Aeronautics and astronautics – Missile stabilization or trajectory control – Automatic guidance
Reexamination Certificate
1998-11-12
2001-02-27
Gregory, Bernarr E. (Department: 3662)
Aeronautics and astronautics
Missile stabilization or trajectory control
Automatic guidance
C244S003150, C244S075100, C244S11700R, C244S119000, C244S121000, C244S129100, C244S129300, C342S061000, C342S063000
Reexamination Certificate
active
06193188
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to sensors used in flight vehicles, and, more particularly, to a pointing mechanism for sensors used with conformal windows.
Optical sensors are used in aircraft and missile applications to receive radiated energy from a scene and convert it to an electrical signal. The electrical signal is provided to a display or further processed for pattern recognition or the like. The optical sensor and its related optical train, termed a sensor system, are usually packaged in an elongated housing. The sensor may be pivotably mounted within the airframe to allow the optical sensor to be pointed toward subjects of interest.
The sensor system is rather fragile and is easily damaged by dirt, erosion, chemicals, or high air velocity. The sensor system is therefore placed behind a window through which the sensor views the scene and which protects the sensor system from such external agents. The window must be transparent to the radiation of the operating wavelength of the sensor, resist attack from the external forces, and minimally distort the image received by the sensor. The window must also permit the sensor to view the scene over the specified field of regard, which is the specified angular extent over which the sensor must be able to view the scene.
For many applications such as low-speed aircraft and helicopters, the window may be spherical in shape, with the sensor pivot point placed at the center of the sphere to minimize line-of-sight-dependent distortion of the image. However, in higher speed aircraft and missiles the spherical window is unsatisfactory, as it induces a great deal of aerodynamic drag that reduces the maximum speed and range of the vehicle. An elongated, relatively narrow window, termed a conformal window, is therefore preferred for use in high-speed applications to reduce the aerodynamic drag.
The elongated telescope of the sensor system may easily fit within the elongated conformal window when the line of sight of the sensor system lies parallel or nearly parallel to the direction of elongation of the conformal window. If the telescope is pivoted so that the line of sight points at a greater angle to the direction of elongation of the conformal window, the telescope of the sensor system may contact against the inside surface of the window and prevent further movement. One design approach to increasing the allowable pointing angle is to make the elongated telescope of the sensor system and its optics smaller in diameter, but this design variation reduces the aperture size and thence the energy-gathering capability of the sensor system.
There is a need for an improved approach to sensor systems used with conformal windows, which allows the sensor system to be pointed to large line-of-sight pointing angles within the spatial envelope of a conformal window. The present invention fulfills this need, and further provides related advantages.
SUMMARY OF THE INVENTION
The present invention provides a flight vehicle, either a manned vehicle or an unmanned missile, with a sensor system protected by a window such as a conformal window. A pointing mechanism points the sensor system to a desired line-of-sight angle. The pointing mechanism of the invention allows the sensor system to be pivoted to large line-of-sight pointing angles within the available spatial envelope of the conformal window than possible with prior pointing mechanisms. Little weight is added to the structure with the present pointing mechanism, and the size of the optical aperture of the sensor system need not be reduced. Large-aperture sensor systems may therefore be used with conformal windows and pointed to large line-of-sight pointing angles to provide the sensor system with a high field of regard.
In accordance with the invention, a flight vehicle such as a high-speed missile comprises an airframe, a window mounted to the airframe, a sensor system with a field of regard through the window, and a sensor system pointing mechanism supported on the airframe. The sensor system pointing mechanism includes a gimbal structure upon which the sensor system is supported and having at least one rotational degree of movement, and a translational mechanism operable to linearly translate the sensor system in a controllable manner.
In a preferred application, the window is a forward-facing, generally conical or ogival, elongated conformal window that narrows to a closed, pointed forward end and has a relatively large rear end that attaches to the airframe. When the sensor system is pointed forward with a zero or small line-of-sight pointing angle relative to the axis of elongation of the conformal window, the sensor system is positioned as far forwardly as it can reach without contacting the closed end of the window. As the sensor system is pivoted to increasing line-of-sight pointing angles, the sensor system is linearly translated rearwardly into the relatively larger-diameter portion of the conformal window, so that there is more room to accomplish the pivoting to a large angular deviation from the axis of elongation of the conformal window.
Any operable mechanical device may be used to provide the combination of rotational and linear movements. Preferably, the pointing mechanism comprises a slider-crank-type mechanism. There is a pin support on one part of the sensor system and the translational mechanism, and a slot on the other part of the sensor system and the translational mechanism, with the pin support being engaged to the slot. A pivoting drive link extends between the sensor system and the translational mechanism at a position remote from the engagement of the pin support and the slot, whereby rotation of the drive link rotates the sensor system relative to the translational mechanism and also linearly translates the pin support in the slot. The dimensions and linkage lengths of the pointing mechanism may be selected as necessary for various sizes and shapes of the sensor system and the window.
A single motor is operably connected to the pivoting drive link to cause it to rotate, thence providing both the rotation and linear movements. The use of a single motor, rather than two motors (one for translation and one for rotation), is an important advantage of the present invention. The use of a single motor reduces weight, power consumption, and the number of wires that must extend between the stationary airframe and the movable gimbal, and has lower cost. An angular measuring device, such as a resolver or a potentiometer connected to the motor axis, provides feedback data to control the degree of angular deviation.
The present approach allows the sensor system to be optimally positioned for small pointing angles and for larger pointing angles as well, so that the sensor system may have a large field of regard and good optical performance. Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. The scope of the invention is not, however, limited to this preferred embodiment.
REFERENCES:
patent: 4210804 (1980-07-01), LaTorre et al.
Ahmad Anees
Arndt Thomas D.
Collins David W.
Gregory Bernarr E.
Lenzen, Jr. Glenn H.
Raytheon Company
Rudd Andrew J.
LandOfFree
Line of sight pointing mechanism for sensors does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Line of sight pointing mechanism for sensors, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Line of sight pointing mechanism for sensors will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2600890