Process for controlling a Hartmann wavefront sensor (WFS) in an adaptive optic (AO) system
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H04B-010/00
G01J-001/20
G01J-001/10
G01B-011/02
출원번호
US-0060216
(2005-02-17)
등록번호
US-7457545
(2008-11-25)
발명자
/ 주소
Wirth,Allan
Jankevics,Andrew
출원인 / 주소
Northrop Grumman Corporation
대리인 / 주소
Tarolli, Sundheim, Covell & Tummino LLP
인용정보
피인용 횟수 :
9인용 특허 :
16
초록▼
A free-space adaptive optical laser communication system having signal transmission and reception channels at all terminals in the communication system, wherein wavefront sensing (WFS) and wavefront correction mechanisms are employed along signal transmission and reception channels of all terminals
A free-space adaptive optical laser communication system having signal transmission and reception channels at all terminals in the communication system, wherein wavefront sensing (WFS) and wavefront correction mechanisms are employed along signal transmission and reception channels of all terminals in the communication system (i.e. adaptive optics) to improve the condition of the laser beam at the receiver (i.e. reduce the size of the spot a the detector plane). in the illustrative embodiment, the WFS mechanisms employ a novel WFS control process, in which active updating of reference positions and subaperture locations on the wavefront sensor. These WFS mechanism can be used in diverse application environments, including but not limited to FSO laser communication systems.
대표청구항▼
What is claimed is: 1. A process in an adaptive optic (AO) system employing a Hartmann wavefront sensor (WFS) to measure a wavefront, and a deformable mirror (DM) for correcting said wavefront, wherein said WFS (I) stores a reference wavefront represented as a set of reference spot positions, and (
What is claimed is: 1. A process in an adaptive optic (AO) system employing a Hartmann wavefront sensor (WFS) to measure a wavefront, and a deformable mirror (DM) for correcting said wavefront, wherein said WFS (I) stores a reference wavefront represented as a set of reference spot positions, and (II) employs a sub-process for controlling the operation of said WFS and adaptively defining each said reference spot position as the center of a subaperture region on said WFS, and wherein said sub-process further includes a fast control loop and first and second slow control loops, and comprises the sequence of: (a) before entering said fast control loop, initializing said sub-process; (b) setting the reference spot positions that represent the reference wavefront of the WFS to initial values, (c) setting the subaperture regions to initial values; (d) entering the fast control loop, capturing a frame of image data from the wavefront containing Hartmann spot images; (e) estimating the position of said Hartmann spot images; (f) subtracting the reference spot positions from the Hartmann spot images so as to determine the displacement of the said Hartmann spot images from said reference spot positions; (g) reconstructing the wavefront by integrating gradient values among said subaperture regions; (h) one of providing and updating drive signals sent to the deformable mirror (DM) within said AO system; (i) at the end of the fast control loop, calculating a system performance metric; and (j) determining whether or not to terminate said fast control loop, wherein if said fast control loop is not to be terminated, the sub-process returns to the step (d). 2. The process of claim 1, wherein the system performance metric is based one or more of the following parameters: a laser communication signal level, a power level provided by a communication laser, a power level detected on a target that receives a communication signal, and the sharpness of a detected image. 3. The process of claim 1, wherein at step (i), enter the first slow control loop, and carry out the following data processing operations: (1) calculating temporal average of the system performance metric using a low-pass filter; (2) calculating the gradient of said system performance metric with respect to each component of the reference positions; (4) updating the reference positions; and (5) perturbing the reference positions, and returning to the fast control loop at step (b) to reset the reference position values in said fast control loop. 4. The process of claim 1, wherein at step (e), enter the second slow control loop and carry out the following data processing operations: (1) comparing time-average positions of Hartman spot images within the given subaperture region to the center location of a given subaperture region within which the Hartmann spot images are detected; and (2) determining whether the time-average position of Hartman spot images within a given subaperture region has moved a distance which exceeds a predetermined threshold value, and if so, then reset the center location of the given subaperture region to the determined time-averaged position of the Hartman spot images within the given subaperture region, and return to the fast control loop where the location of subaperture regions are set. 5. The process of claim 1, wherein at step (j), in the event that said process is not to be terminated, then said process returns to step (d) and captures the next Hartmann spot image, and proceeds forward along the data processing path of the fast control loop; and in the event that said process is to be terminated, then said process terminates the fast control loop and said process is finished. 6. The process of claim 1, wherein at step (e), the position of said Hartmann spot images are estimated with one of a centroid calculation and a spot fitting.
연구과제 타임라인
LOADING...
LOADING...
LOADING...
LOADING...
LOADING...
이 특허에 인용된 특허 (16)
Doucet, Mark A.; Panak, David L., Communication network based on the atmospheric transmission of light.
Ross Monte (St. Louis MO) Lokerson Donald C. (New Carrollton MD) Fitzmaurice Michael W. (Gambrills MD) Meyer Daniel D. (St. Louis MO), Multi-access laser communications transceiver system.
Kintis Mark (Manhattan Beach CA) Isara Scott K. (Torrance CA) Brock John C. (Redondo Beach CA) Tittle Lawrence R. (Palos Verdes Estates CA) Pawlowski Peter R. (Manhattan Beach CA), Photonic interconnect and photonic processing for communications and data handling satellites.
Doucet Mark A. ; Panak David L., Point-to-multipoint wide area telecommunications network via atmospheric laser transmission through a remote optical rou.
Chalfant, III, Charles H.; Tidwell, Terry; Leary, Michael; Borsodi, Liam, Acquisition, tracking, and pointing apparatus for free space optical communications with moving focal plane array.
Kagawa, Keiichiro; Maeda, Yuki; Ohta, Jun, Information-processing system using free-space optical communication and free-space optical communication system.
Jones, Michael I.; Iannello, Christopher J.; Love, Guy L.; Baker, Gary J., Scintillation generator for simulation of aero-optical and atmospheric turbulence.
Majumdar, Arun Kumar; Shay, Thomas Maurice, Wide field-of-view amplified fiber-retro for secure high data rate communications and remote data transfer.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.