Calibration of distance and range measuring devices

Abstract

A process for calibrating a distance and range measurement device (440, 540) coupled to an industrial vehicle (442, 542) includes taking a first measurement from the device at a first yaw angle relative to a roll axis of the device. A second measurement is taken at a second yaw angle relative to the roll axis. The second yaw angle is within an angular tolerance of the first yaw angle but in an opposite direction. The device is calibrated relative to the roll axis when the first and second measurements are within a tolerance of each other. A third measurement is taken of a distance and range measurement device beam emitted from the distance and range measurement device at a pitch angle. The device (440, 540) is calibrated relative to the pitch axis if the third measurement and a virtual launch length are within a tolerance.

Description

[0001] This application is a divisional application of the invention patent application filed on April 23, 2021, with application number 202180028306.6 and invention title "Calibration of Distance and Range Measuring Equipment". Technical Field

[0002] Various aspects of this disclosure generally relate to industrial vehicles and specifically to calibrating distance and range measurement devices (e.g., laser scanners, 3-D cameras, light detection and ranging (LIDAR) devices, etc.) coupled to industrial vehicles. Background Technology

[0003] Businesses, including distributors, retailers, and manufacturers, are deploying wireless strategies to improve efficiency and accuracy. These businesses are also using wireless strategies to mitigate the potential impact of rising labor and logistical costs.

[0004] In a typical wireless implementation, workers connect to a management system running on a corresponding computer system via a mobile wireless transceiver. For example, to move items around an operator's facility, workers often utilize industrial vehicles, including forklifts, manual and electric pallet trucks, etc. The wireless transceiver serves as an interface to the management system to guide workers in their tasks, such as instructing them on where and / or how to select, pack, store, move, temporarily store, handle, or otherwise manipulate items within the operator's facility.

[0005] Wireless transceivers can also be used in conjunction with suitable input devices to scan, sense, or otherwise read markers, tags, or other identifiers to track the movement of designated items within a facility. Input devices coupled to industrial vehicles should be calibrated, including their mechanical orientation, so that they can scan designated viewing areas. This mechanical orientation can compensate for tolerances during the manufacturing of industrial vehicles and allows for higher accuracy in readings from the input devices. Summary of the Invention

[0006] Depending on the context, the processing for calibrating distance and range measuring devices coupled to industrial vehicles (e.g., laser scanners, 3D cameras, LiDAR (Light Detection and Ranging) devices, ultrasonic devices, etc.) involves acquiring a first measurement value from the emission (e.g., a laser beam) of a first yaw angle relative to the roll axis of the distance and range measuring device. For example, the first yaw angle could be 45 degrees, 20 degrees, -70 degrees, etc., relative to the roll axis. In other words, the first yaw angle can be any desired angle relative to the roll axis except zero degrees and ±90 degrees.

[0007] The process also includes acquiring a second measurement value from the emission of a distance and range measuring device at a second yaw angle relative to the roll axis. In some embodiments, the second yaw angle is within the angular tolerance of the first yaw angle, but in the opposite direction relative to the roll axis. For example, if the first yaw angle is 45 degrees, then the second yaw angle is within an angular tolerance of -45 degrees. In another example, if the first yaw angle is -55 degrees, then the second yaw angle is within an angular tolerance of 55 degrees. The angular tolerance can be any number, but a smaller number will provide better calibration results. In some embodiments, two different angles can be used for two yaw angles (i.e., two yaw angles whose absolute values ​​are not within each other's angular tolerances).

[0008] The process also includes determining that the tilt (i.e., the roll angle) relative to the roll axis is correct when the first and second measurements are within each other's roll tolerances. Similarly, the smaller the roll tolerance, the better the calibration of the distance and range measuring equipment. In embodiments using two different yaw angles, one of the measurements should be scaled before comparison to determine if they are within each other's roll tolerances.

[0009] Furthermore, the process includes determining the virtual transmission length based on the length of the scan field, the height of the scan field above the floor, and the pitch angle of the range and range measuring device. Once the virtual transmission length is determined, a third measurement is acquired from the transmission at the pitch angle from the range and range measuring device. The third measurement can be one of the first and second measurements, or neither. If the third measurement and the virtual transmission length are within each other's pitch tolerances, then the range and range measuring device is correctly calibrated relative to the pitch axis (i.e., the pitch angle of the range and range measuring device is correct).

[0010] According to another aspect of this disclosure, in some embodiments, if the second measurement is not within the rolling tolerance of the first measurement, then the distance and range measuring device is not properly calibrated, and the adjustment direction is determined based on the first and second measurements.

[0011] According to other aspects of this disclosure, in various embodiments, the adjustment direction is determined based on a first measurement and a second measurement, and the distance and range measuring device is adjusted by a motor on an industrial vehicle according to the adjustment direction and adjustment magnitude. In other embodiments, the distance and range measuring device is adjusted by a third party (e.g., a technician) according to the adjustment direction and adjustment magnitude.

[0012] According to another aspect of this disclosure, in several embodiments, the adjusted direction is displayed on a monitor of the industrial vehicle. New first and second measurements are obtained with new first and second yaw angles, respectively. In many embodiments, the new first yaw angle is within the angular tolerance of the first yaw angle. However, in some embodiments, the new second yaw angle is not within the angular tolerance of the first yaw angle.

[0013] In many embodiments, if the third measurement is not within the pitch tolerance of the virtual launch length, the distance and range measuring device is not properly calibrated relative to the pitch axis, and an adjustment direction is determined based on the third measurement and the virtual launch length. In some embodiments, the adjustment magnitude is determined based on the third measurement and the virtual launch length, and a motor is used to automatically adjust the distance and range measuring device based on the adjustment direction and magnitude. In other embodiments, the adjustment direction and magnitude are displayed on a display device on the industrial vehicle for a third party to adjust the distance and range measuring device. Attached Figure Description

[0014] Figure 1 This is an example layout of an industrial environment based on various aspects of this disclosure; Figure 2 This is a flowchart of a network system based on various aspects of this disclosure; Figure 3 This is a hardware system diagram that can be used in industrial vehicles according to various aspects of this disclosure; Figure 4 The diagram illustrates, according to various aspects of this disclosure, the process for calibrating the roll angle of a distance and range measuring device coupled to an industrial vehicle; Figure 5 The diagram illustrates, according to various aspects of this disclosure, the process for calibrating the pitch angle of a distance and range measuring device coupled to an industrial vehicle; Figure 6 As shown in various aspects of this disclosure Figure 5 More diagrams of the processing used to calibrate the roll angle and pitch angle of distance and range measurement devices coupled to industrial vehicles; Figure 7 As shown in various aspects of this disclosure Figures 4-6 The flowchart for the processing; Figure 8 The diagram illustrates the indication of the adjustment direction according to various aspects of this disclosure; and Figure 9 This is a block diagram of a computer system having a computer-readable storage medium for implementing functions according to various aspects of this disclosure. Detailed Implementation

[0015] According to various aspects of this disclosure, systems and processes are provided for calibrating distance and range measuring devices (e.g., lasers, scanners, 3-D cameras, light detection and ranging (LIDAR) devices, ultrasonic devices, etc.) coupled to industrial vehicles. Conventional distance and range measuring device calibration processes require a separate laptop computer with an adapter coupled to the sensor of the distance and range measuring device, specialized software on the laptop computer, and a special alignment device. However, with the calibration process and system described herein, distance and range measuring devices can be calibrated without any of these items. Alternatively, a level floor on the industrial vehicle and software can be used to perform the calibration process. In embodiments with automatic adjustment of the distance and range measuring device, a motor for adjusting the distance and range measuring device is also required. However, in embodiments where a third party (e.g., a technician) can adjust the distance and range measuring device based on the adjustment magnitude and direction, a motor is not required.

[0016] Example industrial environment layout

[0017] Now for reference Figure 1 This illustration shows an example of an industrial environment layout 100 (e.g., warehouse, supply yard, loading dock, manufacturing facility, etc.). In a typical picking operation, an operator of an industrial vehicle fills out an order from available inventory items in a storage area located beneath one or more aisles within the industrial environment. In this example, the industrial environment layout 100 has three aisles 102a, 102b, and 102c (collectively referred to as 102), which are separated by three shelving units 104a, 104b, and 104c (collectively referred to as 104).

[0018] A rack is a structure that can be used to store and store a variety of items, such as consumer products or materials, and can vary in size and structure. Examples of racks include, but are not limited to, selective pallet racks, drive-in racks, drive-through racks, flow racks, gravity flow racks, and push-back racks. Racks can also have multiple vertical levels to expand storage capacity.

[0019] During a typical picking operation, the operator can drive industrial vehicle 106 to a first location (e.g., aisle 1) where one or more items from the first order will be picked. In the picking process, the operator retrieves the ordered inventory items from their associated storage area (e.g., shelving) and places the picked inventory on pallets, collection cages, other support structures carried by the industrial vehicle, or on the industrial vehicle itself. The operator then moves the industrial vehicle to the next location where subsequent items will be picked. This process is repeated until all inventory items on the order have been picked. Alternatively, the operator can use industrial vehicle 106 to retrieve packaged items such as pallets, crates, boxes, containers, or other similar items and repeat the process until all packages have been retrieved and moved to a new location.

[0020] Operators may need to repeat the picking process hundreds of times for each order. Furthermore, operators may need to pick a large number of orders per shift. Consequently, operators may spend a significant amount of time relocating and repositioning industrial vehicles, reducing the time available for picking inventory.

[0021] Furthermore, it is not uncommon for multiple operators (each controlling an industrial vehicle) to pick orders simultaneously. For example, three conventional forklifts 106a-c (e.g., counterbalance forklifts, reach trucks, order pickers, stock pickers, stacker cranes, etc.) and one pallet truck 108 (e.g., low-level picker, fast-pick remote truck, centrally controlled pallet truck, etc.) are shown.

[0022] System Overview

[0023] Now refer to the attached diagram, especially Figure 2 A general diagram of system 200 is shown according to various aspects of this disclosure. System 200 shown is a special purpose (specific) computing environment that includes multiple hardware processing devices (generally indicated by reference numeral 202) linked together by one or more networks (generally indicated by reference numeral 204).

[0024] One or more networks 204 provide communication links between various processing devices 202 and may be supported by networking components 206 interconnecting the processing devices 202, including, for example, routers, hubs, firewalls, network interfaces, wired or wireless communication links and corresponding interconnections, cellular stations and corresponding cellular conversion technologies (e.g., conversion between cellular and TCP / IP, etc.). Furthermore, one or more networks 204 may include connections using one or more intranets, extranets, local area networks (LANs), wide area networks (WANs), wireless networks (Wi-Fi), the Internet (including the World Wide Web), cellular and / or other arrangements to enable real-time or other methods (e.g., via time-shifting, batch processing, etc.) communication between the processing devices 202.

[0025] Processing device 202 can be implemented as a server, personal computer, laptop computer, netbook computer, purpose drive device, dedicated computing device and / or other device capable of communicating via network 204. Other types of processing device 202 include, for example, personal data assistant (PDA) processors, handheld computers, cellular devices including cellular mobile phones and smartphones, tablet computers, electronic control units (ECUs), displays for industrial vehicles, etc.

[0026] Furthermore, the processing device 202 is mounted on one or more industrial vehicles 208, such as forklifts, reach trucks, order pickers, automated guided vehicles (AGVs), turret trucks, tractors, pallet trucks, pedestrian stackers, and high-speed picking remote trucks. In the example configuration shown, the industrial vehicle 208 wirelessly communicates with a corresponding networking component 206, which serves as a connection to the network 204, via one or more access points 210. Alternatively, the industrial vehicle 208 may be equipped with Wi-Fi, cellular, or other suitable technologies that allow the processing device 202 on the industrial vehicle 208 to communicate directly with remote devices (e.g., via the network 204).

[0027] The system 200 also includes a processing device implemented as a server 212 (e.g., a web server, file server, and / or other processing device) to support the analytics engine 214 and the corresponding data source (collectively referred to as data source 216). The analytics engine 214 and data source 216 provide domain-level resources to the industrial vehicle 208. Furthermore, data source 216 stores data related to the activities of the industrial vehicle 208.

[0028] In an exemplary implementation, data source 216 includes a collection of databases storing various types of information related to operations (e.g., industrial environments, distribution centers, retail stores, manufacturers, etc.). However, these data sources 216 do not need to be located in the same place. In an illustrative example, data source 216 includes a database that links processes performed for the benefit of the enterprise from multiple different domains. In the illustrated example, data source 216 includes an industrial vehicle information database 218 (supporting processes performed in the industrial vehicle operations domain), a warehouse management system (WMS) 220 (supporting processes related to the movement and tracking of goods within the operating environment performed in the WMS domain), a human resource management system (HRMS) 222 (supporting processes performed in the HRMS domain), a geospatial management system 224 (supporting processes utilizing environment-based location tracking data of industrial vehicles in a geographic domain), and so on. The above list is not exhaustive and is for illustrative purposes only.

[0029] Furthermore, the industrial vehicle 208 may include short-range direct communication with an electronic signage, which may be remote but relatively close to the corresponding industrial vehicle 208 (for example, 15-20 meters). The electronic signage may also be positioned on machines, fixtures, equipment, other objects, industrial vehicle operators, combinations thereof, etc. Electronic signage is discussed in more detail in U.S. Patent Application No. 15 / 685,163, filed August 24, 2017, entitled INDUSTRIAL ELECTRONIC BADGE, the entire contents of which are incorporated herein by reference.

[0030] In some illustrative implementations, the industrial vehicles 208 themselves can communicate directly with each other via electronic signage communication technology (e.g., via short-range direct communication links), thereby forming a mesh network or a temporary mesh network.

[0031] Industrial vehicles

[0032] As described above, in certain contexts and roles, the processing device 202 is located on the industrial vehicle 208. Here, the processing device 202 is a dedicated, specific computer, such as a device installed on or otherwise integrated with the industrial vehicle 208. The processing device 202 includes a processor coupled to memory to execute instructions. However, the execution environment of the processing device 202 is further tied to the industrial vehicle 208, making it a specific machine distinct from a general-purpose computer.

[0033] For example, an example processing device 202 on an industrial vehicle is a mobile asset information linking device as described in U.S. Patent No. 8,060,400 (see Information Linking Device 38), the disclosure of which is incorporated herein by reference in its entirety. In some illustrative implementations, the processing device 202 also communicates with components of the corresponding industrial vehicle 208 (e.g., via a vehicle network bus (e.g., a Controller Area Network bus (CAN bus)), short-range wireless technology (e.g., via Bluetooth or other suitable methods), or other wired connections, examples of which are further described in U.S. Patent No. 8,060,400, which is incorporated herein by reference.

[0034] refer to Figure 3 The processing device 202 is implemented as an information linking device, including the necessary circuitry for wireless communication with components of the industrial vehicle, data and information processing, and wired (and optionally wireless) communication. As several illustrative examples, the processing device 202 includes a transceiver 302 for wireless communication, capable of transmitting and receiving signals. While a single transceiver 302 is shown for convenience, in practice, one or more wireless communication technologies may be provided. For example, the transceiver 302 may be able to communicate with a remote server (e.g., server 212), and thus via... Figure 2 The 802.11.xx access point 210 and Figure 2 The transceiver 302 interacts with the analysis engine 214. It may also optionally support other wireless communications, such as cellular, Bluetooth, infrared (IR), or any other technology or combination thereof. For example, using a cellular-to-IP (Internet Protocol) bridge, the transceiver 302 may be able to communicate directly with a remote server (e.g., a manufacturer's server) using cellular signals. The transceiver 302 may also communicate with a wireless remote control device that controls the industrial vehicle 208. The remote control device may be controlled by the industrial vehicle operator or by system 200.

[0035] The processing device 202 also includes a control module 304 having a processor coupled to memory to implement computer instructions. Furthermore, the control module 304 implements processing such as operator login, pre-use inspection checklists, data monitoring, and other features, examples of which are described more fully in U.S. Patent No. 8,060,400 to Wellman, which is incorporated herein by reference.

[0036] The processing equipment 202 also includes a vehicle power activation circuitry system 306 to selectively enable or disable the industrial vehicle 208. In some implementations, the vehicle power activation circuitry system 306 may, for example, partially or fully enable the industrial vehicle 208 for operation depending on the correct operator login. For example, the industrial vehicle power activation circuitry system 306 may provide selective power to components via power line 308. Various functions of the industrial vehicle 208 may be controlled by the vehicle power activation circuitry system 306 (e.g., in conjunction with control module 304), such as traction control, steering control, braking control, drive motors, etc.

[0037] Furthermore, the processing device 202 includes a monitoring input / output (I / O) module 310 for communicating with peripheral devices (such as sensors, instruments, encoders, switches, etc. (represented uniformly by reference numeral 312)) installed on or otherwise mounted on an industrial vehicle via wired or wireless connections.

[0038] Processing device 202 is coupled to and / or communicates with other industrial vehicle system components via a suitable industrial vehicle network system 314 (e.g., a vehicle network bus). Industrial vehicle network system 314 is any wired or wireless network, bus, or other communication capability that allows the electronic components of industrial vehicle 208 to communicate with each other. As an example, industrial vehicle network system may include Controller Area Network (CAN) bus, ZigBee, Bluetooth, Local Area Network (LIN), Time-Triggered Data Bus Protocol (TTP), or other suitable communication strategies.

[0039] As will be described more fully herein, the use of the industrial vehicle network system 314 enables the seamless integration of components of the processing device 202 on the industrial vehicle 208 into local electronics, including the controller of the industrial vehicle 208. Furthermore, the monitoring I / O module 310 can bridge any electronic peripheral device 312 to the industrial vehicle network system 314. For example, as shown, the processing device 202 connects to, understands, and is able to communicate with local vehicle components such as controllers, modules, devices, bus-enabled sensors, displays, lights, light strips, sound-emitting devices, headphones, microphones, haptic devices, etc. (uniformly indicated by reference numeral 316).

[0040] The processing device 202 can also communicate with the key fob 318 (or keypad, card reader, or any other device) to receive operator login credentials. Furthermore, the processing device 202 may include a display and / or other features to provide the desired processing capabilities.

[0041] According to other aspects of this disclosure, an environment-based location tracking system 320 can be provided on industrial vehicle 208, which can communicate across industrial vehicle network system 314. The environment-based location tracking system 320 enables industrial vehicle 208 to spatially perceive its location within an industrial environment. The environment-based location tracking system 320 may include a local sensing system that utilizes tags, including RFID (Radio Frequency Identification), beacons, lights, or other external devices, to allow spatial perception within the industrial environment. The environment-based location tracking system 320 can use one or more of a Global Positioning System (GPS) or triangulation system to determine its location. The environment-based location tracking system 320 can also utilize knowledge read from vehicle sensors, encoders, accelerometers, and other systems that allow location determination.

[0042] As another example, the environment-based location tracking system 320 may include a transponder and can triangulate the position of an industrial vehicle within an industrial environment. Furthermore, the environment-based location tracking system 320 may use a combination of the above and / or other techniques to determine the current (real-time) position of the industrial vehicle. Thus, in some implementations, the position of the industrial vehicle can be determined continuously (e.g., every second or less). Alternatively, other sampling intervals can be derived to determine the position of the industrial vehicle over time continuously (e.g., at discretely defined time intervals, periodic or other constant and repeating time intervals, intervals based on interruptions, triggers, or other methods).

[0043] The processing device 202 can also be connected to other devices, such as third-party devices 322, such as RFID scanners, displays, meters, weight sensors, forklift load sensors, or other devices.

[0044] Calibrate roll angle

[0045] Turn now Figure 4 The top-to-bottom diagram illustrates the process for calibrating the roll angle of a distance and range measuring device 440 (e.g., a laser, scanner, 3-D camera, LIDAR device, ultrasonic device, etc.) mounted to an industrial vehicle 442, where the calibration is relative to the roll axis of the distance and range measuring device 440. As used herein, the roll axis 444 is an axis extending from the front of the distance and range measuring device to the rear of the distance and range measuring device.

[0046] When calibrating the distance and range measuring device 440, the device is activated such that an emission 446 from the device (e.g., a laser beam if the device includes a laser) is at a first yaw angle 448 relative to the roll axis 444 and pointed towards the ground at a distance from the industrial vehicle (e.g., one meter in front of the vehicle). The sensor 450 senses the reflection of the emission and converts the reflection (e.g., using the time of flight of the emission) into a emission length of the first angle. Therefore, a first measurement value is obtained for the emission from the distance and range measuring device at the first yaw angle relative to the roll axis of the device.

[0047] A second measurement is acquired to determine the length of the second launch 454 at a second yaw angle 452 (similar to the above). In many embodiments, the first and second measurements can be acquired from a single scan that includes both the first and second yaw angles. The second yaw angle can be within the angular tolerance of the first yaw angle (the smaller the tolerance, the more accurate the calibration), but in the opposite direction to the first yaw angle relative to the roll axis. For example, if the first yaw angle is at +45 degrees to the roll axis (in the roll-pitch plane), then the second yaw angle can be within the angular tolerance of -45 degrees to the roll axis in the roll-pitch plane (e.g., 0.01 degrees).

[0048] Furthermore, two different angles can be used for two yaw angles (i.e., two yaw angles whose absolute values ​​are not within the angular tolerance). Then, one of the measurements should be scaled before making the following comparison. For example, the first measurement should be scaled by dividing the cosine of the first yaw angle by the cosine of the second yaw angle. On the other hand, the second measurement can be scaled by dividing the cosine of the second yaw angle by the cosine of the first yaw angle. Therefore, if the first yaw angle is 45 degrees and the second yaw angle is -20 degrees, then the first measurement is scaled by 0.707 / 0.94 = 0.752. Note that if the first yaw angle is 45 degrees and the second yaw angle is +20 degrees, then the result for the example is the same.

[0049] If the difference between the first and second measurements is within the rolling tolerance, then the roll angle is correctly determined. In some embodiments, determination includes comparing the first and second measurements, and if they are within each other's rolling tolerances (the smaller the rolling tolerance, the more accurate the calibration), then the roll angle of the distance and range measuring device is correctly calibrated. For example, if the first measurement is 1.540 meters, the second measurement is 1.538 meters, and the rolling tolerance is 0.003 meters, then the first and second measurements are within the rolling tolerance. In some embodiments, the comparison is performed by a processor on the industrial vehicle. In other embodiments, the comparison is performed by a processor separate from the industrial vehicle. Recall that if two different yaw angles are used (i.e., two yaw angles whose absolute values ​​are not within the angular tolerance), then one of the measurements should be scaled as described above.

[0050] If the first measurement is not within the rolling tolerance of the second measurement, then the distance and range measuring device 440 must be rolled. In this case, if the first measurement is greater than the second measurement, then the distance and range measuring device 440 should roll clockwise (standing behind the industrial vehicle). On the other hand, if the second measurement is greater than the first measurement, then the distance and range measuring device 440 should roll counterclockwise (standing behind the industrial vehicle) (i.e., determine the adjustment direction). The clockwise / counterclockwise example discussed above assumes that the first angle is positively angled to the rolling axis; if the first yaw angle is negatively angled to the rolling axis, then the clockwise / counterclockwise direction will be reversed. Furthermore, the magnitude of the difference between the first and second measurements will guide how many degrees the distance and range measuring device 440 should roll (i.e., determine the adjustment range).

[0051] If the first measurement is not within the rolling tolerance of the second measurement, the distance and range measuring device 440 can be adjusted (e.g., rolled) according to the adjustment direction and adjustment magnitude. In some embodiments, the adjustment is performed automatically by the industrial vehicle. In other embodiments, the adjustment direction and adjustment magnitude are displayed on the screen of the industrial vehicle or transmitted (as described above) to a remote device for display. In some embodiments, the roll angle of the distance and range measuring device is considered calibrated after adjustment. In other embodiments, after adjustment, two more measurements (i.e., a new first measurement and a new second measurement) are obtained as described above. In some of these embodiments, the new first yaw angle and the new second yaw angle are the same angles as the first and second yaw angles described above. However, in other embodiments, the new first yaw angle and the new second yaw angle are different angles from the first and second yaw angles described above. For example, if the first and second yaw angles are at +45 degrees and -45 degrees to the rolling axis, respectively, then the new first yaw angle and the new second yaw angle could be at +20 degrees and -20 degrees to the rolling axis, respectively. Repeat the process iteratively until the first and second measurements are within each other's rolling tolerances.

[0052] Calibrate pitch angle

[0053] Figures 5-6 The process for calibrating a distance and range measuring device 540 (e.g., a laser, scanner, 3-D camera, optical detection and ranging (LIDAR) device, ultrasonic device, etc.) coupled to an industrial vehicle 542 is illustrated, wherein calibration is performed relative to the pitch axis 554 of the distance and range measuring device 540. As used herein, the pitch axis 554 is an axis perpendicular to the front of the distance and range measuring device.

[0054] The scanning field is defined as having a length of 556, which is the distance from the distance and range measuring device 540 to the end of the scanning field, the end of the scanning field ending at a predetermined distance 558 (typically a few centimeters) above the floor. Figure 5 As shown, the scan field extends 270 degrees in front of the distance and range measuring device. However, the scan field can be any desired size. A scan field length of 556 (specified as L) can be used. sf The virtual launch length 560 (specified as L) is determined by the predetermined distance 558 (specified as h) and the angle 562 of the distance and range measuring device relative to the pitch axis 554 in the yaw-roll plane (i.e., the pitch angle that the distance and range measuring device should have when it is correctly pitched (i.e., correctly calibrated relative to the pitch axis) (specified as α). b Determine L. b The formula is: Lb = L sf +(h / sin(α)) in: L sf It is the length of the scan field; h is the height at which the scan field ends above the floor; and α is the angle when the pitch angle of the distance and range measuring device is correct.

[0055] To calibrate the distance and range measuring device 540 along the pitch axis 554 (i.e., to determine if the distance and range measuring device is pitching correctly), a transmitter 546 from the distance and range measuring device 540 is guided to the floor. Figure 5 As shown, launcher 546 is aligned with the roll axis. However, launcher 546 can yaw at any angle (while still remaining within the scan field and the launcher can impact the ground / floor).

[0056] Measurements are acquired from the transmission from the distance and range measuring device. These measurements may be a first measurement obtained from the aforementioned calibration process for the roll-off angle, a second measurement obtained from the aforementioned calibration process for the roll-off angle, or measurements independent of those measurements. The measurements are then compared to a virtual transmission length. In some embodiments, the comparison is performed by a processor on the industrial vehicle. In other embodiments, the comparison is performed by a processor separate from the industrial vehicle.

[0057] If the difference between the measured value and the virtual launch length is within the pitch tolerance, then the pitch angle is correctly determined. In some embodiments, the determination includes comparing the measured value with the virtual launch length to determine whether the measured value is within the pitch tolerance of the virtual launch length.

[0058] However, if the measured value is outside the pitch tolerance of the virtual transmission length, and if the measured value is greater than the virtual transmission length, then the range and range measuring device should pitch downwards as the adjustment direction. On the other hand, if the measured value is less than the virtual transmission length, then the range and range measuring device should pitch upwards. The difference between the measured value and the virtual transmission length is related to the adjustment range (e.g., how many degrees) by which the range and range measuring device should pitch.

[0059] If the measured value is not within the pitch tolerance of the virtual launch length, the distance and range measuring device 540 can be adjusted according to the adjustment direction and adjustment magnitude. In some embodiments, the adjustment is performed automatically by the industrial vehicle. In other embodiments, the adjustment direction and adjustment magnitude are displayed on the industrial vehicle's screen or transmitted (as described above) to a remote device for display. In some embodiments, after adjustment, a new measured value is then acquired as described above. Therefore, this process can be repeated iteratively until the measured value is within the pitch tolerance of the virtual launch length. In other embodiments, it is assumed that the distance and range measuring device is correctly calibrated after adjustment.

[0060] Overall calibration processing

[0061] Figure 7 This is a flowchart illustrating the overall processing 700 for calibrating a distance and range measuring device (e.g., laser, scanner, 3-D camera, LiDAR device, ultrasonic device, etc.) coupled to an industrial vehicle. At 702, a first measurement is acquired for a emission from the distance and range measuring device at a first yaw angle relative to the roll axis of the industrial vehicle. For example, the distance and range measuring device is activated such that the emission from the device is at the first yaw angle relative to the roll axis and pointed at the ground at a distance from the industrial vehicle (e.g., one meter in front of the industrial vehicle). A sensor senses the reflection of the emission and converts the reflection (e.g., using the time of flight of the emission) into the first measurement of the emission at the first yaw angle. The first yaw angle can be any angle within the scanning field of the distance and range measuring device except zero degrees and + / - ninety degrees. For example, the first yaw angle can be forty-five degrees relative to the roll axis. As another example, the first yaw angle can be negative twenty degrees relative to the roll axis.

[0062] At point 704, a second measurement value is acquired from the emission from the distance and range measuring device at a second yaw angle relative to the roll axis. As described above, the first and second measurement values ​​can be acquired during a single scan. The second yaw angle can be within the angular tolerance of the first yaw angle, but in the opposite direction to the first yaw angle relative to the roll axis. Alternatively, the two yaw angles can be two different angles (i.e., two yaw angles whose absolute values ​​are not within the angular tolerance). Then, one of the measurement values ​​should be scaled before making the following comparison. For example, the first measurement value should be scaled by dividing the cosine of the first yaw angle by the cosine of the second yaw angle. On the other hand, the second measurement value can be scaled by dividing the cosine of the second yaw angle by the cosine of the first yaw angle.

[0063] At point 706, the roll angle of the distance and range measuring device is determined to be correct when the first and second measurements are within the rolling tolerance. In many embodiments, the roll angle is correctly calibrated if the difference between the first and second measurements is within the rolling tolerance. In some embodiments, the determination is performed by a processor on the industrial vehicle. In other embodiments, the determination is performed by a processor separate from the industrial vehicle. For more accurate calibration, the rolling tolerance should be a small number. If the first and second measurements are within the rolling tolerance, the roll angle of the distance and range measuring device is correct (i.e., the distance and range measuring device rotates correctly along the rolling axis). In cases where two different yaw angles are used for the first and second yaw angles, a scaled measurement should be compared with an unscaled measurement. For example, a scaled first measurement is compared with an unscaled second measurement. Alternatively, an unscaled first measurement is compared with a scaled second measurement.

[0064] If the first and second measurements are not within each other's rolling tolerances (i.e., the rolling angle is incorrect), then the distance and range measuring device must be rolled around the rolling axis by rolling adjustment. In this case, if the first measurement is greater than the second measurement, then the distance and range measuring device should roll clockwise around the rolling axis. On the other hand, if the second measurement is greater than the first measurement, then the distance and range measuring device should roll counterclockwise around the rolling axis (i.e., determine the rolling adjustment direction). The clockwise / counterclockwise example discussed above assumes that the first yaw angle is positively angled to the rolling axis; if the first yaw angle is negatively angled to the rolling axis, then the clockwise / counterclockwise direction will be reversed. Furthermore, the adjustment magnitude can be based on the difference between the first and second measurements (i.e., determine the rolling adjustment magnitude). In some embodiments, a processor on an industrial vehicle is used to determine the rolling adjustment direction and rolling adjustment magnitude, while in other embodiments, a processor separate from the industrial vehicle is used to determine the rolling adjustment direction and rolling adjustment magnitude.

[0065] In some embodiments, the rolling adjustment (i.e., based on the rolling adjustment magnitude and direction) is performed automatically by the industrial vehicle. In other embodiments, the rolling adjustment direction and magnitude are displayed on a screen of the industrial vehicle or transmitted to a remote device for display.

[0066] In some embodiments, after the roll adjustment, two more measurements are obtained as described above. In some of these embodiments, the new first yaw angle and the new second yaw angle are the same angles as the first yaw angle and the second yaw angle described above. However, in other embodiments, the new first yaw angle and the new second yaw angle are different angles from the first yaw angle and the second yaw angle described above. For example, if the first yaw angle and the second yaw angle are at +45 degrees and -45 degrees to the roll axis, respectively, then the new first yaw angle and the new second yaw angle may be at +20 degrees and -20 degrees to the roll axis, respectively. This process can be repeated until the first and second measurements are within the roll tolerance.

[0067] At point 708, the virtual launch length (i.e., the expected launch length when the distance and range measuring device is correctly calibrated) is determined based on the length of the scan field, the height at which the scan field ends above the floor, and the angle of the distance and range measuring device relative to the pitch axis of the industrial vehicle. For example, the virtual launch length (L...) b It can be determined by the following equation: L b = L sf +(h / sin(α)) in: L sf It is the length of the scan field; h is the height at which the scan field ends above the floor; and α is the angle when the pitch angle of the distance and range measuring device is correct.

[0068] At 710, a third measurement is acquired from a transmission from a distance and range measuring device at a third angle (i.e., pitch angle) relative to the pitch axis of the industrial vehicle. In some embodiments, a first measurement at 702 is used as the third measurement. In various embodiments, a second measurement at 704 is used as the third measurement. In several embodiments, the third measurement differs from the first measurement at 702 and the second measurement at 704. Furthermore, the transmission used for the third measurement can be any yaw angle in the scan field relative to the roll axis, except for zero degrees and + / - ninety degrees.

[0069] At point 712, the third measurement is then compared to the virtual launch length determined at point 708. If the measurement is within the pitch tolerance of the virtual launch length, then the pitch angle of the distance and range measuring device is correct.

[0070] On the other hand, if the measured value is outside the pitch tolerance of the virtual launch length (i.e., the pitch angle is incorrect), then if the measured value is greater than the virtual launch length, the range and range measuring device should pitch downwards (i.e., a pitch adjustment should be made) as the pitch adjustment direction. Conversely, if the measured value is less than the virtual launch length, the range and range measuring device should pitch upwards. The difference between the measured value and the virtual launch length is related to the pitch adjustment range (e.g., how many degrees) that the range and range measuring device should pitch.

[0071] If the measured value is not within the pitch tolerance of the virtual launch length, the distance and range measuring device can be adjusted according to the pitch adjustment direction and pitch adjustment magnitude. In some embodiments, the pitch adjustment is performed automatically by the industrial vehicle. In other embodiments, the pitch adjustment direction and pitch adjustment magnitude are displayed on the industrial vehicle's screen or transmitted to a remote device for display. In some embodiments, after the pitch adjustment, another third measurement is obtained as described above, and steps 708-712 are repeated until the measured value is within the pitch tolerance of the virtual launch length. In other embodiments, it is assumed that the pitch angle of the distance and range measuring device is correctly calibrated after the pitch adjustment.

[0072] Once the roll angle and pitch angle of the distance and range measuring device are correctly calibrated, an indication that both angles are correctly calibrated (i.e., a correctly calibrated indication) can be stored in the memory of the industrial vehicle.

[0073] The calibration process 700 can be performed in different orders. For example, in Figure 7 In this process, 702-706 are executed before 708-712. However, 708-712 can be executed simultaneously with 702-706 or before 702-706.

[0074] Typically, distance and range measurement device calibration requires a separate laptop computer with an adapter coupled to the laser sensor, specialized software on the laptop, and a special alignment device. With the calibration process 700 described above, the distance and range measurement device can be calibrated without any of these items. Alternatively, a level floor on an industrial vehicle and software can be used to perform the calibration process. In embodiments where the distance and range measurement device is automatically adjusted, a motor is also required for adjusting the device. However, in embodiments where a third party (e.g., a technician) adjusts the distance and range measurement device based on the adjustment magnitude and direction, a motor is not required.

[0075] Onboard auxiliary

[0076] In embodiments where the determination and comparison are performed by an industrial vehicle and the distance and range measuring devices are not automatically adjusted, the adjustment direction, adjustment range, or both can be displayed on the industrial vehicle's display device. Figure 8 An embodiment of a display 800 on a display device in an industrial vehicle is shown. The display 800 includes an icon of a distance and range measuring device 870, an indication 872 of which axis is being calibrated, and an adjustment direction 874. In some embodiments, the adjustment magnitude is also displayed. The adjustment direction 874 and magnitude can be displayed in real time, so that a technician knows how to adjust the distance and range measuring device. Furthermore, when the distance and range measuring device is correctly calibrated in one or both directions (i.e., as described above, the roll angle and / or pitch angle are correct), the display can indicate to the technician that adjustment in that direction should be stopped (if only one angle is correct) or stopped completely (if both the roll angle and pitch angle are correct).

[0077] In other embodiments, the display device may be a set of light-emitting diodes (LEDs). For example, if the display device has left and right LEDs, then when the right LED is activated, the adjustment should be clockwise, and when the left LED is activated, the adjustment should be counterclockwise. In many embodiments, the brightness of the LEDs indicates the adjustment magnitude. For another example, if the display device has eight LEDs, then the four LEDs on the right side of the display device can be used to indicate clockwise adjustment, and the other four LEDs can be used to indicate counterclockwise adjustment. In this example, the adjustment magnitude can be indicated by how many LEDs are activated. For example, activating the rightmost three LEDs will indicate a larger clockwise adjustment compared to only activating the rightmost two LEDs. In some embodiments, the display device may have separate sets of LEDs to indicate adjustments to the roll and pitch angles. In other embodiments, the display device has a set of LEDs and an indicator of which adjustment (roll or pitch) is required.

[0078] In embodiments where adjustments are not performed automatically (e.g., by a service technician), an indication that an adjustment has been made is sent to the processor. This indication may be provided by a technician, automatically using sensors on distance and range measuring devices, using a timer to assume an adjustment has been made, or a combination thereof.

[0079] Other matters

[0080] Figure 9This is a block diagram of a data processing system depicted according to an embodiment. The data processing system 900 may include a symmetric multiprocessor (SMP) system or other configurations including multiple processors 910 connected to a system bus 930. Alternatively, a single processor 910 may be used. Local memory 920 is also connected to the system bus 930. An I / O bus bridge 940 is connected to the system bus 930 and provides an interface to an I / O bus 950. The I / O bus may be used to support one or more buses and corresponding devices, such as storage devices 960, removable media storage devices 970, input / output devices (I / O devices) 980, network adapters 990, etc. The network adapter may also be coupled to the system to enable the data processing system to couple to other data processing systems or remote printers or storage devices via an intermediate private or public network.

[0081] Devices such as graphics adapters, storage devices, and computer-usable storage media on which computer-usable program code is implemented can also be connected to the I / O bus. The computer-usable program code can be executed to implement any aspect of this embodiment, for example, to implement any aspect of any of the methods and / or system components shown in the above figures.

[0082] As those skilled in the art will recognize, aspects of this disclosure can be implemented as systems, methods, or computer program products. Therefore, aspects of this disclosure can take the form of entirely hardware embodiments, entirely software embodiments (including firmware, resident software, microcode, etc.), or embodiments combining software and hardware aspects, all of which are collectively referred to herein as “circuit,” “module,” or “system.” Furthermore, aspects of this disclosure can take the form of computer program products implemented on one or more computer-readable storage media having computer-readable program code implemented thereon.

[0083] Any combination of one or more computer-readable media may be used. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, for example, but not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination of the foregoing. More specific examples (not an exhaustive list) of computer-readable storage media will include: electrical connections having one or more wires, portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing. In the context of this document, a computer-readable storage medium can be any tangible medium that can contain or store programs for use by or in connection with an instruction execution system, apparatus, or device. Computer storage media do not include propagating signals.

[0084] Computer-readable signal media may include, for example, propagated data signals in baseband or as part of a carrier wave in which computer-readable program code is implemented. Such propagated signals may take any of a variety of forms, including, but not limited to, electromagnetic, optical, or any suitable combination thereof. A computer-readable signal medium may be any computer-readable medium that is not a computer-readable storage medium but can communicate, propagate, or transmit programs for use by or in connection with an instruction execution system, apparatus, or device.

[0085] Program code implemented on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, fiber optic cable, RF, or any suitable combination thereof.

[0086] Computer program code used to perform the operations of various aspects of this disclosure may be written in any combination of one or more programming languages, including object-oriented programming languages ​​(such as Java, Smalltalk, C++, etc.) and conventional procedural programming languages ​​(such as the "C" programming language or similar programming languages). The program code may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer via any type of network (including a local area network (LAN) or a wide area network (WAN)), or may be connected to an external computer (e.g., through the network of an internet service provider).

[0087] This document describes aspects of the disclosure with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams.

[0088] These computer program instructions may also be stored in a computer-readable medium that can direct a computer, other programmable data processing apparatus or other device to operate in a particular manner, causing the instructions stored in the computer-readable medium to produce an article of writing, which includes instructions that implement the functions / actions specified in one or more blocks of a flowchart and / or block diagram.

[0089] Computer program instructions may also be loaded onto a computer, other programmable data processing apparatus or other equipment to cause a series of operational steps to be performed on the computer, other programmable apparatus or other equipment to produce computer-implemented processing, such that the instructions, which execute on the computer or other programmable apparatus, provide processing for implementing the functions / actions specified in one or more blocks of a flowchart and / or block diagram.

[0090] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code, including one or more executable instructions for implementing one or more specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a non-linear order as indicated in the drawings. For example, depending on the functions involved, two blocks shown sequentially may actually be executed substantially simultaneously, or sometimes in reverse order. It will also be noted that each block illustrated in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a system based on dedicated hardware or a combination of dedicated hardware and computer instructions that performs the specified functions or actions.

[0091] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that the terms “comprising” and / or “including,” when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0092] All components or steps in the following claims, along with their corresponding structures, materials, actions, and equivalents of the functional elements, are intended to include any structure, material, or action for performing a function in combination with other claimed elements, as specifically claimed. The description in this disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limiting to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of these embodiments. The aspects of this disclosure were chosen and described in order to best explain the principles and practical application of these embodiments and to enable others skilled in the art to understand the various embodiments with various modifications suitable for the particular intended use.

Claims

1. A method for calibrating a distance and range measurement device coupled to an industrial vehicle, the method comprising: A first measurement value is acquired from a launch from a distance and range measuring device at a first yaw angle relative to the rolling axis of the distance and range measuring device, wherein the rolling axis is an axis extending from the front of the distance and range measuring device to the rear of the distance and range measuring device; A second measurement value is acquired from a launch at a second yaw angle relative to the roll axis from a distance and range measuring device; When the difference between the first and second measurements is within the rolling tolerance, the rolling angle of the distance and range measuring device is correctly determined using the processor.

2. The method of claim 1, further comprising: When the difference between the first and second measurements is not within the rolling tolerance, it is incorrect to determine the rolling angle of the distance and range measuring equipment. as well as The adjustment direction is determined based on the first and second measurements.

3. The method of claim 2, further comprising: The adjustment range is determined based on the first and second measurements. as well as The distance and range measuring device is adjusted by the amount of adjustment relative to the rolling axis in the adjustment direction using a motor.

4. The method of claim 2, further comprising: Displaying direction adjustment instructions on the display equipment of industrial vehicles; Indication that the receiving distance and range measuring equipment has been adjusted; A new first measurement value is obtained from the launch of the distance and range measuring device at a new first yaw angle relative to the rolling axis of the distance and range measuring device; A new second measurement value is obtained from the launch of the distance and range measuring device at a new second yaw angle relative to the roll axis; as well as When the difference between the new first measurement and the new second measurement is within the rolling tolerance, the rolling angle of the distance and range measuring device is correctly determined using the processor.

5. The method of claim 4, wherein: The new first yaw angle is within the angular tolerance of the first yaw angle; and The new second yaw angle is within the angular tolerance of the second yaw angle.

6. The method of claim 4, wherein: The new first yaw angle is not within the angular tolerance of the first yaw angle; and The new second yaw angle is not within the angular tolerance of the second yaw angle.

7. The method of claim 1, wherein: Determining the roll angle of a distance and range measuring device using a processor when the difference between the first and second measurements is within the rolling tolerance includes: determining the roll angle of a distance and range measuring device using a processor on an industrial vehicle when the difference between the first and second measurements is within the rolling tolerance.

8. The method of claim 1, wherein: Determining the roll angle of the distance and range measuring device using a processor when the difference between the first and second measurements is within the rolling tolerance includes: determining the roll angle of the distance and range measuring device using a processor separate from the industrial vehicle when the difference between the first and second measurements is within the rolling tolerance.

9. The method of claim 1, further comprising: Once the roll angle of the distance and range measuring device is determined to be correct, an indication of correct calibration is stored.

10. The method of claim 1, wherein acquiring a first measurement value from a launch from a distance and range measuring device at a first yaw angle relative to the roll axis of the distance and range measuring device comprises: A first measurement value is obtained from a laser beam emitted from a laser at a first yaw angle relative to the rolling axis of the distance and range measuring device.

11. The method of claim 1, wherein acquiring the second measurement value from the launch at a second yaw angle relative to the roll axis from the distance and range measuring device comprises: A second measurement is obtained from a launch from a distance and range measuring device at a second yaw angle relative to the rolling axis, wherein the second yaw angle is within the angular tolerance of the first yaw angle, but in the opposite direction to the first yaw angle relative to the rolling axis.

12. The method of claim 1, wherein acquiring the second measurement value from the launch at a second yaw angle relative to the roll axis from the distance and range measuring device comprises: A second measurement is obtained from a launch from a distance and range measuring device at a second yaw angle relative to the roll axis, wherein the second yaw angle is different from the first yaw angle.

13. The method of claim 12, further comprising: The first measurement value is scaled based on the first yaw angle and the second yaw angle to create a scaled first measurement value; The statement that determining the roll angle of the distance and range measuring device using the processor is correct when the difference between the first and second measurements is within the rolling tolerance includes: determining the roll angle of the distance and range measuring device using the processor is correct when the difference between the scaled first and second measurements is within the rolling tolerance.

14. The method of claim 12, further comprising: The second measurement value is scaled based on the first yaw angle and the second yaw angle to create a scaled second measurement value; The statement that determining the roll angle of the distance and range measuring device correctly using the processor when the first and second measured values ​​are within the rolling tolerance includes: determining the roll angle of the distance and range measuring device correctly using the processor when the difference between the first measured value and the scaled second measured value is within the rolling tolerance.

15. A method for calibrating a distance and range measuring device coupled to an industrial vehicle, the method comprising: The virtual transmission length is determined based on the length of the scan field, the height of the scan field above the floor, and the pitch angle of the distance and range measuring device relative to the pitch axis of the distance and range measuring device, where the length of the scan field is the distance from the distance and range measuring device to the end of the scan field; Acquire a third measurement value from a transmission from a distance and range measuring device at a third angle relative to the pitch axis of the distance and range measuring device; and When the difference between the third measurement and the virtual launch length is within the pitch tolerance, it is correct to use the processor to determine the pitch angle of the distance and range measuring device.

16. The method of claim 15, further comprising: When the difference between the measured value and the virtual transmission length is not within the pitch tolerance, the pitch angle of the distance and range measuring device is incorrect; as well as The adjustment direction is determined based on the measured values ​​and the virtual launch length.

17. The method of claim 16, further comprising: The adjustment range is determined based on the measured values ​​and the virtual launch length; as well as The distance and range measuring device is adjusted by the amount of adjustment relative to the pitch axis in the adjustment direction using a motor.

18. The method of claim 16, further comprising: Displaying direction adjustment instructions on the display equipment of industrial vehicles; Adjustment of the receiving distance and range measuring equipment; Acquire new measurement values ​​from the transmission from the distance and range measuring device at a new angle relative to the pitch axis of the distance and range measuring device; and When the new measurement is within the pitch tolerance of the virtual launch length, it is correct to use the processor to determine the pitch angle of the distance and range measuring device.

19. The method of claim 15, further comprising: Once the pitch angle of the distance and range measuring device is determined to be correct, a correct calibration indication is stored.

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