Patent Publication Number: US-11385134-B1

Title: Method and apparatus for vehicle inspection and safety system calibration using projected images

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is related to, and claims priority from, co-pending U.S. patent application Ser. No. 16/990,427 filed on Aug. 11, 2020, which in turn claims priority to U.S. patent application Ser. No. 15/722,913 filed on Oct. 2, 2017, now U.S. Pat. No. 10,788,400, and which in turn claims priority from U.S. Provisional Patent Application Ser. No. 62/406,679 filed on Oct. 11, 2016, each of which are herein incorporated by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     The present application is related to systems and methods for the inspection and calibration of vehicle safety systems, and in particular, to vehicle service equipment configured to utilize at least one projector to emit electromagnetic energy during a vehicle safety system inspection or calibration procedure, aiding the placement of a vehicle service fixture relative to the vehicle, or providing vehicle onboard sensors with signal input simulating, to sensors onboard the vehicle, at least a portion of a test drive scenario. 
     Within the automotive industry there are an increasing number of vehicle manufacturers producing vehicles equipped with onboard sensors such as radar, LIDAR, ultrasonic, and optical systems for monitoring the external surroundings of the vehicles. These systems include Lane Departure Warning systems (LDW), Lane Keep Assist systems (LKA), Blind Spot Detection systems (BSD), collision mitigation braking systems (CMBS), Adaptive Cruise Control systems (ACC), peripheral vision camera systems, reverse camera systems (backup alarms), and night vision camera systems. As vehicle sensor systems become more advanced, the onboard systems rely on input received from these monitoring sensors to provide driver warnings, automate vehicle functions (such as parallel parking), and implement safety features (such as automatic collision avoidance braking and automatically maintaining vehicle spacing). 
     In order for these various systems to function properly in a vehicle environment, it is necessary to ensure that the vehicle onboard sensors are aligned to specific predetermined or known orientations relative to the vehicle body, such as a centerline, or a direction of vehicle movement, such as a thrust line. If a sensor is misaligned, data acquired may not represent the presence of an object which is adjacent to, or approaching the vehicle, or may be insufficient to identify the location of observed objects. Failure to detect or properly identify observed objects may lead to situations in which warnings are not provided by the vehicle, and corrective actions are not taken, or alternatively, to situations in which warnings or corrective action are provided or taken in error. Failure of such an onboard vehicle system to properly detect and locate objects in the vicinity of the vehicle could lead to collisions between the vehicle and the object. 
     Some automotive manufacturers have established requirements for the alignment or calibration of the various vehicle sensors which observe or monitor the vehicle external environment. These requirements may necessitate the placement of observable or reflective calibration targets at precise locations relative to an identifiable or measured point on, or associated with, the vehicle. With a calibration target properly positioned, a vehicle sensor can be aligned or calibrated with reference to the observable calibration target. 
     For example, to perform an aiming or calibration procedure for a vehicle equipped with a safety system employing radar devices concealed in inconspicuous locations, such as at the front of the vehicle or behind the vehicle rear bumper cover, manufacturers may require the vehicle to be positioned on a level surface with a radar-reflective target placed at a specific distance of up to eight meters from the portion of the vehicle housing the radar device. The specific distance from the vehicle, and any lateral offset distance from the vehicle center line or thrust line, varies between vehicle models. Typically, a vehicle manufacturer will specify the placement location for the calibration target by providing instructions for measuring specific distances and angles relative to the vehicle. Recognizing the need to position observable or reflective calibration targets in precise locations, it would be beneficial to provide vehicle service technicians with a method and apparatus for aiding in quickly identifying placement locations for calibration targets relative to a vehicle undergoing a service or inspection procedure without requiring the operator to manually measure distances or angles. 
     In addition to, or independent of the need to position observable or reflective calibration targets in precise locations in proximity to a vehicle undergoing a safety system inspection or calibration procedure, some automotive manufactures have established vehicle safety system inspection or calibration requirements which necessitate that the vehicle be driven on a test drive, during which the various onboard sensors observe the movement of objects and roadway markings in relation to the vehicle. These test drives enable the sensors to “learn” how observations relate to the vehicle motion. Specific test drive durations and requirements vary between vehicle models, and may require specific distances to be driven, and specific speeds to be reached. Additional requirements include achieving at least a minimum duration of travel on a straight-line road. 
     Recognizing that the requirements for a vehicle test drive may be impractical or impossible for some vehicle service shops, due to geographic location, time restrictions, or local traffic conditions, it would be beneficial to provide vehicle service technicians with a method and apparatus for simulating a vehicle test drive condition to vehicle onboard sensors while the vehicle remains within a vehicle service bay. These vehicle onboard sensors may include optical cameras which observe visible features, or radar units which emit radar signals and receive back reflected energy from various reflective surfaces in the vehicle environment. The simulation operates to provide input to the vehicle onboard sensors in an expected format, emulating the appearance of objects and environments in motion which might be encountered during an actual vehicle test drive on a roadway. 
     BRIEF SUMMARY OF THE INVENTION 
     In an embodiment of the present disclosure, a vehicle service system configured to measure or determine one or more spatial parameters of a vehicle undergoing a safety system service or inspection procedure further includes an optical projector configured to project an optical image onto a surface in proximity to the vehicle. A processor of the vehicle service system is configured with suitable software instructions to control the optical projector, to select or render images for projection, and to position and/or orient a projection axis of the optical projector. The processor is further configured with software instructions to operate the optical projector during a vehicle safety system service or inspection procedure in order to project markings onto a floor surface in proximity to the vehicle identifying one or more locations relative to the determined vehicle centerline or thrust line, at which an observable fixture should be placed for observation by a safety system sensor onboard the vehicle. 
     In a further embodiment of the present disclosure, a vehicle service system configured to measure spatial parameters of a vehicle, such as, but not limited to, a vehicle centerline or a vehicle thrust line, further includes an optical projector configured to project optical video imagery representative of roadway features observed during a vehicle test drive onto a receiving surface in front of a vehicle undergoing a safety system service or inspection procedure within a vehicle service area. A processor of the vehicle service system is configured with suitable software instructions to control the optical projector in order to simulate the visual appearance of roadway features moving relative to the vehicle centerline or thrust line while the vehicle remains stationary within the vehicle service area. The processor of the vehicle service system may be further configured to interface with the vehicle onboard control systems and emulate signals required to simulate movement of the vehicle in synchronization with the projected optical video imagery. Optionally, the vehicle service system is further configured to monitor signals generated by one or more safety system sensors observing the projected optical video imagery, and/or the vehicle on-board controls system, in order to determine if the safety system sensors and/or control system, are responding as expected to the simulated test drive conditions. 
     In yet another embodiment of the present disclosure, a vehicle service system configured to measure spatial parameters of a vehicle, such as, but not limited to, a vehicle centerline or a vehicle thrust line, further includes a radar emitter configured to emit radar-frequency electromagnetic energy representative of either stationary or moving objects within a field of view of a radar system onboard a vehicle undergoing a safety system service or inspection procedure within a vehicle service area. A processor of the vehicle service system is configured with suitable software instructions to control the radar emitter in order to simulate the radar reflections of objects moving relative to the vehicle centerline or thrust line while the vehicle remains stationary within the vehicle service area. The processor of the vehicle service system may be further configured to interface with the vehicle onboard control systems and emulate signals required to simulate movement of the vehicle in synchronization with the emitted radar signals. Optionally, the vehicle service system is further configured to monitor signals generated by one or more radar systems onboard the vehicle, and/or the vehicle on-board controls system, in order to determine if the radar systems and/or control system, are responding as expected to the emitted radar signals. 
     The foregoing features, and advantages set forth in the present disclosure as well as presently preferred embodiments will become more apparent from the reading of the following description in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       In the accompanying drawings which form part of the specification: 
         FIG. 1  is a top plan view of a vehicle service bay associated with a vehicle service system and optical projector of the present disclosure, illustrating exemplary observable indicia projected onto surfaces by the optical projector; 
         FIG. 2  is a side view of a vehicle service bay associated with a vehicle service system and optical projector of the present disclosure, illustrating video images projected onto a screen in front of a vehicle for observation by a vehicle on-board optical sensor system; and 
         FIG. 3  is a top plan view of a vehicle service bay associated with a vehicle service system and a radar emitter fixture of the present disclosure, illustrating a range of controlled movement for an emitter on the fixture when simulating objects moving off-axis relative to a vehicle based radar sensor system. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings. It is to be understood that the drawings are for illustrating the concepts set forth in the present disclosure and are not to scale. 
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. 
     DETAILED DESCRIPTION 
     The following detailed description illustrates the invention by way of example and not by way of limitation. The description enables one skilled in the art to make and use the present disclosure, and describes several embodiments, adaptations, variations, alternatives, and uses of the present disclosure, including what is presently believed to be the best mode of carrying out the present disclosure. 
     Procedures of the present disclosure for facilitating, during a vehicle service or inspection, the alignment and calibration of vehicle onboard sensors which monitor or observe the external environment surrounding the vehicle, such as radar, LIDAR, infrared, or optical sensors used for blind spot monitoring, cross-traffic monitoring, lane departure warnings, collision avoidance systems, and automatic cruise control, are illustrated with reference to the accompanying illustrations. It will be understood by those of ordinary skill in the art that these procedures are intended to be implemented while the vehicle body is stationary and disposed on a generally level surface, such as within a service bay or shop environment in which precision measurements associated with the vehicle can be acquired. External access to the vehicle onboard sensors or to the mounting structures in which they are secured is often required, and may necessitate the removal of vehicle components such as bumper covers or access panels prior to beginning any alignment or calibration procedures, depending upon the vehicle manufacturer&#39;s guidelines and stated procedures. 
     In order to conduct alignment or calibration procedures required for many different types of vehicle onboard sensors, it is necessary to place an observable target or calibration fixture for a selected vehicle onboard sensor within a field of view for the selected sensor, at one or more manufacturer-specified locations  200  which are relative to the stationary vehicle. In a first embodiment illustrated with reference to  FIG. 1 , a procedure of the present disclosure for positioning such an observable target or calibration fixture begins by moving the vehicle  100  into a vehicle service area  10 , such as a shop service bay or inspection lane, within which measurements associated with parameters of the vehicle  100  can be acquired. One or more parameters of the vehicle  100  are measured within a spatial frame of reference, such as by a vehicle wheel alignment measurement system  110  consisting of suitable measurement sensors  112  and having a processor  114  configured with software to interact with the measurement sensor and various output devices for conveying information to an operator or external systems. The processor  114  may be contained within a separate console, such as shown in  FIGS. 1-3 , or may be contained within the same structure as the measurement sensors  112 . An exemplary alignment measurement system is a HawkEye Elite™ Alignment system, manufactured and sold by Hunter Engineering Company of St. Louis, Mo., but those of ordinary skill in the art will recognize that any of a variety of vehicle measurement systems may be utilized, provided that the system used is capable of establishing a location of the vehicle  100  within a spatial frame of reference. The vehicle measurement system  110  is preferably machine-vision based, and configured to measure parameters which include, but are not limited to, the vehicle centerline CL, the vehicle thrust line TL, and the position of one or more of the vehicle wheels or body panels. 
     Once the location of the vehicle  100 , or a specific point on the vehicle such as a position of a vehicle onboard sensor, is established within the spatial frame of reference, the manufacturer-specified location  200  for the observable target or calibration fixture is determined relative to the vehicle  100  or identified point within the same spatial frame of reference. Often, the manufacturer-specified location  200  will correspond to a location which is displaced along, or laterally from, an orthogonal axis originating at a specific point on the vehicle  100 , such as the front or rear bumper centerline CL. An operator or service technician is traditionally required to determine the axis in question, and then utilize a measuring tape to traverse a specified distance, such as eight meters, along that axis together with any required lateral displacement, to reach the manufacturer-specified location  200  for the observable target or calibration fixture placement. In an improvement to the traditional techniques, a machine vision vehicle inspection system can be configured to observe the relative position of a reference target associated with the observable target or calibration fixture, and guide the operator to the correct placement position. 
     With a method of the present disclosure, the need for an operator to utilize measuring tapes, or to identify a placement axis along which an observable target or calibration fixture must be moved, is eliminated by the use of an optical projection system  300  under control of the vehicle measurement system  110 . Upon identifying the location of the vehicle  100  within the spatial frame of reference, a processor  114  of the vehicle measurement system  110 , configured with suitable software instructions, calculates the location within the same spatial frame of reference which corresponds to the manufacturer-specified location  200  for placement of the observable target or calibration fixture relative to the vehicle  100 . The optical projection system  300 , such as a laser or an image projection system, under control of the processor  114 , is activated to project visible or observable indicia  202  onto a surface at the calculated location  200 , providing an operator with a visible indication at that location, such as where to place the observable target or calibration fixture. 
     It will be recognized that a variety of techniques may be utilized to enable the optical projection system  300  to project the visible indication at the calculated location  200  within the vehicle service bay  10 . For example, if the optical projection system  300  is configured with a fixed projection field PA, the projection system may be mounted within a motor-driven multi-axis gimbal system, under control of the vehicle service system processor  114 . Preferably the projection system  300  is disposed at a location, such as near the service bay ceiling, which provides a clear line of sight towards the vehicle and floor surfaces on which an observable target or calibration fixture may be placed. Once the location  200  for the visible indicia is calculated, the processor  114  generates commands to actuate the motor-drive multi-axis gimbal system to orient the projection field PA towards the calculated location on the floor surface, and activates the projection system  300  to project the selected visible or observable indicia  202  there upon. Alternatively, if the projection system  300  is configured with a steerable projection field, such as MEMS micro-mirrors or adaptive optical elements, the projection field PA itself may be directed towards the calculated location by commands from the processor  114  if it lies within a steerable range of the projection field. 
     In addition to utilizing the projection system  300  to project visible indicia at a location  200  for the placement of an observable target or calibration fixture, the projection system  300  may be utilized to illuminate or identify specific points on the vehicle  100  to guide an operator or to enable an operator to detect misalignment or displacement of vehicle body panels. For example, the processor  114  may be configured for access to a database containing relative spatial coordinates of various vehicle-specific body dimensions or reference points. Once a vehicle is identified within the vehicle service area, and the location of the vehicle relative to the projection system  300  frame of reference determined, the processor  114  can be utilized to direct the projection system  300  to illuminate one or more points on the vehicle body which should coincide with vehicle body features, such as body panel edges, reference marks, etc. An operator can then compare the illuminated points with the corresponding vehicle body features to determine if there is misalignment or distortion present in the vehicle body, such as may be caused by damage to the vehicle structure. Such illuminated points may further be utilized to aid in the replacement or repair of the vehicle body features by providing a visual guide for use during installation or straightening/repositioning of the vehicle body features. 
     In yet another alterative configuration, the projection system  300  is configured to project a two-dimensional image which illuminates a large area of the service bay  10 , including the calculated placement location  200 . To aid in target or fixture placement, the vehicle service system processor  114  is configured to generate an image which includes the selected visible or observable indicia  202  at an image location which will optically project onto the calculated location  200  within the service bay  10  when the generated image is projected by the projection system  300 . The vehicle service system processor  114  is configured to direct the projection system  300  to project the generated image into the service bay  10 , such that the visible or observable indicia  202  appears at the calculated location  200 . 
     If the vehicle service system includes a measurement system configured to observe surfaces within the service bay  10 , the vehicle service system processor  114  may be configured to acquire information representative of the actual three-dimensional surfaces within the area in which visible indicia  202  is to be projected. Exemplary measurement systems may operate by stereo imaging of the surfaces or the imaging of a point cloud of points projected onto the three-dimensional surfaces. Using the acquired information representative of the three-dimensional surfaces, the vehicle service system processor  114  may alter or adjust the shape or configuration of the visible or observable indicia  202  prior to projection by the projection system  300  in order to accommodate for uneven or irregular surface features present at the location  200  at which the visible or observable indicia is to be projected. 
     Optionally, the vehicle service system processor  114  may be configured to direct the projection system  300  to project a series of discrete images, video imagery, outlined features, dynamic visible indicia, text, messages, optical target elements, or other observable elements onto the illuminated surfaces within the vehicle service bay  10 . These messages may include operator instructions, such as seen at  202   a  in  FIG. 1 , symbolic guidance, vehicle measurements, warnings, or other visual elements comprising at least a portion of a user interface display. For example, as seen in  FIG. 1 , measurement bar graph display  202   b  associated with an axis SA of a vehicle safety system sensor  102  or vehicle thrust line TL can be projected directly onto a floor surface  10  in proximity to the vehicle  100 , easily visible to an operator making adjustments to the position or orientation of the vehicle safety system sensor  102 . Similarly, optical target elements may be projected onto the various surfaces in the vehicle environment for observation by vehicle on-board optical sensors, replacing or eliminating the need to the placement of physical target structures or calibration fixtures. 
     In a further embodiment, illustrated in  FIG. 2 , the vehicle service system is configured to control the projection system  300  to simulate optical conditions a vehicle  100  may encounter during a test drive, as may be required to reset or recalibrate an optical onboard sensor system  104 . Simulation of vehicle test drive conditions optionally includes interaction between the vehicle service system processor  114  and vehicle communication paths which convey signals to a vehicle controller during vehicle operation. The vehicle service system processor  114  provides the vehicle controller with signals emulating input which the vehicle controller expects during an actual test drive, while the vehicle  100  remains stationary within the vehicle service bay  10 . These expected signals may include, engine state signals, speed sensor signals, transmission gear selection signals, and steering angle signals. Alternatively, the vehicle  100  may be disposed on suitable rolling support surfaces, such as a dynamometer, and/or steering surfaces, such as turn plates, permitting the wheels of the vehicle  100  to roll and/or steer without moving the vehicle body, thereby permitting the vehicle  100  to achieve at least some of the actual operating conditions experienced during a driven road test. 
     As part of the simulation of the test drive conditions, the vehicle service system processor  114  conveys video data to the projection system  300  to project a simulated test drive environment onto a screen or other projection surface  302  disposed within a field of view SFOV of an optical sensor system  104  onboard a vehicle undergoing a service or inspection procedure. Alternatively, a large-scale active display, such as an LED monitor or e-paper display, may be utilized instead of the projection system  300  and screen  302  without departing from the scope of the disclosure. The simulated test drive environment presented to the optical sensor system  104  includes various animated elements representing conditions which the vehicle  100  may encounter during an actual test drive, including, but not limited to, a road surface, moving and stationary vehicles, pedestrians, landscaping, road surface markings, street signs, and varied lighting or weather conditions. The vehicle service system processor  114  is configured to generate the video imagery to simulate the test drive environment as it would appear to the optical sensor system  104  onboard the vehicle during an actual test drive, with visible objects and features animated to simulate motion within the sensor field of view SFOV in accordance with simulated movement of the vehicle  100 . 
     During a simulated test drive, the vehicle service system processor  114  is operatively coupled to the vehicle communication bus, or alternatively, directly to the output communication lines from the vehicle onboard optical sensor system  104 , to receive output signals generated by the vehicle onboard optical sensor system  104  in response to observation of the projection which is simulating the test drive environment. The received output signals are evaluated by the vehicle service system processor  114  to determine if the optical sensor system  104  is functioning within acceptable limits, and/or responding to the simulated test drive environment as expected. 
     A number of vehicles utilize radar-based sensor systems  106  instead of, or in conjunction with, optical based sensor systems. Calibration or inspection procedures for some radar-based sensor systems require radar reflective targets to be disposed at a significant distance (&gt;eight meters) from the vehicle  100 . Placement of a radar-reflective target at these distances may not be possible in a typical vehicle service bay environment. One option is to provide the radar-based sensor systems with reflected or returned radar signals which have been attenuated or modulated to appear as if they are reflected from targets located at the required distance, but which are actually reflected from targets disposed at closer distances, such as shown in published PCT application WO 2015/148830 A1 and in U.S. Pat. No. 6,329,952 B1 to Grace. These reflected or returned radar signals may be Doppler shifted to simulate the appearance of a target which is approaching or receding from the radar-based sensor system onboard the vehicle. However, Doppler shifting only simulates the appearance of a target which is approaching or receding along an axis RA directly in-line with the radar-based sensor system  106 . 
     In order to simulate at least some of the conditions a vehicle  100  may encounter during a test drive, as may be required to reset or recalibrate a radar-based onboard sensor system  106 , it is necessary to provide reflected or returned radar signals RS to the radar-based sensor system  106  which are representative of vehicles or objects which are laterally displaced from the vehicle thrust line or center line, and/or which are moving at an angle relative to the vehicle thrust line or center line. For example, returned radar signals RS which are representative of approaching vehicles in adjacent lanes, cross-traffic, or vehicles which are changing lanes in front of the vehicle  100  undergoing the service procedure. 
     In a further embodiment of the present disclosure, as illustrated in  FIG. 3 , the vehicle service system incorporates an emitter system  400  configured to emit electromagnetic energy at select frequencies visible to a vehicle onboard radar-based sensor system  106  such as a forward collision avoidance system, a blind-spot detection system, or a cross-traffic warning system. The emitter system  400  is operatively coupled to, and controlled by, the processor  114  of the vehicle service system  110 , and is disposed within the vehicle service bay  10  at a location which is within a field of view for the radar-based sensor system  106  onboard the vehicle  100  undergoing testing. To simulate objects approach or receding from the vehicle  100  which are laterally displaced from the vehicle thrust line or axis of detection RA for the radar-based sensor system, the emitter system  400  is mounted to a support frame or track  402  adapted for a limited range of lateral movement, such as transverse to the vehicle thrust line, vehicle centerline, or the radar axis RA, within a horizontal plane. Optionally, the support frame or track  402  may be adapted to further provide for vertical movement in a plane transverse to the vehicle thrust line, center line, or radar axis RA. Under control of the vehicle service system processor  114 , the emitter system  400  is moved at least laterally while emitting electromagnetic energy RS towards the vehicle  100  in order to simulate a parallax effect of an offset object approaching towards, receding from, or passing the vehicle  100  as observed by the radar-based sensor system  106  onboard the vehicle. Lateral (and optionally, vertical) movement of the emitter system  400  may be uniform, or may be variable to simulate a changing rate of displacement as an object approaches towards or recedes from, the vehicle  100 . 
     As with simulation of a vehicle test drive condition for an optical onboard sensor system  104 , simulation of moving target objects for a radar system  106  onboard the vehicle  100  optionally includes interaction between the vehicle service system processor  114  and vehicle onboard systems which convey signals to a vehicle onboard controller during vehicle operation in order to provide the vehicle onboard controller with signals emulating those which would be expected during actual driving conditions, while the vehicle  100  remains stationary within the vehicle service bay  10 . These may include, for example, inertial signals, GPS navigation signals, engine state signals, speed sensor signals, transmission gear selection signals, and steering angle signals. These signals may be emulated either by directly accessing the vehicle data communications bus (for vehicles which are configured with an access point) to inject the required digital signals on appropriate input lines to the vehicle onboard controller, or by providing external (analog) input to the various sensors onboard the vehicle  100  simulating the required environmental conditions. As previously noted, the vehicle  100  may be disposed with the wheels on rolling surfaces, such as a dynamometer, or turning surfaces such as turn plates, permitting actual rolling or steering movement of the vehicle wheels while the vehicle body remains generally stationary, enabling the vehicle onboard sensors to provide at least some of the expected input to the vehicle onboard controller without the need for signal emulation. 
     As part of the simulation of moving objects for the vehicle radar-based sensor systems  106 , the vehicle service system processor  114  is configured with software instructions to generate a movement profile for the emitter system  400  which simulates the motion and radar-reflection appearance of an object moving relative to the vehicle  100  within a field of view of the radar-based sensor system  106 . The simulated objects include various elements which a radar-based sensor system  106  may encounter during driving conditions, including, but not limited to, moving and stationary vehicles, pedestrians, street signs, and fixed structures such as buildings, overpasses, and guardrails. The vehicle service system processor  114  controls the emitter system  400  to implement the generated movement profile during the emission of electromagnetic energy at the selected frequencies. Concurrently, through signals from the radar-based sensor system  106  onboard the vehicle  100 , or the control system of the vehicle, are monitored by the vehicle service system processor  114  to evaluate responses to the provided input in order to determine if the radar-based sensor system  106  is functioning within manufacturer tolerances. 
     It will be recognized that while the aforementioned embodiment has been described in the context of a radar-based sensor system  106  onboard the vehicle, similar simulation on moving objects for sensor systems onboard the vehicle which observe other frequencies of the electromagnetic spectrum, such as optical, near infrared, infrared, and far infrared may be implemented using the same principals, using emitters configured to provide signals appropriately tuned for observation by the specific type of sensor system. 
     In a further embodiment (not shown), a target structure for a vehicle-based LIDAR sensor may be provided on a movable support structure under control of the vehicle service system processor. The target structure is configured to provide a target visible to a vehicle-based LIDAR sensor during testing or calibration of the vehicle systems. The movable support structure incorporates drive mechanisms, such as stepper motors, and associated mechanical components to enable the vehicle service system processor to selectively move the target relative to the vehicle undergoing testing, facilitating testing of the vehicle-based LIDAR sensor to track a moving object. The selective movement may be horizontally transverse to the vehicle direction of travel, simulating cross-traffic, or may be parallel to the vehicle direction of travel, simulating approaching or receding objects along a roadway. 
     The present disclosure can be embodied in-part in the form of computer-implemented processes and apparatuses for practicing those processes. The present disclosure can also be embodied in-part in the form of computer program code containing instructions embodied in tangible media, or another computer readable non-transitory storage medium, wherein, when the computer program code is loaded into, and executed by, an electronic device such as a computer, micro-processor or logic circuit, the device becomes an apparatus for practicing the present disclosure. 
     The present disclosure can also be embodied in-part in the form of computer program code, for example, whether stored in a non-transitory storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the present disclosure. When implemented in a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits. 
     As various changes could be made in the above constructions without departing from the scope of the disclosure, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.