IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0472690
(2006-06-22)
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등록번호 |
US-7359038
(2008-04-15)
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발명자
/ 주소 |
- Donoghue,Patrick J.
- Hsu,David Y.
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출원인 / 주소 |
- Donoghue,Patrick J.
- Hsu,David Y.
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대리인 / 주소 |
Patti, Hewitt & Arezina LLC
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인용정보 |
피인용 횟수 :
1 인용 특허 :
4 |
초록
▼
Ground targets can be passively identified on uneven terrain from an observation point elevation above a known reference point, a line-of-sight inclination angle, an azimuth angle and a digital terrain elevation database wherein actual elevations of surrounding latitude and longitude coordinates are
Ground targets can be passively identified on uneven terrain from an observation point elevation above a known reference point, a line-of-sight inclination angle, an azimuth angle and a digital terrain elevation database wherein actual elevations of surrounding latitude and longitude coordinates are stored and retrievable. Using the observation point's elevation above the known reference point and using the line-of-sight elevation angle from the observation point to the ground target, an initial estimate of the latitude and longitude coordinates of the ground target is made and used as an index into a digital terrain elevation database.
대표청구항
▼
What is claimed is: 1. A method of identifying the location of a ground target from an observation point that is at an elevation above a first reference point, the first reference point having an elevation above sea level and latitude and longitude coordinates, the method comprising the steps of: a
What is claimed is: 1. A method of identifying the location of a ground target from an observation point that is at an elevation above a first reference point, the first reference point having an elevation above sea level and latitude and longitude coordinates, the method comprising the steps of: a) determining the observation point's elevation above the first reference point; b) determining the line-of-sight elevation angle from the observation point to the ground target; c) determining an azimuth angle to the ground target; d) calculating the latitude and longitude coordinates of the ground target using the latitude and longitude coordinates of the first reference point, the observation point elevation above ground, the line-of-sight elevation angle to the ground target and the azimuth angle to the ground target; e) reading from a data base, the earth's surface elevation above sea level at the ground target location determined from step d); f) determining the difference between the earth's surface elevation above sea level at the ground target location estimate determined from step d) and the earth's surface elevation above sea level at the first reference point determined in step a); g) if the result of step f) is zero or substantially equal to zero, determine the ground target location to be at an elevation above sea level determined in step e) and to have the longitude and latitude determined in step d); h) if the result of step f) is non-zero, determine a second reference point elevation from the difference obtained in step f) and then; i) assign the second reference point elevation determined in step h) to be the first reference point elevation to be used in a recalculation of step d); then ii) iteratively calculate steps d) to h) until the difference obtained in step f) is zero or substantially equal to zero. 2. The method of claim 1, wherein the step of calculating the latitude and longitude coordinates of the location of the ground target, further comprises the step of: calculating the latitude and longitude of the ground target from the latitude and longitude of the first reference point, using one of the sine and cosine of the line-of-sight elevation angle. 3. The method of claim 1, wherein the step of calculating the latitude and longitude coordinates of the location of the ground target, further comprises the step of: calculating the latitude and longitude of the ground target from the latitude and longitude of the first reference point, using one of the sine and cosine of the azimuth angle. 4. The method of claim 1, wherein the step of calculating the line of sight distance from the observation point to the ground target using one of the sine and cosine of the line-of-sight elevation angle. 5. The method of claim 1, further comprising the step of determining the latitude and longitude of the first reference point using a global positioning system. 6. A method of identifying the location of a ground target from an observation point that is at an elevation above a first reference point, the first reference point having an elevation above sea level and latitude and longitude coordinates, the method comprising the steps of: a) determining the observation point's elevation above the first reference point; b) determining the line-of-sight elevation angle from the observation point to the ground target; c) determining an azimuth angle to the ground target; d) calculating the latitude and longitude coordinates of the ground target using the latitude and longitude coordinates of the first reference point, the observation point elevation above ground, the line-of-sight elevation angle to the ground target and the azimuth angle to the ground target; e) reading from a data base, the earth's surface elevation above sea level at the ground target location determined from step d); f) determining the difference between the earth's surface elevation above sea level at the ground target location estimate determined from step d) and the earth's surface elevation above sea level at the first reference point determined in step a); g) if the result of step f) is zero or substantially equal to zero, determine the ground target location to be at an elevation above sea level determined in step e) and to have the longitude and latitude determined in step d); h) if the result of step f) is non-zero, determine a second reference point elevation from the difference obtained in step f) and the first reference point elevation, then: i) adjust the first reference elevation used in step d) by a predetermined amount, to be re-used in a re-calculation of step d); then ii) iteratively calculate steps d) to h) until the difference obtained in step f) is zero or substantially equal to zero. 7. The method claim 6, wherein step h) of adjusting the first reference point elevation further comprises the step of decreasing the first reference point elevation by a first amount. 8. The method claim 6, wherein step h) of adjusting the first reference point elevation further comprises the step of increasing the first reference point elevation by a first amount. 9. The method of claim 1, wherein the step of determining the line-of-sight elevation angle from the observation point to the ground target further comprises the step of determining the line-of-sight elevation using at least one of: a camera; a helmet mounted display (HMD); a Target Sighting System (TSS). 10. The method of claim 6, wherein the step of determining the line-of-sight elevation angle from the observation point to the ground target further comprises the step of determining the line-of-sight elevation using at least one of: a camera, a helmet mounted display (HMD), or a Target Sighting System (TSS). 11. An apparatus for passively determining the location of a ground target from an observation point, the apparatus comprising: a) a computer; b) camera targeting system coupled to said computer, which determines an angle of inclination between said ground target and said observation point; c) a navigation system coupled to said computer and which determines the location of said observation point; d) a terrain database coupled to said computer, said terrain database storing information about terrain around where a ground target is located; e) a storage device operatively coupled to said computer, said storage device storing computer program instructions, which when executed cause the computer to: i) determine the observation point's elevation above the first reference point; ii) determine the line-of-sight elevation angle from the observation point to the ground target; iii) determine an azimuth angle to the ground target; iv) calculate the latitude and longitude coordinates of the ground target using the latitude and longitude coordinates of the first reference point, the observation point elevation above ground, the line-of-sight elevation angle to the ground target and the azimuth angle to the ground target; wherein the computer program instructions cause the computer to: i) read from a data base, the earth's surface elevation above sea level at the around target location; ii) determine the difference between the earth's surface elevation above sea level at the around target location and the earth's surface elevation above sea level at the first reference point, and iii) if the result of step ii) is zero or substantially equal to zero, determine the ground target location to be at an elevation above sea level and to have the longitude and latitude determined in step (d)(iv); iv) if the result of step ii) is non-zero, determine a second reference point elevation for the ground target location and then; v) assign the second reference point elevation determined to be the first reference point elevation to be used in a recalculation of ground target location; then vi) iteratively calculate the location of the ground target until the difference is zero or substantially equal to zero. 12. The apparatus of claim 11, wherein the computer program instructions cause the computer to calculate the latitude and longitude of the ground target from the latitude and longitude of the first reference point, using one of the sine and cosine of the line-of-sight elevation angle. 13. The apparatus of claim 11, wherein the computer program instructions cause the using one of the sine and cosine of the azimuth angle. 14. The apparatus of claim 11, wherein the computer program instructions cause the computer to calculate a line of sight distance from the observation point to the ground target using one of the sine and cosine of the line-of-sight elevation angle. 15. The apparatus of claim 11, wherein the camera targeting system is comprised of a camera; a helmet mounted display (HMD); a Target Sighting System (TSS). 16. The apparatus of claim 11, wherein the navigation system is comprised of: a global positioning system. 17. The apparatus of claim 11, wherein the navigation system is comprised of: an inertial navigation system. 18. An apparatus for passively determining the location of a ground target from an observation point, the apparatus comprising: a) a computer; b) camera targeting system coupled to said computer, which determines an angle of inclination between said ground target and said observation point; c) a navigation system coupled to said computer and which determines the location of said observation point; d) a terrain database coupled to said computer, said terrain database storing information about terrain around where a ground target is located; e) a storage device operatively coupled to said computer, said storage device storing computer program instructions, which when executed cause the computer to: i) determine the observation point's elevation above the first reference point; ii) determine the line-of-sight elevation angle from the observation point to the ground target; iii) determine an azimuth angle to the ground target; iv) calculate the latitude and longitude coordinates of the ground target using the latitude and longitude coordinates of the first reference point, the observation point elevation above ground, the line-of-sight elevation angle to the around target and the azimuth angle to the round target; wherein the computer program instructions cause the computer to: read from a data base, the earth's surface elevation above sea level at the ground target location determined from step d)(iv); i) determining the difference between the earth's surface elevation above sea level at the ground target location estimate determined from step d)(iv) and the earth's surface elevation above sea level at the first reference point; ii) if the result of step i) is zero or substantially equal to zero, determine the ground target location to be at an elevation above sea level determined in step d)(iv); iii) if the result of step i is non-zero, determine a second reference point elevation from the difference obtained in step d)(iv) and the first reference point elevation, then: iv) adjust the first reference elevation used in step d)(iv) by a predetermined amount, to be re-used in a re-calculation of steps d)(i)-d)(iv); then v) iteratively calculate until the difference obtained in step f) is zero or substantially equal to zero. 19. The apparatus of claim 18, wherein the camera targeting system is comprised of a camera, a helmet mounted display (HMD), or a Target Sighting System (TSS). 20. An apparatus for passively determining the location of a ground target from an observation point, the apparatus comprising: a) a computer; b) a targeting system means for determining an angle of inclination between said ground target and said observation point, said targeting system means being coupled to said computer; c) a navigation system means for determining the location of said observation point, said navigation system means being coupled to said computer; d) a terrain database coupled to said computer, said terrain database storing terrain data for an area wherein said ground target is located; i) a storage device coupled to said computer, said storage device storing computer program instructions to control said computer to determine the altitude and longitude and latitude of said ground target from data obtained from said targeting system means, said navigation system means and said terrain database; wherein the computer program instructions cause the computer to: i) read from a data base, the earth's surface elevation above sea level at the around target location; ii) determine the difference between the earth's surface elevation above sea level at the ground target location and the earth's surface elevation above sea level at the first reference point, and iii) if the result of step ii) is zero or substantially equal to zero, determine the ground target location to be at an elevation above sea level and to have the longitude and latitude determined in step (d)(iv); iv) if the result of step ii) is non-zero, determine a second reference point elevation for the ground target location and then: v) assign the second reference point elevation determined to be the first reference point elevation to be used in a recalculation of ground target location; then vi) iteratively calculate the location of the ground target until the difference is zero or substantially equal to zero.
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