US 11,726,199 B2
Methods, computer programs, radar systems, antenna systems, and flying platforms for detecting a horizontally buried linear object
Hans Hellsten, Linköping (SE)
Assigned to SAAB AB, Linköping (SE)
Appl. No. 16/979,093
Filed by SAAB AB, Linköping (SE)
PCT Filed Mar. 8, 2019, PCT No. PCT/SE2019/050205
§ 371(c)(1), (2) Date Sep. 8, 2020,
PCT Pub. No. WO2019/172833, PCT Pub. Date Sep. 12, 2019.
Claims priority of application No. 1850261-7 (SE), filed on Mar. 9, 2018.
Prior Publication US 2020/0408896 A1, Dec. 31, 2020
Int. Cl. G01S 13/88 (2006.01); G01S 13/90 (2006.01)
CPC G01S 13/885 (2013.01) [G01S 13/90 (2013.01); G01S 13/9011 (2013.01); G01S 13/9019 (2019.05); G01S 13/9076 (2019.05)] 12 Claims
OG exemplary drawing
 
1. A feature detection based method performed in a radar system for synthetic aperture radar, SAR, vertical imaging for detecting a horizontally buried linear object, the horizontally buried linear object having a longitudinal extension, while the radar system moves on a flying platform along a trajectory corresponding to a synthetic aperture, the method comprising:
transmitting and receiving radar signals while moving along the trajectory corresponding to the synthetic aperture, wherein transmitting and receiving radar signals further comprises focusing the transmitted radar signal based on a received nadir radar signal reflection, wherein focusing the transmitted radar signal comprises:
determining a flight height of the flying platform based on the received nadir radar signal reflection, and
determining a refractive index of the ground based on a signal strength of the received nadir radar signal reflection,
wherein focusing the transmitted radar signal is based on the determined flight height and the determined refractive index,
forming a SAR image based on collected data representing radar signal reflections received from ground; and
detecting one or more features in the formed SAR image relating to the horizontally buried linear object,
wherein said trajectory being oriented in a direction substantially perpendicular to an expected orientation of the longitudinal extension of the horizontally buried object and traversing the horizontally buried object.