Systems and methods for a terrain contour matching navigation system
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
G01S-013/00
G01S-007/40
B29C-045/00
G06F-019/00
G06F-007/00
출원번호
UP-0554802
(2006-10-31)
등록번호
US-7522090
(2009-07-01)
발명자
/ 주소
Hawkinson, Wesley J.
출원인 / 주소
Honeywell International Inc.
대리인 / 주소
Fogg & Powers LLC
인용정보
피인용 횟수 :
7인용 특허 :
9
초록▼
Systems and methods for terrain contour matching navigation are provided. In one embodiment, a method for terrain contour matching navigation comprises: receiving at least one sample point representing the position of an aircraft, the at least one sample point including a horizontal position and an
Systems and methods for terrain contour matching navigation are provided. In one embodiment, a method for terrain contour matching navigation comprises: receiving at least one sample point representing the position of an aircraft, the at least one sample point including a horizontal position and an altitude sample; correlating a first sample point of the at least one sample point across a reference basket array having a plurality of elements; determining a correlation quality; when the correlation quality does not achieve a pre-determined quality threshold, performing at least one additional correlation of an additional sample point of the at least one sample point across the reference basket array; and when the correlation quality does achieve a pre-determined quality threshold, calculating a position error based on the correlating of the first sample point and any additional correlations of any additional sample points.
대표청구항▼
What is claimed is: 1. A terrain contour matching navigation system for an aircraft, the system comprising: an inertial navigation system configured to output a navigation solution including a horizontal position of the aircraft and a vertical inertial altitude of the aircraft; a clearance altimete
What is claimed is: 1. A terrain contour matching navigation system for an aircraft, the system comprising: an inertial navigation system configured to output a navigation solution including a horizontal position of the aircraft and a vertical inertial altitude of the aircraft; a clearance altimeter configured to output a clearance altitude of the aircraft above a terrain; a memory programmed with a contour map; and a processor coupled to the inertial navigation system, the clearance altimeter and the memory; wherein the processor is programmed with a reference basket selector to select a reference basket area from the memory; wherein the processor is programmed to calculate a first single sample point comprising the horizontal position of the aircraft and an altitude sample, the altitude sample based on a difference between the vertical inertial altitude and the clearance altitude; wherein the processor is programmed with a correlation function that correlates the first single sample point over the reference basket area to determine a position in the reference basket area corresponding to a predicted position of the aircraft and further determine a correlation quality; wherein when the correlation quality does not achieve a pre-determined quality threshold, the processor is programmed to calculate an additional sample point and the correlation function correlates the additional sample point over the reference basket area to determine the position in the reference basket area corresponding to the predicted position of the aircraft and further determine the correlation quality; and wherein when the correlation quality does achieve a pre-determined quality threshold, the processor is programmed with a position error output function that calculates a horizontal position error and vertical position error based on the position in the reference basket area corresponding to the predicted position of the aircraft. 2. The system of claim 1, wherein the reference basket selector is configured to select a reference basket area that includes an area of the contour map based on the navigation solution output of the inertial navigation system and an uncertainty in the horizontal position of the navigation solution. 3. The system of claim 2, wherein the inertial navigation system further comprises a Kalman filter configured to output quality data that represent the uncertainty in the navigation solution; and wherein the reference basket selector is configured to select a reference basket area further based on the quality data from the Kalman filter. 4. The system of claim 1, wherein the correlation function performs a correlation based on at least one of a minimum variance technique and a minimum absolute deviation technique. 5. The system of claim 1, wherein the processor is further configured to output a correction factor based on the horizontal position error and the vertical position error; and wherein the inertial navigation system is configured to receive the correction factor and determine the navigation solution based on the correction factor. 6. A method for terrain contour matching navigation, the method comprising: receiving at least one sample point representing the position of an aircraft, the at least one sample point including a horizontal position and an altitude sample; correlating a first sample point of the at least one sample point across a reference basket array having a plurality of elements; determining a correlation quality; when the correlation quality does not achieve a pre-determined quality threshold, performing at least one additional correlation of an additional sample point of the at least one sample point across the reference basket array; and when the correlation quality does achieve a pre-determined quality threshold, calculating a position error based on the correlating of the first sample point and any additional correlations of any additional sample points, wherein calculating the position error comprises: determining a column number and a row number of an element of the reference basket array having the smallest correlation value; calculating a first horizontal position error Δx based on the equation: Δx=(minimum_cell_x-(x+1)/2)*basket_cell_size_x; and calculating a second horizontal position error Δy based on the equation: Δy =(minimum_cell_y-(y+1)/2)*basket_cell_size_y; wherein minimum_cell_x is based on the column number of the element of the reference basket array having the smallest correlation value, minimum_cell_y is based on the row number of the element of the reference basket array having the smallest correlation value, x is based on a number of columns of the reference basket array, y is based on a number of rows of the reference basket array, and basket_cell_size_x and basket_cell_size_y are based on dimensions of a physical area represented by a single element of the reference basket array. 7. The method of claim 6, further comprising selecting a reference basket area from a contour map based on the horizontal position and an uncertainty in the horizontal position, wherein the reference basket array is based on the reference basket area. 8. The method of claim 6, wherein the altitude sample represents a difference between a vertical inertial altitude based on sensor data and a clearance altitude based on sensor data, and wherein the horizontal position represent a longitude position based on sensor data and a latitude position based on sensor data. 9. The method of claim 6, wherein correlating a first sample point across a reference basket array further comprises: determining a difference between the altitude sample and altitude values contained in the reference basket array; determining a correlation value for each of the plurality of elements of the reference basket array based on the difference between the altitude sample and altitude values contained in the reference basket array; and determining which element of the reference basket array has the smallest correlation value. 10. The method of claim 9, wherein determining a correlation value further comprises performing a sequential computation to determine a correlation value based on a standard deviation for each element of the reference basket array. 11. The method of claim 10, wherein determining a correlation quality further comprises determining whether a standard deviation associated with an element of the reference basket array having the smallest correlation value achieves a predetermined threshold. 12. The method of claim 9, wherein determining a correlation value further comprises: performing a sequential computation to determine a correlation value minimum absolute deviation (MAD) for each element of the reference basket array. 13. The method of claim 9, wherein determining a correlation quality further comprises: evaluating a correlation surface representing correlation values associated with each element of the reference basket array to determine if a slope of the correlation surface in a region of the reference basket array having the smallest correlation value achieves a predetermined threshold. 14. The method of claim 6, wherein calculating a position error further comprises calculating a vertical position error Δz based on the equation: Δz=difference_sum(minimum_cell_x minimum_cell_y)/n; wherein n equals a total number of samples points correlated across the reference basket array. 15. A terrain contour matching navigation system for an aircraft, the system comprising: a first sensing means for determining a horizontal position and an inertial altitude of the aircraft; a second sensing means for determining a clearance altitude of the aircraft; means for processing responsive to the first sensing means and the second sensing means, wherein the means for processing is configured to determining at least one sample point based on the horizontal position and a difference between the clearance altitude and the inertial altitude; and means for storing a reference basket array having a plurality of elements, wherein each element includes an altitude value based on a contour map; wherein the means for processing is further configured to correlate a first single sample point of the at least one sample point across the reference basket array and determine an element of the reference basket array having a smallest correlation value; wherein the means for processing is farther configured to determine whether a correlation quality achieves a pre-determined quality threshold by evaluating a correlation surface representing correlation values associated with each element of the reference basket array to determine if a slope of the correlation surface in a region of the reference basket array having the smallest correlation value achieves the predetermined quality threshold; wherein when the correlation quality does not achieve the pre-determined quality threshold, the means for processing is further configured to perform at least one additional correlation of an additional single sample point of the at least one sample point across the reference basket array; and wherein when the correlation quality does achieve the pre-determined quality threshold, the means for processing is further configured to calculate a position error based on the correlating of the first single sample point and any additional correlations of any additional single sample points. 16. The system of claim 15, wherein the means for processing is further configured to select the reference basket array from the means for storing, wherein the reference basket array represents an area of the contour map based on the horizontal position determined by the first sensing means and an uncertainty in the horizontal position. 17. The system of claim 15, wherein the means for processing is further configured to compute a correlation that determines an element of the reference basket array having a smallest correlation value based on at least one of a minimum variance technique and a minimum absolute deviation technique. 18. The system of claim 15, wherein the means for processing is configured to output a correction factor based on the position error. 19. The system of claim 18, wherein the first sensing means is configured to receive the correction factor and further determine the horizontal position and the inertial altitude of the aircraft based on the correction factor.
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이 특허에 인용된 특허 (9)
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