Telefonaktiebolaget Lm Ericsson (publ)

Ab Volvo

Sten H Ahlbom

Bengt Lennart Andersson

Ragner Arvidsson

Martin Henning Heed

The present invention relates to methods and to arrangements for monitoring an object which emits a rotating or oscillating beam whose angular velocity is unknown. The time points at which the beam passes a predetermined number of measuring positions are determined. An angular velocity start value is generated and a predetermined number of object position determinations (at least two independent determinations) are made on the basis of the determined time points, the measuring positions and the start value. It is determined whether or not the position determinations can be considered to be sufficiently in agreement with one another. When agreement is considered sufficient, the start value is accepted as an approximate value, this value approximating the angular velocity of the beam with an acceptable degree of accuracy. If the position determinations are not found to be sufficiently in agreement, the start value is modified and new position determinations are made. This procedure is repeated as often as is required for the position determinations to become sufficiently in agreement with one another, wherewith the start value is accepted as a approximate value of the angular velocity. Subsequent to having obtained the approximate value of the angular velocity, a final position determination of the object can be made.

Method and arrangement for monitoring objects

A method and a system for determining an altitude of an object of interest, for example, an airplane that transmits electromagnetic radiation in the form of radar signals. A number of sub-units that can detect the radar signals are spread out in an area, preferably in a large geographical area, where the radar signals of the airplane/object it is possible to detect. The sub-units communicate to the information center when they are able to detect the radar signals. The information center determines the altitude of the airplane based on the airplanes line of sight, i.e., its radar horizon, and thus which sub-units can detect the radar signals.

System and method for measurement

A system for surveillance of, and taking measures in respect of, phenomena that are observable. The system includes at least one information center with associated cells that can be divided into one or more groups. The system also includes means for communication between an information center and each cell. Each cell includes at least one sensor, with which chemical or physical measuring methods can be used to observe the phenomenon or detect the signals which the phenomenon generates. This system further includes at least three cells that are distributed geographically in the area of interest in a sufficiently dense net. In the cells the signals can be used for determining for example the time, place, intensity or the type of the phenomenon. Data can be transferred from the cells to their respective information center for processing. Activities can be initiated and carried out by equipment inside or outside the cells in accordance with rules in the cells, and these activities can be started as a response to the detected signals.

System for surveillance

System for determining the position of radar transmitters where the system includes at least one information center with associated cells and means of communication between the information center and the cells with a restricted transfer rate utilising existing infrastructure in the country, such as for example a national telephone network and also mobile telephone networks and their base stations. Each cell includes at least one sensor in order to be able to detect radar signals. Leading edges of pulses in the radar signals are detected and time-marked after which they are sorted according to PRI (Pulse Repetition Interval). The time of arrival for the first pulse in a pulse train is calculated and data reduced by modulo calculation to a value that as a maximum is the propagation time difference for pulses between two cells in a pair of cells/sensors that are used together for calculating the bearing. Bearings calculated from at least two pairs of cells are correlated in the information center which thereafter calculates the position of the radar transmitter.

System for direction determination

A self-pivoting vehicle with steering wheel(s) and driving wheel(s), possibly combined, a drive motor and a steering means for pivoting said steering wheel(s). At least one measuring wheel rolls freely against the floor under the vehicle, or two such wheels are journalled at different points on the vehicle for measuring off distances rolled. A computing unit and steering mechanism pivot said steering wheel. The computing unit receives measured values from the measuring wheel(s) for computing the deviation of the vehicle by dead reckoning from a predetermined desired trajectory for the vehicle, and gives off a steering angle signal for deviation correction to the steering mechanism.

Self-piloting vehicle

In a wheeled vehicle steered by dead reckoning, which calculates its own position on the basis of distances determined by rolling-off measurement, the error in position determination will increase gradually and necessitate updating. A floor is provided with markings which are observed by a linear detector mounted transversely in the vehicle, and linear images are obtained. At least two different measurements are carried out of the position of a marking in relation to the vehicle, and the distance travelled by the vehicle between the measurements is measured. From these three measured distances, the angle between the vehicle and the marking can be determined. An additional marking forming an angle with the first marking makes it possible to determine the position in the direction of movement of the vehicle as well.

Method for updating in a wheeled vehicle steered by dead reckoning

In steering a wheeled vehicle along a path marked on the supporting surface, a single linear detector is used which is rigidly mounted in the vehicle perpendicular to the principal direction of movement of the vehicle. As the vehicle moves, the position of the path in the transverse field of view of the detector is measured repeatedly, in the form of lateral deviations .DELTA.x, simultaneously with the distances s.sub.1, s.sub.2 . . . in the direction of movement between successive lateral deviation measurements. The deviation between the direction of the path marked and the path actually travelled by the vehicle is thus obtained, in the form of a lateral deviation .DELTA.x, and an attitude deviation .phi.=(.DELTA.x.sub.2 -.DELTA.x.sub.1)/s.sub.1. These two deviation variables will make possible corrective steering of the vehicle to the marked path.

Device for steering a steerable wheeled vehicle

A device for orienting a movable object such as a lifting fork truck in a certain position relative to a second object such as a load, the device having light-emitting device for illuminating the second object so that an image with lighter and darker fields is created thereon, a photoelectric detector movable together with the movable object to scan the image, electronic control equipment connected to the detector for receiving signals therefrom, and operating equipmenT for the movable object, connected to the control equipment to receive signals therefrom and to orient the movable object, dependent on the signals of the photoelectric detector, to the control equipment.

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Vastra Frolunda, Sweden

Sten H Ahlbom