US 12,291,356 B2
Safe landing point search device for searching for safe landing point by using contour line information with respect to terrain map, and safe landing point search method
Youeyun Jung, Daejeon (KR); Hyochoong Bang, Daejeon (KR); and Seongheon Lee, Daejeon (KR)
Assigned to KOREA AEROSPACE RESEARCH INSTITUTE, Daejeon (KR)
Appl. No. 17/785,242
Filed by KOREA AEROSPACE RESEARCH INSTITUTE, Daejeon (KR)
PCT Filed Mar. 19, 2020, PCT No. PCT/KR2020/003782
§ 371(c)(1), (2) Date Jun. 14, 2022,
PCT Pub. No. WO2021/096000, PCT Pub. Date May 20, 2021.
Claims priority of application No. 10-2019-0143976 (KR), filed on Nov. 12, 2019.
Prior Publication US 2023/0348115 A1, Nov. 2, 2023
Int. Cl. B64G 1/62 (2006.01); B64G 1/66 (2006.01)
CPC B64G 1/62 (2013.01) [B64G 1/66 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A landing method of an unmanned exploration device comprising:
executing, by a safe landing point search device having a processor, operations for searching a safe landing point in a scanning area of an unmanned exploration device, wherein the operations comprise:
obtaining, by the safe landing point search device, a terrain map of a planned landing point;
generating, by the safe landing point search device, a plurality of contour lines in the obtained terrain map,
wherein each of the plurality of contour lines connects points having a same height in the obtained terrain map and represents a height different from other contour lines, and
wherein the plurality of contour lines comprises a first number (L) of contour line groups based on predetermined criteria, wherein the predetermined criteria include a reference minimum height value, a reference maximum height value, a preset minimum interval value, and a preset height interval value, by using the obtained terrain map, wherein the first number (L) of contour line groups is determined by dividing the preset height interval value by the preset minimum value, and the preset height interval value is set equal to a threshold height enabling safe landing; and
wherein each of the first number (L) of contour line groups includes a second number (M) of contour lines, separated by the preset height interval value, between the reference minimum height value and the reference maximum height value, and each height of the second number (M) of contour lines in each of the first number (L) of contour line groups does not overlap;
generating, by the safe landing point search device, the first number (L) of contour line maps, wherein each contour line map includes the second number (M) of contour lines belonging to each of the first number (L) of contour line groups and represents terrain conditions at different heights corresponding to a respective contour line of the second number (M) of contour lines; and
detecting, by the safe landing point search device, a largest empty circle (LEC) having a radius greater than or equal to a lower-limit radius in each of the first number (L) contour line maps, wherein the lower-limit radius is determined using the threshold height enabling safe landing; and
determining, by the safe landing point search device, a real-time hazard by using surrounding terrain information obtained from at least the terrain map, a sensor unit and a laser;
determining, by the safe landing point search device, the safe landing point in the planned landing point based on a largest radius among the first number (L) of LECs and a plurality of parameters including a diameter of the unmanned exploration device, field of view, measuring altitude, and margin related to the scanning area, and the real-time hazard;
outputting, by the safe landing point search device, the safe landing point having no real-time hazard and transmitting the safe landing point to the unmanned exploration device; and
enabling, by the safe landing point search device, landing of the unmanned exploration device on the safe landing point that is geographically safe and includes no valley or steep slope.