Patent Publication Number: US-2022230550-A1

Title: 3d localization and mapping systems and methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62/857,225 filed on Jun. 4, 2019 and entitled “ 3 D LOCALIZATION AND MAPPING SYSTEMS AND METHODS,” which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     One or more embodiments relate generally to mapping and more particularly, for example, to localization and mapping systems and methods with rangefinders for unmanned aerial vehicles. 
     BACKGROUND 
     Modern unmanned sensor platforms, such as unmanned aerial vehicles (UAVs), remotely operated underwater vehicles (ROVs), unmanned (water) surface vehicles (USVs), and unmanned ground vehicles (UGVs) are able to operate over long distances and in all environments; rural, urban, and even underwater. Such systems typically must be small enough to satisfy mission requirements, and mission requirements typically include size, weight, and power constraints. General operational demands have increased as the demand for performance of unmanned platforms has increased. Thus, there is a need in the art for methodologies to reliably provide localization and mapping for unmanned platforms as the general operational demands increase. 
     SUMMARY 
     Localization and mapping systems and related techniques are provided to improve the operation of unmanned mobile sensor or survey platforms. One or more embodiments of the described localization and mapping systems may advantageously include a single element rangefinder (SER). The SER may include a single ranging sensor element and that may be used to provide ranging sensor data indicating a distance between the SER and a surface intercepting a sensor axis of the SER corresponding to the single ranging sensor element. One or more embodiments of the described localization and mapping system may include a gimbal system to couple the SER to a mobile platform and adjust a relative orientation of the SER relative to the mobile platform. One or more embodiments of the described localization and mapping system may include a logic device to determine a three-dimensional spatial occupancy map based on a horizontal planar occupancy map and a vertical occupancy map. 
     In one embodiment, a system includes a mobile platform, a SER, a gimbal system, and a logic device configured to communicate with the SER, the gimbal system, and/or the mobile platform. The SER may include a single ranging sensor element, where the SER is configured to provide ranging sensor data indicating a distance between the SER and a surface intercepting a sensor axis of the SER corresponding to the single ranging sensor element. The gimbal system may be configured to couple the SER to the mobile platform and adjust an orientation of and aim the SER relative to the mobile platform. The logic device may be configured to generate a horizontal planar occupancy map based, at least in part, on an altitude and a projected course of the mobile platform; to generate a vertical planar occupancy map based, at least in part, on the projected course of the mobile platform; and to determine a three-dimensional occupancy map based on the horizontal planar occupancy map and the vertical planar occupancy map. 
     In another embodiment, a method includes generating a horizontal planar occupancy map based, at least in part, on a first set of ranging sensor data provided by a SER coupled to a mobile platform via a gimbal system, an altitude of the mobile platform, and a projected course of the mobile platform, where the SER comprises a single ranging sensor element configured to provide ranging sensor data indicating a distance between the SER and a surface intercepting a sensor axis of the SER corresponding to the single ranging sensor element, and where the gimbal system is configured to adjust an orientation of and aim the SER relative to the mobile platform; generating a vertical planar occupancy map based, at least in part, on a second set of ranging sensor data provided by the SER and the projected course of the mobile platform; and determining a three-dimensional occupancy map based, at least in part, on the horizontal planar occupancy map and the vertical planar occupancy map. 
     The scope of the invention is defined by the claims, which are incorporated into this section by reference. A more complete understanding of embodiments of the present invention will be afforded to those skilled in the art, as well as a realization of additional advantages thereof, by a consideration of the following detailed description of one or more embodiments. Reference will be made to the appended sheets of drawings that will first be described briefly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a diagram of a survey system in accordance with an embodiment of the disclosure. 
         FIG. 2  illustrates a diagram of a survey system including mobile platforms in accordance with an embodiment of the disclosure. 
         FIG. 3A  illustrates a side view of a mobile platform of a survey system maneuvering in a survey area in accordance with an embodiment of the disclosure. 
         FIG. 3B  illustrates a top view of a mobile platform of a survey system maneuvering in a survey area in accordance with an embodiment of the disclosure. 
         FIG. 3C  illustrates a vertical planar occupancy map generated by a mobile platform of a survey system in accordance with an embodiment of the disclosure. 
         FIG. 3D  illustrates a horizontal planar occupancy map generated by a mobile platform of a survey system in accordance with an embodiment of the disclosure. 
         FIG. 3E  illustrates a three-dimensional occupancy map generated by a mobile platform of a survey system in accordance with an embodiment of the disclosure. 
         FIG. 3F  illustrates a three-dimensional occupancy map generated by a mobile platform of a survey system in accordance with an embodiment of the disclosure. 
         FIG. 4A  illustrates a survey area associated with a mission objective for a mobile platform of a survey system in accordance with an embodiment of the disclosure. 
         FIG. 4B  illustrates a course for a mobile platform of a survey system based, at least in part, on a mission objective and a three-dimensional occupancy map associated with a survey area in accordance with an embodiment of the disclosure. 
         FIG. 5  illustrates a flow diagram of various operations to provide a three-dimensional occupancy map of a survey area in accordance with an embodiment of the disclosure. 
         FIG. 6  illustrates a flow diagram of various operations to maneuver a mobile platform of a survey system within a survey area in accordance with an embodiment of the disclosure. 
     
    
    
     Embodiments of the present disclosure and their advantages are best understood by referring to the detailed description that follows. It is noted that sizes of various components and distances between these components are not drawn to scale in the figures. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures. 
     DETAILED DESCRIPTION 
     Modern unmanned sensor platforms, such as unmanned aerial vehicles (UAVs), remotely operated underwater vehicles (ROVs), unmanned (water) surface vehicles (USVs), and unmanned ground vehicles (UGVs) are able to operate over long distances and in a variety of environments. Such systems typically rely on a navigation system to operate in unknown or unmapped environments. In traversing such environments, collecting spatial information about the environments can be helpful to augment a conventional navigation system and/or provide sufficient situational awareness to maneuver through such environments when a conventional navigation system is unable to provide reliable estimates of a position and/or orientation of a mobile platform. 
     Small UAVs (e.g., below 250 g) have size, weight, and power constraints for the various sensors and components of the UAVs. In order to satisfy the various constraints for a particular mission, functional or operational trade-offs, replacements, and/or substitutions may be required. For example, the size and/or weight of sensors that can be carried onboard a UAV to facilitate localization and mapping may be restricted due to the constraints of a mission objective. Cameras may be used as a source for localization information when navigating in GPS-denied environments, but cameras can be difficult to operate in darkness, smoke, fog, and/or survey areas with few distinct visual features. Additionally, cameras sometimes have problems detecting reflective surfaces, such as glass and mirrors. Time-of-flight sensors such as radar, sonar, and LIDAR may compensate for the weaknesses of vision-based systems such as cameras, but such systems are often too heavy to include in a relatively small UAV. 
     Three-dimensional localization and mapping systems and related techniques are provided to improve the operational flexibility and reliability of unmanned sensor platforms. For example, the present disclosure includes systems and techniques that provide for robust position and orientation estimates for UAV operation in situations where conventional navigation systems (e.g., GPS and/or magnetic compass) and/or vision-based systems for the UAV lack sufficient spatial resolution or have otherwise failed. For example, vision-based systems for navigation may fail when the UAV is operating in complete darkness in a cave or building and/or while flying through thick smoke in a burning building. Embodiments disclosed herein address these deficiencies by providing a three-dimensional localization and mapping system including a relatively lightweight single element rangefinder (SER) and configured to scan in a specific pattern that allows an unmanned sensor platform to calculate a limited but sufficient three-dimensional map of the environment and the unmanned platform&#39;s position within the three-dimensional map. 
     In some embodiments, a three-dimensional localization and mapping system includes a mobile platform and a SER including a single ranging sensor element. The SER may be configured to provide ranging sensor data indicating a distance between the SER and a surface intercepting a sensor axis of the SER corresponding to the single ranging sensor element. The system may include a gimbal system configured to couple the SER to the mobile platform and adjust a relative orientation of the SER relative to the mobile platform. The system may include a logic device configured to communicate with the SER, the gimbal system, and/or the mobile platform. The logic device may be configured to generate a horizontal planar occupancy map based, at least in part, on an altitude and a projected course of the mobile platform, to generate a vertical planar occupancy map based, at least in part, on the projected course of the mobile platform, and to determine a three-dimensional occupancy map based on the horizontal planar occupancy map and the vertical planar occupancy map. In various embodiments, a three-dimensional localization and mapping method includes generating a horizontal planar occupancy map based, at least in part, on an altitude and a projected course of a mobile platform, generating a vertical planar occupancy map based, at least in part, on the projected course of the mobile platform, and determining a three-dimensional occupancy map based on the horizontal planar occupancy map and the vertical planar occupancy map. 
       FIG. 1  illustrates a block diagram of a survey system  100  including a mobile platform  110  with a SER  145 , in accordance with an embodiment of the disclosure. In various embodiments, system  100  and/or elements of system  100  may be configured to fly over a scene or survey area, to fly through a structure, or to approach a target and image or sense the scene, structure, or target, or portions thereof, using gimbal system  122  to aim imaging system/sensor payload  140  at the scene, structure, or target, or portions thereof, for example. Resulting imagery and/or other sensor data may be processed (e.g., by sensor payload  140 , mobile platform  110 , and/or base station  130 ) and displayed to a user through use of user interface  132  (e.g., one or more displays such as a multi-function display (MFD), a portable electronic device such as a tablet, laptop, or smart phone, or other appropriate interface) and/or stored in memory for later viewing and/or analysis. In some embodiments, system  100  may be configured to use such imagery and/or sensor data to control operation of mobile platform  110  and/or sensor payload  140 , as described herein, such as controlling gimbal system  122  to aim sensor payload  140  towards a particular direction, or controlling propulsion system  124  to move mobile platform  110  to a desired position in a scene or structure or relative to a target. 
     In the embodiment shown in  FIG. 1 , survey system  100  includes mobile platform  110 , optional base station  130 , and at least one imaging system/sensor payload  140 . Mobile platform  110  may be implemented as a mobile platform configured to move or fly and position and/or aim sensor payload  140  (e.g., relative to a designated or detected target). As shown in  FIG. 1 , mobile platform  110  may include one or more of a controller  112 , an orientation sensor  114 , a gyroscope/accelerometer  116 , a global navigation satellite system (GNSS)  118 , a communications module  120 , a gimbal system  122 , a propulsion system  124 , and other modules  126 . Operation of mobile platform  110  may be substantially autonomous and/or partially or completely controlled by optional base station  130 , which may include one or more of a user interface  132 , a communications module  134 , and other modules  136 . In other embodiments, mobile platform  110  may include one or more of the elements of base station  130 , such as with various types of manned aircraft, terrestrial vehicles, and/or surface or subsurface watercraft. Sensor payload  140  may be physically coupled to mobile platform  110  and be configured to capture sensor data (e.g., visible spectrum images, infrared images, narrow aperture radar data, and/or other sensor data) of a target position, area, and/or object(s) as selected and/or framed by operation of mobile platform  110  and/or base station  130 . In some embodiments, one or more of the elements of system  100  may be implemented in a combined housing or structure that can be coupled to or within mobile platform  110  and/or held or carried by a user of system  100 . 
     Controller  112  may be implemented as any appropriate logic device (e.g., processing device, microcontroller, processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), memory storage device, memory reader, or other device or combinations of devices) that may be adapted to execute, store, and/or receive appropriate instructions, such as software instructions implementing a control loop for controlling various operations of mobile platform  110  and/or other elements of system  100 , such as the gimbal system  122 , for example. Such software instructions may also implement methods for processing infrared images and/or other sensor signals, determining sensor information, providing user feedback (e.g., through user interface  132 ), querying devices for operational parameters, selecting operational parameters for devices, or performing any of the various operations described herein (e.g., operations performed by logic devices of various elements of system  100 ). 
     In addition, a non-transitory medium may be provided for storing machine readable instructions for loading into and execution by controller  112 . In these and other embodiments, controller  112  may be implemented with other components where appropriate, such as volatile memory, non-volatile memory, one or more interfaces, and/or various analog and/or digital components for interfacing with devices of system  100 . For example, controller  112  may be adapted to store sensor signals, sensor information, parameters for coordinate frame transformations, calibration parameters, sets of calibration points, and/or other operational parameters, over time, for example, and provide such stored data to a user using user interface  132 . In some embodiments, controller  112  may be integrated with one or more other elements of mobile platform  110 , for example, or distributed as multiple logic devices within mobile platform  110 , base station  130 , and/or sensor payload  140 . 
     In some embodiments, controller  112  may be configured to substantially continuously monitor and/or store the status of and/or sensor data provided by one or more elements of mobile platform  110 , sensor payload  140 , and/or base station  130 , such as the position and/or orientation of mobile platform  110 , sensor payload  140 , and/or base station  130 , for example. Such sensor data may include ranging sensor data provided SER  145 . In various embodiments, ranging sensor data provided by SER  145  indicates a distance between SER  145  and a surface intercepting a sensor axis of SER  145  corresponding to a single ranging sensor element of SER  145 . In some embodiments, such ranging sensor data may be used to generate a three-dimensional occupancy map for the environment or survey area in which mobile platform  110  is operating, localize mobile platform  110  within the occupancy map, and/or determine a projected course or avoidance course for mobile platform  110  according to the occupancy map. For example, a first set of ranging sensor data may be provided by SER  145 , and the first set of ranging sensor data may be used to generate a horizontal planar occupancy map. A second set of ranging sensor data may be provided by SER  145 , and the second set of ranging sensor data may be used to generate a vertical planar occupancy map. In some embodiments, the first set of ranging sensor data may correspond to a horizontal planar scan relative to mobile platform  110 , and the second set of ranging sensor data may correspond to a vertical planar scan relative to mobile platform  110 . In various embodiments, sensor data may be monitored and/or stored by controller  112  and/or processed or transmitted between elements of system  100  substantially continuously throughout operation of system  100 , where such data includes various types of sensor data, control parameters, and/or other data, as described herein. 
     Orientation sensor  114  may be implemented as one or more of a compass, float, accelerometer, and/or other device capable of measuring an orientation of mobile platform  110  (e.g., magnitude and direction of roll, pitch, and/or yaw, relative to one or more reference orientations such as gravity and/or Magnetic North), gimbal system  122 , imaging system/sensor payload  140 , and/or other elements of system  100 , and providing such measurements as sensor signals and/or data that may be communicated to various devices of system  100 . Gyroscope/accelerometer  116  may be implemented as one or more electronic sextants, semiconductor devices, integrated chips, accelerometer sensors, accelerometer sensor systems, or other devices capable of measuring angular velocities/accelerations and/or linear accelerations (e.g., direction and magnitude) of mobile platform  110  and/or other elements of system  100  and providing such measurements as sensor signals and/or data that may be communicated to other devices of system  100  (e.g., user interface  132 , controller  112 ). GNSS  118  may be implemented according to any global navigation satellite system, including a GPS, GLONASS, and/or Galileo based receiver and/or other device capable of determining absolute and/or relative position of mobile platform  110  (e.g., or an element of mobile platform  110 ) based on wireless signals received from space-born and/or terrestrial sources (e.g., eLoran, and/or other at least partially terrestrial systems), for example, and capable of providing such measurements as sensor signals and/or data (e.g., coordinates) that may be communicated to various devices of system  100 . In some embodiments, GNSS  118  may include an altimeter, for example, or may be used to provide an absolute altitude. 
     Communications module  120  may be implemented as any wired and/or wireless communications module configured to transmit and receive analog and/or digital signals between elements of system  100 . For example, communications module  120  may be configured to receive flight control signals and/or data from base station  130  and provide them to controller  112  and/or propulsion system  124 . In other embodiments, communications module  120  may be configured to receive images and/or other sensor information (e.g., visible spectrum and/or infrared still images or video images) from sensor payload  140  and relay the sensor data to controller  112  and/or base station  130 . In some embodiments, communications module  120  may be configured to support spread spectrum transmissions, for example, and/or multiple simultaneous communications channels between elements of system  100 . Wireless communication links may include one or more analog and/or digital radio communication links, such as WiFi and others, as described herein, and may be direct communication links established between elements of system  100 , for example, or may be relayed through one or more wireless relay stations configured to receive and retransmit wireless communications. Communication links established by communication module  120  may be configured to transmit data between elements of system  100  substantially continuously throughout operation of system  100 , where such data includes various types of sensor data, control parameters, and/or other data, as described herein. 
     Gimbal system  122  may be implemented as an actuated gimbal mount, for example, that may be controlled by controller  112  to stabilize sensor payload  140  relative to a target or to aim sensor payload  140  (e.g., or components coupled thereto, such as SER  145 ) according to a desired direction and/or relative orientation or position. As such, gimbal system  122  may be configured to provide a relative orientation of sensor payload  140  (e.g., relative to an orientation of mobile platform  110 ) to controller  112  and/or communications module  120  (e.g., gimbal system  122  may include its own orientation sensor  114 ). In other embodiments, gimbal system  122  may be implemented as a gravity driven mount (e.g., non-actuated). In various embodiments, gimbal system  122  may be configured to provide power, support wired communications, and/or otherwise facilitate operation of articulated sensor/sensor payload  140 . In further embodiments, gimbal system  122  may be configured to couple to a laser pointer, range finder, and/or other device, for example, to support, stabilize, power, and/or aim multiple devices (e.g., sensor payload  140  and one or more other devices) substantially simultaneously. 
     In some embodiments, gimbal system  122  may be adapted to rotate sensor payload  140  +−90 degrees, or up to 360 degrees, in a vertical plane relative to an orientation and/or position of mobile platform  110 . In some embodiments, gimbal system  122  may be configured to limit rotation of SER  145  such that SER  145  provides angle-limited ranging sensor data corresponding to an arcuate portion of a horizontal or vertical plane centered on a projected course for mobile platform  110  and comprising an angular width between, for example, 5 degrees angular width and 180 degrees angular width. In other embodiments, such angular width may be greater than 180 degrees or less than 5 degrees, depending on the desired application. In further embodiments, gimbal system  122  may rotate sensor payload  140  to be parallel to a longitudinal axis or a lateral axis of mobile platform  110  as mobile platform  110  yaws, which may provide 360 degree ranging and/or imaging in a horizontal plane relative to mobile platform  110 . In various embodiments, controller  112  may be configured to monitor an orientation of gimbal system  122  and/or sensor payload  140  relative to mobile platform  110 , for example, or an absolute or relative orientation of an element of sensor payload  140  (e.g., SER  145 ). Such orientation data may be transmitted to other elements of system  100  for monitoring, storage, or further processing, as described herein. 
     Propulsion system  124  may be implemented as one or more propellers, turbines, or other thrust-based propulsion systems, and/or other types of propulsion systems that can be used to provide motive force and/or lift to mobile platform  110  and/or to steer mobile platform  110 . In some embodiments, propulsion system  124  may include multiple propellers (e.g., a tri, quad, hex, oct, or other type “copter”) that can be controlled (e.g., by controller  112 ) to provide lift and motion for mobile platform  110  and to provide an orientation for mobile platform  110 . In other embodiments, propulsion system  124  may be configured primarily to provide thrust while other structures of mobile platform  110  provide lift, such as in a fixed wing embodiment (e.g., where wings provide the lift) and/or an aerostat embodiment (e.g., balloons, airships, hybrid aerostats). In various embodiments, propulsion system  124  may be implemented with a portable power supply, such as a battery and/or a combustion engine/generator and fuel supply. 
     Other modules  126  may include other and/or additional sensors, actuators, communications modules/nodes, and/or user interface devices, for example, and may be used to provide additional environmental information related to operation of mobile platform  110 , for example. In some embodiments, other modules  126  may include a humidity sensor, a wind and/or water temperature sensor, a barometer, an altimeter, a radar system, a proximity sensor, a visible spectrum camera or infrared camera (with an additional mount), an irradiance detector, and/or other environmental sensors providing measurements and/or other sensor signals that can be displayed to a user and/or used by other devices of system  100  (e.g., controller  112 ) to provide operational control of mobile platform  110  and/or system  100 . 
     In some embodiments, other modules  126  may include one or more actuated and/or articulated devices (e.g., multi-spectrum active illuminators, visible and/or IR cameras, radars, sonars, and/or other actuated devices) coupled to mobile platform  110 , where each actuated device includes one or more actuators adapted to adjust an orientation of the device, relative to mobile platform  110 , in response to one or more control signals (e.g., provided by controller  112 ). In particular, other modules  126  may include a stereo vision system configured to provide image data that may be used to calculate or estimate a position of mobile platform  110 , for example, or to calculate or estimate a relative position of a navigational hazard in proximity to mobile platform  110 . In various embodiments, controller  112  may be configured to use such proximity and/or position information to help safely pilot mobile platform  110  and/or monitor communication link quality, as described herein. 
     User interface  132  of base station  130  may be implemented as one or more of a display, a touch screen, a keyboard, a mouse, a joystick, a knob, a steering wheel, a yoke, and/or any other device capable of accepting user input and/or providing feedback to a user. In various embodiments, user interface  132  may be adapted to provide user input (e.g., as a type of signal and/or sensor information transmitted by communications module  134  of base station  130 ) to other devices of system  100 , such as controller  112 . User interface  132  may also be implemented with one or more logic devices (e.g., similar to controller  112 ) that may be adapted to store and/or execute instructions, such as software instructions, implementing any of the various processes and/or methods described herein. For example, user interface  132  may be adapted to form communication links, transmit and/or receive communications (e.g., infrared images and/or other sensor signals, control signals, sensor information, user input, and/or other information), for example, or to perform various other processes and/or methods described herein. 
     In one embodiment, user interface  132  may be adapted to display a time series of various sensor information and/or other parameters as part of or overlaid on a graph or map, which may be referenced to a position and/or orientation of mobile platform  110  and/or other elements of system  100 . For example, user interface  132  may be adapted to display a time series of positions, headings, and/or orientations of mobile platform  110  and/or other elements of system  100  overlaid on a geographical map, which may include one or more graphs indicating a corresponding time series of actuator control signals, sensor information, and/or other sensor and/or control signals. 
     In some embodiments, user interface  132  may be adapted to accept user input including a user-defined target heading, waypoint, route, and/or orientation for an element of system  100 , for example, and to generate control signals to cause mobile platform  110  to move according to the target heading, route, and/or orientation, or to aim sensor payload  140  accordingly. In other embodiments, user interface  132  may be adapted to accept user input modifying a control loop parameter of controller  112 , for example. In further embodiments, user interface  132  may be adapted to accept user input including a user-defined target attitude, orientation, and/or position for an actuated or articulated device (e.g., sensor payload  140 ) associated with mobile platform  110 , for example, and to generate control signals for adjusting an orientation and/or position of the actuated device according to the target altitude, orientation, and/or position. Such control signals may be transmitted to controller  112  (e.g., using communications modules  134  and  120 ), which may then control mobile platform  110  accordingly. 
     Communications module  134  may be implemented as any wired and/or wireless communications module configured to transmit and receive analog and/or digital signals between elements of system  100 . For example, communications module  134  may be configured to transmit flight control signals from user interface  132  to communications module  120  or  144 . In other embodiments, communications module  134  may be configured to receive sensor data (e.g., visible spectrum and/or infrared still images or video images, or other sensor data) from sensor payload  140 . In some embodiments, communications module  134  may be configured to support spread spectrum transmissions, for example, and/or multiple simultaneous communications channels between elements of system  100 . In various embodiments, communications module  134  may be configured to monitor the status of a communication link established between base station  130 , sensor payload  140 , and/or mobile platform  110  (e.g., including packet loss of transmitted and received data between elements of system  100 , such as with digital communication links), as described herein. Such status information may be provided to user interface  132 , for example, or transmitted to other elements of system  100  for monitoring, storage, or further processing, as described herein. 
     Other modules  136  of base station  130  may include other and/or additional sensors, actuators, communications modules/nodes, and/or user interface devices used to provide additional environmental information associated with base station  130 , for example. In some embodiments, other modules  136  may include a humidity sensor, a wind and/or water temperature sensor, a barometer, a radar system, a visible spectrum camera, an infrared camera, a GNSS, and/or other environmental sensors providing measurements and/or other sensor signals that can be displayed to a user and/or used by other devices of system  100  (e.g., controller  112 ) to provide operational control of mobile platform  110  and/or system  100  or to process sensor data to compensate for environmental conditions, such as an water content in the atmosphere approximately at the same altitude and/or within the same area as mobile platform  110  and/or base station  130 , for example. In some embodiments, other modules  136  may include one or more actuated and/or articulated devices (e.g., multi-spectrum active illuminators, visible and/or IR cameras, radars, sonars, and/or other actuated devices), where each actuated device includes one or more actuators adapted to adjust an orientation of the device in response to one or more control signals (e.g., provided by user interface  132 ). 
     In embodiments where imaging system/sensor payload  140  is implemented as an imaging device, imaging system/sensor payload  140  may include imaging module  142 , which may be implemented as a cooled and/or uncooled array of detector elements, such as visible spectrum and/or infrared sensitive detector elements, including quantum well infrared photodetector elements, bolometer or microbolometer based detector elements, type II superlattice based detector elements, and/or other infrared spectrum detector elements that can be arranged in a focal plane array. In various embodiments, imaging module  142  may include one or more logic devices (e.g., similar to controller  112 ) that can be configured to process imagery captured by detector elements of imaging module  142  before providing the imagery to memory  146  or communications module  144 . More generally, imaging module  142  may be configured to perform any of the operations or methods described herein, at least in part, or in combination with controller  112  and/or user interface  132 . 
     In some embodiments, sensor payload  140  may be implemented with a second or additional imaging modules similar to imaging module  142 , for example, that may include detector elements configured to detect other electromagnetic spectrums, such as visible light, ultraviolet, and/or other electromagnetic spectrums or subsets of such spectrums. In various embodiments, such additional imaging modules may be calibrated or registered to imaging module  142  such that images captured by each imaging module occupy a known and at least partially overlapping field of view of the other imaging modules, thereby allowing different spectrum images to be geometrically registered to each other (e.g., by scaling and/or positioning). In some embodiments, different spectrum images may be registered to each other using pattern recognition processing in addition or as an alternative to reliance on a known overlapping field of view. 
     In one embodiment, sensor payload  140  may include SER  145 . SER  145  may be implemented with a single ranging sensor element and may be configured to provide ranging sensor data indicating a distance between SER  145  and a surface intercepting a sensor axis of SER  145  corresponding to its single ranging sensor element. In various embodiments, SER  145  may be configured or adapted to provide relatively precise, substantially real-time range measurements and present relatively low power consumption to mobile platform  110  (e.g., less than 1 mW, continuous). For example, SER  145  may be configured to determine a distance between SER  145  and targets that are moving or stationary relative to mobile platform  110 . In some embodiments, SER  145  may include one or more logic devices (e.g., similar to controller  112 ) that may be configured to process ranging sensor data generated by the sensor element of SER  145  before providing ranging sensor data to memory  146  or communications module  144 . More generally, SER  145  may be configured to perform any of the operations or methods described herein, at least in part, or in combination with controller  112 , communications module  120 , gimbal system  122 , and/or other elements of sensor payload  140  and/or mobile platform  110 . 
     Communications module  144  of sensor payload  140  may be implemented as any wired and/or wireless communications module configured to transmit and receive analog and/or digital signals between elements of system  100 . For example, communications module  144  may be configured to transmit infrared images from imaging module  142  to communications module  120  or  134 . As another example, communications module  144  may be configured to transmit measurement ranges from SER  145  to communications module  120  or  134 . In other embodiments, communications module  144  may be configured to receive control signals (e.g., control signals directing capture, focus, selective filtering, and/or other operation of sensor payload  140 ) from controller  112  and/or user interface  132 . In some embodiments, communications module  144  may be configured to support spread spectrum transmissions, for example, and/or multiple simultaneous communications channels between elements of system  100 . In various embodiments, communications module  144  may be configured to monitor and communicate the status of an orientation of the sensor payload  140  as described herein. Such status information may be provided to SER  145 , for example, or transmitted to other elements of system  100  for monitoring, storage, or further processing, as described herein. 
     Memory  146  may be implemented as one or more machine readable mediums and/or logic devices configured to store software instructions, sensor signals, control signals, operational parameters, calibration parameters, infrared images, and/or other data facilitating operation of system  100 , for example, and provide it to various elements of system  100 . Memory  146  may also be implemented, at least in part, as removable memory, such as a secure digital memory card for example including an interface for such memory. 
     Orientation sensor  148  of sensor payload  140  may be implemented similar to orientation sensor  114  or gyroscope/accelerometer  116 , and/or any other device capable of measuring an orientation of sensor payload  140 , imaging module  142 , and/or other elements of sensor payload  140  (e.g., magnitude and direction of roll, pitch, and/or yaw, relative to one or more reference orientations such as gravity, Magnetic North, and/or an orientation of mobile platform  110 ) and providing such measurements as sensor signals that may be communicated to various devices of system  100 . Gyroscope/accelerometer (e.g., angular motion sensor)  150  of sensor payload  140  may be implemented as one or more electronic sextants, semiconductor devices, integrated chips, accelerometer sensors, accelerometer sensor systems, or other devices capable of measuring angular velocities/accelerations (e.g., angular motion) and/or linear accelerations (e.g., direction and magnitude) of sensor payload  140  and/or various elements of sensor payload  140  and providing such measurements as sensor signals that may be communicated to various devices of system  100 . 
     Other modules  152  of sensor payload  140  may include other and/or additional sensors, actuators, communications modules/nodes, cooled or uncooled optical filters, and/or user interface devices used to provide additional environmental information associated with sensor payload  140 , for example. In some embodiments, other modules  152  may include a humidity sensor, a wind and/or water temperature sensor, a barometer, a radar system, a visible spectrum camera, an infrared camera, a GNSS, and/or other environmental sensors providing measurements and/or other sensor signals that can be displayed to a user and/or used by imaging module  142  or other devices of system  100  (e.g., controller  112 ) to provide operational control of mobile platform  110  and/or system  100  or to process imagery to compensate for environmental conditions. 
     In general, each of the elements of system  100  may be implemented with any appropriate logic device (e.g., processing device, microcontroller, processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), memory storage device, memory reader, or other device or combinations of devices) that may be adapted to execute, store, and/or receive appropriate instructions, such as software instructions implementing a method for providing sensor data and/or imagery, for example, or for transmitting and/or receiving communications, such as sensor signals, sensor information, and/or control signals, between one or more devices of system  100 . In addition, one or more non-transitory mediums may be provided for storing machine readable instructions for loading into and execution by any logic device implemented with one or more of the devices of system  100 . In these and other embodiments, the logic devices may be implemented with other components where appropriate, such as volatile memory, non-volatile memory, and/or one or more interfaces (e.g., inter-integrated circuit (I2C) interfaces, mobile industry processor interfaces (MIPI), joint test action group (JTAG) interfaces (e.g., IEEE 1149.1 standard test access port and boundary-scan architecture), and/or other interfaces, such as an interface for one or more antennas, or an interface for a particular type of sensor). 
     Sensor signals, control signals, and other signals may be communicated among elements of system  100  using a variety of wired and/or wireless communication techniques, including voltage signaling, Ethernet, WiFi, Bluetooth, Zigbee, Xbee, Micronet, or other medium and/or short range wired and/or wireless networking protocols and/or implementations, for example. In such embodiments, each element of system  100  may include one or more modules supporting wired, wireless, and/or a combination of wired and wireless communication techniques. In some embodiments, various elements or portions of elements of system  100  may be integrated with each other, for example, or may be integrated onto a single printed circuit board (PCB) to reduce system complexity, manufacturing costs, power requirements, coordinate frame errors, and/or timing errors between the various sensor measurements. Each element of system  100  may include one or more batteries, capacitors, or other electrical power storage devices, for example, and may include one or more solar cell modules or other electrical power generating devices. In some embodiments, one or more of the devices may be powered by a power source for mobile platform  110 , using one or more power leads. Such power leads may also be used to support one or more communication techniques between elements of system  100 . 
       FIG. 2  illustrates a diagram of survey system  200  including mobile platforms  110 A and  110 B, each with SERs  145 /sensor payloads  140  and associated gimbal systems  122  in accordance with an embodiment of the disclosure. In the embodiment shown in  FIG. 2 , survey system  200  includes base station  130 , mobile platform  110 A with articulated imaging system/sensor payload  140  and gimbal system  122 , and mobile platform  110 B with articulated imaging system/sensor payload  140  and gimbal system  122 , where base station  130  may be configured to control motion, position, and/or orientation of mobile platform  110 A, mobile platform  110 B, and/or sensor payloads  140 . More generally, survey system  200  may include any number of mobile platforms  110 ,  110 A, and/or  110 B. 
       FIG. 3A  illustrates a side view of mobile platform  110  of survey system  100  maneuvering in a survey area  300  in accordance with an embodiment of the disclosure.  FIG. 3B  illustrates a top view of mobile platform  110  of survey system  100  maneuvering in survey area  300 . In various embodiments, mobile platform  110  may be implemented similarly to mobile platforms of survey systems  100  and/or  200  of  FIGS. 1-2 . As shown in  FIGS. 3A-B , survey area  300  may correspond to a particular area to be traversed and/or surveyed by mobile platform  110 , for example, and may include various obstacles (e.g., navigation impediments, obstructions, structures) that mobile platform  110  is configured to avoid as it maneuvers from a starting position (e.g., an anchor position  335 ) to a final destination (e.g., a projected destination  340 ) within survey area  300 . In general, anchor position  335 , projected destination  340 , and/or a projected course  320  between them may be selected by a user and/or dictated by logistics of mobile platform  110 , a survey pattern associated with survey area  300 , and/or an overall mission objective, as described herein. 
     In the embodiments depicted in  FIGS. 3A-B , survey area  300  may correspond to a cave with one or more stalactites  310 , stalagmites  315 , a cave floor  330 , a cave ceiling  325 , and/or cave walls  326 . Each navigation impediment or limit represents a maneuvering obstruction that should be avoided by mobile platform  110  as mobile platform  110  traverses survey area  300  from anchor position  335  to projected destination  340  along projected course  320 . Projected course  320  may be a simplified linear course of travel for mobile platform  110  between anchor position  335  and projected destination  340 . Projected course  320  may be adjusted based on obstacles discovered by mobile platform  110  (e.g., using SER  145 ) as it traverses survey area  300 , and adjustments or changes to projected course  320  may be referred to herein as avoidance courses. In various embodiments, projected destination  340  may be determined by mobile platform  110  based, at least in part, on a determined projected course  320 , for example, and/or GPS coordinates generated by mobile platform  110  or received by mobile platform  110  (e.g., from base station  130 ) as part of a mission objective, as described herein. 
     Although  FIGS. 3A-B  show survey area  300  corresponding roughly to a cave, other survey areas and environments are contemplated in which mobile platform  110  traverses and avoids various other types of maneuvering obstructions. For example, mobile platform  110  may traverse survey areas with other natural maneuvering obstructions such as trees; survey areas with artificial maneuvering obstructions such as man-made structures, building interiors, survey areas inundated with thick smoke or other environmental conditions that impair visible spectrum vision, burning buildings, and various other survey areas with any number and kind of navigation obstacles. 
     In the embodiments shown in  FIGS. 3A-B , mobile platform  110  is shown with a heading or direction of flight along projected course  320  that originates at anchor position  335  and ends at projected destination  340 . A longitudinal axis of mobile platform  110  may be parallel to such heading and/or project from a front of mobile platform  110  and, in various embodiments, may be aligned with projected course  320  for mobile platform  110  as mobile platform  110  traverses projected course  320 . In  FIGS. 3A-B , projected course  320  and the longitudinal axis of mobile platform  110  are shown parallel to an X-axis of a coordinate system associated with mobile platform  110 . Rotation of mobile platform  110  about such longitudinal axis may be referred to as a roll rotation. A vertical axis of mobile platform  110  may project from a top of mobile platform  110  and, in some embodiments, may be parallel (e.g., anti-parallel) with the direction of gravity relative to mobile platform  110 . In some embodiments, such vertical axis may be selected to be perpendicular to a ground surface beneath mobile platform  110  (e.g., cave floor  330 ), for example, or may be selected to be rotated away from a top of mobile platform  110 . In the embodiments shown in  FIGS. 3A-B , the vertical axis is shown parallel to the Z-axis of the coordinate system associated with mobile platform  110 , as depicted in  FIG. 3A . A plane spanning the longitudinal axis and the vertical axis of mobile platform  110  may be referred to as the longitudinal plane, sagittal plane, or vertical plane. Rotation of mobile platform  110  about such longitudinal axis may be referred to as a yaw rotation. A lateral axis of mobile platform  110  may be perpendicular to both the longitudinal axis and the vertical axis of mobile platform  110 . In this regard, the longitudinal, vertical, and lateral axis may be orthogonal to each other and form a local coordinate frame of mobile platform  110 . A plane spanning the lateral axis and the longitudinal axis of mobile platform  110  may be referred to as the latitude plane, transverse plane, or horizontal plane. Rotation of mobile platform  110  about such lateral axis may be referred to as a pitch rotation. 
     In various embodiments, anchor position  335  acts as an origin for an established coordinate frame for mobile platform  110 . While navigating from anchor position  335  to projected destination  340 , mobile platform  110  may be configured to maneuver primarily in a series of straight line segments in order to safely avoid maneuvering obstructions identified by survey system  100 . For example, if no maneuvering obstructions are detected, a single straight line segment projected course  320  may be projected between anchor position  335  (e.g., an origin of motion for mobile platform  110 ) and projected destination  340  (e.g., a final destination for mobile platform  110 , such as a mission objective/observation position), and mobile platform  110  may traverse survey area  300  accordingly. In some embodiments, various other straight line segments may be formed between anchor position  335  and one or more avoidance destinations along one or more avoidance courses determined by mobile platform  110  as mobile platform  110  maneuvers to final projected destination  340 . Mobile platform  110  may travel along such straight line segments to avoid colliding into maneuvering obstructions intersecting projected course  320 , for example, by maneuvering laterally around or vertically under or above an obstacle. In this regard, mobile platform  110  may adjust projected course  320  to create an avoidance course to avoid colliding into such maneuvering obstructions. 
     In various embodiments, mobile platform  110  may be configured to determine an avoidance course for mobile platform  110  based, at least in part, on a three-dimensional occupancy map (e.g., generated using ranging sensor data provided by SER  145 ) and projected destination  340  associated with projected course  320 . For example, mobile platform  110  (e.g., a logic device of mobile platform  110 ) may be configured to determine an avoidance course to maneuver mobile platform  110  from an avoidance anchor position on projected course  320  to an avoidance destination selected to avoid one or more maneuvering obstructions identified in such three-dimensional occupancy map, for example, and/or to minimize overall flight time, distance traveled, and/or to adhere to various other mission objectives. Mobile platform  110  may then maneuver from the avoidance anchor position to the avoidance destination along such avoidance course, as described herein. 
     In some embodiments, mobile platform  110  may perform a scan of survey area  300  relative to mobile platform  110  to provide ranging sensor data. Mobile platform  110  may, for example, use SER  145  coupled to gimbal system  122  to perform a scan of survey area  300  to provide one or more sets of ranging sensor data indicating a distance between SER  145  and a surface within survey area  300  intercepting a sensor axis of SER  145  corresponding to a single ranging sensor element of SER  145 . Each set of ranging sensor data may correspond to different scans performed by SER  145  and/or mobile platform  110 . For example, a first set of ranging sensor data may correspond to a horizontal planar scan of survey area  300  and a second set of ranging sensor data may correspond to a vertical planar scan of survey area  300 . A controller of mobile platform  110  may communicate with gimbal system  122  to adjust an orientation of SER  145  relative to mobile platform  110  to facilitate scanning survey area  300  using SER  145 . In various embodiments, a three-dimensional occupancy map sufficient to safely maneuver mobile platform  110  within scene  300  may be determined based, at least in part, on a horizontal planar occupancy map based on one or more such horizontal planar scans of survey area  300  and a vertical planar occupancy map based on one or more such vertical planar scans, as described herein. 
       FIG. 3C  illustrates a two-dimensional vertical planar occupancy map  301  generated by mobile platform  110  of survey system  100  in accordance with an embodiment of the disclosure. For example, mobile platform  110  may be configured to use SER  145  to perform a vertical scan of survey area  300  of  FIGS. 3A-B  (e.g., corresponding to a scan across at least a portion of the plane of the page for  FIG. 3A ) to measure distances between mobile platform  110  and maneuvering obstructions in the associated vertical plane and to generate vertical planar occupancy map  301 . In some embodiments, generating vertical planar occupancy map  301  includes rotating SER  145  about a horizontal axis of mobile platform  110  and within a vertical plane defined, at least in part, by projected course  320  of mobile platform  110 , to generate sets of ranging sensor data; determining a set of distances and corresponding relative orientations of SER  145  (e.g., associated with surfaces intersecting the vertical plane while SER  145  is rotated about a horizontal axis of mobile platform  110 ) based, at least in part, on the sets of ranging sensor data; and generating vertical planar occupancy map  301  based, at least in part, on the set of distances and corresponding relative orientations of SER  145 , as described herein. For example, relative orientations of SER  145  may be determined through use of orientation sensor  114  (e.g., a compass/magnetometer), gyroscope/accelerometer  116  (e.g., by detecting gravity and/or integrating detected angular accelerations), and/or by receiving relative orientations from gimbal system  122 . 
     In some embodiments, vertical planar occupancy map  301  may be used to prevent mobile platform  110  from drifting vertically while traversing projected course  320 , thereby allowing horizontal planar occupancy map  302  of  FIGS. 3D-E  to remain valid to guide maneuvering of mobile platform  110  within survey area  300 , as described herein. For example, a vertical scan of SER  145  may be used to update vertical planar occupancy map  301  and a position of mobile platform  110  within vertical planar occupancy map  301 . Vertical planar occupancy map  301  and associated information may be monitored by controller  112  to prevent mobile platform  110  from drifting vertically along a vertical axis associated with mobile platform  110 . 
     In various embodiments, vertical planar occupancy map  301  may be implemented as a two-dimensional geospatial map representative of a vertical plane spanning the vertical and longitudinal axes of mobile platform  110 , for example, and may also be implemented as an occupancy grid associated with a vertical plane relative to mobile platform  110 . In some embodiments, anchor position  335  (e.g., an initial or starting position for traversing survey area  300 ) may be used or established as an origin of vertical planar occupancy map  301 . More generally, the origin of vertical planar occupancy map  301  may be established as a current position of mobile platform  110  within survey area  300 /vertical planar occupancy map  301 . 
     In some embodiments, mobile platform  110  may be configured to perform a vertical scan (e.g., also referred to herein as referred to herein as a longitudinal scan) by yawing or panning gimbal system  122  and/or mobile platform  110  to aim sensor payload  140  and/or a sensor axis of SER  145  parallel to projected course  320  and/or parallel to a vertical plane defined, at least in part, by projected course  320 , and then pitching or tilting gimbal system  122  and/or mobile platform  110  to scan or orient sensor payload  140  and/or SER  145  across a vertical scan angle  375  (e.g., in a vertical plane defined in  FIG. 3C  as parallel to the X and Z axes) centered about a longitudinal axis of mobile platform  110 , to measure distances to and/or associated with maneuvering obstructions in such vertical plane relative to mobile platform  110  as mobile platform  110  maneuvers along projected course  320  towards projected destination  340 . For example, distances from SER  145 /mobile platform  110  to portions of stalactite  310 , stalagmite  315 , cave ceiling  325 , and cave floor  330  of survey area  300  may be measured during such vertical scan. Such vertical scan may be used to generate vertical planar occupancy map  301  and/or determine a position of mobile platform  110  within vertical planar occupancy map  301 . 
     In some cases, vertical scan angle  375  may correspond to a full revolution of SER  145  (e.g., a 360 degree vertical scan). In other cases, vertical scan angle  375  may be less than a full revolution (e.g., +−90 degrees about projected course  320 , +−45 degrees about projected course  320 , or any range of solid angle between approximately 5 and 180 degrees about projected course  320 ). In some embodiments, a vertical scan angle  375  that is less than a full revolution may be used to increase operational efficiency by conserving power and time during vertical scans. In some embodiments, vertical planar occupancy map  301  may include an angular limited planar occupancy map generated based, at least in part, on angle-limited ranging sensor data. The angle-limited ranging sensor data may correspond to an arcuate portion of a vertical plane centered on projected course  320  an including an angular width between 5 degrees angular width and 180 degrees angular width. 
     As shown in vertical planar occupancy map  301  of  FIG. 3C , the vertical scan may capture a stalactite portion  350 , a stalagmite portion  365 , a cave ceiling portion  345 , and a cave floor portion  370  corresponding to survey area  300 . Lines of sight (e.g., shadow boundaries)  351  and  366  represent the lines of sight of mobile platform  110  (e.g., the boundaries of vertical planar occupancy map  301  due to shadows cast by maneuvering obstructions) in survey area  300  as mobile platform  110  performs a vertical scan at anchor position  335 . For example, stalactite  310  and stalagmite  315  of survey area  300  may partially obscure a scan view of mobile platform  110  in the vertical plane, decreasingly and/or differently as mobile platform  110  traverses survey area  300 . Additional vertical scans performed while mobile platform  110  traverses survey area  300  may be used to fill such obscured portions of vertical planar occupancy map  301 . 
     In various embodiments, mobile platform  110  may use vertical planar occupancy map  301  to determine a projected or avoidance course for mobile platform  110  as it maneuvers from anchor position  335  to projected destination  340 . For example, if projected course  320  is obstructed by a maneuvering obstacle detected in vertical planar occupancy map  301 , mobile platform  110  may perform further scans to update vertical planar occupancy map  301  and/or determine an appropriate avoidance course to reach projected destination  340  based, at least in part, on vertical planar occupancy map  301 . In an embodiment, vertical planar occupancy map  301  may remain valid (e.g., for maneuvering mobile platform  110 ) while a lateral position of mobile platform  110  within survey area  300  substantially matches a lateral position of anchor position  335  (e.g., absolute or relative lateral positions). For example, vertical planar occupancy map  301  may be used to safely avoid maneuvering obstructions along projected course  320  while mobile platform  110  maintains projected course  320  without drifting laterally away from projected course  320 . 
     In some embodiments, when a projected or avoidance course requires a new heading for mobile platform  110 , mobile platform  110  may be configured to yaw to adjust its heading such that mobile platform  110  may maneuver along the new projected or avoidance course. When a new heading has been established to align with the new projected or avoidance course, mobile platform  110  may redefine the absolute orientations of its longitudinal and lateral axes so that they correspond to the new heading for mobile platform  110 . Upon completing a heading adjustment, mobile platform  110  may generate a new and differently oriented vertical occupancy map, corresponding to the new heading/projected or avoidance course by performing an additional vertical scan using SER  145 , as described herein. Establishing such new and differently oriented vertical occupancy map may be referred to herein as performing a vertical occupancy map switch. 
     In performing a vertical occupancy map switch, drift along any axis relative to mobile platform  110  should be avoided. For example, mobile structure  110  may be configured to use gimbal system  122  and/or SER  145  to help keep a vertical position of mobile platform  110  substantially constant during a yaw rotation to change a heading of mobile platform  110  and while performing a vertical occupancy map switch, which may allow a corresponding horizontal planar occupancy map (e.g., described with reference to  FIG. 3D ) to remain valid for maneuvering mobile platform  110  within survey area  300 . In general, mobile platform  110  should not maneuver within survey area  300  without valid vertical and horizontal planar occupancy maps, as described herein, and upon detecting an occupancy map has become invalid (e.g., due to spatial drift beyond a maximum drift threshold), mobile platform  110  may be configured to halt traversal of survey scene  300  until valid occupancy maps can be generated using SER  145 . 
       FIG. 3D  illustrates a two-dimensional horizontal planar occupancy map  302  generated by mobile platform  110  of survey system  100  in accordance with an embodiment of the disclosure. For example, mobile platform  110  may be configured to use SER  145  to perform a horizontal scan of survey area  300  of  FIGS. 3A-B  (e.g., corresponding to a scan across at least a portion of the plane of the page for  FIG. 3B ) to measure distances between mobile platform  110  and obstructions in the associated horizontal plane and to generate horizontal planar occupancy map  302 . In some embodiments, generating horizontal planar occupancy map  302  includes rotating SER  145  and/or mobile platform  110  about a vertical axis of mobile platform  110  and within a horizontal plane defined, at least in part, by projected course  320  of mobile platform  110 , to generate sets of ranging sensor data; determining a set of distances and corresponding relative orientations or bearings of SER  145  and/or mobile platform  110  (e.g., associated with surfaces intersecting the horizontal plane while SER  145  is rotated about a vertical axis of mobile platform  110 ) based, at least in part, on the sets of ranging sensor data; and generating horizontal planar occupancy map  302  based, at least in part, on the set of distances and corresponding relative orientations or bearings of SER  145  and/or mobile platform  110 , as described herein. For example, relative orientations or bearings of SER  145  and/or mobile structure  110  may be determined through use of orientation sensor  114  and/or gyroscope/accelerometer  116 , by receiving relative orientations and/or bearings from gimbal system  122 , and/or by controlling mobile platform  101  to rotate about its vertical axis according to a known yaw rate, for example, and indexing the set of distances by time in order to identify corresponding relative orientations and/or bearings. 
     In some embodiments, horizontal planar occupancy map  302  may be used to prevent mobile platform  110  from drifting laterally (e.g., or uncontrollably horizontally) while traversing projected course  320 , thereby allowing vertical planar occupancy map  301  (e.g., of  FIGS. 3C  and E) to remain valid to guide maneuvering of mobile platform  110  within survey area  300 , as described herein. For example, a horizontal scan of SER  145  may be used to update horizontal planar occupancy map  302  and a position of mobile platform  110  within horizontal planar occupancy map  302 . Horizontal planar occupancy map  302  and associated information may be monitored by controller  112  to prevent mobile platform  110  from drifting horizontally along a lateral and/or longitudinal axis associated with mobile platform  110 . 
     In various embodiments, horizontal planar occupancy map  302  may be implemented as a two-dimensional geospatial map representative of a horizontal plane spanning the longitudinal and lateral axes of mobile platform  110 , for example, and may also be implemented as an occupancy grid associated with a horizontal plane relative to mobile platform  110 . In some embodiments, anchor position  335  (e.g., an initial or starting position for traversing survey area  300 ) may be used or established as an origin of horizontal planar occupancy map  302 . More generally, the origin of horizontal planar occupancy map  302  may be established as a current position of mobile platform  110  within survey area  300 /horizontal planar occupancy map  302 . 
     In some embodiments, mobile platform  110  may be configured to perform a horizontal scan (e.g., also referred to herein as referred to herein as a lateral scan) by yawing or panning gimbal system  122  and/or mobile platform  110  to aim sensor payload  140  and/or a sensor axis of SER  145  parallel to projected course  320  and/or parallel to a horizontal plane defined, at least in part, by an altitude and/or a projected course (e.g., projected course  320 ) of mobile platform  110 , and then yawing or panning gimbal system  122  and/or mobile platform  110  to scan or orient sensor payload  140  and/or SER  145  across a horizontal scan angle  385  (e.g., in a horizontal plane defined in  FIG. 3D  as parallel to the X and Y axes) centered about a longitudinal axis of mobile platform  110 , to measure distances to maneuvering obstructions in such horizontal plane relative to mobile platform  110  as mobile platform  110  maneuvers along projected course  320  toward projected destination  340 . 
     For example, distances from SER  145 /mobile platform  110  to portions of stalactite  310 , stalagmite  315 , and cave walls  326  of survey area  300  may be measured during such horizontal scan. Such horizontal scan may be used to generate horizontal planar occupancy map  302  and/or determine a position of mobile platform  110  within horizontal planar occupancy map  302 . 
     In some cases, horizontal scan angle  385  may correspond to a full revolution of SER  145  (e.g., a 360 degree horizontal scan). In other cases, horizontal scan angle  385  may be less than a full revolution (e.g., +−90 degrees about projected course  320 , +−45 degrees about projected course  320 , or any range of solid angle between approximately 5 and 180 degrees about projected course  320 ). In some embodiments, a horizontal scan angle  385  that is less than a full revolution may be used to increase operational efficiency by conserving power and time during horizontal scans. In some embodiments, horizontal planar occupancy map  302  may include an angular limited planar occupancy map generated based, at least in part, on angle-limited ranging sensor data. The angle-limited ranging sensor data may correspond to an arcuate portion of a horizontal plane centered on projected course  320  an including an angular width between 5 degrees angular width and 180 degrees angular width. 
     As shown in horizontal planar occupancy map  302  of  FIG. 3D , a horizontal scan may capture a stalactite portion  395 , a stalagmite portion  390 , and cave wall portions  392  corresponding to survey area  300 . Lines of sight (e.g., shadow boundaries)  396 A-B and  391 A-B represent the lines of sight of mobile platform  110  (e.g., the boundaries of horizontal planar occupancy map  302  due to shadows cast by maneuvering obstructions) in survey area  300  as mobile platform  110  performs a horizontal scan at anchor position  335 . For example, stalactite  310  and stalagmite  315  of survey area  300  may partially obscure a scan view of mobile platform  110  in the horizontal plane, decreasingly and/or differently as mobile platform  110  traverses survey area  300 . Additional horizontal scans performed while mobile platform  110  traverses survey area  300  may be used to fill such obscured portions of horizontal planar occupancy map  302 . 
     In various embodiments, mobile platform  110  may use horizontal planar occupancy map  302  to determine a projected or avoidance course for mobile platform  110  as it maneuvers from anchor position  335  to projected destination  340 . For example, if projected course  320  is obstructed by a maneuvering obstacle detected in horizontal planar occupancy map  302 , mobile platform  110  may perform further scans to update horizontal planar occupancy map  302  and/or determine an appropriate avoidance course to reach projected destination  340  based, at least in part, on horizontal planar occupancy map  302 . In an embodiment, horizontal planar occupancy map  302  may remain valid (e.g., for maneuvering mobile platform  110 ) while a vertical position of mobile platform  110  within survey area  300  substantially matches a vertical position of anchor position  335  (e.g., absolute or relative vertical positions). For example, horizontal planar occupancy map  302  may be used to safely avoid maneuvering obstructions along projected course  320  while mobile platform  110  maintains projected course  320  without drifting vertically away from projected course  320 . 
     In some embodiments, when a projected or avoidance course requires adjusting an altitude for mobile platform  110 , mobile platform  110  may be configured to use propulsion system  124  to adjust its altitude along the projected or avoidance course to reach a final or avoidance altitude/position. When a final or avoidance altitude has been reached, mobile platform  110  may redefine the altitude of its longitudinal and lateral axes so that it corresponds to the new altitude for mobile platform  110 . Upon completing an altitude adjustment, mobile platform  110  may generate a new horizontal occupancy map, corresponding to the new altitude, by performing an additional horizontal scan using SER  145 , as described herein. Establishing such new horizontal occupancy map may be referred to herein as performing a horizontal occupancy map switch. 
     In performing a horizontal occupancy map switch, drift along the longitudinal and lateral axes (e.g., horizontal drift) relative to mobile platform  110  should be avoided. For example, mobile structure  110  may be configured to use gimbal system  122  and/or SER  145  to help keep a horizontal position of mobile platform  110  within survey area  300  substantially constant while changing an altitude of mobile platform  110  and while performing a horizontal occupancy map switch, which may allow a corresponding vertical planar occupancy map (e.g., described with reference to  FIG. 3V ) to remain valid for maneuvering mobile platform  110  within survey area  300 . 
     In various embodiments, a lack of information about the horizontal planar occupancy map at the new altitude may induce or at least allow for horizontal drift when performing a horizontal planar occupancy map switch, due to reliance on previous (e.g., before the altitude adjustment) horizontal planar occupancy maps. Such horizontal drift may be prevented, mitigated, and/or reduced by performing one or more frontal scans that at least partially span a horizontal and a vertical axis relative to mobile platform  110 , while adjusting the altitude of mobile platform  110 , for example, and determining and/or updating a corresponding frontal occupancy map based on the frontal scans. In various embodiments, each individual frontal scan may be a single scan of SER  145  between a heading of mobile platform  110  and a vertical axis of mobile platform  110 . Mobile platform  110  may be configured to reference such frontal occupancy map while adjusting its altitude to help prevent horizontal drift. With an appropriate frontal occupancy maps, both longitudinal and lateral coordinates for mobile platform  110  within survey area  300  may be recovered at the new vertical coordinate (e.g., the new altitude). In general, such drift mitigation may be performed as part of a horizontal occupancy map switch, as described herein. A similar technique may be used to mitigate spatial drift during a vertical occupancy map switch, as described herein. 
       FIG. 3E  illustrates a three-dimensional occupancy map  303  generated by mobile platform  110  of survey system  100  in accordance with an embodiment of the disclosure. In various embodiments, three-dimensional occupancy map  303  may include and/or be determined based on vertical planar occupancy map  301  and horizontal planar occupancy map  302 , as described herein. For example, three-dimensional occupancy map  303  may include occupancy information (e.g., positions of surfaces of objects within survey area  300 ) derived from vertical planar occupancy map  301 , horizontal planar occupancy map  302 , and/or a frontal occupancy map generated by SER  145  of mobile platform  110 . Three-dimensional occupancy map  303  may provide occupancy information associated with survey area  300  to estimate at least a partial extent of six degrees of freedom (e.g., 6 DoF) associated with motion of mobile platform  110 . In general, occupancy information from vertical and horizontal planar occupancy maps  301  and  302  may be combined to determine three-dimensional occupancy map  303 . 
     In various embodiments, mobile platform  110  may be configured to determine an avoidance course for mobile platform  110  based, at least in part, on three-dimensional occupancy map  303  and projected destination  340  associated with projected course  320 . Such avoidance course may be determined to allow mobile platform  110  to maneuver from an avoidance anchor position on projected course  320  to an avoidance destination horizontally and/or vertically spaced from projected course  320  to avoid one or more maneuvering obstructions identified in three-dimensional occupancy map  303 , such as stalactite portions  350  and  395  and/or stalagmite portions  365  and  390 , as shown in  FIGS. 3C-D . For example, mobile platform  110  may be configured to determine an avoidance course for mobile platform  110  by identifying one or more maneuvering obstructions along projected course  320  based, at least in part, on three-dimensional occupancy map  303 , and determining an avoidance course for mobile platform  110  based, at least in part, on the identified one or more maneuvering obstructions. 
     In some embodiments, mobile platform  110  may be configured to identify one or more maneuvering obstructions along projected course  320  by identifying surfaces represented in three-dimensional occupancy map  303  that intersect and/or reside within a collision risk volume disposed about projected course  320  and/or mobile platform  110  based, at least in part, on projected course  320  (e.g., a direction and/or extent of projected course  320 ) and three-dimensional occupancy map  303  (e.g., portions or surfaces of maneuvering obstructions represented in three-dimensional occupancy map  303 ); and aggregating adjoining surfaces of the identified surfaces to form the one or more maneuvering obstructions along projected course  320 . In various embodiments, a collision risk volume may be determined based on the dimensions and/or physical features of mobile platform  110 . For example, mobile platform  110  will not be able to travel through a narrow portion of survey area  300  (e.g., narrower than an extent of mobile platform  110 ) if the narrow portion of survey area  300  includes surfaces that fall within a collision risk volume disposed about projected course  320 . In one case, intersecting surfaces represented in three-dimensional occupancy map  303  may indicate a maneuvering obstruction along projected course  320 , and adjoining surfaces of the identified surfaces may be aggregated to form one or more maneuvering obstructions (e.g., portions of stalactite  310  and/or stalagmite  315 ) along projected course  320 . 
     In some embodiments, mobile platform  110  may be configured to determine velocity information associated with one or more objects identified within the three-dimensional occupancy map. Such velocity information may be derived from Doppler shifts provided in the ranging sensor data provided by SER  145  or by comparing the three-dimensional occupancy map to a prior-determined three-dimensional occupancy map of the same survey area  300 . Objects with relative velocities approaching mobile platform  110  may be highlighted in a critical color (e.g., red or orange) within three-dimensional occupancy map  303  when rendered for a user (e.g., via user interface  132 ), for example, and may be used by mobile platform  110  to help determine an avoidance course to avoid both stationary and mobile maneuvering obstructions within survey area  300 . 
       FIG. 3F  illustrates a three-dimensional occupancy map  304  generated by mobile platform  110  of survey system  100  in accordance with an embodiment of the disclosure. As shown in  FIG. 3F , mobile platform  110  uses SER  145  to generate vertical planar occupancy map  301 A and horizontal planar occupancy map  302 A as mobile platform  110  travels along projected course  320  through hole  398  and approaches a maneuvering obstruction (e.g., a wall as shown in three-dimensional occupancy map  304 ) approximately at vertical occupancy map switch position  321 , where mobile platform  110  changes its heading to travel along avoidance course  322  to avoid the detected wall. As mobile platform  110  travels along avoidance course  322 , mobile platform  110  uses SER  145  to update/generate horizontal planar occupancy map  302 A and to generate new vertical planar occupancy map  301 B, as shown. 
     While vertical and horizontal planar occupancy maps  301  and  302  are generally described and presented as perpendicular to each other in  FIGS. 3A-F , in other embodiments, they may not be perpendicular to each other (they may be non-orthogonal), for example, may generally not be parallel/perpendicular, respectively, to gravity, and/or may not be substantially aligned with a longitudinal, lateral, or vertical axis of mobile platform  110 . For example, in some embodiments, horizontal planar occupancy map  301  may be oriented parallel to a local ground surface (e.g., cave floor  330  beneath mobile platform  110 ) within survey area  300 , where the local ground surface includes a slope that is not perpendicular to gravity, and vertical planar occupancy map  302  may be oriented parallel to gravity or may be oriented perpendicular to horizontal planar occupancy map  301 . In other embodiments, vertical planar occupancy map  302  may be oriented perpendicular to a local ground surface and horizontal planar occupancy map  301  may be oriented perpendicular to gravity. In further embodiments, an intersection line between a horizontal scan plane corresponding to horizontal planar occupancy map  301  and a vertical scan plane corresponding to vertical planar occupancy map  302  may be aligned to a direction of travel for mobile platform  110 , such as projected course  320 , which may not be perpendicular or parallel to gravity. In a specific embodiment, horizontal planar occupancy map  301  may be oriented parallel to a local ground surface and vertical planar occupancy map  302  may be aligned with trunks of trees within a survey area (e.g., generally aligned with gravity). In general, vertical planar occupancy map  301  and/or horizontal planar occupancy map  302  may be aligned with a coordinate frame of the mobile platform  110 , a projected course through survey area  300 , or local topography of survey area  300 . 
       FIG. 4A  illustrates a survey area  400  associated with a mission objective for mobile platform  110  of survey system  100  in accordance with an embodiment of the disclosure. For example, such mission objective may include using localization and mapping to reach destination  420  (e.g., a projected destination) to monitor or image  410  at a preselected altitude (denoted as Dz in  FIG. 4A ). In some embodiments, such mission objective includes maneuvering mobile platform  110  from anchor position  415  to destination  420  according to various mission criteria associated with the mission objective. For example, such mission criteria may require mobile platform  110  travel a selected (e.g., maximum or minimum) translational distance, denoted as Dx in  FIG. 4A , from anchor position  415  to destination  420 , and/or may require mobile platform  110  adjust its altitude according to various limits as it navigates from anchor position  415  to destination  420 . 
     In a particular embodiment, such mission objective may include mobile platform  110  completing a designated task at destination  420 . For example, such designated task may include adjusting gimbal system  122  and/or orienting mobile platform  110  such that an imaging module (e.g., imaging module  142 ) of mobile platform  110  may be used to capture images and/or video of target  410 , such as from a particular perspective or viewing position. In another embodiment, such task may include adjusting gimbal system  122  and/or orienting mobile platform  110  such that SER  145  may be used to measure a distance from destination  420  to target  410  (e.g., a surface of target  410 ), for example, or to measure or estimate an external size of target  410 . In some embodiments, imaging module  142  may capture a first set of image data corresponding to a first set of ranging sensor data and capture a second set of image data corresponding to a second set of ranging sensor data. System  100  and/or  200  may generate a three-dimensional image map corresponding to a three-dimensional occupancy map (e.g., determined by use of SER  145 , as described herein) based, at least in part, on the first and second sets of image data and the three-dimensional occupancy map. For example, such three-dimensional image map may include a spatial overlay of the image data onto the three-dimensional occupancy map. In some cases, an image sensor of imaging module  142  includes a visible spectrum image sensor, an infrared spectrum image sensor, a thermal image sensor, and/or a multi-spectrum image sensor. In various embodiments, the target  410  may be a structure, person, object, and/or any desired survey position designated by a mission objective associated with survey area  400 . 
     In some embodiments, mission criteria of such mission objective may include directives to avoid maneuvering obstructions along a projected course from anchor position  415  to destination  420 . For example, such mission criteria may include avoiding trees (e.g., trees  425 ,  430 , and  435 ) as mobile platform  110  traverses survey area  400 . In another example, such mission criteria may include avoiding various other maneuvering obstructions that may prevent mobile platform  110  from safely following a projected course within survey area  400 . In a specific embodiment, such mission criteria may include staying within vertical boundaries  440  and  445  (e.g., roughly corresponding to a vertical foliage thickness associated with trees  425 ,  430 , and  435 ) as mobile platform  110  traverses survey area  400  (e.g., so as to reduce risk of visual and/or audible identification of mobile platform  110  from above or below such foliage). As such, vertical boundaries  440  and  445  may be selected to provide a range of altitudes in which mobile platform  110  may maneuver without being detected by adversaries/third parties and/or target  410 . 
       FIG. 4B  illustrates a course for mobile platform  110  of survey system  100  based, at least in part, on a mission objective (e.g., observation of target  410 ) and a three-dimensional occupancy map (e.g., similar to three-dimensional occupancy map  303  of  FIG. 3E and/or 304  of  FIG. 3F ) associated with survey area  400  in accordance with an embodiment of the disclosure. As shown in  FIG. 4B , mobile platform  110  may be configured to maneuver through survey area  400  and avoid maneuvering obstructions (e.g., trees  425 ,  430 , and  435 ) during performance of a particular mission objective. At anchor position  415 , mobile platform  110  may perform a vertical scan and a horizontal scan to generate a three-dimensional occupancy map, as described herein. For example, mobile platform  110  may generate a vertical planar occupancy map and a horizontal planar occupancy map based on the vertical scan and the horizontal scan, respectively, and determine a three-dimensional occupancy map based on such vertical and horizontal planar occupancy maps. In some embodiments, mobile platform  110  may determine a projected course  465 A based on anchor position  415 , destination  420 , and such three-dimensional occupancy map. Mobile platform  110  may then maneuver toward destination  420  along projected course  465 A while performing vertical and/or horizontal scans to update a corresponding vertical occupancy map and/or horizontal planar map, and, thereby, update the corresponding three-dimensional occupancy map, as described herein. 
     In the embodiment shown in  FIG. 4B , at anchor position  446 , mobile platform  110  performs a full scan (e.g., a vertical scan and a horizontal scan, using SER  145 ) and generates and/or updates a three-dimensional occupancy map based on the resulting updated vertical and/or horizontal occupancy maps. Such three-dimensional occupancy map may indicate that tree  425  obstructs maneuvering of mobile platform  110  along projected course  465 A from anchor position  415  to destination  420 . As such, mobile platform  110  may be configured to determine that tree  425  obstructs projected course  465 A, for example, and to determine, based on the generated three-dimensional occupancy map, an avoidance course  465 B that avoids collision with tree  425 . Mobile platform  110  may then adjust its heading and/or perform a vertical occupancy map switch, as described above, and travel towards anchor position/avoidance destination  450  along avoidance course  465 B to proceed towards destination  420  and avoid tree  425 . Intermediate positions associated with a course of mobile platform  110  within survey area  400 , such as anchor position  450 , selected to avoid maneuvering obstructions on a particular projected/avoidance course may be referred to as avoidance anchor positions or avoidance destinations (e.g., depending on whether mobile platform  110  is traveling toward or away from such position). 
     Upon reaching anchor position  450 , mobile platform  110  may perform a full scan and determine that tree  425  is no longer obstructing traversal to destination  420 . Mobile platform  110  may adjust its heading and continue toward destination  420  along projected course  465 C, which may be selected to minimize excursions outside survey area  400  and/or based on other mission criterial associated with the overall mission objective. Upon reaching anchor position  455 , mobile platform  110  may perform further scans using SER  145  and determine that tree  435  is obstructing maneuvering of mobile platform  110  along projected course  465 C. Mobile platform  110  may then determine an avoidance course  465 D to avoid collision with tree  435  and/or move closer to destination  420 . Mobile platform  110  may then adjust its heading and travel towards anchor position/avoidance destination  460  along avoidance course  465 D to proceed towards destination  420  and avoid tree  435 . Upon reaching anchor position  460 , mobile platform  110  may perform further scans and/or determine that tree  430  is obstructing avoidance course  465 D. Mobile platform  110  may determine an avoidance course  465 E to avoid collision with tree  430  and/or move closer to destination  420 . Mobile platform  110  may then change its heading and travel towards anchor position/avoidance destination  470  along avoidance course  465 E to proceed towards destination  420  and avoid trees  430  and/or  435 . Upon reaching anchor position  470 , mobile platform  110  may perform further scans using SER  145  and determine a projected course to reach destination  420  by traveling in a straight line course to anchor position  475 . At anchor position  475 , mobile platform  110  may determine that an altitude adjustment is necessary to reach destination  420 . Mobile platform  110  may adjust its altitude and/or perform a horizontal map switch, as described above, then maneuver to destination  420  after determining that there are no remaining maneuvering obstacles along projected/closing course  465 F. 
     In some embodiments, mobile platform  110  may be configured to determine closing course  465 F for mobile platform  110  based, at least in part, on projected destination  420  associated with projected course  465 F, where closing course  465 F is configured to maneuver mobile platform  110  from avoidance destination  475  (e.g., one of the anchor positions of  FIG. 4B  that avoids an obstruction) to projected destination  420 , and then to maneuver itself from avoidance destination  475  to projected destination  420  along projected course  465 F. While mobile platform  110  maneuvers from avoidance destination  475  to projected destination  420 , mobile platform  110  may continue to perform vertical and/or horizontal scans to determine and/or update a three-dimensional obstruction map and avoid maneuvering obstructions by determining corresponding avoidance courses, as described herein. More generally, as mobile platform  110  maneuvers within survey area  400  between trees  425 ,  430 , and  435 , and performs scans using SER 145 , mobile platform  110  may be configured to determine various projected and/or avoidance courses within the constraints of mission criteria associated with an overall mission objective, such as vertical boundaries  440  and  445  shown in  FIG. 4A . 
       FIG. 5  illustrates a flow diagram of various operations to provide a three-dimensional occupancy map of a survey area in accordance with an embodiment of the disclosure. As such, process  500  provides for mapping of a survey area and localization of mobile platform  110  within the survey area using SER  145  coupled to mobile platform  110 . In some embodiments, the operations of  FIG. 5  may be implemented as software instructions executed by one or more logic devices or controllers associated with corresponding electronic devices, sensors, and/or structures depicted in  FIGS. 1-4B . For example, the mobile platform described with reference to process  500  of  FIG. 5  may be implemented according to any one of mobile platforms  110 ,  110 A, or  110 B of  FIGS. 1-4B . More generally, the operations of  FIG. 5  may be implemented with any combination of software instructions, mechanical elements, and/or electronic hardware (e.g., inductors, capacitors, amplifiers, actuators, or other analog and/or digital components). 
     It should also be appreciated that any step, sub-step, sub-process, or block of process  500  may be performed in an order or arrangement different from the embodiments illustrated by  FIG. 5 . For example, in some embodiments, one or more blocks may be omitted from or added to the process. Furthermore, block inputs, block outputs, various sensor signals, sensor information, calibration parameters, and/or other operational parameters may be stored to one or more memories prior to moving to a following portion of a corresponding process. Although process  500  in  FIG. 5  is described with reference to systems of  FIGS. 1-4B , process  500  may be performed by other systems different from those systems and including a different selection of electronic devices, sensors, assemblies, mechanisms, platforms, and/or platform attributes. 
     At block  502 , a horizontal planar occupancy map is generated for a horizontal plane. In some embodiments, the horizontal planar occupancy map is generated by rotating the mobile platform about a vertical axis of the mobile platform to generate a first set of ranging sensor data using a SER with a single ranging sensor element; determining a set of distances and corresponding relative bearings associated with surfaces intersecting the horizontal plane while the mobile platform is rotated about the vertical axis of the mobile platform, based, at least in part, on the first set of ranging sensor data; and generating the horizontal planar occupancy map based, at least in part, on the set of distances and relative bearings of the mobile platform. 
     In some embodiments, a controller for a mobile platform may communicate with a gimbal system coupled to the mobile platform. The gimbal system may adjust a sensor payload to align a SER, coupled to the sensor payload, with a horizontal plane relative to a coordinate system established by the mobile platform. In some embodiments, the mobile platform may then perform a horizontal scan by yawing through 360 degrees of rotation and measuring the distances between the mobile platform and obstacles in the horizontal plane. In various embodiment, the distances determined as a result of the horizontal scan are used to generate the horizontal planar occupancy map and the mobile platform&#39;s position within the horizontal planar occupancy map. In other embodiments, the distances determined as a result of the horizontal scan are used to update an existing horizontal occupancy map. This horizontal occupancy map may be monitored by the mobile platform to prevent drift in the lateral direction so that a vertical occupancy map remains valid. 
     At block  504 , the vertical occupancy map is generated for a vertical plane. In some embodiments, generating the vertical planar occupancy map includes rotating a SER about a horizontal axis of a mobile platform and within a vertical plane defined, at least in part, by a projected course of the mobile platform, to generate a second set of ranging sensor data; determining a set of distances and corresponding relative orientations of SER  145  associated with surfaces intersecting the vertical plane while SER  145  is rotated about the horizontal axis of the mobile platform based, at least in part, on the second set of ranging sensor data; and generating the vertical planar occupancy map based, at least in part, on the set of distances and relative orientations of SER  145 . 
     In some embodiments, a vertical scan may be performed by yawing the mobile platform to align SER  145  with the longitudinal axis of the established coordinate system for the mobile platform. The gimbal system may be controlled to cause angular rotation in the sensor payload such that SER  145 , coupled to the sensor payload, may be used to measure distances to obstacles in the vertical plane. In some embodiments, the measurements captured by SER  145  may be used to update the vertical occupancy map and the mobile platform&#39;s position within the vertical occupancy map. In various embodiments, information associated with the vertical occupancy map may be used to prevent drift along the vertical axis of the established coordinate system for the mobile platform. In an aspect, preventing drift along the vertical axis ensures that the horizontal planar occupancy map remains valid. 
     At block  506 , a three-dimensional occupancy map is determined based on the horizontal occupancy map and the vertical occupancy map. In an embodiment, information associated with the horizontal occupancy map and vertical planar map may be combined in a manner to provide the three-dimensional occupancy map. In an embodiment, the mobile platform may determine its own position relative to the three-dimensional occupancy map based on the three-dimensional occupancy map. For example, an origin position for the three-dimensional occupancy map may represent the mobile platform&#39;s position relative to the three-dimensional occupancy map. In an embodiment, the three-dimensional occupancy map may be represented as a three-dimensional occupancy grid. 
       FIG. 6  illustrates a flow diagram of various operations to maneuver a mobile platform of a survey system within a survey area in accordance with an embodiment of the disclosure. As such, process  600  provides for mapping of a survey area and localization of mobile platform  110  within the survey area using SER  145  coupled to mobile platform  110 . In some embodiments, the operations of  FIG. 6  may be implemented as software instructions executed by one or more logic devices or controllers associated with corresponding electronic devices, sensors, and/or structures depicted in  FIGS. 1-4B . More generally, the operations of  FIG. 6  may be implemented with any combination of software instructions, mechanical elements, and/or electronic hardware (e.g., inductors, capacitors, amplifiers, actuators, or other analog and/or digital components). 
     It should also be appreciated that any step, sub-step, sub-process, or block of flow diagram  600  may be performed in an order or arrangement different from the embodiments illustrated by  FIG. 6 . For example, in other embodiments, one or more blocks may be omitted from or added to the process. Furthermore, block inputs, block outputs, various sensor signals, sensor information, calibration parameters, and/or other operational parameters may be stored to one or more memories prior to moving to a following portion of a corresponding process. Although the process described in flow diagram  600  is described with reference to devices, sensors, and/or structures depicted in  FIGS. 1-4B , the process may be performed by other systems different from those devices, sensors, and/or structures and including a different selection of electronic devices, sensors, assemblies, mechanisms, platforms, and/or platform attributes. 
     At block  602 , a projected course including an anchor position and a destination is determined. In an embodiment, a controller may determine that the mobile platform has arrived at an anchor position according to a previously generated three-dimensional occupancy map. For example, the anchor position may be determined to be an origin position of the three-dimensional occupancy map. In some embodiments, the controller may also communicate with a GNSS to determine that the mobile platform has arrived at an anchor position. In other embodiments, the controller may determine that the mobile platform has arrived at an anchor position by referencing a distance of the mobile platform to any obstacles determined to be from the three-dimensional occupancy map. In other embodiments, the controller may determine that an obstacle obstructs the mobile platform on a projected course and sets an anchor position at a location before the obstacle to prevent collision with the obstacle. 
     In an embodiment, the destination is determined by the mobile platform communicating with a base station. For example, the communications module of the base station may transmit a GPS coordinate to the communication module of the mobile platform, and the transmitted GPS coordinate that is received by the mobile platform may be the destination. In some embodiments, the destination may be determined based on a previous destination for the mobile platform. In this regard, the mobile platform (or base station) may store in memory any destinations from previous courses traveled by the mobile platform. The destinations may be retrieved from a memory source. In some embodiments, the controller may determine an avoidance destination based on a perspective destination being invalid. For example, if the perspective destination is a location in which a mobile platform may not physically maneuver, the controller will determine an avoidance destination to which the mobile platform may physically maneuver. 
     At block  604 , a three-dimensional occupancy map is determined. In an embodiment, a horizontal planar occupancy map is generated for a horizontal plane. In some embodiments, a controller for a mobile platform may communicate with a gimbal system coupled to the mobile platform. The gimbal system may adjust a sensor payload to align a SER, coupled to the sensor payload, with a horizontal plane relative to a coordinate system established by the mobile platform. In some embodiments, the mobile platform may then perform a horizontal scan by yawing through 360 degrees of rotation and measuring the distances between the mobile platform and obstacles in the horizontal plane using SER  145 . In various embodiment, the distances determined as a result of the horizontal scan are used to generate the horizontal planar occupancy map and the mobile platform&#39;s position within the horizontal planar occupancy map. In other embodiments, the distances determined as a result of the horizontal scan are used to update an existing horizontal occupancy map. This horizontal occupancy map may be monitored by the mobile platform to prevent drift in the lateral direction so that a vertical occupancy map remains valid. 
     In an embodiment, the vertical occupancy map is generated for a vertical plane. In an embodiment, a vertical scan may be performed by yawing the mobile platform to align SER  145  with the longitudinal axis of the established coordinate system for the mobile platform. The gimbal system may be controlled to cause angular rotation in the sensor payload such that SER  145 , coupled to the sensor payload, may be used to measure distances to obstacles in the vertical plane. In some embodiments, the measurements captured by SER  145  may be used to update the vertical occupancy map and the mobile platform&#39;s position within the vertical occupancy map. In various embodiments, information associated with the vertical occupancy map may be used to prevent drift along the vertical axis of the established coordinate system for the mobile platform. In an aspect, preventing drift along the vertical axis ensures that the horizontal planar occupancy map remains valid. 
     In various embodiments, the three-dimensional occupancy map is determined based on the horizontal planar occupancy map and the vertical planar occupancy map. In an embodiment, information associated with the horizontal occupancy map and vertical planar map may be combined in a manner to provide the three-dimensional occupancy map. In an embodiment, the mobile platform may determine its own position relative to the three-dimensional occupancy map based on the three-dimensional occupancy map. For example, an origin position for the three-dimensional occupancy map may represent the mobile platform&#39;s position relative to the three-dimensional occupancy map. In an embodiment, the three-dimensional occupancy map may be represented as a three-dimensional occupancy grid. 
     At block  606 , an avoidance course is determined. The avoidance course may include an avoidance anchor position and an avoidance destination based on the three-dimensional occupancy map. Determining the avoidance course for the mobile platform may be based, at least in part, on the three-dimensional occupancy map and/or a projected destination associated with the projected course. The avoidance course facilitates maneuvering the mobile platform from an avoidance anchor position on the projected course on the projected course to an avoidance destination to avoid one or more maneuvering obstructions identified in the three-dimensional occupancy map. In an aspect, the avoidance course may be determined by performing full scans and determining a direction in the vertical plane or horizontal plane that avoids the obstacle. The mobile platform may then maneuver in the direction to avoid the obstacle along the avoidance course. In an aspect, the mobile platform continuously or intermittently performs full scans along a projected course and/or avoidance course to determine if an avoidance course is required due to an obstruction. 
     At block  608 , the mobile platform maneuvers from the avoidance anchor position to the avoidance destination according to the avoidance course. In an embodiment, the avoidance course may be determined to be the minimum amount of movement required to maneuver from the avoidance anchor position to the avoidance destination along straight line segments. For example, the avoidance course may be a minimum amount of movement required to maneuver to avoid an identified obstruction. 
     By providing such systems and techniques for three-dimensional mapping and localization, embodiments of the present disclosure substantially improve the operational flexibility and reliability of unmanned sensor platforms. For example, the present disclosure provides robust position and orientation techniques for situations where vision-based systems may fail on unmanned sensor platforms. The present techniques address the size, weight, and power consumption constraints of unmanned sensor platforms. Moreover, such systems and techniques may be used to increase the operational safety of unmanned mobile sensor platforms above that achievable by conventional systems. As such, embodiments provide mobile sensor platforms systems with significantly increased survey convenience and performance. 
     Where applicable, various embodiments provided by the present disclosure can be implemented using hardware, software, or combinations of hardware and software. Also, where applicable, the various hardware components and/or software components set forth herein can be combined into composite components comprising software, hardware, and/or both without departing from the spirit of the present disclosure. Where applicable, the various hardware components and/or software components set forth herein can be separated into sub-components comprising software, hardware, or both without departing from the spirit of the present disclosure. In addition, where applicable, it is contemplated that software components can be implemented as hardware components, and vice-versa. 
     Software in accordance with the present disclosure, such as non-transitory instructions, program code, and/or data, can be stored on one or more non-transitory machine readable mediums. It is also contemplated that software identified herein can be implemented using one or more general purpose or specific purpose computers and/or computer systems, networked and/or otherwise. Where applicable, the ordering of various steps described herein can be changed, combined into composite steps, and/or separated into sub-steps to provide features described herein. 
     Embodiments described above illustrate but do not limit the invention. It should also be understood that numerous modifications and variations are possible in accordance with the principles of the present invention. Accordingly, the scope of the invention is defined only by the following claims.