Communications: directive radio wave systems and devices (e.g. – Aircraft landing system
Reexamination Certificate
1998-08-27
2001-01-30
Sotomayor, John B. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Aircraft landing system
C342S034000, C342S035000, C342S036000, C342S055000, C342S078000
Reexamination Certificate
active
06181271
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a target locating system and an approach guidance system which can be used to exactly guide a flying object to a narrow landing space, for example, in bad weather.
Systems for performing exact target locating include, for example, a radar system and an optical sensor such as a stereo-camera. These systems, however, have the following problems.
The optical sensor has high precision in target locating, but a distance for locating tends to be greatly shortened due to weather, e.g. rain or fog.
On the other hand, the radar system can perform target locating without great influence by weather. However, when target locating is performed with use of a radar system having a low frequency band, a large-sized antenna needs to be used in order to increase angular resolution, because of low frequencies used. In addition, in order to attain a good distance resolution, a method of decreasing a transmission pulse width or a frequency modulation transmission method such as chirp modulation needs to be used. In either method, however, it is necessary to increase the frequency band width. If the frequencies employed are low, it becomes difficult to maintain the frequency band width.
As stated above, the conventional target locating systems are inevitably influenced by weather and can hardly perform exact target locating.
A conical tracking radar system, for example, may be used as target locating system. An antenna apparatus used in the conical tracking radar system comprises a primary horn for radiating an antenna beam and a reflector, situated opposite to the radiation face of the primary horn, for reflecting the antenna beam and emitting it to the outside. The antenna beam radiated by the primary horn is rotated about the antenna visual line and scanned conically. In this case, the antenna apparatus is rotated, with the primary horn being angularly offset from the antenna visual line.
The primary horn of the antenna apparatus is provided with a rotary drive mechanism. This drive mechanism becomes an obstruction to block the antenna beam reflected from the reflector, resulting in a decrease in antenna efficiency.
Moreover, a structure such as a rotary joint for rotating the primary horn needs to be provided midway along a feed line. The use of the rotary joint causes mixing of noise in the antenna beam, variation in amplitude and phase, etc., thus considerably degrading the quality of the antenna beam. These drawbacks become conspicuous as the frequencies used become higher. Furthermore, if that portion of the feed line serving as electric wave propagation path, at which the rotary joint is provided, is mechanically rotated, the feed line, for example, may be broken. Thus, the reliability of the feed line itself, that is, the reliability of the system, may deteriorate.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a target locating system and an approach guidance system capable of preventing the distance for locating from greatly decreasing due to weather, etc. and performing exact target locating in the vicinity of a landing point.
Another object of the invention is to provide a conical scan type antenna system capable of preventing the antenna efficiency and antenna beam quality from greatly decreasing, thus enhancing the reliability of the system.
According to an aspect of the invention, there is provided a target locating system comprising:
a milli-wave radar system for obtaining first target position information of a flying object being about to land, by capturing and tracking the flying object from a maximum detection distance;
a stereo-camera system for taking over the tracking of the flying object in the vicinity of a landing point by acquiring the first target position information of the flying object from the milli-wave radar system, and obtaining second target position information having higher precision than the first target position information; and
a controller for managing the first target position information of the milli-wave radar system and the second target position information of the stereo-camera system, controlling the milli-wave radar system to capture and track the flying object to the vicinity of the landing point, and controlling the stereo-camera system to capture and track the flying object at the time of landing of the flying object.
With the above structure, the flying object being about to land is captured and tracked by the milli-wave radar system, which is less susceptible to weather, etc., in a range between a maximum detection distance of the milli-wave radar system and the vicinity of the landing point, and the flying object is, in turn, captured and tracked by the stereo-camera system with high locating precision at the landing point.
Thus, the locating distance for the flying object being about to land is less decreased due to weather, etc., and exact target locating can be carried out in the vicinity of the landing point.
According to another aspect of the invention, there is provided an approach guidance system comprising:
a target locating system including a milli-wave radar system for obtaining first target position information of a flying object being about to land, by capturing and tracking the flying object from a maximum detection distance, a stereo-camera system for taking over the tracking of the flying object in the vicinity of a landing point by acquiring the first target position information of the flying object from the milli-wave radar system, and obtaining second target position information having higher precision than the first target position information, and a controller for managing the first target position information of the milli-wave radar system and the second target position information of the stereo-camera system, controlling the milli-wave radar system to capture and track the flying object to the vicinity of the landing point, and controlling the stereo-camera system to capture and track the flying object at the time of landing of the flying object; and
a control apparatus for guiding the flying object which is a target to the vicinity of the landing point on the basis of the first target position information output from the milli-wave radar system of the target locating system, and guiding the flying object to the landing point on the basis of the second target position information output from the stereo-camera system of the target locating system.
With this structure, the target position information of the flying object obtained by the milli-wave radar system and the target position information of the flying object obtained by the stereo-camera system is transmitted to the control apparatus. Thus, the control apparatus guides the flying object to the vicinity of the landing point, using the target position information from the milli-wave radar system which is less susceptible to weather, etc. In the vicinity of the landing point, the control apparatus guides the flying object to the landing point, using the target position information from the stereo-camera system with high location precision.
Accordingly, the flying object can be exactly guided to the landing point, without influence of weather, etc.
According to still another aspect of the invention, there is provided a conical scan type antenna system connected to a transmission/reception system and comprising a primary radiator for transmitting and receiving an antenna beam and a reflector, situated opposite to a radiation surface of the antenna beam of the primary radiator, for reflecting the antenna beam,
wherein the reflector is angularly offset from an antenna visual line to incline the antenna beam, and the reflector is rotated about the antenna visual line to conically scan the antenna beam.
In the above structure, it is preferable that the feed line from the transmission/reception system to the primary radiator does not pass through the rotary mechanism for the reflector.
According to the above structure, the reflector is rotated to conically scan the antenna beam, and
Chiba Masaaki
Hosaka Naoki
Kabushiki Kaisha Toshiba
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Sotomayor John B.
LandOfFree
Target locating system and approach guidance 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 Target locating system and approach guidance system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Target locating system and approach guidance system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2522180