Abstract: The present invention provides a radio navigation emulating GPS device. In one embodiment, the radio navigation emulating GPS device receives an identifier associated with a conventional radio navaid. The present radio navigation emulating GPS device then retrieves latitude and longitude information corresponding to the received conventional radio navaid from a database. A satellite based position information system generates position information for the aircraft on which the present radio navigation emulating GPS device is disposed. The present radio navigation emulating GPS device then generates navigation information for the aircraft using the retrieved latitude and longitude information and the satellite based position information for the aircraft. The present radio navigation emulating GPS device then presents the navigation information in a manner which emulates the presentation of navigation information generated by a conventional radio navigation device.

Abstract: A route guidance apparatus comprises a guiding device for, every time a turning point for which guidance is to be provided existing on a route for reaching a destination is approached, providing travel guidance for that turning point by at least a voice generated from a voice generating device. In particular, when the turning point for which guidance is to be provided is included in a traffic circle and the route turns from the traffic circle to an exit road toward an outer side thereof at the turning point, the guiding device provides travel guidance specifying how many ahead the exit road to be taken is among exit roads toward the outer side of the traffic circle. As a result, travel guidance with which a user can exit from the traffic circle through a correct exit.

Abstract: A technique for determining a gyro zero voltage is provided. A gyroscope ("gyro") is installed in an automobile as a component of an on-board navigation system. The gyro outputs a voltage representing an angular velocity of the vehicle. The gyro output voltage representing zero angular velocity ("gyro zero voltage") is determined by first determining when the vehicle is stationary based upon the amount of noise in the output voltage of the gyro. When the vehicle is determined to be stationary, the gyro zero voltage is measured.

Abstract: A navigational aid assists a person driving a vehicle in maintaining a desired distance from a reference line. It is particularly useful in navigating agricultural vehicles. The navigational aid includes an upright rail mounted adjacent a window in the cab of the vehicle. A marker is carried by the rail and may be positioned on the line of sight from the driver to the reference line. Driving the vehicle with the marker maintained on the line of sight keeps the vehicle at a constant distance from the reference line. The marker may be an element slidably mounted on the rail.

Abstract: A method and apparatus for maintaining the integrity of spacecraft based time and position using GPS (11) is disclosed. A GPS receiver is provided with a Receiver Autonomous Integrity Monitor (RAIM) processor (12) and a Kalman filter (14). GPS signals are received from at least four GPS satellites and processed in the GPS receiver to provide time and position information. Periodically, an extended fault vector is formed in the Kalman filter with propagated open-loop position and velocity measurements. The extended fault vector is used to isolate and remove failing GPS satellites.

Abstract: A system and method for generating a minimum-cost airline flight plan from a point of origin through a set of fix points to a destination point. A set of navigation airways from the point of origin to the destination point, including predefined fix points and vectors for high altitude flight, and a set of predetermined flight planning altitudes is stored in a database. Operational data for the flight and weather data for the flight is also stored in the database, as well as station data, station approach and departure procedures, predefined flight restricted areas, and flight performance data. The predefined fix points are transformed from the Cartesian plane onto a new coordinate system based on the great circle route between the origin and the destination. Each transformed fix point is assigned an ordinal value, and an acyclic network is constructed based on the ordinal values and within a feasible search region which excludes any flight restricted areas.

Abstract: A terrain awareness system (TAS) provides LOOK-AHEAD/LOOK-DOWN as well as LOOK-UP terrain advisory and warning indications to the pilot of an aircraft of a hazardous flight condition. The TAS includes an airport data base as well as a terrain data base that is structured to provide various resolutions depending on the topography of the particular geographic area of interest. Navigational data from a satellite-based navigational system, such as a global positioning system (GPS), is used to provide a LOOK-AHEAD/LOOK-DOWN and LOOK-UP terrain advisory and terrain warning indications based upon the current position and projected flight path of the aircraft. Since the terrain advisory and the warning signals are a function of the flight path of the aircraft, nuisance warnings are minimized.

Abstract: The invention is characterized in that the street and street number of a waypoint, or of a point nearest to the waypoint, is located and input by an input means whereby the desired street name and street number are entered and stored as the waypoint name. In case the street name of the waypoint, or of a point nearest to the waypoint, cannot be found, the name of facility nearest to the waypoint, or the longitude and latitude of the waypoint, is entered and stored as the waypoint name.

Abstract: A navigation apparatus provided with: a vertical movement detecting device for detecting a presence or absence of a movement in a vertical direction of a moveable body associated with the movement of the movable body; a judging device for judging a position in the vertical direction of the movable body on the basis of the presence or absence of the movement in the vertical direction detected by the detecting device; and a notifying device for notifying a present position of the movable body on the basis of the position in the vertical direction judged by the judging device.

Abstract: A device for assisting the piloting of a vehicle by instruments. Various indications are displayed on an aircraft head-up view finder including a horizontal line graduated in terms of heading, a perpendicular line graduated in terms of atitude, an aircraft symbol representing the direction of the longitudinal axis of the aircraft above the horizontal line and a velocity vector symbol representing the tracking slope followed by the aircraft with respect to the ground. These are determined with respect to the tracking and atitude scales. The guidance window whose position is references with respect to the same axis is also displayed. The pilot must control the aircraft as to bring the velocity vector into the guidance window and keep it there. The window is placed on the screen at a position which is computed by the computer and which corresponds to the direction of a point of the desired path of the aircraft, this point being at a predetermined distance ahead of the aircraft.

Abstract: A vehicular operation processing system has a memory card for storing coordinates of a plurality of check point sets, each of which is composed of a set of check points, and an ECU for, when determining that a vehicle has approached to any one of the check point sets based on the coordinate of a current vehicle position and the coordinate of the check point set, detecting a next check point based on a relation between each of check points contained in that check point set and a check point detected in the last time and performing associated processes such as a voice guidance and automatic sampling of operation record for that check point.

Abstract: The present invention relates to a enclosure for a control surface position transmitter used on aerospace vehicles. The enclosure has improved capability for protecting the components of the position transmitter from damage caused by moisture-induced corrosion. The enclosure is a can-shaped structure that includes separate compartments for its mechanical and electronic components. A series of channels and passageways allow air to circulate freely in and out of the mechanical component compartment, and the electronic component compartment includes a low power heater to keep the electronic components dry and moisture-free.

Abstract: The invention provides a system for passive measurement of atmospheric temperature using a passive direction detector for detecting the energy of a narrow wavelength band emanating from a volume of atmospheric gas. The resulting signal can be associated with an effective temperature. The effective temperature can be associated with an effective range. The system generates a temperature map which can determine, at predetermined time intervals, atmospheric temperatures in an azimuth plane associated with a predefined range from the detector. The temperature map can then be used to calculate temperature gradients that in turn can be used to compute the vertical wind vector difference and to determine the presence of clear air turbulence.

Abstract: An atmospheric water vapor sensing system uses Global Positioning Satellites (GPS) to determine the refractivity and Slant-path Water Vapor Delay (SWD) between an Earth-based GPS receiver and a plurality of satellite-based GPS transmitters. The system provides improved precision in position calculation measurements by eliminating the refractivity effects of water vapor. No other system inputs are required apart from conventional GPS satellite signals and conventional satellite orbit data to implement the method. SWD arises from the refractivity in the integrated atmospheric water vapor in a column of atmosphere at an acute angular line-of-sight path between the Earth-based GPS receiver and any one of the plurality of satellite-based GPS transmitters. The system is especially useful in monitoring the Earth's crustal deformation.

Abstract: An external storage device having navigation data and programs stored therein to perform a route search and provide route guidance, and a central processing unit which includes a program storage flash memory and program loading means for loading programs from the external storage device into the flash memory. The programs stored in the flash memory are run to perform a route search and provide route guidance. The central processing unit compares a version of each program stored in flash memory with a version of the program stored in external storage device, so that when the version of the program stored in the external storage device is more current than that stored in the flash memory, the program is loaded from the external storage device into the flash memory.

Abstract: A navigation apparatus reduces route search time while providing guidance in conformity with drivers' preferences, by selectively conducting either a full-range route search or a more limited, local area search, in accordance with detected conditions and responsive to occurrence of an off-route event. For example, the full-range route search is conducted pursuant to a determination that the vehicle has gone straight at a predetermined number of certain intersections where current guidance has directed a turn.

Abstract: A process for managing air speed of an aircraft in flight. The method includes a first step of determining a point on the flight path at which it is theoretically possible to comply with a required time constraint by following a pre-established speed profile. In a second step, a speed is computed and a fresh speed profile is determined. This is obtained by determining speed corrections segment-by-segment from the point up to the last modifiable segment. The speed change in each segment is restricted to a maximum value. The new speed is computed on the basis of the curve showing the flight time t as a function of the speed V. This curve is approximated by a curve satisfying an equation with three coefficients (C.sub.1, C.sub.2, C.sub.3):V=c.sub.1 /t+c.sub.2 /t.sup.2 +c.sub.3 /t.sup.3Compliance with time constraints are ensured by this method while meeting the requirements of the pilot and air traffic controllers.

Abstract: The invention relates to a vehicle location display for a navigation system. The vehicle location display operates in either a graphical display mode or a textual display mode. In the graphical display mode the vehicle location display automatically scales the display to display the current location of the vehicle on the street currently being traveled, the previous cross street, the next cross street, and other vehicle information. When traveling on a freeway, the graphical display mode displays the current location of the vehicle on the freeway being traveled, the previous cross street and the next cross street. In the textual display mode the vehicle location display provides the current vehicle location by street or freeway name, city, county, state, latitude and longitude coordinates. In addition, the current compass heading, the previous cross street and the next cross street are provided.

Abstract: An informational/positional guide, which is disposable in an aircraft instrumentation interface, used with at least one mechanical guide key configured to guide interface engagement, and the guide key having an orientation specific to a particular type of aircraft equipment configuration, the guide is provided with a key engagement member. The key engagement member is formed to engage the guide key and is disposable in a variety of angular orientations to facilitate engagement with the guide key. The key engagement member is further provided with an aircraft equipment configuration sensor for identifying the aircraft equipment configuration type in response to sensed orientation of the key engagement member and for generating an electronic signal in response to the identification of the orientation of the key engagement member.

Abstract: The detection of components that cause p-static interference with communications and navigation equipment is essential to the maintenance of an aircraft. A p-static source locator uses two leads to supply a voltage between components of the aircraft. If the components are not properly electrically bonded, a radio receiver detects the p-static interference created when sparking occurs between the inadequately bonded components. The p-static source locator may be implemented in a single hand-held unit that is simple to transport and use. Moreover, the locator uses low voltage potential differences for operator safety.

Abstract: A navigation system and method for diving operation in view of facilitating navigation under water to a specific location, in particular navigation back to a dive starting point, i.e., to the place from which the diving was started. The system includes a base station fixed to the starting point, such as a boat or equivalent, and arranged to transmit a signal to its environment, and a mobile unit carried along by the diver. The mobile unit includes a compass and a locating part which receives the signal transmitted by the base station. The locating part converts the signal to information on the return direction, and combines the information on the return direction with the magnetic information on the direction obtained from the compass, so that the information on the return direction from the position of the diver when the signal is received is maintained irrespective of the momentary location and position of the diver and the mobile unit.

Abstract: Processes and algorithms to determine and correct key error sources in an inertial navigator. These key error sources are azimuth misalignment error and all gyro drift rate errors ("North", "East" and "Down"). Thus the invention provides improved directional accuracy and improved navigation performance. The processes and algorithms can be implemented within the system computer to determine and correct for the system error sources thus determined automatically.

Abstract: The improved vehicle navigation system can take advantage of the recent availability of low cost micro-machined and piezoelectric sensors, and partially overcomes the low dynamics and line of sight limitations of GPS receivers without resorting to the hard wired approach described above. The low cost sensors introduce system level errors due to their inherent DC offset and drift rates. The improved vehicle navigation system minimizes both the sensor induced errors and GPS low dynamic limitations by using a zero motion detection system as a self contained (within the navigation system), vehicle independent device.

Abstract: A pseudo gyro emulates mechanical gyros by software processes by processing space system appendage measurement data and reaction wheel tachometer data within reference and control systems of a satellite using principals of conservation of momentum to compute the vehicular bus angular velocity rate data by accounting for the momentum transfer between the satellite, the bus, and the appendages for providing accurate relative vehicular position and angular velocity rate data as an integral part of attitude reference and control systems now having higher reliability, longer life times, lower power consumption, and more accurate vehicular angular velocity rate data generated within high bandwidth operations.

Abstract: A method of determining bad travel distances during traveling of a motor vehicle having a fuel tank, includes the steps of providing a differential pressure sensor at the fuel tank, determining by the differential pressure sensor a filling level of the fuel tank and producing a filling level pressure signal, determining by the differential pressure sensor a gas pressure inside the fuel tank and producing a gas pressure signal, and determining a bad travel distance by evaluating fluctuations in at least one of the pressure signals.

Abstract: The invention provides a system for passive measurement of atmospheric temperature using a passive direction detector for detecting the energy of a narrow wavelength band emanating from a volume of atmospheric gas. The resulting signal can be associated with an effective temperature. The effective temperature can be associated with an effective range. The system generates a temperature map which can determine, at predetermined time intervals, atmospheric temperatures in an azimuth plane associated with a predefined range from the detector. The temperature map can then be used to calculate temperature gradients that in turn can be used to compute the vertical wind vector difference and to determine the presence of clear air turbulence.

Abstract: A method and apparatus for measuring the lift generated by airfoils of an aircraft. This real-time analysis is accomplished by measuring a differential pressure between the upper and lower lift surfaces of the airfoils. The system comprises the steps of: a) measuring an actual differential pressure between the upper and lower lift surfaces for a given aircraft speed, b) transmitting this actual differential pressure measurement to a computer, c) comparing the actual differential pressure measurement with an optimal pressure differential for the same aircraft speed. The apparatus comprises a fixed array of differential pressure sensor mechanisms for measuring actual pressure differentials and a computer for comparing optimal differential pressure measurements to the actual differential pressure measurements. Each sensor mechanism preferably contains a piezoelectric sensor that communicates with the upper and lower lift surfaces.

Abstract: A navigation apparatus which can preferentially recognize important information on a map hidden by buildings, mountains, etc. Which were stereoscopically displayed and enables a set route or a present position of a vehicle to be easily recognized. A navigation apparatus has: a recording medium on which at least map data having a road and shape data which is included in the map data and serves as a main landmark object to recognize a feature of a map have been recorded; an image forming unit for forming image information when the map data is seen from a desired sight point position on the basis of the map data and the shape data; a display unit for displaying on the basis of the image information formed by the image forming unit; and a control unit for controlling the recording medium, image forming unit, and display unit.

Abstract: A system and method for determining the angular orientation of a body moving in object space. The invention is usable to detect and identify the angular orientation of the body relative to the theoretical plane of gravity and thereby relative to any other theoretical plane between zero and three-hundred sixty degrees therefrom. The invention is operable regardless of whether the body is rotating with an angular velocity, either natural and/or induced. The invention may employ one or more analog and/or digital sensors. The analog sensor may be an accelerometer. The system may be used to provide real-time orientation data to permit the body to be guided or directed towards a desired destination or simply to permit the orientation of the body to be known, controlled or varied as desired.

Abstract: The improved vehicle navigation system and method uses information from a Global Positioning System (GPS) to obtain velocity vectors, which include speed and heading components, for propagating or "dead reckoning" the vehicle position from a previous position to a current position. The improved vehicle navigation system has a GPS receiver which provides the GPS velocity information which is calculated from a full set of GPS delta range measurements. GPS position data alone is not accurate enough for certain applications, such as turn-by-turn route guidance in automobile applications, because its error may be 100 m and there is considerable position drift, even when stationary. GPS velocities are much more accurate than the position data, 1 m/s or thereabouts, and can be used to propagate a known position forward and be more accurate over time than the GPS position solution. These velocities are instantaneous and not those computed from differencing two positions.

Abstract: The invention provides a system for passive measurement of atmospheric temperature using a passive direction detector for detecting the energy of a narrow wavelength band emanating from a volume of atmospheric gas. The resulting signal can be associated with an effective temperature. The effective temperature can be associated with an effective range. The system generates a temperature map which can determine, at predetermined time intervals, atmospheric temperatures in an azimuth plane associated with a predefined range from the detector. The temperature map can then be used to calculate temperature gradients that in turn can be used to compute the average Richardson number over an atmospheric layer and other atmospheric conditions to predict the presence of clear air turbulence.

Abstract: A navigation apparatus displays a map so as to support a travel of a movable body.

Abstract: This invention concerns improvements to gravity gradient instruments (GGI) and in particular to the accelerometers that are paired within these instruments. Accelerometers have a proof mass suspended by a spring within a magnetic field. An internal feedback loop provides a signal related to movement of the proof mass back through a reaction coil retaining the proof mass in the magnetic field, to maintain the proof mass stationary. An external feedback loop adjusts the accelerometer scale factor. The internal feedback loop provides second order compensation to the proof mass and the spring stiffness. In a further aspect the invention is a method of matching accelerometer pairs.

Abstract: Gravitation in three dimensions is measured using an accelerometer attached to a carrier, a satellite navigation receiver and a computer. The satellite navigation receiver determines a position and attitude, and changes in the position and attitude over time. The computer calculates complete kinematics in inertial space from the timely changes of the determined position and attitude and calculates the gravitation by subtracting the kinematic acceleration from the one observed by the accelerometer. In a preferred embodiment the accelerometer is connected tightly to the carrier. At most, damping elements may be mounted between the accelerometer and the carrier. The accelerometer can be a single accelerometer or a triplet of non-parallel accelerometers. The satellite navigation receiver may be one instrument equipped with three or more antennae or a set of three or more single instruments connected to each other.

Abstract: A method and apparatus for automatic event detection and processing is provided. A positioning system receiver includes a position measurement device and a logging device. The position measurement device is configured to receive and process signals from a positioning system. The logging device is coupled to the position measurement device for recording data received from the position measurement device. The logging device records the data at a current logging rate. The positioning system receiver detects an event via an external sensor or with reference to satellite data, for example. In response to the event, the logging device automatically modifies data logging processing such as the current logging rate. Additionally, to allow a post processing system to go backwards in time relative to the event, the current logging rate may be increased for a predetermined amount of time preceding the occurrence of the event.

Abstract: Route guidance for vehicle navigation in which a destination in a category of places is searched for and guidance along a suitable guide route to the destination is performed. If the user's original purpose cannot be achieved even after reaching the destination, another destination in the same category of places is automatically searched for and guidance to the new destination is performed along a suitable guide route. If e.g. the category is convenience stores, then convenience stores within a certain range of the user's vehicle position are searched to find the nearest destination. A guide route to the destination is found (excluding congested roads or roads under traffic control on the basis of road traffic information obtained e.g. from ATIS).

Abstract: An apparatus and method for tracking a vehicle is provided. The vehicle tracking system may include an inertial measurement unit for providing inertial vehicle state characteristics of the vehicle. The inertial measurement unit may include at least one gyro and at least one accelerometer. The vehicle tracking system additionally includes an inertial converter for generating vehicle state information from the inertial vehicle state characteristics. Clinometers are utilized within the vehicle tracking system to initialize the gyros and may additionally provide acceleration information. The vehicle tracking system may additionally include one or more redundant sensors for providing redundant state information. The redundant sensors can include an odometer/tachometer, Global Positioning System receiver, tag receiver, and a map matching system. A Kalman filter may be utilized to reduce error within the vehicle tracking system and improve the accuracy thereof.

Abstract: An optimum route searching device 5 conducts a search in a predetermined area on road network data on a lower hierarchical level to obtain minimum arrival costs to individual nodes in the search area and then selects a node located on an upper hierarchical level existing in from the search area. Then the optimum route searching device 5 obtains a remaining cost to a node common with the upper hierarchical level which first appears on the upper hierarchical level existing link. Then the optimum route searching device 5 obtains a minimum arrival cost from the starting point of the search to the common node on the basis of the minimum arrival cost to the selected node and the remaining cost to the common node. The minimum arrival cost to the common node obtained at this time is used as initial conditions for a route search performed on the road network data on the upper hierarchical level.

Abstract: An arrangement of a speed sensor on a personal watercraft better shields the sensor from damage while simplifying the layout and arrangement of the sensor on the underside of the watercraft hull. The hull includes a pump chamber formed in part by a front wall. The speed sensor is attached to the wall with a portion of the sensor projecting below a housing of the sensor. A ride plate covers a lower opening of the pump chamber and fits about the sensor housing. In this location, the speed sensor does not interfere with the arrangement or operation of steering or trim mechanisms used with a jet propulsion unit housed within the pump chamber. The speed sensor also is generally protected in this location and is not visible from the rear of the watercraft to improve the watercraft's aesthetics.

Abstract: A navigation apparatus includes a guide unit (4) to extract a guide target intersection located on a path and to which a driver should be guided depending upon map data stored in a map information storage unit (1) and the path set by a path setting unit (2), and detect a distance between the two adjacent guide target intersections so as to concurrently provide guides about the two guide target intersections together with a relationship therebetween when the distance is within a specified value, or a guide unit (55) to extract an intersection between the extracted guide target intersection and a current position detected by a current position detecting unit (3) so as to display the intersection concurrently with the guide target intersection.

Abstract: Three rate gyros are mounted to a ballistic body to provide an autonomous navigation system. A roll gyro, a yaw gyro and a pitch gyro are rigidly fixed to the ballistic body. Each gyro is arranged to be responsive to a roll rate about an input axis that is substantially orthogonal to any other gyro. The roll-rate gyro has its input axis aligned parallel to the body spin axis. An on-board processor utilizes recursive Kalman-filtering to determine the roll angle, i.e., the local vertical direction, from the gyro outputs.

Abstract: Signals exchanged between a fixed infrastructure (110-116) and a mobile unit (160) give rise to M channel quality metrics. The channel quality metrics are mapped, via predetermined relationships (501-503), in to M corresponding time of arrival variances, which in turn are used to derive M-1 time of arrival differential variances. A time of arrival differential weighting matrix including, in part, the time of arrival differential variances, is used to calculate a WLS solution, which solution is an estimate of a location of the mobile unit. This procedure may be implemented using an infrastructure-based location processor (130) operating in conjunction with the mobile unit, or may be performed by either the location processor or mobile unit alone.

Abstract: A map display apparatus according to the present invention has a display device capable of displaying a road map in different map forms in a base screen region and a window screen region. A control circuit determines whether the window screen is provided or not on the basis of input information entered through an input device, and determines which one of a planimetric map and a bird's-eye view is displayed in the base screen and the window screen. Either of the planimetric map and the bird's-eye view are displayed using road map data as a common map data base stored in a map storage memory, which eventually reduces the cost of the apparatus. When the window screen is displayed, a range of the road map including at least a range of the road map displayed in the base screen is displayed in the window screen, and an indication representing the range of the road map displayed in the base screen is displayed in the window screen.

Abstract: A navigation system permits the user to designate certain roads or areas to avoid when planning a route. The navigation system generally includes a database of road segments and a cost associated with the road segments, such as estimated time of travel across that road segment and estimated length of travel across that road segment. The navigation system determines a route from a selected beginning point to a desired destination by evaluating the cost of the road segments to be traveled in several potential routes and recommends the potential route having the lowest total cost. The user can selectively modify the cost of selected road segments to indicate a preference or avoidance of such roads. By increasing the cost of a road segment, the navigation system is less likely to recommend a potential route which includes that road segment. Similarly, by decreasing the cost of a selected road segment, the navigation system is more likely to recommend a potential route which includes that road segment.

Abstract: An instrumented device for the study of airflow over a structure (10), comprises a support (16) forming a thin plate (24) adapted to be applied and shaped to the contour of a predetermined region of the structure. Connection structure (22) cements a portion of an inner surface of the support to that predetermined region, leaving a space (36) of low height between an inner surface of the plate (24) of the support and that predetermined region. This height is substantially equal to the thickness of said cementing structure. Instrumentation (18) is connected to the support, a portion (28) of this instrumentation and wire connections (20) therefor being disposed in that space (36), whereby the device is adapted to form a skin on the structure.

Abstract: The improved vehicle navigation system and method uses information from a Global Positioning System (GPS) to obtain velocity vectors, which include speed and heading components, for "dead reckoning" the vehicle position from a previous position. If information from the GPS is not available, then the improved vehicle navigation system uses information from an orthogonal axes accelerometer, such as two or three orthogonally positioned accelerometers, to propagate vehicle position. Because the GPS information should almost always be available, the improved vehicle navigation system relies less on its accelerometers, thereby allowing the use of less expensive accelerometers. The improved vehicle navigation system retains the accuracy of the accelerometers by repeatedly calibrating them with the velocity data obtained from the GPS information. The improved vehicle navigation system calibrates the sensors whenever GPS data is available (for example, once a second at relatively high speeds).

Abstract: Center lines, i.e., precise road network information may be extracted relative to road margin information in a large-scale map based on teaching road network information (first configuration). Then, center lines, i.e., detailed road network information may be extracted relative to narrow road margin segments whose respective road plane sides have not defined yet, on the basis of road margin segments whose respective road plane sides have already been defined (second configuration). Then, finished road network information may be extracted by correcting road network information derived from the second configuration (third configuration).

Abstract: A centimeter level survey system includes reference base station and rover GPS units connected by a radio data link. Each includes recorders for the storage of raw measurement information including range, phase, cycle counts and time information. The rover unit is typically moved to points of interest during a survey while the base remains over a fixed, and known location. Generally, the base antenna is located to optimize a clear view of the sky. The rover is subject to interruption of the radio data link from the primary reference station. During periods that the rover is initialized and in contact with the primary reference station base station over the radio data link, the rover provides real time centimeter level position solutions to a survey user, otherwise, the rover records its raw measurements in a file that begins with the last valid initialization information and that ends with any newly reestablished initialization information.

Abstract: In accordance with the disclosed method, an attitude determining device which is installed onboard a mobile craft, like an aircraft, for example, at an unknown orientation with respect to the reference coordinate system of the craft senses its installation orientation with respect to an earth frame coordinate system when the craft is at rest to obtain a static orientation measurement thereof. Thereafter, an attitude of the mobile craft with respect to the earth frame is measured with the attitude determining device and such measurement is compensated with the static orientation measurement to obtain attitude information of the craft's reference coordinate system with respect to the earth frame coordinate system. The installation orientation of the attitude determining device may be sensed while the craft is at rest in either a leveled or unleveled condition.

Abstract: A three-axis attitude orientation system for a spacecraft is described. The single sensor provides roll and pitch information by locating the centroid of the earth and using this as a reference point. The system determines yaw by tracking the position of stars which appear in the field of view around the earth. Three-axis attitude is determined through ultraviolet imaging of the earth's limb and adjacent stars. A diffractive optics sensor and intensified CCD array are utilized for this purpose.