Abstract: Techniques are described for performing vehicle operation that comprises determining, by a computer located in a vehicle and for each of a first driving mode and a second driving mode, a set of values of a predicted trajectory along which the vehicle is predicted to operate in a driving mode; performing a first determination that the vehicle is not operable in the first driving mode; performing a second determination that the vehicle is operable in the second driving mode; and causing, in response to the second determination, the vehicle to operate in the second driving mode by sending one or more driving related commands to one or more apparatus in the vehicle.

Abstract: A driver pre-abnormal detection apparatus includes: sensors to acquire travel environment information of a vehicle; an in-vehicle camera that detects the driver's sightline; and a controller configured to detect a driver's pre-abnormal state based on the travel environment information and the driver's sightline. The controller identifies a visual recognition required point to be visually recognized by the driver based on the travel environment information, determines whether the driver has visually recognized the visual recognition required point based on the driver's sightline, and detects the driver's pre-abnormal state based on a fact that the driver has not visually recognized the visual recognition required point.

Abstract: A system for monitoring a driver operating a vehicle includes an input configured to receive eye tracking data for the driver. The system includes a processing block configured to determine gaze movement characteristics for the driver from the eye tracking data. The system includes a determination block configured to determine characteristics indicative of diminished driver control from the determined gaze movement characteristics. The determination block determines diminished driver control from the determined gaze movement characteristics being outside predetermined baseline gaze movement characteristic ranges derived from prerecorded gaze movement characteristic data for the driver.

Abstract: A controller acquires a driving load score based on the travel environment information, acquires a distracted state occurrence score based on the driving load score and an elapsed time with the driving load score, acquires a search behavior score based on the travel environment information and the driver's sightline when the distracted state occurrence score is equal to or higher than a specified value, acquires a distracted state level of the driver based on the search behavior score and an elapsed time with the search behavior score, and determines that the driver is in the distracted state when the distracted state level is equal to or higher than a threshold and the search behavior score is increased in response to an increase in the driving load score.

Abstract: An information processing device calculates a feature related to driving of a driver. The information processing device includes: a processor that calculates the feature; and a transmission unit that transmits the calculated feature to an outside. The processor identifies whether there is a predetermined situation in which a risk in relation to a preceding vehicle occurs, and calculates, as the feature, information related to a behavior of the driver for reducing the risk when the predetermined situation is identified.

Abstract: A method (200) for calibrating a vehicle sensor (105) mounted on a vehicle (110) includes: scanning a marker (120) in the area of the vehicle sensor (105) by a sensor device (115); determining a first pose of the marker (120) in relation to the sensor device (115); scanning a structural feature (140) of the vehicle (110) by the sensor device (115); determining a second pose of the vehicle (110) in relation to the sensor device (115); and determining a third pose of the marker (120) in relation to the vehicle (110) on the basis of the first pose and the second pose.

Abstract: A driving assistance device includes a memory and a processor. The processor acquires travel information including acceleration of a moving body. The processor presents, to the moving body, information regarding cargo collapse on the moving body that is specified on the basis of a distribution of the acceleration of the moving body in multiple axes on the basis of the travel information.

Abstract: Techniques are described that facilitate predicting and minimizing risks associated with vehicle usage contexts. In one example, a method comprises obtaining, by a system comprising a processor, vehicle state information identifying occupants and objects of a vehicle and relative positions of the occupants and the objects about the vehicle in association with a current usage context of the vehicle. The method further comprises determining, by the system, an assessment of potential injuries associated with the current usage context of the vehicle based on analysis of the vehicle state information, wherein the analysis comprises evaluating potential movement of the occupants and the objects. The method further comprises determining, by the system, risk information regarding a risk associated with the current usage context of the vehicle as a function of the assessment.

Abstract: Disclosed are systems and methods for a sensor synchronization system. In some aspects, a method includes synchronizing sensors of an autonomous vehicle (AV) to cause sampling of a first sensor of the sensors to occur in alignment with sampling of a second sensor of the sensors; determining a sampling time point for the first sensor based on the synchronizing the sensors, the sampling time point comprising a time when the first sensor is in alignment with the second sensor; providing the sampling time point to the first sensor; determining, at a controller circuit of the first sensor, an offset of the first sensor to apply to a local system time of the first sensor to cause a data acquisition of the first sensor to occur at the sampling time point; and causing the data acquisition to be performed at the first sensor using the sampling time point and the offset.

Abstract: The disclosed technology provides solutions for maintaining autonomous vehicle (AV) tests and, provides methods for evaluating test relevance and for determining how to fix outdated AV tests. In some aspects, a process of the disclosed technology includes steps for associating a set of test metrics with an AV test, monitoring operation of an AV to identify one or more behaviors performed by the AV in the simulated environment and determining a validity of the AV test with respect to the simulated environment based on the AV behaviors and the set of test metrics. Systems and machine-readable media are also provided.

Abstract: A method and an apparatus of correcting steering of a driving vehicle associated with autonomous driving determine a current driving mode of the driving vehicle among a plurality of driving modes, determine whether a driver performs the steering of the driving vehicle when the determined current driving mode is an autonomous driving mode, set an additional target rack position input to a road wheel actuator, and correct a steering direction of the driving vehicle.

Abstract: A vehicle, a method of controlling a vehicle, and a non-transitory computer readable storage medium are described. The vehicle can comprise a management and control system associated to onboard systems and/or to a driving input interface and/or to the engine and/or powertrain and/or to at least one wheel and/or to the chassis. The management and control system can: determine aggregated command outputs; detect one or more dynamic parameters exceeding a threshold safety value; selectively prioritize each of the aggregated command outputs based on one or more of the dynamic parameters to change from a user-selected driving mode to a safety driving mode; and change the prioritized safety driving mode back to the user-selected driving mode in response to the one or more of the dynamic parameters no longer exceeding the threshold safety value.

Abstract: With reference to a message table associating a plurality of messages to be notified to a driver of a vehicle with a first condition, a second condition, last notification time of the message, and renotification requirement, a notification device selects messages associated with an identified first condition corresponding to a situation of surroundings of a vehicle or a state of a driver, selects, from among the messages associated with the identified first condition, messages associated with an identified second condition corresponding to a state of the driver, specifies, from among the messages associated with the identified second condition, a message without a record of last notification time or a message with a record of last notification time and with a renotification requirement requiring a renotification, and notifies the specified message to the driver through an output device.

Abstract: There is provided with a control apparatus. A first obtaining unit obtains position information of a vehicle. A first setting unit sets a remote operation permitted range of the vehicle on a basis of movement information of the vehicle in a first predetermined period based on the position information. A determination unit determines whether or not to restrict a remote operation input to the vehicle from an associated user terminal that is a user terminal associated with the vehicle on a basis of a stop position of the vehicle based on the position information and the remote operation permitted range. The movement information includes the position information of the vehicle and a visit situation to the position in the first predetermined period.

Abstract: A vehicle-mounted apparatus (10) according to the present invention includes: a surrounding object information acquisition unit (11) that acquires surrounding object information relating to a surrounding object being an object detected in surroundings of a vehicle; a line-of-sight information acquisition unit (12) that acquires line-of-sight information of a driver of the vehicle; an operation information acquisition unit (13) that acquires operation information indicating an operation performed by the driver on the vehicle; an operation intention information generation unit (14) that generates operation intention information associating an operation indicated by the operation information with the surrounding object causing the operation indicated by the operation information, based on the surrounding object information, the line-of-sight information, and the operation information; and a transmission and reception unit (15) that transmits the operation intention information to a surrounding vehicle.

Abstract: A driving assistance device includes a storage medium configured to store computer-readable instructions, and a processor connected to the storage medium, in which the processor executes the computer-readable instructions to determine whether to urge a driver of a mobile object to accelerate or decelerate on the basis of a state of the mobile object, to cause a speaker to output a notification sound urging the driver of the mobile object to accelerate or decelerate on the basis of a result of the determination, to cause the speaker to output a fundamental sound when causing the speaker to output the notification sound, and then cause the speaker to output one or more additional sounds whose pitch is different from a pitch of the fundamental sound, and to cause the speaker to output the one or more additional sounds whose pitch is higher than the pitch of the fundamental sound when the driver of the mobile object is urged to accelerate.

Abstract: An information notification system notifies a user of a vehicle of information. A first condition is that one or more time-designated speed limit signs recognized by a camera mounted on the vehicle designate all times of day as a whole. The information notification system determines whether or not the first condition is satisfied. When the first condition is not satisfied, the information notification system notifies the user of at least a legal speed limit on a road on which the one or more time-designated speed limit signs are installed, based on reference information on the legal speed limit in a region in which the vehicle is used.

Abstract: A display system includes: a first display device displaying an image in a first region to cause the image to be visually recognized in a position at a first distance from a visual line of a driver of an auto-vehicle; a second display device displaying an image in a second region to cause the image to be visually recognized at a second distance greater than the first distance from the visual line; and a display controller displaying a warning image in the second region if a first condition is satisfied, moving the warning image to display a warning image in the first region if a second condition in which a warning level is higher than that of the first condition is satisfied after the first condition is satisfied, then updating the warning image to an updated warning image, and then moving the updated warning image to the second region.

Abstract: A vehicle includes a social media information acquisition unit, a collector, a browsing time acquisition unit, an extractor, and a control processor. The social media information acquisition unit communicates with portable devices of occupants in the vehicle to acquire social media information of the occupants from the portable devices. The collector collects search keywords from the social media information of the occupants. The browsing time acquisition unit acquires information on browsing time for each of the search keywords from the social media information. The extractor extracts a common subject based on the search keywords collected from all of the portable devices of the occupants in a communicable state, and the information on the browsing time. The control processor determines content of a proposal to be provided to the occupants in the vehicle based on the common subject, and notifies the occupants of the content of the proposal.

Abstract: A vehicle includes a fatigue state detector, an information provider, and a processor. The fatigue state detector is configured to detect a fatigue degree of an occupant of the vehicle. The information provider is configured to provide various pieces of information related to traveling of the vehicle to the occupant. The processor is configured to change a frequency of providing the various pieces of the information by the information provider, depending on the fatigue degree of the occupant.

Abstract: A system includes an agricultural implement and a tractor for pulling the implement. The implement includes a frame supporting at least one ground-engaging tool and at least one image imager system coupled to a longitudinal end of the frame. The tractor includes a central controller, wherein the at least imager system is operably coupled to the central controller. The central controller is configured to receive image data from an imager system, analyze the image data to identify at least one mark formed in a soil surface, and responsive to identifying the at least one mark, cause feedback regarding a current position and orientation of the implement and an ideal position and orientation of the implement to be output via an input/output device.

Abstract: An electronic device includes a first acquisition part that acquires a first set speed set on the basis of a speed limit which is (i) recognized on the basis of an image of a sign of a road on which a vehicle is located, captured by an imaging part or (ii) identified from map information of the road; a second acquisition part that acquires a second set speed set by a user of the vehicle; and a notification control part that causes a notification part to provide a first notification when a vehicle speed exceeds the first set speed, and causes the notification part to provide a second notification which is distinguishable from the first notification when the vehicle speed exceeds the second set speed.

Abstract: An electronic device includes a storage that stores map information, an acquisition part that acquires a speed limit indicated by a sign included in a captured image generated by a camera included in a vehicle and a position of the vehicle, and a display control part that causes a display part to display the speed limit indicated by the sign included in the captured image, wherein the display control part does not cause the display part to display a speed limit which is acquired by the acquisition part while a distance between the vehicle and a branch point is less than a threshold value.

Abstract: Techniques are provided for vehicle and mobility path recommendations. In one embodiment, the techniques involve identifying emergency response factors in historical telematics data, categorizing emergency situation outcomes based on the emergency response factors, identifying patterns between the emergency response factors and the emergency situation outcomes, generating a vehicle recommendation based on the identified patterns, determining a location of a vehicle referenced by the vehicle recommendation, generating a mobility path recommendation based on the vehicle recommendation and the location of the vehicle referenced by the vehicle recommendation, and transferring the vehicle recommendation and the mobility path recommendation to an emergency services entity.

Abstract: According to a method for road marking detection, a sensor datasets depicting a road marking (7) at a first and a second measurement instance are generated by an environmental sensor system (4) and a parameter characterizing a motion of the environmental sensor system (4) is determined. A first and a second observed state vector describing the road marking (17) at the first and the second measurement instance, respectively, are generated based on the sensor datasets. A predicted state vector for the second measurement instance is computed depending on the at least one motion parameter and the first observed state vector and a corrected state vector for the second measurement instance is generated depending on the predicted state vector and the second observed state vector.

Abstract: Systems and methods for training and executing machine learning models to generate lane index values are disclosed. A method includes identifying a set of image data captured by at least one autonomous vehicle when the at least autonomous vehicle is positioned in a lane of a roadway and respective ground truth localization data; determining a plurality of lane index values for the set of image data based on the ground truth localization data; labeling the set of image data with the plurality of lane index values, the lane index values representing a number of lanes from a leftmost or rightmost lane to the lane in which the at least one autonomous vehicle was positioned; and training, using the labeled set of image data, a plurality of machine learning models that generate a left lane index value and a right lane index value as output.

Abstract: Systems and methods for training and executing machine learning models to generate lane index values are disclosed. A method includes identifying a set of image data captured by at least one autonomous vehicle when the at least autonomous vehicle is positioned in a lane of a roadway and respective ground truth localization data; determining a plurality of lane index values for the set of image data based on the ground truth localization data; labeling the set of image data with the plurality of lane index values, the lane index values representing a number of lanes from a leftmost or rightmost lane to the lane in which the at least one autonomous vehicle was positioned; and training, using the labeled set of image data, a plurality of machine learning models that generate a left lane index value and a right lane index value as output.

Abstract: A computer-implemented method of deriving a vehicle dynamic library including at least two optimized vehicle dynamic implementation models is provided. The method comprises defining at least two operational design domains, choosing one vehicle dynamic abstract model, choosing one vehicle dynamic implementation model to be optimized, simulating the vehicle dynamic abstract model for each operational design domain, wherein the simulation generates reference trajectories, optimizing the vehicle dynamic implementation model for each operational design domain so as to create at least two optimized vehicle dynamic implementation models, wherein each optimization is based on at least one of said generated reference trajectories, validating each optimized vehicle dynamic implementation model to achieve a validation level for each optimized vehicle dynamic implementation model, and saving each optimized vehicle dynamic model together with its validation level.

Abstract: A method of automatically detecting a dynamic object recognition error in an autonomous vehicle is provided. The method includes parsing sensor data obtained by frame units from a sensor device equipped in an autonomous vehicle to generate raw data by using a parser, analyzing the raw data to output a dynamic object detection result by using a dynamic object recognition model, determining that detection of a dynamic object recognition error succeeds by using an error detector when the dynamic object detection result satisfies an error detection condition, and storing the raw data and the dynamic object detection result by using a non-volatile memory when the detection of the dynamic object recognition error succeeds.

Abstract: Techniques for predicting an object trajectory or scene information are described herein. For example, the techniques may include inputting tokens representing discrete behavior into a machine learned model. The machine learned model may output a sequence of tokens that is usable by another machine learned model to generate an object trajectory (e.g., position data, velocity data, acceleration data, etc.) for one or more objects in the environment. The object trajectory can be sent to a vehicle computing device for consideration during vehicle planning, which may include simulation.

Abstract: Aspects of the subject technology relate to systems, methods, and computer-readable media for grouping behaviors based on behavior signatures. Event data gathered for an autonomous vehicle (AV) test is accessed. A signature for the AV behavior is identified from the event data. The signature is defined by features occurring during the AV behavior. The signature for the AV behavior is compared to signatures of one or more other AV behaviors. AV behaviors, including the AV behavior, are grouped together from a comparison of corresponding signatures across the plurality of AV behaviors.

Abstract: Provided is a mobile object control device configured to: recognize a surrounding situation of a mobile object; set, based on the recognized surrounding situation, a risk area in which positions of the surrounding situation are associated with risk values that are indicator values indicating degrees to which the mobile object is to avoid traveling; generate a target trajectory indicating a route along which the mobile object is to travel in future; cause the mobile object to travel along the generated target trajectory; and set at least one observation point in each of three or more provisional trajectories branching at a specific location ahead of the mobile object, and generate the target trajectory based on the risk area and the at least one observation point.

Abstract: System, methods, and other embodiments described herein relate to estimating reachable states for a vehicle using a neural model. In one embodiment, a method includes generating an unverified command by a first controller and a safety command by a second controller for a projected path by an automated driving system (ADS) associated with a vehicle. The method also includes estimating reachable states by a neural network (NN) model that uses the unverified command and an initial condition for the vehicle, the reachable states representing positions and orientations for the vehicle within a bounded time and a state space associated with the initial condition and the projected path. The method also includes, upon determining that the reachable states satisfy collision criteria, executing by the vehicle a maneuver with the safety command for the projected path and generating subsequent commands using vehicle data from the first controller and the second controller.

Abstract: Method for planning an at least partially automated driving process by means of a driver assistance system (2) of a vehicle (1).

Abstract: A route planner detects a pedestrian from surrounding data representing a situation of surroundings of a vehicle, identifies a position of a pause-by object in the surroundings of the vehicle prompting the pedestrian to pause, creating a travel route over which the vehicle will travel when the pedestrian is detected, assuming the pedestrian will enter a road on which the vehicle will travel when the identified position of the pause-by object is not in the vicinity of the pedestrian, and assuming the pedestrian will not enter the road when the identified position of the pause-by object is in the vicinity of the pedestrian.

Abstract: A control system for an autonomous vehicle includes a time sensitive network switch and a control system interface. The control system interface includes a primary processing unit, a secondary processing unit, and a fault detection module. The control system receives a trajectory of an autonomous vehicle. The fault detection module detects a fault condition with the primary processing unit and prevents the primary processing unit from transmitting a primary control signal in response to the fault condition. The primary control signal is for autonomous control of the autonomous vehicle.

Abstract: Techniques for predicting an object trajectory or scene information are described herein. For example, the techniques may include inputting latent variable data into a machine learned model. The machine learned model may output an object trajectory (e.g., position data, velocity data, acceleration data, etc.) for one or more objects in the environment based on the latent variable data. The object trajectory can be sent to a vehicle computing device for consideration during vehicle planning, which may include simulation.

Abstract: Systems and techniques are described herein for determining at least one location of at least one target vehicle relative to a lane. For instance, a method for determining at least one location of at least one target vehicle relative to a lane is provided.

Abstract: A method of controlling switching to a manual driving mode of an autonomous vehicle, enables switching to the manual driving mode to be safely performed without interfering with a nearby vehicle in a safe lane or a safe place according to a surrounding driving environment by allowing a driver to select between switching to the manual driving mode while driving or switching to the manual driving mode after stopping to switch to the manual driving mode while the autonomous vehicle is driven in an autonomous driving mode.

Abstract: A vehicle comprises a frame having a drive system with a controller operably connected to the drive system. It also has a compartment having a driver position for a driver and a passenger position for a passenger, with a plurality of vehicle control inputs at the driver position connected to the controller and an interface device configured for communication with the driver. The controller is operable to engage in a training protocol in which the driver is granted progressively increasing control over the vehicle based on driver performance.

Abstract: According to one aspect, a method includes obtaining a command on a vehicle, the command being arranged to identify a first action to be taken by the vehicle, wherein the vehicle is in a first vehicle state and the command has a first command state. The method also includes determining, on the vehicle, whether the first command state is consistent with the first vehicle state. When it is determined that the first command state is consistent with the first vehicle state, the method includes executing the first command. When it is determined that the first command state is not consistent with the first vehicle state, the method includes identifying the first command as an illegitimate command and ignoring the illegitimate command.

Abstract: In one aspect, a track structure usable by a wheeled vehicle for hauling a payload up an inclined enclosed passageway comprises a hollow rigid center rail member configured to act as both a center rail for the wheeled vehicle and as a ventilation duct. Opposite lateral faces of the hollow center rail member have respective wheel contact surfaces grippable by an opposed pair of inwardly-biased drive wheels of the wheeled vehicle. Rail support structure depends from the hollow center rail member. An elevated pair of rails is attached to the rail support structure, the rails being on opposite sides of and substantially parallel to the hollow center rail member. Each rail is supported by the rail support structure so as to provide an upper, lower, and lateral surface suitable for rolling engagement by a weight-bearing wheel, undermount wheel, and guide wheel, respectively, of the wheeled vehicle.

Abstract: A rail vehicle front end has a center buffer coupling with a free coupling end section such that the free coupling end section is connectable to a further center buffer coupling of a further rail vehicle front end. The center buffer coupling extends along a longitudinal axis in a rest position. The center buffer coupling is mounted in such a way that the free coupling end section can be pivoted with respect to the longitudinal axis. The rail vehicle front end has a front panel that radially surrounds the center buffer coupling at least in sections such that a front opening pointing substantially in the longitudinal direction is defined between the front panel and the center buffer coupling. A cover device for covering the front opening extending between a front panel and a center buffer coupling of a rail vehicle is also disclosed.

Abstract: A wall structure for forming a wall of a rail vehicle car body, the wall structure comprising a metal panel having an aperture formed therein; and a fibre-reinforced-plastic (FRP) strengthening system attached to the metal panel at a corner of the aperture. The FRP strengthening system comprises a stack of FRP laminae arranged such that, progressing through the stack starting from a base lamina, the area of each lamina in the stack is less than that of the previous lamina.

Abstract: A locked-axle spring compression system and method configured to raise a rail vehicle wheel off a rail and transport the raised wheel along a rail is presented. In one embodiment, the present disclosure discloses a system that can raise the locked-axle rail wheel off the rail and allowing the locked-axle train to be transported off the main line. One or more coil springs can be disposed between the truck frame and the journal box to distribute the weight of the train and forces acting thereon. The present disclosure provides a technological solution missing from conventional systems by at least providing a platform for an actuator configured to exert a force on one or more train elements to compress the coil springs and allow the locked-axle wheel to be raised off a surface (e.g., railroad track rail), by overcoming the coil spring pressure to raise the wheel off the rail.

Abstract: A locked-axle spring compression system and method configured to raise a rail vehicle wheel off a rail and transport the raised wheel along a rail is presented. In one embodiment, the present disclosure discloses a system that can raise the locked-axle rail wheel off the rail and allowing the locked-axle train to be transported off the main line. One or more coil springs can be disposed between the truck frame and the journal box to distribute the weight of the train and forces acting thereon. The present disclosure provides a technological solution missing from conventional systems by at least providing a platform for an actuator configured to exert a force on one or more train elements to compress the coil springs and allow the locked-axle wheel to be raised off a surface (e.g., railroad track rail), by overcoming the coil spring pressure to raise the wheel off the rail.

Abstract: A symmetrical multi-unit railroad freight car, such as a 3-pack railroad intermodal well car, has body units that are connected symmetrically. The body units have a symmetrical arrangement of end trucks and shared trucks. The end trucks are 70 Ton Trucks. The shared trucks are 125 Ton trucks. The trucks have passive steering using geometric rocker stiffnesses. The rockers in the end trucks have a smaller radius of curvature than the rockers in the shared trucks. The spring groups in the shared trucks are stiffer than the spring groups in the end trucks. The spring groups in the end trucks have a different proportion of damping when empty, a shorter live load range of travel, and greater reserve travel than the shared trucks. The end trucks and the shared trucks have four-cornered damper groups that have the same sized damper wedges. The damper wedges have non-metallic wear pads.

Abstract: A coupler arrangement for a rail vehicle comprises a coupler head and an uncoupling device having at least one handle which is manually swivelable about an axis of rotation (A) in a swivel direction (S) from a first position, in which the coupler head is in a state in which it is coupled to or ready to couple with the coupler head of another coupler arrangement, into a second position, in which the coupler head is in an uncoupled state. In one embodiment the handle comprises a handle arm which is oriented horizontally when the handle is either in the first or in the second position. In another embodiment the handle is mechanically lockable by moving, preferably shifting or tilting, at least a portion of the handle in a locking direction from the second position into a third position, wherein the locking direction differs from the swivel direction (S).

Abstract: A crane-less locked axle cradle system configured to lift a rail vehicle wheel off a rail and transport the lifted wheel along a rail is presented. The present disclosure discloses a system that can lift the locked-axle wheel off the rail with no crane thereby allowing the train with a locked axle to be transported off the mainline in a shorter period of time. A cradle system can have two parts (male and female members with wedges and rail wheels) that can be mated with each other around a rail wheel. As the male and female members are pulled together, locked wheel engagers can couple with different portions of the locked-axle wheel, causing the locked-axle wheel to lift off the rail given the gradient of the wedge or rotation of the wheel. In another embodiment, the wheel lifting can be assisted by an air bag, hydraulic cylinder, jack, or other.

Abstract: A transportation system includes a first passageway and a second passageway arranged in a side-by-side configuration. A first propulsion system is operable to move a first capsule within the first passageway and a second propulsion system is operable to move a second capsule within the second passageway. The second propulsion system is integrally formed with the first propulsion system.