| 摘要 |
1502178 Detecting atmospheric turbulence E F FLINT 26 Nov 1975 [10 Feb 1975] 48522/75 Heading G1A In a system providing discrete measurements of temperature within a field of view ahead of an aircraft, processing apparatus comprises means for providing: consecutive first signals representing the mean temperature within the field; consecutive second signals representing the temperature difference between two vertically-spaced regions; consecutive third signals by combination of first and second signals; fourth signals by storing and averaging third signals; and a warning upon a predetermined difference detected between third and fourth signals. A radiometer 20, Fig. 1, carried in an aircraft 19 includes a black-body temperature reference and a rotary chopper and filter coupled to a processing lens for deriving compensated temperature data from infrared radiation detected at points 1 - 10 in a circle 23 subtending subtending 4 degrees at the aircraft. At first a wavelength of 13.8Á the radiometer has an effective range of about 16 miles; and at a second wavelength the range is about 8 miles. The difference between measurements made at these two wavelengths provides a signal relatively free from cloud ice effects. The circle is swept once a second. Temperature-representative signals SR, Fig. 2 are averaged, 37, to give mean first signal S S , and the difference Sv between temperatures at e.g. points 1 and 6 is calculated to give second signals at 39. Third signals Ssv representing S S + Sv are successively stored for two minutes at 43 and then discarded, a fourth signal representing the running average SA appearing at a line 44. Consecutive third signals S SV are compared with their own running average S A at 45, the magnitude of the difference Sw being compared with thresholds S T1 and S T2 to give a steady light 50 or a more urgent flashing light. Warning is thus given on the occurrence of variations either in temperature along the flight path or in vertical temperature gradient across it. The temperature pattern is displayed by concentric circles of respectively blue and yellow lamps 61-80 energized by gated signals from a comparator 53 indicating a temperature above or below the two-minute average. A biasing signal SB deducts the difference signal Sv from S A , so that the comparator reference is effectively a long-term average of signals S S ; thus in smooth flying conditions the upper half of the display will normally be blue and the lower half yellow. |
