Communications: directive radio wave systems and devices (e.g. – Return signal controls radar system – Receiver
Reexamination Certificate
2003-06-03
2004-06-15
Tarcza, Thomas H. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Return signal controls radar system
Receiver
C342S095000
Reexamination Certificate
active
06750806
ABSTRACT:
CROSS REFERENCE TO PRIOR APPLICATION
Applicant hereby claims foreign priority under 35 U.S.C. § 119 from Swiss Patent Application No. 2002 1001/02 filed 12 Jun. 2002, the disclosure of which is herein incorporated by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a method of tracking a target and a target tracking system.
The present invention is particularly, but not exclusively, implemented in the context of tracking flying targets which are to be combated.
Typically, a search sensor and a tracking sensor are used for this purpose. The search sensor, which covers a search space, is particularly intended for the purpose of searching its search space for a target located therein and determining target information in this way, which describes at least the movement of the target and/or the track of the target in the past. The target information typically includes further data about the target, particularly about the type of target. In general, it is expedient to design the search sensor in such a way that it may be active using a large range and in a wide angular region, i.e., in a broad search space, and may provide detailed target information. Search sensors typically operate using relatively low search clock rates. Extrapolative flight path data is then established from the data determined by the search sensor, which describes the expected movement of the target in the future. This flight path data is essentially used for the purpose of performing a coarse alignment of the tracking sensor. The tracking sensor is frequently designed so that it covers a tracking space which is more restricted than the search space of the search sensor. After taking over the target from the search sensor, the tracking sensor must search for the target again in a starting phase of its activity before it may detect the target, align itself to the target, and track the target.
The main disadvantage of this typical method is that the target is not taken over by the tracking sensor without problems. The problems are particularly severe in this case if the tracking sensor has worse vision properties and/or a significantly smaller field of view and/or a different range than the search sensor. A further disadvantage is that the search clock rate of the sensor, which at least partially determines the method sequence, and which is used to provide the target aircraft data for the tracking sensor, is relatively low, but the search clock rate may not be increased at an acceptable cost.
A method and a system for a fire-control system of a manually aimable weapon are known from U.S. Pat. No. 5,379,676. In this case, a sensor system is provided, having a radar device and an electro-optical recognition system in the form of an FLIR camera. This method and this system are relatively complex in their construction, but the results achieved therewith are still not satisfactory.
SUMMARY OF THE INVENTION
It is therefore the object of the present invention,
to suggest an improved method of the type initially cited; and
to provide a target tracking system for performing this method, using which the disadvantages of the related art are avoided.
The novel method runs as follows: The search sensor searches its search space for a target, as in the typical method. In this case, the search space is searched at a first clock rate and/or search clock rate in multiple search passes. The search clock rate does not have to be precisely constant for this purpose. The search sensor determines an image sequence from each viewing angle, the time interval of the images of an image sequence being determined by the first clock rate and/or search clock rate. Digital images are also to be understood as images in this context. For rotating sensors, the first clock rate and/or search clock rate generally corresponds to the number of search sensor rotations per unit of time. If a target is located in the search space, the search sensor establishes target information at its search clock rate during multiple sequential search passes and/or search sensor rotations. The target information describes, possibly using interpolations, the track which the target has already flown through. The target information may also contain further details about the target, for example, information about the target type or results of a friend/foe query, through which targets detected are classified as objects to be combated, i.e., actual targets, or as friendly aircraft. With knowledge of the target information of multiple search passes, but possibly only using the target information relating to enemy targets, an expected flight path and/or flight path data, which describe the flight path the target is expected to take in the future, are provided through extrapolation. Instead of taking over the target directly, as in the typical method, searching for the target from the beginning once again at this time, and tracking it autonomously, in the novel method, the tracking sensor does not track the sensor autonomously, but externally controlled. The external control is performed on the basis of the flight path data provided to the tracking sensor at a second clock rate, which is higher than the first clock rate and/or search clock rate. During the transition phase, the externally controlled tracking sensor is aimed at the expected flight path, even if the target is in the tracking space, but may not be sensed by the tracking sensor. As soon as the target may be sensed, it is detected by the tracking sensor, through which the transition phase and/or the external control of the tracking sensor is ended. From now on, the tracking sensor is tracked on the target autonomously and/or tracks the target autonomously. During the transition phase, the target may not be directly sensed by the tracking sensor, but the tracking sensor nonetheless tracks the target in a way which may be referred to as “blind”, at least approximately in the scope of the possible precision, which is determined by extrapolation, among other things. Searching for the target again, this time by the tracking sensor, is not necessary. In the moment in which it may directly sense the target, the tracking sensor is already aimed at the target. In practice, a target point, which the tracking sensor is aimed at, and the target point surroundings are shown with the aid of a display unit (in the form of a monitor, for example), an arrangement in which the target point occupies the center of the monitor typically being selected. In the novel method, when the target may be sensed directly by the tracking sensor, it appears in direct proximity to the target point (or within a gate which is displayed on the monitor); the target would appear exactly around the target point if the actual flight path was coincident with the extrapolated flight path and no other uncompensated errors were noticeable. For transmission within the system of the data used in connection with the novel method, the target tracking system also has the typical suitable transmission means. In addition, it is also to be noted that the particular data is, of course, also updated continuously or in a clocked way, taking the particular newest target information into consideration.
The advantages achieved using the present invention are essentially as follows: an operator at the tracking sensor must neither perform manual search movements nor initiate automatic search movements as long as no target appears on the monitor of the tracking sensor; reasons that no target appears could be as follows: the target is not yet in the tracking space and/or is too small; the target is in the tracking space, but the view of the target is covered or not recognizable due to atmospheric absorption. At latest when the target reaches the tracking space, the tracking sensor acts, with the aid of the external control, as it would if it was able to detect the target, although it is “target-blind”; the tracking sensor may possibly also be aimed at the target and/or the suspected flight path before the target reaches the tracking space. In any case,
Andrea Brian
Oerlikon Contraves AG
Tarcza Thomas H.
LandOfFree
Method of tracking a target and target tracking system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of tracking a target and target tracking system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of tracking a target and target tracking system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3311308