Method and system of determining miss-distance

Patent metadata

Field	Value
Publication number	US-2020182590-A1
Application number	US-201716472757-A
Country	US
Kind code	A1
Filing date	Dec 24, 2017
Priority date	Dec 26, 2016
Publication date	Jun 11, 2020
Grant date	—

Abstract

The presently disclosed subject matter includes a computerized method and system for determining miss-distance between platforms. The proposed method and system make use of an electro optic sensor (e.g. camera) mounted on one of the platforms for obtaining additional data which is used for improving the accuracy of positioning data obtained from conventional positioning devices. A navigation error is calculated where the relative position of the two platforms is converted to the camera reference frame. Once the navigation error is available, it can be used to correct a measured miss-distance.

First claim

1 . A computer implemented method of determining miss-distance between an intercepting platform and a target platform; the intercepting platform is launched towards the target platform and comprises a camera and at least one positioning device; the method comprising using at least one processor for:
i. executing a navigation errors calculation process, comprising: for at least one image captured by the camera at a time t Fi during flight of the intercepting platform towards the target platform: calculating relative position of the intercepting platform and the target platform, based on navigation data of the intercepting platform determined by the at least one positioning device and navigation data of the target platform; transforming the relative position to camera field of view (CFOV) reference frame; calculating rectified relative position values in the camera Y and Z components, based on camera data; and calculating relative position error values in the Y and Z axes in the camera's focal-plane array (FPA), based on a difference between the relative position and rectified relative position values; ii. executing a navigation miss-distance correction process, comprising: determining relative position of the intercepting platform and target platform at miss-distance time; and correcting relative position using the relative position error values.

2 . The method according to claim 1 , wherein the camera data used for calculating the rectified relative position values includes the relative position of the platform in camera field of view reference frame and camera line of sight (CLOS) unit vector components.

3 . The method according to claim 1 , wherein executing a navigation errors calculation process further comprises:
for each captured image at time t Fi : utilizing the at least one positioning device for determining navigation data of the intercepting platform; calculating attitude of the camera onboard the intercepting platform, in the reference frame of the intercepting platform; applying image processing on the captured image for determining CLOS; and transforming relative position to the CFOV reference frame.

4 . The method according to claim 1 , wherein executing the navigation errors calculation process further comprises:
capturing multiple images and calculating respective relative position error values, wherein each respective relative position error value is associated with a certain captured image.

5 . The method according to claim 4 further comprising:
calculating final position error values based on the respective relative position error values.

6 . The method according to claim 1 further comprising an attitude errors determining process, comprising:
selecting a first image at time t F1 and a second image at time t F2 ;
for each one of the first image and second image:

determining relative position in the CFOV reference frame;
calculating rectified relative position values in the camera Y and Z axes; and
using LOS component u Y and u Z at t F1 and t F2 to compute angle errors.

7 . The method according to claim 1 further comprising synchronizing clocks onboard the intercepting platform and the target platform.

8 . The method according to claim 1 further comprising determining whether one or more termination conditions have been fulfilled, and terminating the navigation errors calculation process if they have.

9 . The method according to claim 1 further comprising identifying miss-distance time.

10 . (canceled)

11 . (canceled)

12 . A computerized device configured for determining miss-distance between an intercepting platform and a target platform; the intercepting platform is launched towards the target platform and comprises a camera and at least one positioning device; the computerized device comprising at least one processor configured to:
i. execute the navigation errors calculation process, comprising: for at least one image captured by the camera at a time t Fi during flight of the intercepting platform towards the target platform: calculate relative position of the intercepting platform and the target platform, based on navigation data of the intercepting platform determined by the at least one positioning device and navigation data of the target platform; transform the relative position to camera field of view (CFOV) reference frame; calculate rectified relative position values in the camera Y and Z components, based on camera data t; and calculate relative position error values in the Y and Z axes in the camera's focal-plane array (FPA), based on a difference between the relative position and rectified relative position values; ii. execute the navigation miss-distance correction process, comprising: determine relative position t I of the intercepting platform and target platform at miss-distance time t I ; and correct relative position t I using the relative position error values.

13 . The computerized device according to claim 12 , wherein the camera data used for calculating the rectified relative position values includes the relative position of the platform in camera field of view reference frame and camera ling of sight (CLOS) unit vector components.

14 . The computerized device according to claim 12 , wherein the at least one processor is further configured, for executing the navigation errors calculation process, to:
for each captured image at time t Fi : utilize the at least one positioning device for determining navigation data of the intercepting platform; calculate attitude of the camera onboard the intercepting platform, in the reference frame of the intercepting platform; operate an image processor to process the captured image for determining CLOS; and transform relative position to the CFOV reference frame.

15 . The computerized device according to claim 12 , wherein the at least one processor is further configured, for executing the navigation errors calculation process, to:
receive multiple images captured during flight of the intercepting platform toward the target platform, each image is associated with a respective time t Fi ; and calculate a respective captured image for each one of the multiple images.

16 . The computerized device according to claim 12 , wherein the at least one processor is further configured to:
calculate final position error values based on the respective relative position error values.

17 . The computerized device according to claim 12 , wherein the at least one processor is further configured to execute an attitude errors determining process, comprising:
selecting a first image at time t F1 and a second image at time t F2 ;
for each one of the first image and second image:
determining relative position in the CFOV reference frame; calculating rectified relative position values in the camera Y and Z axes; and using LOS component uY and uZ at t F1 and t F2 to compute angle errors.

18 . The computerized device according to claim 12 , wherein the at least one processor is further configured to synchronize clocks onboard the intercepting platform and the target platform.

19 . The computerized device according to claim 12 , wherein the at least one processor is further configured to: determine whether one or more termination conditions have been fulfilled, and terminate the navigation errors calculation process if they have.

20 . The computerized device according to claim 19 , wherein the at least one processor is further configured to identify miss-di

Assignees

• Israel Aerospace Ind Ltd

Inventors

• Maidanik Michael
• Golan Oded M
• Livne Miki
• Rovinsky Jacob

Classifications

• G01C21/1656

  with passive imaging devices, e.g. cameras · CPC title

• G06T7/70

  Determining position or orientation of objects or cameras (camera calibration G06T7/80) · CPC title

• F41G7/34 Primary

  based on predetermined target position data · CPC title

• F41G7/006

  Guided missiles training or simulation devices · CPC title

• F41G7/001 Primary

  Devices or systems for testing or checking · CPC title