US 12,253,649 B1
Method and apparatus for measuring optical turbulence using an unmanned aerial vehicle
Alexis Henry Clark, Owens Crossroads, AL (US); and Levi Judah Smolin, Huntsville, AL (US)
Assigned to BlueHalo, LLC, Huntsville, AL (US)
Filed by BlueHalo, LLC, Huntsville, AL (US)
Filed on Apr. 12, 2022, as Appl. No. 17/718,580.
Claims priority of provisional application 63/260,042, filed on Aug. 6, 2021.
Int. Cl. G01W 1/00 (2006.01); B64C 39/02 (2023.01); G01K 1/02 (2021.01); G01K 1/14 (2021.01); G01K 3/08 (2006.01); G01P 5/00 (2006.01); B64U 10/13 (2023.01); B64U 101/35 (2023.01)
CPC G01W 1/00 (2013.01) [B64C 39/024 (2013.01); G01K 1/026 (2013.01); G01K 1/14 (2013.01); G01K 3/08 (2013.01); G01P 5/00 (2013.01); B64U 10/13 (2023.01); B64U 2101/35 (2023.01); B64U 2201/20 (2023.01); G01W 2001/003 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for measuring optical turbulence using an unmanned aerial vehicle, the method comprising:
a) generating, by a first temperature sensor operatively connected to a central processing board, both of which are mounted on the unmanned aerial vehicle, first temperature measurement information at a first sampling rate, the first temperature measurement information associated with a first temperature at the first temperature sensor during a first period of time defined by a first start time and a first end time;
b) generating, by a first wind speed sensor operatively connected to the central processing board and mounted on the unmanned aerial vehicle, first wind speed measurement information at the first sampling rate, the first wind speed measurement information associated with a first wind speed at the first wind speed sensor during the first period of time;
c) generating, by a first barometric pressure sensor operatively connected to the central processing board and mounted on the unmanned aerial vehicle operatively connected to the central processing board, first barometric pressure measurement information at the first sampling rate, the first barometric pressure measurement information associated with a first barometric pressure at the first barometric pressure sensor during the first period of time;
d) transmitting, from the first temperature sensor to the central processing board, the first temperature measurement information generated during the first period of time;
e) transmitting, by the central processing board from the first wind speed sensor to the central processing board, the first wind speed measurement information generated during the first period of time;
f) transmitting, from the first barometric pressure sensor to the central processing board, the first barometric pressure measurement information generated during the first period of time;
g) storing, by the central processing board, in memory, operatively connected to the central processing board, the first temperature measurement information, the first wind speed measurement information, and the first barometric pressure measurement information;
h) obtaining, by a digital software system mounted on the unmanned aerial vehicle and operably connected to the memory, the first temperature measurement information, the first wind speed measurement information, and the first barometric pressure measurement information;
i) determining, by the digital software system:
i. first power spectral density information associated with a first plurality of frequencies based at least on the first temperature measurement information;
ii. second power spectral density information associated with the first plurality of frequencies based at least on the first wind speed measurement information; and
iii. a first sensor cutoff frequency associated with at least one of the first temperature sensor and the first wind speed sensor;
j) decimating, by the digital software system, the first temperature measurement information, the first wind speed measurement information, and the first barometric pressure measurement information to a second sampling rate during the first period of time based at least on the first power spectral density information, the second power spectral density information, and the first sensor cutoff frequency;
k) calculating, by the digital software system, a first estimated sensor spacing value based at least on the decimated first wind speed measurement information, and the first start time and the first end time associated with the first period of time;
wherein the first estimated sensor spacing value is calculated by the formula:

OG Complex Work Unit Math
wherein r is the first estimated sensor spacing value, Ū is a first wind speed value from the first wind speed measurement information, t1 corresponds to the first start time associated with the first period of time, and t2 corresponds to the first end time associated with the first period of time;
l) determining, by the digital software system, a first temperature structure coefficient based at least on the first estimated sensor spacing value and the decimated first temperature measurement information during the first period of time;
m) determining, by the digital software system, a first refractive-index structure coefficient indicative of optical turbulence during the first period of time based at least on the first temperature structure coefficient, the decimated first temperature measurement information, and the decimated first barometric pressure measurement information; and
n) transmitting, by the digital software system to an optical system, the first refractive-index structure coefficient.