Windshear radar system with upper and lower elevation radar scans
First Claim
1. A method of detecting hazardous windshear, comprising:
- (a) scanning the atmosphere in an upper radar scan;
(b) determining first hazard candidates in the upper scan;
(c) scanning the atmosphere in a lower radar scan;
(d) determining second hazard candidates in the downward scan responsive to the first hazard candidates; and
(e) characterizing the total hazard responsive to the second hazard candidates.
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Accused Products
Abstract
The present invention is an airborne radar system which scans the flight path of an aircraft with two radar scans, an upper elevation pointing above local level and a lower elevation scan pointing below the glide slope. The radar returns from the upper elevation scan are used to detect the core of the microburst. The core and a model of the windshear which uses the core are used to select angles and range cell candidates, in a lower elevation scan, for hazard detection processing. The candidates in the lower scan, which is pointing at the ground, are used to create a hazard map tested against a predetermined hazard threshold. A threshold violation results in a pilot alert. The hazard map includes a vertical factor determined through model coefficients in the radial outflow as a function of altitude. The invention applies the model to determine the total hazard factor along the glideslope using the vertical hazard of the model and altitude scaling of the horizontal hazard from the lower bar elevation to the glideslope of the aircraft. The present invention also includes a radar scan with two pulse repetition frequencies which allows the elimination of non-correlated returns. The system also includes post detection integration with a sliding azimuth window to enhance the signal to noise ratio. The system also combines velocities within a single range gate to produce a velocity representing the windspeed at that range.
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Citations
18 Claims
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1. A method of detecting hazardous windshear, comprising:
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(a) scanning the atmosphere in an upper radar scan; (b) determining first hazard candidates in the upper scan; (c) scanning the atmosphere in a lower radar scan; (d) determining second hazard candidates in the downward scan responsive to the first hazard candidates; and (e) characterizing the total hazard responsive to the second hazard candidates. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of hazardous windshear detection, comprising:
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(a) scanning the atmosphere in an upper radar scan; (b) scanning the atmosphere in a lower radar scan; and (c) determining a downdraft core size from the upper and lower scans.
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15. An airborne method of detecting hazardous windshear from an aircraft, comprising:
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(a) scanning the atmosphere in an upper radar scan at approximately five degrees above local level of the aircraft using two pulse repetition frequencies and receiving upper radar returns; (b) performing post detection integration of the upper returns using a sliding azimuth window; (c) performing ordered constant false alarm rate processing on the upper returns using a nonrectangular window oriented with respect to loci of hazardous windshear; (d) combining correlated upper returns on a range gate basis; (e) scanning the atmosphere in a lower radar scan approximately down a glideslope of the aircraft using the two repetition frequencies and receiving lower radar returns; (f) performing steps (b)-(d) on the lower returns; (g) determining a centroid, an upper diameter and an upper radial outflow of a hazard candidate from the upper returns; (h) selecting a portion of the lower returns for processing responsive to the hazard candidate; (i) determining a lower diameter and a lower radial outflow of the candidate from the portion; (j) vertically profiling the candidate; (k) determining a total hazard; (l) scaling the total hazard to the glideslope; and (m) comparing the scaled total hazard to a threshold and warning the pilot when the threshold is exceeded.
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16. An airborne method of detecting hazardous windshear, comprising:
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(a) scanning the atmosphere in a radar scan and receiving radar returns; (b) performing post detection integration of the radar returns using an azimuth sliding window; and
integrated returns.
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17. An airborne method of detecting hazardous windshear, comprising:
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(a) scanning the atmosphere in a radar scan and receiving radar returns; (b) performing constant false alarm rate processing on the returns; and (c) detecting windshear from the processed returns.
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18. An airborne method of detecting hazardous windshear, comprising:
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(a) scanning the atmosphere in upper and lower radar scans; (b) profiling the windshear from the upper and lower radar scans using a linear relationship between radial outflow and altitude; (c) determining the hazard from the profile.
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Specification