Long Range Oblique Photography Research Articles

Improving Target Geolocation Accuracy with Multi-View Aerial Images in Long-Range Oblique Photography

Target geolocation in long-range oblique photography (LOROP) is a challenging study due to the fact that measurement errors become more evident with increasing shooting distance, significantly affecting the calculation results. This paper introduces a novel high-accuracy target geolocation method based on multi-view observations. Unlike the usual target geolocation methods, which heavily depend on the accuracy of GNSS (Global Navigation Satellite System) and INS (Inertial Navigation System), the proposed method overcomes these limitations and demonstrates an enhanced effectiveness by utilizing multiple aerial images captured at different locations without any additional supplementary information. In order to achieve this goal, camera optimization is performed to minimize the errors measured by GNSS and INS sensors. We first use feature matching between the images to acquire the matched keypoints, which determines the pixel coordinates of the landmarks in different images. A map-building process is then performed to obtain the spatial positions of these landmarks. With the initial guesses of landmarks, bundle adjustment is used to optimize the camera parameters and the spatial positions of the landmarks. After the camera optimization, a geolocation method based on line-of-sight (LOS) is used to calculate the target geolocation based on the optimized camera parameters. The proposed method is validated through simulation and an experiment utilizing unmanned aerial vehicle (UAV) images, demonstrating its efficiency, robustness, and ability to achieve high-accuracy target geolocation.

Athermal Performance of A Dual-Band LOROP Sensor with an All-SiC Telescope

In this paper, the athermal performance of a long-range oblique photography (LOROP) sensor with an all-SiC telescope is described. The dual-band LOROP sensor includes a visible and nearinfrared (VNIR) band and a mid-wave infrared (MWIR) band, which use a common reflective mirror system. The Cassegrain telescope is composed entirely of SiC to achieve an athermal characteristic. During the flight, a thermal effect on the optical system is observed to be negligible, and the athermal performance was found to be extremely stable. Particularly, no performance degradations due to the temperature gradient were observed.

Aerooptical Design of a Long-Range Oblique Photography Pod

In recent years, the long-range oblique photography (LOROP) technique has become a preferred technique for aerial photography. The LOROP technique provides a safer mission e ight proe le for medium- and highaltitude photography. Most of the LOROP cameras are designed for pod applications and not for internal aircraft installation.Thetechniquerequiresthattheopticalwindowswouldresideone atplanesonthesidesofthecontaining pod. Consequently, performance of the LOROP camera strongly depends on the quality of the e ow around the windows. Furthermore, issues of aerooptical qualities of the e ow must be taken into account in the design of the pod geometry. The aerooptical design process of the LOROP pod is described. The design was conducted using computational e uid dynamics methods. Results from wind-tunnel experiments and a photograph taken by the camera during a supersonic e ight are presented to validate the numerical simulations results.