Abstract: Methods and systems are provided for guiding or otherwise assisting energy management of an aircraft radar vectoring en route to a runway. A method involves dynamically determining an updated predicted lateral trajectory for the radar vectoring when the current aircraft status fails to satisfy a trajectory execution criterion for a previously-predicted lateral trajectory by iteratively adjusting a runway interception point defining a segment aligned with the runway until arriving at the updated predicted lateral trajectory for which a stabilization criterion for the runway can be satisfied. The method determines a target value for an energy state parameter of the aircraft at a current location on the updated predicted lateral trajectory and provides indication of a recommended action to reduce a difference between a current value for the energy state parameter and the target value.

Abstract: Methods and system for alerting descent with respect to at least one of minimum sector altitude, minimum safe altitude and terrain clearance floor in an aircraft. The methods and systems receive at least one of a minimum sector altitude value, a minimum safe altitude value and a terrain clearance floor value based on a flight plan of the aircraft or a location of the aircraft. A movement trajectory of the aircraft is predicted. The aircraft predicted movement trajectory is evaluated with respect to the at least one of the minimum sector altitude value, the minimum safe altitude value and the terrain clearance floor value. An alert is output when the evaluation predicts convergence of the aircraft predicted movement trajectory and the at least one of the minimum sector altitude value, the minimum safe altitude value and the terrain clearance floor value.

Abstract: Methods and systems are provided for guiding or otherwise assisting operation of an aircraft when diverting from a flight plan. One method involves determining a gliding trajectory for the aircraft based at least in part on a current altitude of the aircraft, providing a graphical representation of the gliding trajectory for the aircraft, identifying a plurality of landing locations within a range defined by the gliding trajectory from the aircraft, and for each landing location of the plurality of landing locations, providing a graphical representation of a respective landing location with respect to the gliding trajectory at a respective altitude associated with the respective landing location and at a respective distance with respect to a graphical representation of the aircraft corresponding to a respective geographic distance between a current location of the aircraft and the respective landing location.

Abstract: An aircraft and method for controlling a following aircraft in reference to a target aircraft including receiving, in a flight management system of the following aircraft, information related to the target aircraft, setting a required time of arrival at an achieve-by-point abeam of the target aircraft target reference point, and after the achieve-by-point is reached, flying the following aircraft to maintain a fixed separation until a defined termination point has been reached.

Abstract: Described is a method that involves operating an unmanned aerial vehicle (UAV) to begin a flight, where the UAV relies on a navigation system to navigate to a destination. During the flight, the method involves operating a camera to capture images of the UAV's environment, and analyzing the images to detect features in the environment. The method also involves establishing a correlation between features detected in different images, and using location information from the navigation system to localize a feature detected in different images. Further, the method involves generating a flight log that includes the localized feature. Also, the method involves detecting a failure involving the navigation system, and responsively operating the camera to capture a post-failure image. The method also involves identifying one or more features in the post-failure image, and determining a location of the UAV based on a relationship between an identified feature and a localized feature.

Abstract: A method and system for automated air traffic management of unmanned vehicles that assures safety and continuous flow, even for vehicles of wide-ranging capabilities. Some embodiments include onboard equipment that distributes the burden of management across all the vehicles in a given airspace so that autonomous cooperation between vehicles creates useful group-level behavior. Vehicles carry definitions of rules of interaction on shared flyways. In conjunction with a means of exchanging location and velocity information with close neighbors, onboard algorithms calculate complementary navigation vectors that inform each vehicle's autopilot of a cooperative trajectory. The collective result of individual, autonomous decisions is cooperation at a group scale that manages traffic features such as density and spacing without the need for a ground-based communication infrastructure.

Abstract: A method and system for communicating and sharing information for an aircraft are disclosed. In one aspect, the method includes identifying a situation from among a set of predetermined situations and obtaining, from a data structure recorded beforehand, a first set of information elements associated with the identified situation. The method also includes determining, from the first set of information elements, and from pieces of information recorded beforehand, a set of pieces of information unavailable in the first system and establishing at least one first request to be sent from the first system to at least one second system. The method further includes sending the at least one first request from the first system to the at least one second system.

Abstract: A method and apparatus of turning an aircraft for interval management. Interval management information identifying a desired spacing between the aircraft and a target aircraft is received. Turn information is determined using a performance gain factor. The turn information identifies a turn point for the aircraft. The performance gain factor identifies a desired portion of achieving the desired spacing due to turning the aircraft at the turn point and a desired portion of achieving the desired spacing due to changing speed of the aircraft. The turn information is used to turn the aircraft at the turn point.

Abstract: A system and method for aircraft performance predictions for descent and approach phases are disclosed. In one embodiment, cruise computation is stopped substantially around a default distance from a destination. Further, current predicted aircraft state is determined using a total energy of the aircraft starting from the default distance. Furthermore, descent and approach phase profiles are computed using the determined current predicted aircraft state. In addition, the aircraft performance predictions are obtained using the computed descent and approach phase profiles.

Abstract: Example systems and methods for controlling aircraft arrivals at a waypoint are disclosed. An example method for controlling aircraft arrivals at a merging waypoint includes defining a tie waypoint at a first distance from the merging waypoint and generating a first parameter set of flight instructions for aircraft arriving at the tie waypoint. The first parameter set includes an aircraft speed instruction for a target separation between a first aircraft arriving at a target waypoint downstream of the tie waypoint and a second aircraft arriving at the target waypoint. The example method includes defining a diversionary flight path at a second distance from the merging waypoint. The second distance is less than the first distance. The method also includes generating a second parameter set of flight instructions for the aircraft arriving at the diversionary flight path.

Abstract: This disclosure relates to a system for preventing collisions with a terrain. The system includes a detecting means for detecting risks of collision with the terrain after a predetermined forecasting delay. The system further includes a determining means for determining, based on a trajectory followed by the aircraft, a possible limit point for success of the vertical terrain avoidance maneuver. The system further includes indication means for giving indications on azimuth clearance sections, around the direction in which the aircraft is moving, suitable for success of the vertical terrain avoidance maneuver. The system further includes means for estimating a free-travel distance in each azimuth clearance sector on a straight distancing trajectory with constant gradient and over a distance correspond to more than one minute of flight, the free-travel distance being free of potential conflicts with the terrain.

Abstract: An aircraft terrain awareness warning system is disclosed that includes an interface for entering flight plan details of an aircraft including at least one waypoint. The terrain awareness warning system is configured such that potential-terrain-collision alerts are suppressed in the aircraft during landing operations performed at waypoints associated with landing zones.

Abstract: A runway digital wind indicator system senses wind conditions at multiple locations, aggregates this data, and communicates up-to-date, usable information to pilots. Meteorological information, including wind speed, direction, and change (i.e., gustiness) plus temperature, humidity, barometer, wind shear, etc., can be sensed by three or more sensor pods placed along a runway (at least one at each end and another in the middle of a given runway). Data from these pods is then transferred to a computer receiver that processes the information into a real-time, concise, readable format that can be displayed to air traffic control, sent to runway digital display signs placed in proximity to runways for direct pilot reference, and/or posted to websites/internet locations that can then be used to wirelessly relay the information to any of a plethora of digital devices that can be accessed directly by a pilot.

Abstract: A method and system for providing taxiway navigational information to a crewmember of an airplane taxiing at an airport. An airport taxiway navigation system (“ATNS”) that executes on an onboard computer system that displays a map of the taxiways of an airport, receives the name of each taxiway of the taxi route specified by the taxi clearance, and highlights the taxiways on a displayed map to provide a visual indication of the cleared taxi route for the crewmembers.

Abstract: A method and apparatus are present for monitoring a runway. Data is received about the runway from a number of sensors associated with an aircraft while the aircraft performs an operation on the runway. A number of conditions are identified for the runway using the data received from the number of sensors.

Abstract: Methods and apparatus are provided for automated control of aerodrome lighting. An exemplary system includes a communication radio, an aerodrome lighting data source, and a processor. The communication radio is configured to selectively transmit radio frequency (RF) signals. The aerodrome lighting data source is configured to at least selectively supply aerodrome lighting data representative of light control characteristics of aerodrome lighting associated with individual aerodromes. The processor is in operable communication with the aerodrome lighting data source and the communication radio, and is configured to selectively retrieve, from the aerodrome lighting data source, aerodrome lighting data associated with an individual aerodrome, and selectively command the communication radio to transmit RF signals consistent with the light control characteristics associated with the individual aerodrome.

Abstract: A system for preventing light pollution includes one or more radar units that monitor for vehicles in a volume surrounding or containing one or more obstructions having one or more obstruction lights. A master radar detection processing unit receives sensed radar detection information from the one or more radar units with associated radar signal processing units and determines whether a vehicle is present within the monitored volume. A plurality of obstruction light controller units are interconnected in a network, such as a wireless network. Each obstruction light controller unit turns on an obstruction light when a vehicle enters the monitored volume or a failure condition exists, and turns off the obstruction light when the vehicle has vacated the monitored volume and no failure condition exists. The one or more radar units can transmit sensed radar detection information to a master radar detection processing unit via the network.

Abstract: A flight control system for a flying object comprises a flying object, a navigating means provided in the flying object, a position measuring unit 17, a flight control unit 18 for controlling the navigating means, and a main arithmetic control unit 19 for controlling the position measuring unit and the flight control unit, and in the flight control system for a flying object, the position measuring unit has a GPS device 23 for measuring a ground coordinate of the flying object and a vertical camera 13 for taking a digital image below the flying object and measures an altitude of the flying object based on images at two points taken by the vertical camera, on ground coordinates of the two points measured by the GPS device, and on a focal length of the vertical camera, and the main arithmetic control unit controls the navigating means via the flight control unit based on the measured altitude and makes the flying object fly at a predetermined altitude.

Abstract: A method and system for displaying three dimensional images of runways and terrain, as well as additional information, on one or more screens of an avionics display system is provided. The system merges elevation information for terrain points and elevation information for runway points by grouping runways together that are within a threshold distance of each other. For each group, a plane is calculated. The calculated plane is then projected onto all of the runways within the group. The plane may also be projected onto a subset of neighboring terrain points. The adjusted elevation created by the projection of the plane are then used in creating the images for display on the synthetic vision display. The result is that all of the runways within a group, along with their neighboring terrain, are displayed as being coplanar.

Abstract: Techniques are disclosed for a video surveillance system to learn to recognize complex behaviors by analyzing pixel data using alternating layers of clustering and sequencing. A combination of a self organizing map (SOM) and an adaptive resonance theory (ART) network may be used to identify a variety of different anomalous inputs at each cluster layer. As progressively higher layers of the cortex model component represent progressively higher levels of abstraction, anomalies occurring in the higher levels of the cortex model represent observations of behavioral anomalies corresponding to progressively complex patterns of behavior.

Abstract: Methods and apparatus are provided for automated control of aerodrome lighting. An exemplary system includes a communication radio, an aerodrome lighting data source, and a processor. The communication radio is configured to selectively transmit radio frequency (RF) signals. The aerodrome lighting data source is configured to at least selectively supply aerodrome lighting data representative of light control characteristics of aerodrome lighting associated with individual aerodromes. The processor is in operable communication with the aerodrome lighting data source and the communication radio, and is configured to selectively retrieve, from the aerodrome lighting data source, aerodrome lighting data associated with an individual aerodrome, and selectively command the communication radio to transmit RF signals consistent with the light control characteristics associated with the individual aerodrome.

Abstract: A system and method to facilitate approach of a VTOL aircraft to an offshore facility includes inputting a waypoint for a landing platform of an offshore facility into an aircraft module, inputting an offset distance from the landing platform into the aircraft module, inputting a minimum descent height into an aircraft module, and inputting a final approach inbound course toward the landing platform into the aircraft module.

Abstract: A present novel and non-trivial system, apparatus, and method for generating HUD image data from synthetic image data is disclosed. Based on a multi-channel pixel intensity data set generated by a synthetic vision system, a single-channel pixel intensity data set representative of a lighted solid image of terrain comprised of a plurality of intensities of one color may be generated. The single-channel pixel intensity image data set may be determined as a function of multi-channel pixel intensity data set and channel weighting, where channel weighting may be based on sky and/or terrain colors employed by an SVS. Based on the multi-channel pixel intensity data set, a three-dimensional perspective scene outside the aircraft may be presented to the pilot on a HUD combiner. Also, the multi-channel pixel intensity data set may be modified by using at least one chroma key, where such chroma key may be assigned to a specific multi-channel pixel intensity value.

Abstract: A system and method of conveying missed approach procedures to a pilot are provided. The system and method include rendering a graphic representation of at least one leg of the missed approach procedure on a display. A determination is made as to whether the aircraft is at least substantially flying the at least one leg of the missed approach procedure. At least one visual characteristic of the rendered graphic is selectively varied based on the determination of whether the aircraft is at least substantially flying the at least one leg of the missed approach procedure.

Abstract: Disclosed is a method and device, which provide an enhanced ability to monitor the navigation of an aircraft during a phase of flight in which the aircraft is close to the ground in which the aircraft uses positional information supplied by a satellite positioning system for the navigation. A display screen is used to display a first characteristic sign representing a selected setpoint value for a height parameter of the aircraft. The display screen also displays a second characteristic sign representing a current auxiliary value expressed in the form of an achievable height parameter. An alert is emitted when the second characteristic sign is determined to be within a predetermined height value of the first characteristic sign, and the alert is shown in visual format on the display screen. An alarm is also emitted following a predetermined time after the alert is emitted, if the setpoint value is not replaced by a new setpoint value.

Abstract: A method and device to assist in the piloting of an aircraft in a landing phase may apply a maximum braking of the aircraft if there is a risk of longitudinal departure from a runway.

Abstract: Techniques are disclosed for a video surveillance system to learn to recognize complex behaviors by analyzing pixel data using alternating layers of clustering and sequencing. A combination of a self organizing map (SOM) and an adaptive resonance theory (ART) network may be used to identify a variety of different anomalous inputs at each cluster layer. As progressively higher layers of the cortex model component represent progressively higher levels of abstraction, anomalies occurring in the higher levels of the cortex model represent observations of behavioral anomalies corresponding to progressively complex patterns of behavior.

Abstract: Techniques are disclosed for a video surveillance system to learn to recognize complex behaviors by analyzing pixel data using alternating layers of clustering and sequencing. A video surveillance system may be configured to observe a scene (as depicted in a sequence of video frames) and, over time, develop hierarchies of concepts including classes of objects, actions and behaviors. That is, the video surveillance system may develop models at progressively more complex levels of abstraction used to identify what events and behaviors are common and which are unusual. When the models have matured, the video surveillance system issues alerts on unusual events.

Abstract: The invention pertains to optoelectronic devices for aiding the guidance and taxiing of aircraft, comprising a so-called head-up collimator allowing the presentation of information in the pilot's visual field. It applies notably to large-size civil aircraft of the Boeing 747 or Airbus A380 type. The optoelectronic device comprises means for calculating a deviation factor for the actual trajectory of said aircraft relative to a theoretical trajectory on said traffic way, means for generating symbols and at least one head-up collimator comprising means for displaying and superimposing said symbols on the outside landscape. The deviation factor is calculated on the basis of an angle (PÂ?G) and that the means for generating symbols generate a symbol representing said deviation factor, so as to be superimposed on said traffic way.

Abstract: Disclosed is a device for aiding the piloting of an aircraft in an approach phase during landing. The device includes a guidance system for aiding guidance of the aircraft. Controllers can be actuated by the system during an initial phase in accordance with a first guidance mode and during a terminal phase in accordance with a second guidance mode. The transition between the first and second guidance modes can be achieved automatically by the guidance system.

Abstract: A display system and method for an aircraft displays, in real-time, the protected airspace associated with a CTL maneuver. The system processes aircraft approach category data and determines the protected airspace based at least in part on the processed aircraft approach category. An image representative of the determined protected airspace is displayed on the aircraft flight deck display system.

Abstract: This invention provides a system and method for autonomously tracking a moving target from unmanned aerial vehicles (UAVs) with a variety of airframe and sensor payload capabilities so that the target remains within the vehicle's sensor field of view regardless of the specific target motion patterns. The invention uses information about target location, UAV platform type and states, sensor payload capability, and ratio of target-to-UAV speeds to select from a suite of sub-algorithms, each of which generates desired platform positions (in form of waypoints) and/or sensor orientation commands to keep the target in view.

Abstract: The invention relates to a method to help a person responsible for a vehicle on an airport to follow running procedures in the airport, the vehicle including a device for using the method, including: a database including: data modelling all or some of an airport environment; one or several acquisition devices for acquiring procedures applicable to the running operation on the airport; one or several devices configured to acquire and determine vehicle status information; calculation means using the database; graphic transcription means and warning means; means of generating sound and visual alarms; wherein the assistance method includes at least the following steps: determine applicable procedures; continuously calculate deviations between the behaviour of the vehicle and applicable procedures; graphic transcription of progress of the vehicle while running and deviations from applicable procedures; trigger visual and/or sound alerts when a predetermined deviation threshold is crossed.

Abstract: The present invention relates to an object oriented architecture that includes a plurality of host aircraft interface objects that enable a plurality of different host aircraft or variants to be attached or interfaced to an associated store, such as a targeting pod or a weapon system. The union of all aircraft hosts and variants are packaged and maintained as one executable capable of adapting to the predetermined suite of identified hosts and host variants. At least one or more interface objects provide a virtual translation layer which is dynamically determined and allocated during instantiation. Auto detection of the host aircraft/host aircraft variant provides the specific interface protocol by which the store can process and provide status via a predetermined signal format.

Abstract: Optical device for indicating the glide angle for aircraft, comprising at least one unit (10) for generating a light ray with a predefined colour, at least one unit (20) for transmitting said light ray and creating a light image, and at least one unit (30) for remotely projecting said light image, characterized in that said generating unit (10) comprises at least one light source consisting of an LED (11) and said unit (20) for transmitting the light ray and creating a light image is of the optical fibre type (21, 22).

Abstract: The flight display includes a vertical terrain profile display having a format that includes a side-on vertical terrain profile comprising a plurality of color filled vertical alerting bands representing areas of terrain that are within defined limits above and below the airplane altitude. A symbol is positioned relative to the side-on vertical terrain profile for representing an altitude and position of the aircraft. Displays of range and altitude are positioned relative to the symbol and side-on vertical terrain profile in predetermined increments. In another broad aspect the side-on vertical terrain profile includes a plurality of color filled horizontal absolute altitude bands representing the absolute altitude of the terrain. These displays may be accompanied by nested color filled blocks representing weather hazards and/or terrain alerting prediction icons.

Abstract: A method for guiding the approach and landing of an aircraft is provided. The method involves receiving navigation information from the aircraft, receiving navigation information from an aircraft carrier, integrating the navigation information from the aircraft with the navigation information from the aircraft carrier to determine a relative velocity and a relative position between the aircraft and the aircraft carrier, and propagating the relative velocity and the relative position forward in time for navigation purposes.

Abstract: The present invention is a flight management system with precision merging that may determine a rejoin turn location based upon a heading to allow proper spacing between an aircraft and an identified target aircraft. The flight management system may monitor for deviation from assigned airspace, winds, turn radius and desired airport speed profile for the approach to further refine a turn-back location. Advantageously, a delay in landing of the target aircraft may not affect the landing approach of other aircraft. This may result in more accurate spacing between aircraft which are closer to the allowed separation minima and may provide an increase in capacity especially in high-density areas.

Abstract: A method, computer program product and apparatus for locating aircraft with respect to airport runways, generating and annunciating imminent landing situational awareness advisories as a function of aircraft height above runway.

Abstract: A system and method for providing autonomous control of unmanned aerial vehicles (UAVs) is disclosed. The system includes a ground station in communication with an unmanned aerial vehicle. The method for providing autonomous control of a UAV includes methods for processing communications between the ground station and UAV. The method also includes procedures for processing commands from the ground station. Also included in the method is a process for estimating the attitude of the UAV and autonomously maintaining its altitude within a desired threshold. The method also includes a process for autonomously orbiting about a specified point in space. Combined with these processes, the method also includes a process for an autonomous takeoff and landing of the UAV.

Abstract: An improved system and method are disclosed for indicating the validity of airport runway visual approach slope indicators on an aircraft display. An aircraft display system is provided, which includes a database for storing data about the specific visual approach slope lighting indicator system being used by each airport of a plurality of airports and any special distance and/or usage limitations associated with each such visual approach slope indicator system, a processing unit, a position determination unit, and a visual display. As an aircraft approaches an airport, the processing unit receives the aircraft's current position from the position determination unit, and compares the aircraft's current position data with the distance and/or usage limitation data stored in the database for the approach slope indicator system being used by that airport.

Abstract: A tracking system (10) for tracking movable assets (16) and several methods for using the system are provided. The tracking system includes a monitoring device (22), a tracking information network (20), a data communication network (18), a tracker tag (12), and a tracking information server (14). The tracker tag uses GPS technology. The tracking information server provides programmed instructions to the tracker tag in messages via a messaging system. The tracker tag selectively retrieves the messages from the messaging system. The tracking information server provides tracking information and related information to a subscriber. In one embodiment, the tracker tag is in communication with an Iridium satellite constellation (28) and tracking information is displayed to the subscriber when the asset is substantially anywhere in the world.

Abstract: A symbology system uses programmable software in a computerized system interacting with the altitude, attitude, air speed, and other flight indicators of an aircraft to create symbology in the pilot's display seen in the field of view of the pilot. The symbology represents a virtual geometric solid form, such as a vertical cylinder, always appearing perpendicular to the horizon and moving across the terrain with the aircraft in the center of the form. The pilot sees a front portion of a virtual series of horizontal circles or other shapes, spaced by a programmable distance, symbolizing the geometric solid form appearing to surround the aircraft. The geometric form references the world as-ground for use in recognizing the attitude of the aircraft-as-figure. On landing, the form appears to stop at the ground and the aircraft appears to descend within it. A virtual bank indicator line changes orientation to the geometric solid corresponding to the attitude change of the aircraft relative to the horizon.

Abstract: An aircraft on-board system for communicating with a ground-based radio transmitter forming a part of a Local Area Augmentation System for aiding in the navigation and landing of the aircraft, comprising a radio receiver adapted to receive signals, including identification signals identifying the Local Area Augmentation System, from the ground-based radio transmitter, a controller coupled to the radio receiver having an entry device for entering the channel number of a desired ground-based radio station and for tuning the on-board radio receiver to a desired frequency and further receiving from the radio signals, including the identification signals, and further having a signaling mechanism for providing to an operator of the aircraft on-board system a message including the identification of the ground-based radio station.

Abstract: An airfield guidance sign. The sign 100 (of FIG. 1a) includes a case (102), a multi-element light source (114) attached to the case (102) for providing light interior to the case (102), a light dispersion subsystem of the case for dispersing the light from the light source (114) substantially uniformly throughout the interior of the case (102); and a side panel (126) forming a side of the case (102) for displaying information.

Abstract: A ground proximity warning system including a pitch angle alerting device, the pitch angle alerting device including warning logic having an input that is structured to receive a signal that is representative of the indicated pitch angle of the aircraft, the warning logic being structured to determine a difference between a pitch angle signal received on the input and a predetermined threshold, the warning logic being structured also to output a signal representative of the difference between the two signals; and an advisory indication generator coupled to accept the output of the warning logic, the advisory indication generator being structured to generate an advisory indication signal as a function of the difference between the two signals.

Abstract: Techniques are described for monitoring runway occupancy and providing an indication of occupancy of a runway to an airplane on final approach the runway. A system, for example, defines and monitors one or more zones on the runway to determine whether the runway is occupied. Such a system includes sensors, such as inductive loop sensors, that may be located proximate to or on the runway, and the system may monitor ingress and egress of objects, such as airplanes or other vehicles on the ground, into and out of the zone in order to determine whether the zone is activated. The sensors may be located at points of entry and exit for the zone. The zones may be located at take-off hold areas of the runway and intersections of the runway with taxiways. A ground-based approach light array of the system may provide the indication of runway occupancy to the airplane.

Abstract: The present invention involves a lighting control module for at least one aviation obstruction light including a microcontroller, and switching means for selectively coupling the aviation obstruction light to a power source, the microcontroller coupled to the switching means and selectively activating the aviation obstruction light. The microcontroller has programming for sensing a master light controller such that if a master light controller is sensed, then the microcontroller coordinates activation of the aviation obstruction light with the master light controller, and if a master light controller is not sensed, then the microcontroller sends activation signals as a master light controller.

Abstract: A device to enable automatic wireless communication with an aircraft after the aircraft has parked at a gate. A terminal cellular bridge (TCB) enables the retrieval of data from, and the sending of data to the aircraft by an internet service provider. The internet service provider uses the Internet to send data to and receive data from a remotely located network operation center and data warehousing center. The data warehousing center provides secure data storage and retrieval, and data processing. The network operations center provides for system control and monitoring.

Abstract: An aerially deployable position marking device includes an elongated housing, a handle secured to the housing, a ground engaging portion at or adjacent the lower end of the housing and at least one locating element which may take the form of visibility enhancing elements which are nonenergized, electrically energized, visibility enhancing devices or acoustic devices or energy releasing elements which release RF signals or other sources of energy as well as other types. Appropriate sources of energy and switch or switches may be provided.