Systems and methods for gimbal mounted optical communication device

Optical communication systems and methods are operable to communicate optical signals across a gimbal system. An exemplary embodiment has a first optical rotary joint with a rotor and a stator, a second optical rotary joint with a rotor and a stator, and an optical connector coupled to the stators of the first and the second optical rotary joints. The stator of the first optical rotary joint is affixed to a first rotational member of the gimbal system. The stator of the second optical rotary joint is affixed to a second rotational member of the gimbal system. A first optical connection coupled to the rotor of the first optical rotary joint and a second optical connection coupled to the rotor of the second optical rotary joint remain substantially stationary as the gimbal system orients an optical communication device in a desired position.

BACKGROUND OF THE INVENTION

Various devices may be mounted on a single axis, a two-axis, or a three-axis gimbal to facilitate orientation of the device towards a desired direction.FIG. 1illustrates a prior art radar antenna102and a two-axis gimbal system104. When the radar antenna102is affixed to the gimbal system104, the radar antenna102may be pointed in a desired horizontal and/or vertical direction. When the gimbal system104includes motors, the radar antenna102may be oriented on a real time basis.

For example, when the radar antenna102is used in a vehicle, such as an aircraft or a ship, the radar antenna102may be continuously swept in a back-and-forth manner along the horizon, thereby generating a view of potential hazards on a radar display. As another example, the radar antenna102may be moved so as to detect a strongest return signal, wherein a plurality of rotary encoders or other sensors on the gimbal system104provide positional information for determining the direction that the radar antenna102is pointed. Thus, based upon a determined orientation of the radar antenna102, and also based upon a determined range of a source of a detected return signal of interest, a directional radar system is able to identify a location of the source.

The two-axis gimbal system104includes a support member106with one or more support arms108extending therefrom. A first rotational member110is rotatably coupled to the support arms108to provide for rotation of the radar antenna102about the illustrated Z-axis. The first rotational member110is rotatably coupled to a second rotational member112to provide for rotation of the radar antenna102about the illustrated Y-axis, which is perpendicular to the Z-axis.

A moveable portion114of the gimbal system104may be oriented in a desired position. One or more connection members116, coupled to the moveable portion114, secure the radar antenna102to the gimbal system104. Motors (not shown) operate the rotational members110,112, thereby pointing the radar antenna102in a desired direction.

The gimbal system104is affixed to a base118. The base118may optionally house various electronic components therein (not shown), such as components of a radar system. Electronic components coupled to the radar antenna102, such as the optical communication device120, are communicatively coupled to the radar system (or to other remote devices) via an optical connection122. The optical communication device120processes detected radar returns into an optical signal that is then communicated to a radar system. The optical connection122may be a fiber optic connection that communicates an optical information signal from the optical communication device120corresponding to radar signal returns detected by the radar antenna102.

As illustrated inFIG. 1, the optical connection122is physically coupled to the base118. The optical connection122flexes as the optical communication device120and the antenna102are moved by the gimbal system104.

Over long periods of time, the optical connection122, and/or its respective point of attachment124, may wear and potentially fail due to the repeated flexing as the radar antenna102is moved by the gimbal system104. Failure of the optical connection122may result in a hazardous operating condition, such as when the radar antenna102and the gimbal system104are deployed in an aircraft. Thus, failure of the optical connection122would cause a failure of the aircraft's radar system. Accordingly, it is desirable to prevent failure of the optical connection122so as to ensure secure and reliable operation of the radar antenna102.

SUMMARY OF THE INVENTION

Systems and methods of communicating optical signals across a gimbal system are disclosed. An exemplary embodiment has a first optical rotary joint with a rotor and a stator, a second optical rotary joint with a rotor and a stator, and an optical connector coupled to the stators of the first and the second optical rotary joints. The stator of the first optical rotary joint is affixed to a first rotational member of the gimbal system. The stator of the second optical rotary joint is affixed to a second rotational member of the gimbal system. A first optical connection coupled to the rotor of the first optical rotary joint and a second optical connection coupled to the rotor of the second optical rotary joint remain substantially stationary as the gimbal system orients an optical communication device in a desired position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 2is a perspective view of an optical information transfer gimbal system200. The exemplary optical information transfer gimbal system200is illustrated as a two-axis gimbal. A first fiber optic rotary joint202and a second fiber optic rotary joint204are part of an optical communication path between an optical communication device120and a remote device206. The optical communication device120and the remote device206are configured to communicate with each other using an optical medium.

The first fiber optic rotary joint202is integrated into a first rotational member208. The first rotational member208is rotatably coupled to the support arms108to provide for rotation of the radar antenna102about the illustrated Z-axis, similar to the above-described first rotational member110. However, the first rotational member208is configured to receive and secure the first fiber optic rotary joint202.

The second fiber optic rotary joint204is integrated into a second rotational member210. The second rotational member210provides for rotation of the radar antenna102about the illustrated Y-axis, which is perpendicular to the Z-axis, and similar to the above-described second rotational member112. However, the second rotational member210is configured to receive and secure the second fiber optic rotary joint204.

FIG. 3is a simplified block diagram of an exemplary optical rotary joint302employed by embodiments of the optical information transfer gimbal system200. The exemplary optical rotary joint302corresponds to the first fiber optic rotary joint202and the second fiber optic rotary joint204illustrated inFIG. 2.

The optical rotary joint302comprises a rotor304, a stator306, and an optional collar308. A bore310or the like in the rotor304is configured to receive an end portion of an optical connection312or another optical structure. In one embodiment, the optical cable extends out from the optical rotary joint302to the remote device206. A bore314or the like in the stator306is configured to receive an end portion of a second optical connection316or another optical structure. The optional collar308includes an optional plurality of apertures318through which screws, bolts or other suitable fasteners may be used to secure the optical rotary joint302to its respective rotational member (not shown). Some embodiments may include optional collars320or the like to facilitate coupling of the rotor304to the end portion of the optical connection312, and/or to facilitate coupling of the stator306to the end portion of the optical connection316.

The optical rotary joint302is configured to secure the optical connection end322of the end portion of the optical connection312, or another optical structure, in proximity to a region326. Further, a second end324of the end portion of the optical connection316, or another optical structure, is secured in proximity to the region326. Accordingly, light carrying an optically encoded signal may be communicated between the optical connection ends322,324via the region326. The region326may have air, gas, index-matching gel, or another index matched material to facilitate communication of light between the optical connection ends322,324.

The end portion of the optical connections312,316are aligned along a common axis of rotation (R). The rotor304is free to rotate about the axis of rotation. Since the end portion of the optical connection312is secured within the bore310of the rotor304, the rotational member is free to rotate without imparting a stress on the end portion of the optical connection312.

FIG. 4is a perspective view illustrating orientation of the two optical rotary joints202,204of an embodiment of the optical information transfer gimbal system. The rotational axis of the first fiber optic rotary joint202is aligned along the Z axis of the optical information transfer gimbal system200. The rotational axis of the second fiber optic rotary joint204is aligned along the Y axis of the optical information transfer gimbal system200(FIG. 2). The stator306of the first fiber optic rotary joint202and the stator of the second fiber optic rotary joint204optically couple to an optical connector402such that optical signals can be communicated there through. The optical connector402may be a short portion of fiber optic cable or another suitable optical connector such as a wave guide or the like. Since the stator306of the first fiber optic rotary joint202is affixed to the first rotational member208(not illustrated inFIG. 4), and since the stator306of the second fiber optic rotary joint204is affixed to the second rotational member210(not illustrated inFIG. 4), the optical connector402remains in a substantially stationary position as the optical information transfer gimbal system200moves the antenna102(FIG. 2).

FIG. 2illustrates a first optical connection212between the base118and the first fiber optic rotary joint202, a second optical connection214between the optical communication device120and the second fiber optic rotary joint204, and a third optical connection216between the base118and the remote device206. (Alternatively, the second optical connection214may be directly connected to the remote device206.) Optical connections212,214, and/or216may be an optical fiber, optical cable, or the like.

During movement of the antenna102, the first optical connection212and the second optical connection214, having their ends secured to their respective rotor304(FIG. 3), remains in a substantially stationary position. That is, as the first rotational member208rotates, the rotation of the rotor304of the first fiber optic rotary joint202allows the first optical connection212to remain substantially stationary, thereby avoiding potentially damaging stresses that might otherwise cause failure of the first optical connection212. Similarly, as the second rotational member210rotates, the rotation of the rotor304of the second fiber optic rotary joint204allows the second optical connection214to remain substantially stationary, thereby avoiding potentially damaging stresses that might otherwise cause failure of the second optical connection214.

As noted above, optical signals are communicated between the optical communication device120and the remote device206. Such optical signals are communicated via the optical connections212,214,216, the optical connector402, and the fiber optic rotary joints202,204. The optical connections212,214,216, and the optical connector402, remain substantially stationary as the optical information transfer gimbal system200moves the antenna102.

In alternative embodiments, the optical information transfer gimbal system200may be a three-axis gimbal system, or a gimbal system with more than three axis. For each gimbal axis, an optical rotary joint302is used to provide a rotatable optical connection.