taking a 40KHz frequency as an example, in an environment with an air temperature of 20°C, the center-to-center spacing of the transducer is 17.5mm. The time interval can be calculated as follows: The 50.99uS time interval allows a maximum of 2.034 sound waves to fall on the transducer surface. A-B This is calculated by dividing the time interval of a 40 kHz wave. Because sound can enter from one side or the other, this allows slightly more than four wavelengths to be evaluated. The incident echo can be considered a plane wave. Sound is a spherical wavefront propagating away from its source. This is true for reflections (echoes) from objects in the sensor's field of view, or for signals received by the sensor from beacons or other external sensors. Using the calculations shown, the incident wavefront can be considered a plane wave for any two receivers simultaneously. Sound waves reflect from objects in the field of view and return to the sensor. Time of flight is used to estimate distance based on the time elapsed since the transmit burst, along with the speed of sound at operating temperature and the time of arrival. Sensors with very accurate distance measurement can use this information to calculate azimuth and elevation using right-angle trigonometry. However, with receivers closely spaced and arrival times typically determined to within a few millimeters using accurate methods, this results in low accuracy estimates of azimuth and elevation. However, when the time of arrival is known to an accuracy of less than one-quarter wavelength of the received sound, incident phase information can be determined with certainty. Large objects within the sensor's central field of view allow phase information to be determined with the accuracy required for time of arrival. Smaller objects and objects outside the sensor's primary central field of view are still received and provide usable distance and less accurate phase information than can be used to estimate azimuth and elevation using this method. The echo is processed electronically. Each transducer may have its own amplifier and associated circuitry. For each transducer, the echo is amplified, and this signal is used for two purposes. These operations occur essentially simultaneously. The amplified echo is sent to a slope integrator circuit. The slope integrator circuit may be an electronic circuit. Alternatively, the slope integrator circuit's function may be accomplished by measuring the amplified sine wave using an analog-to-digital converter and then processing it to find the beginning of the signal. Some analog-to-digital converters may be sufficiently accurate to eliminate the need for an amplified sine wave. The echo is also sent to a zero-crossing detector circuit, which amplifies the waveform before being electrically connected to a zero-crossing comparator circuit. Alternatively, the zero-crossing detector circuit's function may be accomplished by observing the amplified sine wave using an analog-to-digital converter and then processing the sine wave to detect zero crossings. Some analog-to-digital converters may be sufficiently accurate to eliminate the need for an amplified sine wave. A slope integrator is used to determine the arrival time, where the rise integrator is sampled by an analog-to-digital converter and the precise point at which the integrator begins to rise from zero (i.e., the exact arrival time) is determined. The slope of the rise can be used to find the starting point of the rise, i.e., the beginning of the received wave, thereby allowing for an accurate estimation of the arrival time. A secondary purpose is to generate an accurate phase from the zero crossing. It should be noted that a zero crossing detector can be a detector that generates an accurate phase from the incident wave. In one example, the zero crossing time measurement has a one-sigma jitter of 50nS centered around the correct value of 0nS. Therefore, in this example, the zero crossing time measurement error is within plus or minus 100nS over 95% of the time. All zero crossings corresponding to the phase of the incident wave occur in the same plane because they correspond to the angle of incidence of the incident echo. That is, because the incident wave can be modeled as a plane, all zero crossings also lie on this plane. For this incident wave, when off-axis, at a frequency of 40 kHz, its zero crossings repeat every 25 μs (1 / 40 kHz), and the time between transducers (time of flight × distance) is greater than 12.5 μs, so the corresponding phase must be determined. The slope integrator allows the calculation of the exact time of arrival, which, when combined with the burst transmission time and the speed of sound, yields the range to the target. To correctly determine the phase, the time of arrival accuracy must always be within half the wavelength of the detected sound. Time of arrival accuracy is within a few millimeters, allowing the sensor to use phase-corrected time of arrival to calculate azimuth and elevation using both time of arrival and phase. To calculate the azimuth angle using the phase-corrected arrival times, the arrival time difference between the arrival times of two different transducers needs to be calculated, and then the closest matching phase zero crossing of the same polarity is found. The zero crossing found can be a rising zero crossing or a falling zero crossing, but the chosen zero crossing must remain consistent. That is, if a rising zero crossing is chosen, all measurements must be made with respect to the rising zero crossing, and vice versa. For the purposes of this example, a rising zero crossing will be used. Time is used in the calculations rather than distance because time is measured by the microcontroller and therefore does not need to be converted to distance for all real-time operations. The conversion from distance to time is done to find the time distance between the transducers. The time distance between the sensors is only found when the temperature changes. This allows the microcontroller and sensors to use the time measurements they make directly (without conversion) without requiring extensive calculations during the receive portion of the measurement cycle, which allows for better real-time operation. For example, if the arrival time difference between the first transducer A and the second transducer B is 20uS, then the arrival time (ToA) for the first transducer A is found. A ) is closest to the rising zero crossing, and then 20uS later, the arrival time (ToA) of the second transducer B B ), find the closest zero crossing after 20uS. For the purpose of this example, assume that the ToA A ToToA B The closest rising zero crossing of 20uS occurs at 28uS. This can be called ToAP A-B This elevation angle measurement, made using the phase of the incident plane wave, is much more accurate than the elevation angle measurement made using the arrival time alone. Convert the distance between the receiving transducers to time. Using the previously calculated 50.99uS center-to-center transducer spacing and applying a 20uS arrival time difference, the azimuth angle is calculated to be 23.09 degrees using the following equation: Where the general equation is: The equation that applies to the instance value is: However, the azimuth angle may be calculated with higher accuracy using the closest rising zero crossing of 28uS as described above. It can be seen that using the arrival time alone will have an error of about 10 degrees. Using the arrival time phase (ie closest to the identified zero crossing) improves the accuracy of the angle measurement. It should be noted that the elevation angle measurement and calculation is a repeat of the azimuth angle measurement, except that it uses the first transducer A and the third transducer C, so it is ToA A andToA C , and ToAP A-C Because the calculation of elevation angle relies on the same equations and concepts as the calculation of azimuth angle, using only different values, the calculation will not be repeated for the sake of brevity. It should also be noted that the above equation can be further simplified by using the inverse sine, as this removes the "90-" seen in the previous azimuth formula. The general formula is as follows: FIG4 is a top view of an acoustic sensor array 8 according to an exemplary embodiment of the present disclosure. FIG4 illustrates the three acoustic receivers 22 shown in FIG3A-3B, but now with an additional fourth component. This fourth component can be a transmitter 24 or transducer that transmits only sound waves or sound bursts. However, in some examples, the fourth component can also be an acoustic receiver 22 that transmits and receives both sound waves, thereby increasing the total number of acoustic receivers 22 capable of transmitting and receiving incident sound waves to four. The functionality and potential advantages of the transmitter 24 are discussed herein. A fourth transducer can be added to the system, where the fourth transducer transmits only. This eliminates the resonance decay on the receiving transducer and allows the use of near echoes during the resonance decay period to determine azimuth and elevation. The use of an additional fourth transducer removes the burst transmission from the transducer used to determine azimuth and elevation, allowing it to be used for close targets. Even during the transmit burst and resonance decay period, the phase from these nearby targets can be measured by the receiving transducer. Referring to Figures 3A through 4, the minimum transceiver and / or acoustic receiver 22 and acoustic transmitter 24 configuration required to determine the range, elevation, and azimuth of an object is any of the following: three transceivers; three acoustic receivers 22; three acoustic receivers 22 and one acoustic transmitter 24; or any combination thereof. When measuring an object in three dimensions, it is preferred that the acoustic receivers 22 and / or transceivers be placed in a nonlinear configuration. Figure 4 shows a configuration having the minimum number of acoustic receivers 22 required to determine / calculate the range, elevation, and azimuth of an object, with the transmitter 24 positioned proximate to or within the array of acoustic receivers 22. In some examples, the transmitter 24 can be a transceiver, and the acoustic receiver 22 can also be a transceiver. Thus, this configuration provides at least one transceiver and four ways to receive incident sound waves. FIG5A is a front perspective view of an acoustic sensing device 10 according to an exemplary embodiment of the present disclosure. FIG5B is a top view of the acoustic sensing device 10 of FIG5A according to an exemplary embodiment of the present disclosure. FIG5C is a bottom view of the acoustic sensing device 10 of FIG5A according to an exemplary embodiment of the present disclosure. The following examples refer to Figures 5A to 5C. Similar to the previous examples, this description focuses on 40Khz sound. If a different frequency sound is used, the spacing and mathematical relationships must be recalculated using the proposed understanding. In this example, the acoustic sensing device 10 can measure objects or beacons that emit sound waves in three-dimensional space. Here, the waveguide 12 of the acoustic sensing device 10 has at least three acoustic paths 14. Each of the at least three acoustic paths 14 is formed by the interior space of the waveguide 12, bounded by acoustic path sidewalls 16, and each has a central axis 30. Each of the at least three acoustic paths 14 has a first end 14a positioned at the first opening 18 and a second end 14b positioned at the second opening 20. At least three acoustic receivers 22 or transducers are each connected to the second opening 20 of the waveguide 12 of one of the at least three acoustic paths 14. With respect to the central axes 30 of the at least three acoustic paths 14, at the second ends 14b of the at least three acoustic paths 14, the distance D2 between the central axes 30 of the at least three acoustic paths 14 is greater than the distance D1 between the central axes 30 of the at least three acoustic paths 14 at the first ends 14a of the at least three acoustic paths 14. In some examples, the waveguide 12 and the acoustic path sidewalls 16 can be made of plastic, metal, or a composite material. The acoustic path 14 located within the interior space of the waveguide 12 can have a frustoconical shape, such that each first opening 18 has a diameter smaller than the diameter of the second opening 20. In some examples, each first opening 18 can be located on the same flat surface. FIG5B provides a top view of the acoustic sensing device 10 of FIG5A according to another exemplary embodiment of the present disclosure. Each first opening 18 is located on the top flat surface of the waveguide 12, wherein a distance D1 defines the distance between the central axes 30 of the first group of first openings 18a and the second group of first openings 18b. The first group of first openings 18a can include two first openings 18 spaced apart by a distance D1 that is greater than zero but less than half the incident sound wave. Similarly, the second group of first openings 18b can include two first openings 18 spaced apart by a distance D1 that is greater than zero but less than half the incident sound wave. Either the first set of first openings 18a or the second set of first openings 18b can be used to measure either the azimuth or elevation of an object or beacon. FIG5C is a bottom view of the acoustic sensing device 10 of FIG5A according to another exemplary embodiment of the present disclosure. Referring to FIG5A through FIG5C , each second opening 20 is covered by an acoustic receiver 22 or transducer. However, in this example, each second opening 20 is similarly located on the same plane of the waveguide 12, with each second opening 20 being located on the bottom plane of the waveguide 12. Each second opening 20 has a distance D2, which defines the distance between the central axes 30 of each second opening 20 in the second end 14b. The distance D2 between the central axes 30 of each second opening 20 need not be the same and can vary. In other words, the spacing of the acoustic receivers 22 and the distance D2 between each acoustic receiver 22 do not affect the operation of the acoustic sensing device 10. For example, an acoustic sensing device 10 having a cylindrical waveguide 12 may have a top side and a bottom side. Three first openings 18 may be located on the top side of the waveguide 12, each having a diameter of 4.4 mm. The distance D1 between the central axes 30 of each first opening 18 in the first set of first openings 18a may be 5.1 mm, which corresponds to a distance D1 less than half the wavelength of the incident sound wave. Similarly, the distance D1 between the central axes 30 of each first opening 18 in the second set of first openings 18b may be 5.1 mm, which corresponds to a distance D1 less than half the wavelength of the incident sound wave. That is, if a shape similar to a right triangle is drawn between the central axes 30 of each first opening 18, the base and height of the triangle will have a length of 5.1 mm. An acoustic receiver 22 or transducer may be positioned on the bottom side of the waveguide 12, with the distance D2 between the central axes 30 of the second openings 20 being greater than the distance D1 between the central axes of the first openings. In this example, the acoustic receivers 22 or transducers may have a diameter of 16 mm, and the acoustic paths 14 may be positioned so that the first openings 18 and second openings 20 are opposite or aligned with each other in the stacking plane. The second openings 20 (and therefore the acoustic receivers 22 or transducers) may be positioned anywhere on the bottom side of the waveguide 12, i.e., the distance D2 between the central axes 30 of each of the first openings need not be equal. In situations where close or unequal spacing of the second openings 20 (and therefore the acoustic receivers 22 or transducers) is desired, certain unequal distance D2 layouts may be preferred. However, it is preferred that all acoustic paths 14 have substantially the same length. Here, "substantially the same" is understood to mean that the length differences are so small that they do not introduce statistically significant errors when calculating the distance of an object or beacon from the waveguide 12. Such length differences may be caused by typical manufacturing inconsistencies and errors but do not affect the operation and accuracy of the distance measurement. The acoustic paths 14 preferably have substantially the same length to facilitate the incident sound wave's travel through the acoustic paths 14 and to ensure that the incident sound wave travels the same distance regardless of which acoustic path 14 the incident sound wave travels through. The calculations presented herein assume that the acoustic paths 14 have the same length so that the incident sound wave travels the same distance regardless of the acoustic path 14 the incident sound wave takes. In some examples, the acoustic receiver 22 may be referred to as a receiver, a transceiver, a sensor, or a transducer. It should be understood that these refer to acoustic receivers 22 configured as transceivers or having transducers positioned therein. In some examples, a control circuit 26, such as a microcontroller, processing circuit, or analog-to-digital converter, may be used to evaluate incident sound waves. The control circuit 26 may be a separate circuit from the acoustic receiver 22 or may be integrated within the acoustic receiver 22. Further discussion of the function of the control circuit is discussed below. An example operation of the acoustic sensing device 10 shown in Figures 5A to 5C is described herein. The examples, configurations, and measurements presented are for illustrative purposes only and are not intended to limit the scope of this disclosure. The sensor typically initiates a sound burst consisting of sound waves from either the second transducer B or the third transducer C. The sensor transmits short sound bursts, typically 4 to 13 single-frequency ultrasonic waves. When the second transducer B initiates a sound burst, the resonance decay on the second transducer B may render the transducer unable to detect a certain distance (typically approximately 30 cm), and will not allow azimuth measurement during this time. When the third transducer C initiates a sound burst, the resonance decay on the third transducer C may render the transducer unable to detect a certain distance (typically approximately 30 cm), and will not allow elevation measurement during this time. Alternating the sound bursts between the second transducer B and the third transducer C allows elevation and azimuth to be measured every other measurement period during the resonance decay period. The received echo comprises a burst waveform, which further comprises an acoustic wave and the resonant decay left by the burst waveform on the receiving transducer. For the purposes of this example, a wavelength with a frequency of 40 kHz will be used. Note that in this example, any size transducer can be used, and the center-to-center spacing of the transducers is not a concern. When receiving an echo, the acoustic wave reflects from an object in the transducer's field of view and returns to the sensor. Once the sensor receives the echo, it can be electronically processed. Each transducer may have its own amplifier and associated circuitry. For the first transducer A, the second transducer B, and the third transducer C, the echo is amplified, and this signal is used for two purposes. The amplified echo is sent to a slope integrator circuit, which can be a dedicated electronic circuit. Alternatively, the slope integrator circuit's function can be accomplished by measuring the amplified sine wave using an analog-to-digital converter and then processing it to find the beginning of the signal. Some analog-to-digital converters may be sufficiently accurate to eliminate the need for an amplified sine wave. The echo can also be sent to a zero-crossing detector circuit, which can be a zero-crossing comparator circuit. Alternatively, the zero-crossing comparator circuit's function can be accomplished by examining the amplified sine wave using an analog-to-digital converter and then processing it to detect zero crossings. Some analog-to-digital converters may be sufficiently accurate to eliminate the need for an amplified sine wave. The slope integrator determines the arrival time of the analog-to-digital converter's sampling of the rising integrator and determines the exact point at which the integrator begins to rise from zero (i.e., the exact arrival time). A secondary purpose is to derive accurate phase from zero crossings. The zero crossings of the incident wave all occur in the same plane because they correspond to the angle of incidence of the incident echo. That is, because the incident wave can be modeled as a plane, all zero crossings also lie on this plane. Time of flight is used to estimate the distance to objects in the sensor's field of view. This estimate is based on the time elapsed between the onset of the transmit burst (transmit time) and the arrival time, and the speed of sound at the operating temperature. The transmit time, arrival time, and speed of sound at the operating temperature can be used to determine the distance of an object relative to the sensor using the following equation: Figures 5B through 5C illustrate additional aspects of the waveguide 12. By using the waveguide 12, the sensors 22 can have any diameter and any center-to-center spacing relative to each other. The waveguide 12 can have three first openings 18, each having a diameter smaller than the diameter of the corresponding three second openings 20. Furthermore, the distance D1 between the center axes 30 at each first opening 18 is smaller than the distance D2 between the center axes 30 at each second opening 20. A sensor can be connected, attached, or otherwise positioned at each of the three second openings 20. In some examples, the sensor 22 attached to the second opening 20 can be tilted to accommodate the angled linear path of the acoustic path 14. In some examples, the path length of each acoustic path 14 is the same. It should be noted that while the center-to-center spacing of the sensors 22 may not be critical, a center-to-center spacing of the distance D1 between the center axes 30 at each first opening 18 may be required for distance calculations. Thus, the first opening 18 of the waveguide 12 may have a diameter and be positioned such that the center-to-center spacing between the central axes 30 is less than one-half the wavelength for the selected receive frequency and minimum operating temperature of the sensor. This is further described in the following examples and calculations. In some examples, the acoustic receiver 22 may be referred to as a receiver, a transceiver, a sensor, or a transducer. It should be understood that these refer to acoustic receivers 22 configured as transceivers or having transducers positioned therein. The examples, configurations, and measurements presented are for illustrative purposes only and are not intended to limit the scope of the present disclosure. This example uses a 40 KHz frequency with the acoustic sensing device operating at -40°C. The distance direction can be calculated as follows: First, the speed of sound at the operating temperature must be calculated using the equations and understanding presented here: Next, for a frequency of 40 KHz, calculate the time it takes to travel one wavelength. This value is then multiplied by the speed of sound calculated at the operating temperature: The resulting wavelength value is then divided by two to obtain the length of one-half wavelength. From this information, a center-to-center spacing can be selected. For illustrative purposes, a 2.5 mm opening is described with a center-to-center spacing of 3.5 mm between the center axes 30 of the first opening 18. A center-to-center spacing of 3.5 mm allows for normal operation in temperatures as low as -40°C. This spacing is repeated for the first opening 18 and the second opening 20 for both elevation and azimuth. Using this understanding, it can be understood that the waveguide 12 guides the sound from the transducer to the first opening 18 and the second opening 20 while maintaining phase. If a different frequency of sound is used, the spacing must be recalculated using the understanding presented herein. Using this waveguide 12 design, less than half of the 40 kHz wave falls on at least one of the first openings 18 corresponding to the sensors measuring azimuth and elevation. The sound wave is guided to the sensor using the acoustic path 14 of the waveguide 12 and the phase is evaluated. In one embodiment, a zero-crossing circuit such as a comparator is used to evaluate the phase information of the incident sound wave. In another embodiment, an analog-to-digital converter can be used to evaluate the phase and then the wave. To estimate the elevation, at each sensor, the zero crossings of each sound wave received at its individual sensor are compared. The same principle applies to measuring azimuth, where horizontally adjacent first openings 18 are horizontally adjacent to the center first opening 18. All of the first openings 18 can receive the same portion of half the sound wave. The following is a general overview of the calculations used to determine the azimuth angle according to this example. First, the zero crossing times of the same polarity at the first transducer A, the second transducer B, and the third transducer C are recorded. After recording this information, the time difference, previously known as the ToAP measurement of the azimuth angle, can be calculated. A-B The calculations provided previously can then be applied to determine the angle of arrival using the speed of sound at the operating temperature and the center-to-center distance between the first openings 18 corresponding to the first transducer A and the second transducer B. This angle of incidence can be calculated using time units or distance units. In configurations using a microcontroller, time units may be preferred because the arrival time is directly and repeatedly measured, eliminating the need for repeated conversion from time to distance during measurement. The elevation angle can be calculated using the principles presented above and taking advantage of the zero crossing time of the same polarity between the first transducer A and the second transducer B: Table 1 is provided, which illustrates one method for a microcontroller to perform or process the calculations presented herein. The method for calculating the angle of arrival presented in Table 1 differs from the calculations presented previously and may offer additional advantages. Once the operating temperature is known, all calculations are performed in advance and stored in a lookup table, as illustrated in Table 1. Because temperature may change slowly while sensor readings may be rapid, precalculations may allow for faster or more sensitive sensor operation. For simplicity of presentation, only one degree of resolution is used, and therefore 180 values ​​corresponding to each degree are shown. In some instances, an angular resolution greater than one degree may be required, and therefore fewer than 180 values ​​may be stored. In another instance, the angular resolution may be finer and include values ​​between degrees. In this case, more than 180 values ​​may be stored. A modulo operator allows the µS value to be precalculated and then read by the microcontroller for each degree of interest. The modulo operator is the remainder after a division operation. The microcontroller can read the zero crossing data to find the zero crossings on the first transducer A, the second transducer B (for azimuth), and the third transducer C (for elevation). Note that at zero degrees, the microcontroller's reading of the µS value wraps around between the positive and negative directions. That is, the microcontroller measures the time until the next zero crossing. When the angle becomes negative, the microcontroller measures the next zero crossing of the sound wave. This operation provides the same result, but optimizes speed for the microcontroller. Alternatively, the microcontroller could use additional time to sequence this to execute the previously proposed path, but in the current case, this would take additional time. The microcontroller reads the first transducer A and then looks for the next zero crossing of the same polarity on the second transducer B (for azimuth). Substantially simultaneously, the microcontroller looks for the next zero crossing on the third transducer C (for elevation). At zero degrees, the zero crossings occur simultaneously. At +1 degree, the adjacent zero crossing is 0.200 µS later, but at -1 degree, the next zero crossing (as measured by the microcontroller) occurs at 24.800 µS (25 µS - 0.20 µS). Within the negative degree range, the corresponding zero crossing occurs before the zero crossing of the first transducer A and wraps around. This becomes more apparent using the information in Table 1. Table 1. Referring to Table 1, values ​​from -90 to 90 degrees are covered. The initial calculations (shown in column 6) have been discussed previously. It should be noted that the values ​​provided in Table 1 are for an operating temperature of -40°C, a sound frequency of 40 kHz, and a center-to-center spacing of 3.5 mm between the first openings 18. The formula from degrees to time is a sine formula. The modulo operator converts the µS calculated by the previously proposed formula into zero crossings measured by the microcontroller. This method and design allows each echo to be directly estimated for both azimuth and elevation. Compared to the first proposed design and method, the target or object can be much closer in range (less than 30 cm) and still have range, azimuth, and elevation estimated. FIG6 is a front perspective view of an acoustic sensing device 10 according to an exemplary embodiment of the present disclosure. A transducer or dedicated transmitter 24 eliminates transmit resonance decay at acoustic receiver 22, which may be a transceiver, and allows the use of near echoes during the transmit burst transducer resonance decay period to determine azimuth and elevation. Furthermore, because acoustic waves are not transmitted from transmitter 24 using acoustic path 14 or waveguide 12, more usable acoustic energy is emitted from transmitter 24, allowing for better measurements in most situations. In some instances, transmitter 24 may also be a transducer for receiving sound waves from long-range targets. This configuration provides the most accurate distance measurement for long-range targets because the received signal strength is much higher. The placement of transmitter 24 is not critical and can be closer or farther from first opening 18 in waveguide 12. It should be noted that the description and calculations described above with respect to FIG5A through FIG5C also apply to instances with a transmitter 24 or with additional acoustic receivers 22. FIG7 is a side perspective view of an acoustic sensing device according to an exemplary embodiment of the present disclosure. In this example, the waveguide 12 is folded, with acoustic receivers 22 or transducers located on the sidewalls of the waveguide 12. Due to this configuration, each of the first opening 18 and the second opening 20 lies on a vertical plane, making the central axis 30 nonlinear. In other words, in this example, the acoustic path 14 is nonlinear and may have one or more bends, twists, or turns between the first end 14a and the second end 14b. In some examples, an acoustic transmitter 24 may be present. In this example, at least one of the at least three acoustic receivers 22 or transducers receives at least one incident sound wave from the acoustic transmitter 24. Several aspects of these exemplary embodiments are also applicable to other examples, including the use and positioning of acoustic emitters 24. In some examples, acoustic emitters 24 may be connected to waveguide 12 and have an emitting surface 24a. Emitting surface 24a may be the side of acoustic emitter 24 capable of emitting sound waves. Emitting surface 24a may be substantially aligned with the surface of waveguide 12 at the location of the first opening 18 for each of the at least two acoustic pathways 14. In another example, acoustic emitters 24 may be positioned recessed in waveguide 12 relative to the surface of waveguide 12 at the location of the first opening 18 for each of the at least two acoustic pathways 14. In this example, the interior space of the waveguide forms an acoustic duct to guide sound waves outward from sound emitter 24. The sound guide 26 may have a frustoconical shape similar to the acoustic path 14, a bell shape, a horn shape, or any shape that guides sound waves from the emitting surface 24a through the sound guide 26 and then away from the waveguide 12 and ultimately reflects off an object, if present. In a preferred embodiment, each transducer 22 can be an ultrasonic receiver, and the acoustic transmitter 24 can be an ultrasonic transmitter. The ultrasonic receiver and ultrasonic transmitter can have a diameter of 8 mm to 50 mm. The ultrasonic receiver and ultrasonic transmitter can receive and transmit frequencies, respectively, typically 23 kHz, 25 kHz, 32 kHz, 40 kHz, and 50 kHz, falling within the range of 20 kHz to 100 kHz or higher. These ultrasonic receivers and ultrasonic transmitters can be combined into a single unit to form a transceiver, so that the same transceiver can transmit ultrasound and receive reflected ultrasound emitted by the ultrasonic transmitter, or receive incident ultrasound emitted by an object. The minimum transducer 22 and acoustic transmitter 24 configuration required to determine the range, elevation, and azimuth of an object is any of the following: three acoustic receivers 22 or transducers; three acoustic receivers 22 or transducers and one acoustic transmitter 24; or any combination thereof. When measuring an object in three dimensions, it is preferred to place the acoustic receivers 22 or transducers in a nonlinear configuration. In some examples, the acoustic receivers 22 or transducers may alternate between transmitting and receiving over a period of time. In a configuration with four transceivers arranged in a 2×2 configuration (not shown), alternating side-to-side transmission of the acoustic transmitters 24 while all acoustic transmitters 24 receive may provide more robust object detection. The use of a waveguide 12 allows sampling of the incident waveform at distances less than half a wavelength, and similarly allows the use of acoustic receivers 22 or transducers spaced much further apart than half a wavelength. In other words, while the acoustic receivers 22 or transducers can be spaced farther apart, the sonic and ultrasonic waves are received by the first openings 18 positioned less than half a wavelength apart from each other, and thus, each individual wave of the sonic and ultrasonic waves can be evaluated by the acoustic receivers 22 or transducers. The use of a waveguide 12 having a linear or nonlinear acoustic path 14 allows for the routing of phase information as well as the sonic and / or ultrasonic waves to the acoustic receivers 22 or transducers. FIG8A is a perspective view of an acoustic sensor array 8 within a housing 28 according to an exemplary embodiment of the present disclosure. In this example, four acoustic receivers 22 may be positioned within the housing 28. Further aspects of this configuration are described with respect to FIG8B. It should be understood that incident sound waves 34 may arrive from any angle or direction, and that the illustrated directions of incident sound waves 34 are for illustrative purposes only and are not intended to limit the scope of the present disclosure or the functionality or operability of the acoustic sensor array 8 and its components. FIG8B is a top view of the acoustic sensor array 8 of FIG8A according to an exemplary embodiment of the present disclosure. The acoustic sensor array has a first acoustic receiver 22A, wherein the first acoustic receiver has a center point 32A. A second acoustic receiver 22B is positioned adjacent to the first acoustic receiver 22A, and the second acoustic receiver has a center point 32B. The center points 32A, 32B of each of the first acoustic receiver 22A and the second acoustic receiver 22B are along a first axis D. 1. The third acoustic receiver 22C is positioned adjacent to the first acoustic receiver 22A, wherein the third acoustic receiver 22C has a center point 32C, wherein the center points 32A, 32C of each of the first acoustic receiver 22A and the third acoustic receiver 22C are along the second axis D 2 Positioning. Second axis D 2 perpendicular to the first axis D 1, and the third axis D 3 intersects the center point 32C of the third acoustic receiver 22C, and the fourth axis D 4 intersects the center point 32B of the second acoustic receiver 22B. The third axis D 3 perpendicular to the fourth axis D 4. The fourth acoustic receiver 22D is positioned adjacent to the second acoustic receiver 22B and the third acoustic receiver 22C, and the center point 32D of the fourth acoustic receiver 22D is at a distance of 32° from the third axis D. 3 and the fourth axis D 4 are positioned at an offset distance. The incident sound wave 34 has a wavelength corresponding to the frequency of the incident sound wave 34. The fourth acoustic receiver 22D is aligned with the third axis D. 3 and the fourth axis D The offset distance 4 is a distance greater than zero but less than one-half the wavelength of the incident sound wave 34. Acoustic receivers 22A, 22B, 22C, and 22D can themselves be or otherwise have transducers or other sound-transmitting components positioned within the acoustic receivers 22A, 22B, 22C, and 22D. In some examples, control circuit 26, a microcontroller, processing circuitry, or an analog-to-digital converter, can be used to evaluate the incident sound waves. Control circuit 26 can be a separate circuit from acoustic receiver 22 or can be integrated within acoustic receiver 22. Further aspects and details of control circuit 26 are described herein. Incident sound waves 34 can be measured in parallel between the groups of acoustic receivers 22A, 22B, 22C, and 22D. For example, the first group of acoustic receivers 22A and 22B may include a first acoustic receiver 22A and a second acoustic receiver 22B. The second group of acoustic receivers 22C and 22D may include a third acoustic receiver 22C and a fourth acoustic receiver 22D. Control circuitry 26 can be used to measure and compare incident sound waves 34 on the surfaces of each group of acoustic receivers 22A, 22B, 22C, and 22D to provide more accurate distance measurements. For the purposes of this example, the first group of acoustic receivers 22A and 22B and the second group of acoustic receivers 22C and 22D can be considered to measure azimuth in parallel. The third group of acoustic receivers 22A and 22C may include the first acoustic receiver 22A and the third acoustic receiver 22C. The fourth group of acoustic receivers 22B and 22D may include the second acoustic receiver 22D and the fourth acoustic receiver 22D. Control circuitry 26 can be used to measure and compare incident sound waves 34 on the surfaces of each set of acoustic receivers 22A, 22B, 22C, and 22D to provide a more accurate distance measurement. For the purposes of this example, the third set of acoustic receivers 22A and 22C and the fourth set of acoustic receivers 22B and 22D can be considered to be measuring elevation angles in parallel. Parallel measurements are understood to mean that two different sets of acoustic receivers 22A, 22B, 22C, and 22D measure the incident sound waves 34 twice. Control circuitry 26 or another microcontroller can be used to process the data obtained from these parallel measurements and perform correlation calculations on the distance directions corresponding to the sets (i.e., the azimuth and elevation measurements corresponding to their respective sets). In some examples, acoustic receivers 22A, 22B, 22C, and 22D may be referred to as receivers, transceivers, sensors, or transducers. It should be understood that these refer to acoustic receivers 22A, 22B, 22C, and 22D configured as transceivers or having transducers positioned therein. The examples, configurations, and measurements presented are for illustrative purposes only and are not intended to limit the scope of the present disclosure. This example focuses on 40Khz sound. If a different frequency sound is used, the spacing of the transducers and other calculations must be recalculated using the understanding presented herein. For illustrative purposes, this description will discuss the configuration of a waveguide that uses four 16mm transducers to estimate azimuth and elevation. The center-to-center spacing of transducer A to transducer B is 21 mm. The center-to-center spacing of transducer A to transducer C is 21 mm. Transducer D is offset or inset by 3.5 mm, which is less than half the wavelength of 40 kHz at -40°C, or 3.83 mm. For both the elevation and azimuth axes, this results in a direct spacing of 17.5 mm from the AB azimuth axis and 17.5 mm from the AC elevation axis. And the distance from D to B, or from D to C, is a slightly diagonal spacing of 17.85 mm. A method for calculating the diagonal spacing is provided below, where the general equation is: in a is the offset or indentation of the fourth transducer; b is the direct distance between the azimuth and elevation axes. The general equation that applies to this example is: Transducers A and B are directly in the azimuth measurement direction. Transducers C and D are nearly parallel to transducers A and B. Transducers A and C are directly in the elevation direction, and transducers B and D are nearly parallel to transducers A and C. A working example of the transducer configuration of Figures 8A to 8B is provided. The examples, configurations, and measurements presented are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The sensor typically initiates a transmission burst from either transducer C or transducer B. A short sound burst, typically 4 to 13 single-frequency ultrasonic waves, is sent by the sensor. When transducer B initiates a sound burst, the resonance decay on transducer B will cause this transducer to be unable to detect a certain distance (typically about 30 cm) and will not allow azimuth to be measured during this time. When transducer C initiates a sound burst, the resonance decay on transducer C will cause the transducer to be unable to detect a certain distance (typically about 30 cm) and will not allow elevation to be measured during this time. Alternating the transmission of sound bursts between transducers B and C allows elevation and azimuth to be measured every other measurement cycle during the resonance decay period. The received echo comprises a burst waveform, which further comprises a sound wave and the resonant decay left by the burst waveform on the receiving transducer. For illustrative purposes, 40 kHz sound is used. It should be noted that any wavelength can be used. For example, for long distances, lower frequencies such as 23 kHz or 25 kHz can be used because they are not absorbed as quickly by air and allow for longer-range sensors. This example further uses transducers with a diameter of 16 mm. The center-to-center spacing between transducers A and B is 22 mm, and the center-to-center spacing between transducers A and C is also 22 mm. This spacing allows one wave to land on one of the receiving transducers, and potentially a different wave to land on the other receiving transducer. Using transducers A to B, and A to C, that are 16mm diameter and spaced 21mm center to center, this allows one wave to land on the receiving transducer and possibly a different wave to land on a nearby transducer. Using the calculations proposed previously, it is known that the time interval of the 40KHz waves is 25uS. This means that a 40KHz sine wave occurs every 25uS during the duration of the echo. It is well known that the speed of sound in air changes with temperature. Using the calculations proposed previously, the speed of sound in air at 20°C is 343214.6227mm / S. Using the speed of sound in air at a given operating temperature, the wavelength (in mm) can be calculated by multiplying the time interval of the 40KHz waves (25uS) by the speed of sound, which gives a value of 8.57mm. Using the center to center spacing of the transducers, the time interval (TS A-B ) can be calculated using the following equation: When the center-to-center transducer spacing is 22 mm, a maximum of 2.448 waves can fall on the transducer face. A-B This is calculated by dividing the time interval of the 40 kHz wave. Because sound waves can enter from one side or the other, this allows slightly more than four wavelengths to be evaluated. The center-to-center spacing from transducer C to transducer D and from transducer B to transducer D is 17.85mm or a time interval of 52.01uS, which is calculated using the understanding presented herein. This 17.85mm spacing allows 2.08 waves to land on this transducer. Waves coming directly from the side can have a wave spacing of 17.5mm, so when performing the trace calculation, it is better to use 17.68mm, which is the average between 17.5mm and 17.78mm. This offset of up to 0.175mm will result in an error of up to 0.51uS, which is calculated by dividing the offset length (in mm) by the speed of sound at operating temperature. This error is not enough to cause a problem. Sound waves reflect from objects in the transducer's field of view and return to the sensor (or originate from another sensor or beacon). Time of flight is used to estimate distance based on the time elapsed since the transmit burst occurred, along with the speed of sound at operating temperature and the time of arrival. Sensors sensing distance measurements can use this information to calculate azimuth and elevation using the calculations presented herein. With receivers closely spaced together and arrival times typically determined to within a few mm using accurate methods, this can lead to low estimates of azimuth and elevation. Even so, these estimates can still be useful. For example, distance determined by time of flight (which is the difference between the transmit time and the arrival time) can be used to double-check that the direction of arrival phase estimate is within the correct range. Each transducer has its own amplifier and associated circuitry. For each transducer, the echo is amplified, and this signal is used for two purposes. These occur simultaneously. The amplified echo is sent to a slope integrator circuit. This can be an electronic circuit, but it can also be accomplished by measuring the amplified sine wave with an analog-to-digital converter and then processing it to find the beginning of the signal. Some analog-to-digital converters may be sufficiently accurate to eliminate the need for an amplified sine wave, or they may be used in conjunction with an amplifier. The amplified echo is also sent to a zero-crossing detector circuit. This can be an amplified waveform and zero-crossing comparator circuit, but it can also be accomplished by observing the amplified sine wave with an analog-to-digital converter and then processing it to detect zero crossings. Some analog-to-digital converters may be sufficiently accurate to eliminate the need for an amplified sine wave. A slope integrator is used to determine the arrival time, where the rising integrator is sampled by the analog-to-digital converter and the exact point at which the integrator starts to rise from zero (i.e., the exact ToA) is determined, where the slope of the rise can be used to find the starting point of the rise, i.e., the beginning of the received wave, thereby allowing accurate estimation of the arrival time. The zero crossings corresponding to the phase of the incident wave all occur in the same plane because these zero crossings correspond to the angle of incidence of the incident echo. Since all transducers are in the same plane, this allows the evaluation to be simplified. That is, because the incident wave can be modeled as a plane, all zero crossings are also in this plane. Because this incident wave has a zero crossing that repeats every 25uS (1 / 40Khz) for a frequency of 40KHz when off-axis, and the time between transducers (the product of flight time and distance) is greater than 12.5uS, the corresponding phase information is used to determine the elevation and azimuth angles. If the receiving transducers are moved out of the same plane, the calculations and methods described remain valid as long as the new configuration has associated calculations to accommodate the new configuration. Time is used in calculations rather than distance because time is measured by the microcontroller, so no conversion to distance is required for all real-time operations. The conversion from distance to time is done to find the temporal distance between the transducers. The temporal distance between the transducers is only found when the temperature changes. This allows the sensor to use its time measurements directly (without conversion) during the receive portion of the measurement cycle without extensive calculations. This allows for better real-time operation. The number of incident waves includes at least one transmitted wave from the transducer and a resonant decay that is typically longer than the echo wave. Therefore, the piezoelectric transducer will continue to resonate at the transducer's resonant frequency after the acoustic burst, extending the number of available waves for measurement. Therefore, when more waves are included in the transmit burst, more waves are available for measurement. For example, 13 waves may be transmitted, allowing for more waves, and the resonant decay from the transducer will significantly expand the number of measurable waves. A wave falls on receivers A, B, C, and D. When a wave is present at all receivers A, B, C, and D, zero crossings are sampled, with a sampling duration that allows at least one full-wave zero-crossing signal from each transducer relative to the others to be captured. For directions of arrival close to zero degrees, only one wave can fall on all transducers. As the direction of arrival moves toward positive or negative 90 degrees, more and more waves are incident on the face of the transducer. Even so, only waves need to be sampled to measure at least one zero-crossing (i.e., phase) of the wave present on the transducer. This results in all transducers having a wavefront incident on them. Since sampling a full wave at 40 kHz requires 25 μs, and the sampling time may be asynchronous with the incident wave, sampling of at least 51 μs allows a maximum of two waveforms to be pulled from each receiver, a sampling duration that is more than sufficient. Less time can be used, but zero-crossing information may need to be obtained from all transducers used to calculate the direction of arrival. The zero-crossing times of A, B, C, and D are then determined. Generally speaking, it is better to compare the zero-crossing time of the same polarity with the rising zero-crossing time of the same polarity. In other words, the rising zero-crossing time can be used, or the falling zero-crossing time can be used, but for consistency and accuracy, it is better to use the same zero-crossing time. Alternatively, both the rising and falling phases can be used for redundancy, increasing the robustness of the measurement. By adding or subtracting half a wave from the measurement (12.5uS for 40KHz in this example), both the rising and falling zero-crossing times can be used. This can further increase the measurement speed; however, it may introduce some errors. However, these errors are negligible. Continuing with the example of Figures 8A-8B, it should be noted that the following calculations and discussion apply to all subsequent examples shown in Figures 8A-16. Figures 8A-8B illustrate a 40 kHz sound wave at an operating temperature of 20°C, where the center-to-center spacing between transducer A to transducer B and transducer A to transducer C is 21 mm. 17.68 mm is used as the center-to-center spacing between transducer B to transducer D and transducer C to transducer D. Because the transducer spacing is the same for both the elevation axes (A to C and B to D) and the azimuth axes (A to B and C to D), the same calculations and traces apply to each axis. The azimuth calculation uses the time from A to B and the time from C to D. The elevation calculation uses the time from A to C and the time from B to D. For purposes of illustration and not limitation, consider that for azimuth, find the rising zero crossing on transducer A, then find the next rising zero crossing on transducer B. This time difference is called AB T And for the azimuth, again find the rising zero crossing on transducer C from the same set of zero crossing waves, and then find the next rising zero crossing on transducer D. This time difference is called CD T For elevation, use the same principle to find AC T and BD T This will provide four time values: For azimuth time, use AB T and CD T For elevation time, use AC T and BD T . One way to determine the direction of arrival is to provide a trace for the direction of arrival of the values ​​measured by the microcontroller, i.e. calculate all possible angles that can be obtained from the measurements and store these values. T (corresponding to 21mm) and CD T (corresponding to 17.68mm). For elevation time, use AC T (corresponding to 21mm) and BD T(corresponding to 17.68 mm). Since 21 mm and 17.68 mm are the same distances for both azimuth and elevation (corresponding to the same time values), a single lookup table can be used for direction of arrival determination for both azimuth and elevation. If the center-to-center distance values ​​for azimuth and elevation are different, a lookup table is calculated for each axis. The center-to-center distance values ​​may be different to improve the accuracy of the direction of arrival estimate on one axis, or simply for layout reasons. Any method of storing the lookup values ​​may be used. One example is suggested here. If the microcontroller reads time values ​​with 0.5uS resolution, a 50 by 50 lookup table (with 25uS wrapping around to 0uS) may be sufficient to cover the possible values ​​of the direction of arrival set from 0uS to 25uS (25uS = 1 / 40kZ). The microcontroller calculates and stores the values ​​corresponding to the possible direction of arrival resolution readings. This table is partially populated. Some of the 2500 possible lookups will be empty. This is because there is enough resolution to provide an unambiguous result, leaving gaps where no direction of arrival estimate is stored. Other methods (such as hash tables) can be used to reduce the size of this table, but at the expense of some computation time during operation, but many microcontrollers have the 2500 memory slots required to store this information as is. The measurement resolution can be varied. If the microcontroller reads time values ​​at 1 uS resolution, a 25 by 25 lookup table (where 25 uS wraps around to 0 uS) may be sufficient to cover the possible values ​​of the arrival direction set from 0 uS to 25 uS (25 uS = 1 / 40 hz). The microcontroller calculates and stores the values ​​corresponding to the possible arrival direction resolution readings. This table is partially populated. Some of the 625 possible lookups will be empty. This is because there is enough resolution to provide an unambiguous result, leaving gaps where the arrival direction estimate is not stored. The measurement resolution can be increased, but preferably should not be increased above a resolution that cannot provide an unambiguous result. It is also obvious that if the measurement is made at 0.25 uS resolution (twice the accuracy of 0.5 uS), the reported degree resolution will be twice the accuracy and a lookup table of 10,000 memory slots will be required, and some microcontrollers have fast access to tables of this size. The most accurate set of arrival directions in this example is AB and AC. This is because their values ​​are directly in line with the azimuth and elevation, and because they are separated by a larger distance of 21mm (versus an average of 17.65mm). The measurements for the AB and AC axes are considered the most accurate. Because 17.65mm is an estimate (the average of 17.5mm and 17.85mm), the measured phase timing may deviate, and therefore an inaccuracy of up to 0.18mm or 0.56uS is expected. For CD T and BD T Due to jitter noise from the measurement, if a search produces a blank cell, up to 1µS plus or minus (0.5µS above or below two adjacent cells) may be considered. Furthermore, if this is necessary due to a blank cell, adjacent stored values ​​for AB and AC may also be considered. To account for all possible valid values ​​in this search, angular resolution may need to be considered and calculated. When measured with 0.5µS time resolution, direction of arrival resolution is better than 0.5 degrees at low angles and within 1 degree within a range of ±60 degrees. Resolution decreases from -60 to -80 degrees and +60 to +80 degrees. From -80 to -90 degrees and +80 to +90 degrees, these angles typically read approximately the same value. Nevertheless, the sensor can estimate the direction of arrival of the incident wave at all angles. Temperature typically changes slowly, and a change of one degree is unlikely to affect the reading enough to notice a change in the direction of arrival angle using this measurement resolution. Thus, during typical wait times during operation of the sensor, the microcontroller recalculates portions of the lookup table. Example calculations with one-degree resolution are provided. To more fully account for all possible values ​​measured by the microcontroller, the degree resolution must be increased to less than one degree at some angles. For simplicity, one-degree resolution is shown. Using the same calculations but at a higher resolution, a table is constructed to achieve the required resolution for sensor evaluation. The following is a series of calculations. The speed of sound is calculated at the current temperature. For example, at 20°C, the speed of sound has been previously calculated and is known to be 343214.62 mm / s. The time interval for a transducer with a center-to-center spacing of 21 mm is as follows: The time intervals for a transducer with a center-to-center spacing of 17.685 mm are as follows: These values ​​are then used for each separation time / distance to calculate the number of uS (corresponding to degrees) that the sensor would measure if the sound did not have a repeating wave. The individual calculations are as follows: and; Where SuS is time, and the degree value is obtained from Table 2. The modulus operator uses the number of uS per wave (25 uS = 1 / 40 kHz) to map the SuS value to fit the time of a wave. These modulus values ​​match the values ​​measured by the microcontroller. The microcontroller stores the degrees corresponding to the two modulus values. Since the microcontroller reads the values ​​with 0.5 uS resolution, this forms a unique trace of the time value read by the microcontroller. The second lookup table has two time readings corresponding to the angles read by the microcontroller. The widest center-to-center transducer distance interval is 61.19 uS divided by 25 uS, allowing a maximum of plus or minus 2.4476 waves, or 4.9 waves that must be unambiguous. This is further shown in Tables 2A and 2B. Table 2A. A table 2B is also provided, in which the values ​​are sorted in rows of 17.68 mm. Obviously, all values ​​correspond to a unique degree. Table 2B. To further illustrate this example, a portion of Table 2B is provided that looks at the data from the center column of Table 2B sorted by 17.68 mm data to form Table 3. Table 3. The data in Table 3 is centered around 9.5uS, plus or minus 0.5uS, covering a range from 9uS to 10uS, and then sorted by 21mm row. It should be noted that the data does not need to be sorted for operation; the sorting here is only for illustrative purposes and clarity of disclosure. The order in which the sensor uses this trace data is illustrated below. In this example, the sensor measures 9.5uS for a 17.68mm spacing. From the 17.68mm reading of 9uS to 10uS (i.e., 9.5uS + / - 0.5uS on both sides), the sensor can find the value measured for a 21mm spacing. If the 21mm measurement data is 2uS, the angle is -44 degrees. If the 21mm measurement data is 3uS, the angle is -43 degrees. It should be noted that the next angle in the table is very different, such as the uS value for 21mm. If the 21mm measurement data is 7uS, the angle is -15 degrees. If the 21mm measurement data is 10.5uS, the angle is 9 degrees. If the 21mm measurement data is 11.5uS, the angle is 10 degrees. If the 21mm measurement data is 15uS, the angle is 36 degrees. If the 21mm measurement data is 16uS, the angle is 37 degrees. Since this table will represent the actual value read by the sensor during operation, the sensor provides the angle of arrival in degrees without ambiguity. Starting with the 17.68mm data and then using the 21mm data to find the angle will provide the most accurate direction of arrival result. Note that for the sake of simplicity, this method is shown using one degree (rounded). For example, the microcontroller can read 2.5uS, which corresponds to -43.5 degrees, which will be presented in the complete table. If for some reason the 21mm data does not match, a wider search range can be used. Referring to the example above, increasing the data range for the 17.68mm search from 9-10µS to 8.5-10.5µS may help while still providing unambiguous degree results. Table 4 below illustrates this expanded data range. Table 4. FIG. 9 is a top view of an acoustic sensor array 8 according to an exemplary embodiment of the present disclosure. It should be noted that the configuration provided in FIG. 9 is functionally equivalent to the configuration of FIG. 8A-8B for producing unambiguous elevation and azimuth estimates, but may not be optimal because the spacing between the transducers directly aligned with the azimuth (A and B) and the transducers directly aligned with the elevation (A and C) is smaller, which provides slightly lower accuracy for the azimuth and elevation estimates. FIG. 9 contains many of the same features and structures as FIG. 8A-8B , which will not be repeated here for the sake of brevity. FIG10 is a top view of an acoustic sensor array 8 according to an exemplary embodiment of the present disclosure. FIG10 illustrates an additional acoustic receiver 22E or transducer for emitting at least one sound wave. In some examples, this additional acoustic receiver 22E may include a transducer and may be configured as a dedicated transducer to eliminate resonant attenuation on the other acoustic receivers 22A, 22B, 22C, and 22D. Further exemplary descriptions of this configuration are provided herein. The examples, configurations, and measurements presented are for illustrative purposes only and are not intended to limit the scope of the present disclosure. A fifth transducer E can be added as shown in Figure 10, where the fifth transducer E transmits only. This will eliminate the resonance decay on the receiving transducers (A, B, C, D) and allow the use of near echoes to determine the azimuth and elevation angles during the resonance decay. The spacing between the transducers can be increased to improve angular resolution, but not so much that ambiguous results are produced. As the spacing increases, more waves are included in the measurement, providing more angles to sort, but this is predictable and can be calculated. To demonstrate an unambiguous estimate of the direction of arrival, mathematical calculations must be performed at all temperatures and angles at which the sensor is expected to operate, and proof must be given that the chosen configuration provides unambiguous results. For 40 kHz and other ultrasonic frequencies, calculations and measurements using the built-in sensor with closely spaced transducers in the configuration described above work very well for transducers with diameters ranging from 9.4 mm to 25 mm. These configurations can be extended to even smaller diameter transducers and even larger spacing between transducers. Smaller transducers with closer spacing provide the most unambiguous results. FIG11 is a top view of an acoustic sensor array 8 according to an exemplary embodiment of the present disclosure. This is an alternative configuration of acoustic receivers 22A, 22B, 22C, and 22D to the configurations of FIG8A and FIG8B. Further exemplary descriptions of this configuration are provided herein. The examples, configurations, and measurements presented are for illustrative purposes only and are not intended to limit the scope of the present disclosure. FIG11 provides a specific example with specific measurements for illustrative purposes. Specifically, a transducer with a diameter of 9.4 mm radiating 40 kHz sound is shown. Transducers A and B are 12.5 mm apart, transducers A and C are 12.5 mm apart, transducers B through D are 9.66 mm apart, transducers C and D are 9.66 mm apart, and transducer D is 9 mm apart from a line along the center points of transducers A and C, and transducer D is 9 mm apart from a line along the center points of transducers C and D. The line from C to D is off-axis from the line from A to B. However, due to the small diameter of the transducers, closer spacing of the transducers is possible. Therefore, the off-axis between transducers C and D does not affect the ambiguity or accuracy of the angular direction of arrival reading. This is also true for the line formed by transducers B to D and transducers A to C. FIG12 is a top view of an acoustic sensor array 8 according to an exemplary embodiment of the present disclosure. This is an alternative configuration of acoustic receivers 22A, 22B, 22C, and 22D of FIG8A-8B and FIG11. Further exemplary descriptions of this configuration are provided herein. The examples, configurations, and measurements presented are for illustrative purposes only and are not intended to limit the scope of the present disclosure. FIG12 is a diagram of another alternative configuration of an acoustic receiver. FIG12 provides yet another specific example with specific measurements for illustrative purposes. An 18.2 mm diameter 40 kHz transducer is shown, wherein the A to B spacing is 22 mm, the A to C spacing is 22 mm, the B to D spacing is 18.83 mm, the C to D spacing is 18.83 mm, the transducer D to the AC line spacing is 18.5 mm, and the transducer D to the AB line spacing is 18.5 mm. If a configuration requires more pairs of transducers for robustness, measurement redundancy, or to eliminate ambiguity, then the extensions can be implemented as described herein. These configurations of parallel receivers can be extended to almost any configuration that follows these rules. Adding more pairs of parallel receivers removes the possibility of trace ambiguity at any angle. To accurately estimate azimuth and elevation, ideally, the transducers should be configured to provide an unambiguous trace for the direction of arrival angle. The unambiguous trace for the angle is a function of the phase (i.e., zero-crossing measurement) error and the transducer spacing (because this increased spacing requires more possible waves to evaluate and provide an unambiguous direction of arrival angle). As the spacing increases, more sound waves are available to form the angle. Therefore, adding redundant pairs of parallel transducers can provide more detailed traces for each incident angle, thereby eliminating ambiguity and increasing the robustness of the arrival direction estimate. FIG13 is a top view of acoustic sensor array 8 according to an exemplary embodiment of the present disclosure. It should be understood that incident sound waves 34 may arrive from any angle or direction, and the illustrated direction of incident sound waves 34 is for illustrative purposes only and is not intended to limit the scope of the present disclosure or the functionality or operability of acoustic sensor array 8 and its components. The acoustic sensor array 8 has a first acoustic receiver 22A, wherein the first acoustic receiver has a center point 32A. The second acoustic receiver 22F is positioned adjacent to the first acoustic receiver 22A, and the second acoustic receiver has a center point 32F. The center points 32A, 32F of each of the first acoustic receiver 22A and the second acoustic receiver 22F are along the first axis D. 1. The third acoustic receiver 22G is positioned adjacent to the first acoustic receiver 22A, wherein the third acoustic receiver 22G has a center point 32G, wherein the center points 32A, 32G of each of the first acoustic receiver 22A and the third acoustic receiver 22G are along the second axis D 2 Positioning. Second axis D 2 perpendicular to the first axis D 1, and the third axis D 3 intersects the center point 32G of the third acoustic receiver 22G, and the fourth axis D 4 intersects the center point 32F of the second acoustic receiver 22F. The third axis D 3 perpendicular to the fourth axis D 4. The fourth acoustic receiver 22J may be positioned adjacent to the second acoustic receiver 22F and the third acoustic receiver 22G, and the center point 32J of the fourth acoustic receiver 22J may be located at a distance of 30° from the third axis D. 3 and the fourth axis D 4. The incident sound wave 34 has a wavelength corresponding to the frequency of the incident sound wave 34. The fourth acoustic receiver 22J is aligned with the third axis D. 3 and the fourth axis D The offset distance 4 is a distance greater than zero but less than one-half the wavelength of the incident sound wave 34. The acoustic receivers 22A, 22F, 22G, and 22J can themselves be or otherwise have transducers or other sound-transmitting components positioned within the acoustic receivers 22A, 22F, 22G, and 22J. In some examples, the control circuit 26, a microcontroller, processing circuitry, or an analog-to-digital converter, can be used to evaluate the incident sound waves. The control circuit 26 can be a separate circuit from the acoustic receiver 22 or can be integrated within the acoustic receiver 22. Further aspects and details of the control circuit 26 have been previously discussed. In some examples, additional acoustic receivers 22A, 22F, 22G, 22J, 22B, 22C, 22H, 22I, 22K may be used. In one such example, additional acoustic receiver 22B may be positioned adjacent to second acoustic receiver 22F, wherein additional acoustic receiver 22B has a first axis D along which the first acoustic receiver 22B is positioned. Alternatively, the additional acoustic receiver 22C may be positioned adjacent to the third acoustic receiver 22G, wherein the additional acoustic receiver 22C has a center point 32B along the second axis D. 2 is positioned at the center point 32C. In another example, a fifth acoustic receiver 22C and a sixth acoustic receiver 22B can be added to the acoustic sensor array 8. The fifth acoustic receiver 22C can be positioned adjacent to the third acoustic receiver 22G, wherein the fifth acoustic receiver 22C has a center point 32C along the second axis D. 2 is positioned at the center point 32C. The sixth acoustic receiver 22B may be positioned adjacent to the second acoustic receiver 22F, wherein the sixth acoustic receiver 22B has a first axis D along the first axis. 1 locates the center point 32B. Further acoustic receivers 22A, 22F, 22G, 22J, 22B, 22C, 22H, 22I, 22K may be added, which may increase measurement robustness, accuracy, and redundancy. One such example includes adding a seventh acoustic receiver 22I positioned adjacent to the fifth acoustic receiver 22C, wherein the center point 32I of the seventh acoustic receiver 22I is 30° from the fifth axis D. 5 offset positioning. Fifth axis D 5 perpendicular to the second axis D 2 and the fourth axis D 4. The center point 32I of the seventh acoustic receiver 32I has an offset distance greater than zero but less than half the wavelength of the incident sound wave 34. An eighth acoustic receiver 22H may also be added to the acoustic sensor array 8. The eighth acoustic receiver 22H may be positioned adjacent to the sixth acoustic receiver 22B, wherein the center point 32H of the eighth acoustic receiver 22H is offset from the sixth axis D. 6 is positioned offset. The sixth axis D 6 perpendicular to the first axis D 1 and the third axis D 3. The center point 32H of the eighth acoustic receiver 32H has an offset distance greater than zero but less than half the wavelength of the incident sound wave 34. A ninth acoustic receiver 22K may also be added. The ninth acoustic receiver 22K may be a transceiver or transducer that is a dedicated transducer to eliminate resonant attenuation on the other acoustic receivers 22A, 22F, 22G, 22J, 22B, 22C, 22H, 22I. Alternatively, the ninth acoustic receiver 22K may also be used to send and receive acoustic signals, thereby further increasing robustness and redundancy when measuring the incident sound wave 34. The ninth acoustic receiver 22K may be positioned adjacent to the seventh acoustic receiver 22I and the eighth acoustic receiver 22H, with the center point 32K of the ninth acoustic receiver 22K positioned on the fifth axis D. 5 and 6th axis D 6. In other examples, the positioning of the ninth acoustic receiver 22K and the center point 32K of the ninth acoustic receiver 22K can be considered as the mirror image positioning of the first acoustic receiver 22A and the center point 32A of the first acoustic receiver 22A. The incident sound wave 34 can be measured in parallel or multiple times between each set of acoustic receivers 22A, 22F, 22G, 22J, 22B, 22C, 22H, 22I, and 22K. The concept and process of parallel measurement using several transducers are consistent with the parallel measurement understood with respect to Figures 8A and 8B. In some examples, the acoustic receivers 22A, 22F, 22G, 22J, 22B, 22C, 22H, 22I, 22K may be referred to as receivers, transceivers, sensors, or transducers. It should be understood that these refer to acoustic receivers 22A, 22F, 22G, 22J, 22B, 22C, 22H, 22I, 22K configured as transceivers or having transducers positioned therein. The examples, configurations, and measurements presented are for illustrative purposes only and are not intended to limit the scope of the present disclosure. FIG13 illustrates the previously discussed configuration of an acoustic receiver. This configuration uses nine transducers, but still operates with respect to the basic configuration described with respect to FIG8A through FIG13. Using additional transducers provides additional robustness, measurement redundancy, and removes ambiguity. For illustrative purposes, the transducers can be considered to have a diameter of 16 mm and emit 40 kHz sound waves. The following is a description of one possible configuration of nine transducers. It should be noted that the precise measurements and spacing are for illustrative purposes and are not intended to be limiting. The center-to-center spacing of transducer A to transducer F and transducer A to transducer G is 17.5 mm. The center-to-center spacing of transducer F to transducer B and transducer G to transducer C is 21 mm. Therefore, transducers A and B are 38.5 mm apart, and transducers A and C are 38.5 mm apart. This configuration is functionally equivalent to FIG8A through FIG8B, but is completely parallel, so the signal trace corresponding to the arrival angle direction is more accurate. Transducers I and H can be added, with transducer I and transducer F spaced 42 mm apart center-to-center and positioned parallel to transducers A and C. Transducer H is positioned 42 mm apart from transducer G and parallel to transducers A and B. This configuration adds another comparison of direction-of-arrival estimates for azimuth and elevation, further consolidating the trace by improving resolution. Transducer J can be added for transmit, freeing up the other transducers for receive-only use, as this allows transducers A, B, C, G, H, and I to be used for direction-of-arrival estimates for azimuth and elevation, even during transmit bursts. Transducer K and an additional transducer J can be added if placed in the center space between transducers A, B, and C. Transducer K allows for convenient time-of-flight 3D direction-of-arrival calculations, further increasing the robustness of the direction-of-arrival. FIG14A is a top view of a first acoustic sensor array 8A and a second acoustic sensor array 8B according to an exemplary embodiment of the present disclosure. It should be understood that the incident sound waves 34 may arrive from any angle or direction, and the illustrated directions of the incident sound waves 34 are for illustrative purposes only and are not intended to limit the scope of the present disclosure or the functionality or operability of the acoustic sensor array 8 and its components. FIG14B is a perspective view of the first and second acoustic sensor arrays 8A, 8B of FIG14 within a housing 28 according to an exemplary embodiment of the present disclosure. Referring to FIG14A-14B , the configuration of the first and second acoustic sensor arrays 8A, 8B includes a housing 28 having the first and second sensor arrays 8A, 8B, wherein the first and second sensor arrays 8A, 8B are positioned adjacent to each other, or alternatively, the second sensor array 8B is positioned adjacent to the first sensor array 8A. The first acoustic sensor array 8A has a first acoustic receiver 22A, wherein the first acoustic receiver has a center point 32A. The second acoustic receiver 22B is positioned adjacent to the first acoustic receiver 22A, wherein the second acoustic receiver has a center point 32B. The center points 32A, 32B of each of the first acoustic receiver 22A and the second acoustic receiver 22B are along a first axis D. 1. The third acoustic receiver 22C is positioned adjacent to the first acoustic receiver 22A, wherein the third acoustic receiver 22C has a center point 32C, wherein the center points 32A, 32C of each of the first acoustic receiver 22A and the third acoustic receiver 22C are along the second axis D 2 Positioning. Second axis D 2 perpendicular to the first axis D 1, and the third axis D 3 intersects the center point 32C of the third acoustic receiver 22C, and the fourth axis D 4 intersects the center point 32B of the second acoustic receiver 22B. The third axis D 3 perpendicular to the fourth axis D 4. The fourth acoustic receiver 22D is positioned adjacent to the second acoustic receiver 22B and the third acoustic receiver 22C, and the center point 32D of the fourth acoustic receiver 22D is at a distance of 32° from the third axis D. 3 and the fourth axis D 4. The incident sound wave 34 has a wavelength corresponding to the frequency of the incident sound wave 34. The fourth acoustic receiver 22D is positioned relative to the third axis D. 3 and the fourth axis D The offset distance 4 is a distance greater than zero but less than one-half the wavelength of the incident sound wave 34. The acoustic receivers 22A, 22B, 22C, 22D may themselves be or otherwise have transducers or other sound wave emitting components located within the acoustic receivers 22A, 22B, 22C, 22D. The second acoustic sensor array 8B has a first acoustic receiver 22E, wherein the first acoustic receiver has a center point 32E. The second acoustic receiver 22F is positioned adjacent to the first acoustic receiver 22E, and the second acoustic receiver has a center point 32F. The center points 32E, 32F of each of the first acoustic receiver 22E and the second acoustic receiver 22F are along the first axis D. The third acoustic receiver 22G is positioned adjacent to the first acoustic receiver 22E, wherein the third acoustic receiver 22G has a center point 32G, wherein the center points 32E, 32G of each of the first acoustic receiver 22E and the third acoustic receiver 22G are along the second axis D 2 Positioning. Second axis D 2 perpendicular to the first axis D 1, and the third axis D 3 intersects the center point 32G of the third acoustic receiver 22G, and the fourth axis D 4 intersects the center point 32F of the second acoustic receiver 22F. The third axis D 3 perpendicular to the fourth axis D 4. The fourth acoustic receiver 22H is positioned adjacent to the second acoustic receiver 22F and the third acoustic receiver 22G, and the center point 32H of the fourth acoustic receiver 22H is at a distance of 32H from the third axis D. 3 and the fourth axis D 4. The incident sound wave 34 has a wavelength corresponding to the frequency of the incident sound wave 34. The fourth receiver 22H is relative to the third axis D. 3 and the fourth axis D The offset distance 4 is a distance greater than zero but less than one-half the wavelength of the incident sound wave 34. The acoustic receivers 22E, 22F, 22G, 22H themselves may be or otherwise have transducers or other sound wave emitting components located within the acoustic receivers 22E, 22F, 22G, 22H. In some examples, control circuit 26, a microcontroller, processing circuit, or analog-to-digital converter, can be used to evaluate incident sound waves. Control circuit 26 can be a separate, independent circuit from acoustic receiver 22 or can be integrated within acoustic receiver 22. Further aspects and details of control circuit 26 are described herein. In each of the first sensor array 8A and the second sensor array 8B, incident sound waves 34 can be measured in parallel between the groups of acoustic receivers 22A, 22B, 22C, and 22D in the first sensor array 8A and between the groups of acoustic receivers 22E, 22F, 22G, and 22H in the second sensor array 8B. The concept and process of parallel measurement using multiple transducers is consistent with the parallel measurement understood with respect to FIG. 8A and FIG. It should be noted that the center-to-center spacing between the center points 32A, 32B, 32C, 32D, 32E, 32F, 32G, 32H of each acoustic receiver 22A, 22B, 22C, 22D, 22E, 22F, 22G, 22H is used for the calculations presented above, and the angles at which the acoustic receivers 22A, 22B, 22C, 22D, 22E, 22F, 22G, 22H are pointed may not be calculated to determine the distance direction of an object relative to each acoustic sensor array 8A, 8B. In some examples, the center points 32A, 32B, 32C, 32D, 32E, 32F, 32G, 32H in each of the first sensor array 8A and the second sensor array 8B may be positioned in the same plane. In other words, the center points 32A, 32B, 32C, 32D of the acoustic receivers 22A, 22B, 22C, 22D in the first sensor array 8A can all be positioned along the same plane. Similarly, the center points 32E, 32F, 32G, 32H of the acoustic receivers 22E, 22F, 22G, 22H in the second sensor array 8B can all be positioned along the same plane. The directional angles at which the acoustic receivers 22A, 22B, 22C, 22D, 22E, 22F, 22G, 22H point are not important, as long as the acoustic receivers 22A, 22B, 22C, 22D, 22E, 22F, 22G, 22H are positioned along the pattern or axis D within the measured angle or field of view. 1. D 2. D 3. D 4. In some examples, acoustic receivers 22A, 22B, 22C, 22D, 22E, 22F, 22G, and 22H may be referred to as receivers, transceivers, sensors, or transducers. It should be understood that these refer to acoustic receivers 22A, 22B, 22C, 22D, 22E, 22F, 22G, and 22H configured as transceivers or having transducers positioned therein. The examples, configurations, and measurements presented are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The examples, configurations, measurements, and explanations presented below are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The use of a first sensor array 8A and a second sensor array 8B can increase the refinement of the sensor. Each side measures the direction of arrival and the distance to objects in the increased field of view. Because both sides have hemispherical detection areas with overlap in the middle, object detection toward one side of the sensor's field of view can be more robust than using a single sensor configuration alone. The center detection area produces redundant measurements of the same object from different angles. Alternating measurements from one side to the other can provide very fast updates or measurements in the center overlap area. Additionally, this configuration can be configured for only one sensor or transducer to transmit sound waves, so that there is no resonant attenuation on the remaining transducers. This allows the sensor to estimate the direction of arrival and distance to the front of this sensor. In this example, the spacing of interest is the spacing between the centers of the front faces of the transducers / receivers, where the transducers receive or transmit ultrasound. The centers of the front faces of the transducers / receivers are in the same plane, and the angles at which the transducers / receivers point may not be critical if the beams of the four transducers, or the cross patterns along the various axes, overlap within the measured angles or fields of view. FIG15 is a perspective view of an acoustic sensor array 8 in a housing according to an exemplary embodiment of the present disclosure. To reduce production costs, it may be preferable to use acoustic receivers 22 in the central region of the housing 28 because the amount of material required for the housing 28 and the number of acoustic receivers 22 are reduced. As shown, the acoustic receivers 22 positioned to the left and right of the two central acoustic receivers 22 are offset at a predetermined angle so as to better face their respective directions. The principles of this acoustic sensor array 8 are similar to those described with respect to FIG14B , specifically, the center points (not shown) of the front faces of each acoustic receiver 22 can be positioned in the same plane. Similarly, the direction angle at which the transducers / receivers are pointed may not be critical if the beams of the four transducers, or the intersection patterns along the various axes, overlap within the measured angle or field of view. FIG. 16 is a front perspective view of an acoustic sensor array 8 within a housing 28 according to an exemplary embodiment of the present disclosure. In this configuration, each acoustic receiver 22 can be positioned on the housing 28 at an angle so that the acoustic receiver 22 has a wider field of view. In other words, the faces of each of the acoustic receivers 22 can face different directions rather than lying flat along a plane. This positioning can increase the field of view of the acoustic receivers 22, allowing for sensing of incident sound waves 34 from objects or beacons positioned approximately sideways to the housing 28. This configuration can also be described as having the faces of the two central acoustic receivers 22 positioned facing forward, with acoustic receivers 22 positioned on each left and right side of the two central acoustic receivers 22, angled to the left and right, respectively. The principles of this acoustic sensor array 8 are similar to those described with respect to FIG. 14B through FIG. 15 , specifically, the center points (not shown) of the front faces of each of the acoustic receivers 22 can be positioned on the same plane. Similarly, the angle at which the transducers / receivers are pointed may not be critical if the beams of the four transducers, or the intersection patterns along the various axes, overlap within the measured angle or field of view. FIG17 is a flowchart 200 illustrating a method for locating an acoustic receiver for sensing incident sound waves according to an exemplary embodiment of the present disclosure. It should be noted that any process description or block in the flowchart should be understood to represent a module, segment, portion of code or step comprising one or more instructions for implementing the specific logical functions in the process, and that alternative implementations are also included within the scope of the present disclosure, in which the order of execution of functions may differ from that shown or discussed, including being executed substantially simultaneously or in reverse order, depending on the functionality involved, as will be understood by those skilled in the art. Method step 202 includes the step of positioning a first acoustic receiver, wherein the first acoustic receiver has a center point. At step 204, a second acoustic receiver is positioned adjacent to the first acoustic receiver, wherein the second acoustic receiver has a center point, wherein the center point of each of the first and second acoustic receivers is positioned along a first axis. At step 206, a third acoustic receiver is positioned adjacent to the first acoustic receiver, wherein the third acoustic receiver has a center point, wherein the center point of each of the first and third acoustic receivers is positioned along a second axis, wherein the second axis is perpendicular to the first axis, and wherein the third axis intersects the center point of the third acoustic receiver and a fourth axis intersects the center point of the second acoustic receiver, wherein the third axis is perpendicular to the fourth axis. At step 208, a fourth acoustic receiver is positioned adjacent to the second and third acoustic receivers, wherein the center point of the fourth acoustic receiver is positioned at an offset distance from each of the third and fourth axes. At step 210 , an incident sound wave having a wavelength is received, wherein the offset distance is greater than zero but less than half the wavelength of the incident sound wave. FIG18 is a flowchart 300 illustrating a method for determining the distance and direction of an object using an acoustic receiver according to an exemplary embodiment of the present disclosure. It should be noted that any process description or block in the flowchart should be understood to represent a module, segment, portion of code, or step comprising one or more instructions for implementing a specific logical function in the process, and that alternative implementations are also within the scope of the present disclosure, wherein the order of execution of functions may differ from that shown or discussed, including being executed substantially simultaneously or in reverse order, depending on the functionality involved, as will be understood by those skilled in the art. Method step 302 includes the step of using a control device to compare parallel incident sound waves received at each of the first and second groups of acoustic receivers. At step 304, the control device compares parallel incident sound waves received at each of the third and fourth groups of acoustic receivers. At step 306, the location of an object in a spatial environment is determined by the following calculations: determining the elevation angle of the object by comparing parallel measurements between the first and second groups of acoustic receivers; and determining the azimuth angle of the object by comparing parallel measurements between the third and fourth groups of acoustic receivers. To further illustrate the described method, referring to Figures 8A to 13 , the location of an object in a spatial environment can also be calculated using the distance between the object and one of the first acoustic receiver 22A, the second acoustic receiver 22B, the third acoustic receiver 22C, or the fourth acoustic receiver 22D. The elevation angle of the object can be calculated relative to the location of one of the first acoustic receiver 22A, the second acoustic receiver 22B, the third acoustic receiver 22C, or the fourth acoustic receiver 22D. The azimuth angle of the object can be calculated relative to the location of one of the first acoustic receiver 22A, the second acoustic receiver 22B, the third acoustic receiver 22C, or the fourth acoustic receiver 22D. To increase the robustness of the distance measurements described herein, additional acoustic sensors may be added, as described with respect to Figures 10 and 13. This may include adding an acoustic sensor along the first axis D 1 and positioning an additional acoustic receiver 22B having a center point 32B adjacent to the second acoustic receiver 22F and / or along the second axis D 2 and positioning an additional acoustic receiver 22C having a center point 32C adjacent to the third acoustic receiver 22G. Alternatively, the acoustic receiver 22C may be positioned along the second axis D 2 and a fifth acoustic receiver 22C having a center point 32C is positioned adjacent to the third acoustic receiver 22G and along the first axis D 1 and a sixth acoustic receiver 22B having a center point 32B is positioned adjacent to the second acoustic receiver 22F to increase robustness. Further components may be added to the acoustic sensor array 8 to improve the robustness and redundancy of the distance measurement. Positioning the seventh acoustic receiver 22I adjacent to the fifth acoustic receiver 22C may help in this regard. When the seventh acoustic receiver 22I is added, the center point 32I of the seventh acoustic receiver 22I is positioned about the fifth axis D. 5 offset, where the fifth axis D 5 perpendicular to the second axis D 2 and the fourth axis D 4, and wherein the offset distance is greater than zero but less than one-half the wavelength of the incident sound wave 34. Positioning the eighth acoustic receiver 22H can add even further robustness and redundancy to the distance measurement. The eighth acoustic receiver 22H can be positioned adjacent to the sixth acoustic receiver 22B, wherein the center point 32H of the eighth acoustic receiver 22H is positioned from the sixth axis D 6 offset, where the sixth axis D 6 perpendicular to the first axis D 1 and the third axis D 3, and wherein the offset distance is greater than zero but less than half the wavelength of the incident sound wave 34. It should be emphasized that the above-described embodiments of the present disclosure, particularly any "preferred" embodiments, are merely possible examples of implementations, set forth solely for clarity of understanding of the principles of the present disclosure. Many variations and modifications may be made to the above-described embodiment(s) of the present disclosure without materially departing from the spirit and principles of the present disclosure. All such modifications and variations are intended to be included within the scope of the present disclosure and protected by the appended claims. 1: Ultrasonic sensor array 2: Ultrasonic sensor array 5: Transducer 7: Transmitter 8: Acoustic sensor array 8A: First acoustic sensor array 8B: Second acoustic sensor array 9: Incident wave 10: Acoustic sensing device 12: Waveguide 14: Acoustic path 14a: First end 14b: Second end 16: Acoustic path sidewall 18: First opening 18a: First group of first openings 18b: Second group of first openings 20: Second opening 22: Acoustic receiver / transducer 22A: First acoustic receiver 22B: Second acoustic receiver / sixth acoustic receiver 22C: Third acoustic receiver Acoustic receiver / fifth acoustic receiver 22D: fourth acoustic receiver 22E: first acoustic receiver 22F: second acoustic receiver 22G: third acoustic receiver 22H: fourth acoustic receiver / seventh acoustic receiver 22I: eighth acoustic receiver 22J: fourth acoustic receiver 22K: ninth acoustic receiver 24: sound wave transmitter 24a: transmitting surface 26: control circuit / sound guide 28: shell 30: central axis 32A~32K: center point 34: incident sound wave 200: flow chart 202~210: method steps 300: flow chart 302~306: method steps Many aspects of the present disclosure may be better understood with reference to the accompanying drawings. The components in the drawings are not necessarily drawn to scale, with emphasis placed on clearly illustrating the principles of the present disclosure. Additionally, in the drawings, like reference numerals denote corresponding parts throughout the several views. FIG. 1 is a diagram of an ultrasonic sensor array according to the prior art. FIG. 2 is a diagram of incident waves on a transducer according to the prior art. 3A and 3B are top views of an acoustic sensor array according to an embodiment of the present disclosure. FIG. 4 is a top view of an acoustic sensor array according to an embodiment of the present disclosure. FIG. 5A is a front perspective view of an acoustic sensing device according to an embodiment of the present disclosure. FIG. 5B is a top view of the acoustic sensing device of FIG. 5A according to an embodiment of the present disclosure. FIG. 5C is a bottom view of the acoustic sensing device of FIG. 5A according to an embodiment of the present disclosure. FIG. 6 is a front perspective view of an acoustic sensing device according to an embodiment of the present disclosure. FIG. 7 is a side perspective view of an acoustic sensing device according to an embodiment of the present disclosure. FIG. 8A is a perspective view of an acoustic sensor array in a housing according to an embodiment of the present disclosure. FIG. 8B is a top view of the acoustic sensor array of FIG. 8A according to an embodiment of the present disclosure. FIG. 9 is a top view of an acoustic sensor array according to an embodiment of the present disclosure. FIG. 10 is a top view of an acoustic sensor array according to an embodiment of the present disclosure. FIG. 11 is a top view of an acoustic sensor array according to an embodiment of the present disclosure. FIG. 12 is a top view of an acoustic sensor array according to an embodiment of the present disclosure. FIG. 13 is a top view of an acoustic sensor array according to an embodiment of the present disclosure. FIG. 14A is a top view of first and second acoustic sensor arrays according to an embodiment of the present disclosure. FIG. 14B is a perspective view of the first and second acoustic sensor arrays of FIG. 14A in a housing according to an embodiment of the present disclosure. FIG. 15 is a perspective view of an acoustic sensor array in a housing according to an embodiment of the present disclosure. FIG. 16 is a perspective view of an acoustic sensor array in a housing according to an embodiment of the present disclosure. FIG. 17 is a flow chart illustrating a method for positioning an acoustic receiver for sensing incident sound waves according to an embodiment of the present disclosure. FIG. 18 is a flow chart illustrating a method for determining a distance direction of an object using an acoustic receiver according to an embodiment of the present disclosure. 8: Acoustic sensor array 22: Acoustic Receiver 26: Control circuit

Claims

1. A method for sensing an object in a spatial environment, the method comprising the steps of: providing a first acoustic receiver having a center point; positioning a second acoustic receiver adjacent to the first acoustic receiver, wherein the second acoustic receiver has a center point, wherein the center points of each of the first and second acoustic receivers are positioned along a first axis; positioning a third acoustic receiver adjacent to the first acoustic receiver, wherein the third acoustic receiver has a center point, wherein the center points of each of the first and third acoustic receivers are positioned along a second axis, wherein the second axis is perpendicular to the first axis, and wherein a third axis intersects the center point of the third acoustic receiver, wherein at least one of the first, second, or third acoustic receivers has a transducer; emitting at least one sound wave from at least one of the transducers, wherein the at least one emitted sound wave is reflected from an object; The reflected emitted sound wave is received from at least one of the first, second, or third acoustic receivers; and a phase of the incident sound wave is determined by measuring an arrival time, wherein the arrival time is relative to the time of emission of the at least one sound wave and the time of reception of the at least one sound wave by at least one of the first, second, or third acoustic receivers.

2. The method as described in claim 1, wherein the phase information of the at least one incident sound wave is saved by each of the at least two acoustic paths.

3. The method as described in claim 1, further comprising the step of positioning an additional transducer adjacent to at least one of the first, second, or third acoustic receivers, wherein the additional transducer is used to emit at least one emitted sound wave.

4. The method as described in claim 1, 2, or 3, further comprising the steps of: calculating the position of the object using at least one of the following: a distance between the object and at least one of the first, second, or third acoustic receivers; an elevation angle of the object relative to a position of at least one of the first, second, or third acoustic receivers; and an azimuth angle of the object relative to the position of at least one of the first, second, or third acoustic receivers.

5. A system for sensing a plurality of objects in a spatial environment, comprising: a first acoustic receiver having a center point; a second acoustic receiver positioned adjacent to the first acoustic receiver, wherein the second acoustic receiver has a center point, and the center points of each of the first and second acoustic receivers are positioned along a first axis; a third acoustic receiver positioned adjacent to the first acoustic receiver, wherein the third acoustic receiver has a center point, and the center points of each of the first and third acoustic receivers are positioned along a second axis perpendicular to the first axis, wherein a third axis intersects the center point of the third acoustic receiver, and a fourth axis intersects the center point of the second acoustic receiver, wherein the third and fourth axes are different from the first and second axes, respectively, and are perpendicular to them; A fourth acoustic receiver is positioned adjacent to the second and third acoustic receivers, wherein a center point of the fourth acoustic receiver is positioned at an offset distance from each of the third and fourth axes; and an incident sound wave having a wavelength, wherein the offset distance is greater than zero but less than half the wavelength of the incident sound wave.

6. The system as claimed in claim 5, further comprising a controller, wherein the controller compares the incident sound waves received in parallel at a first set of acoustic receivers and a second set of acoustic receivers with the incident sound waves received in parallel at a third set of acoustic receivers and a fourth set of acoustic receivers, wherein each set of acoustic receivers is unique and has at least two acoustic receivers.

7. The system as claimed in claim 5, further comprising an additional acoustic receiver positioned adjacent to the second acoustic receiver, wherein the additional acoustic receiver has a center point positioned along the first axis.

8. The system as described in claim 5 or 7, further comprising an additional acoustic receiver positioned adjacent to the third acoustic receiver, wherein the additional acoustic receiver has a center point positioned along the second axis.

9. The system as claimed in claim 8, further comprising: a fifth acoustic receiver positioned adjacent to the third acoustic receiver, wherein the fifth acoustic receiver has a center point positioned along the second axis; and a sixth acoustic receiver positioned adjacent to the second acoustic receiver, wherein the sixth acoustic receiver has a center point positioned along the first axis.

10. The system as claimed in claim 9, further comprising: a seventh acoustic receiver positioned adjacent to the fifth acoustic receiver, wherein a center point of the seventh acoustic receiver is positioned at an offset distance from a fifth axis, wherein the fifth axis is perpendicular to the second and third axes, and wherein the offset distance is greater than zero but less than half the wavelength of the incident sound wave.

11. The system as claimed in claim 10, further comprising: an eighth acoustic receiver positioned adjacent to the sixth acoustic receiver, wherein a center point of the eighth acoustic receiver is positioned at an offset distance from a sixth axis, wherein the sixth axis is perpendicular to the first axis and the fourth axis, and wherein the offset distance is greater than zero but less than half the wavelength of the incident sound wave.

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