Method and apparatus for location information acquisition in GNSS shadow area using drones including prism
The present disclosure provides a location information acquisition method of a computing device, including the steps of: acquiring first location information at which an electro-optical topographic surveying device is located in response to a received satellite Global Navigation Satellite System (GNSS) signal; acquiring photography information for positioning of a target object photographed by a drone while the drone is flying in a GNSS shadow area from the drone equipped with a survey prism that reflects light waves from the surveying device; calculating absolute coordinates of the target object corresponding to the surveying device based on reflective metering of the survey prism and the photography information for positioning; and calculating GNSS based second location information as location information of the target object using the absolute coordinates and the first location information.
1 . A location information acquisition method of a computing device, comprising the steps of:
acquiring first location information at which an electro-optical topographic surveying device is located in response to a received Global Navigation Satellite System (GNSS) satellite signal;
acquiring photography information for positioning of a target object photographed by a drone while the drone is flying in a GNSS shadow area from the drone equipped with a survey prism that reflects light waves from the surveying device;
calculating absolute coordinates of the drone corresponding to the surveying device based on reflective metering of the survey prism and the photography information for positioning;
calculating GNSS based second location information as location information of the target object using the absolute coordinates and the first location information;
determining a first point at which the drone is currently located as a reference point, and controlling relative location change movement of the drone on the basis of the reference point when a grey zone is identified, the grey zone in which a reflective metering strength of the survey prism is equal to or less than a threshold; and
estimating and calculating the absolute coordinates of the drone located at the grey zone using a change in reflective metering strength of the survey prism detected with the relative location change movement of the drone,
wherein
the photography information for positioning includes at least one of a photography image of the target object or an orthomosaic image using the photography image,
the photography information for positioning includes the photography image of the target object and further includes photographing time information corresponding to the photography image,
the surveying device includes a plurality of surveying devices disposed at a plurality of preset locations at which GNSS signals are received,
the step of calculating the absolute coordinates comprises the step of processing synchronization correction of the photographing time information using a preset weight matrix table for each location range by bundle block adjustment according to a relative coordinate relationship between the plurality of surveying devices,
the preset weight matrix table comprises pre-calculated weight values for each bundle block, and
the photographing time is a data acquisition time of survey data, and the data acquisition time is corrected based on the pre-calculated weight values.
2 . The location information acquisition method of the computing device according to claim 1 , wherein the survey prism is formed to allow for reflection of light at 360° in all directions by collimation of the surveying device, and is attached to a specific location of the drone.
3 . The location information acquisition method of the computing device according to claim 2 , wherein the specific location corresponds to any one of a top, a bottom or a side of the drone.
4 . The location information acquisition method of the computing device according to claim 1 , wherein the photography information for positioning includes the photography image of the target object and further includes photographing time information corresponding to the photography image, and
wherein the photographing time information includes GNSS based time information synchronized with GNSS time information of the surveying device.
5 . The location information acquisition method of the computing device according to claim 1 , wherein the photography information for positioning includes the photography image of the target object and further includes photographing time information corresponding to the photography image, and the photographing time information is unsynchronized with the surveying device, and
wherein the step of calculating the absolute coordinates comprises the steps of:
comparing first survey data by the reflective metering of the survey prism acquired at a preset data acquisition time, with second survey data acquired according to the photographing time information; and
calculating the absolute coordinates corresponding to the photography image based on survey information close within a threshold as a result of the comparison.
6 . A non-transitory computer readable recording medium storing computer program to enable a computer to perform the method of claim 1 .
7 . A computing device comprising:
a processor; and
one or more memory devices communicatively coupled to the processor,
wherein the one or more memory devices stores instructions operable when executed by the processor to perform the steps of:
acquiring first location information at which an electro-optical topographic surveying device is located in response to a received satellite Global Navigation Satellite System (GNSS) signal;
acquiring photography information for positioning of a target object photographed by a drone while the drone is flying in a GNSS shadow area from the drone equipped with a survey prism that reflects light waves from the surveying device, and calculate absolute coordinates of the drone corresponding to the surveying device based on reflective metering of the survey prism and the photography information for positioning;
calculating GNSS based second location information as location information of the target object using the absolute coordinates and the first location information;
determining a first point at which the drone is currently located as a reference point, and controlling relative location change movement of the drone on the basis of the reference point when a grey zone is identified, the grey zone in which a reflective metering strength of the survey prism is equal to or less than a threshold; and
estimating and calculating the absolute coordinates of the drone located at the grey zone using a change in reflective metering strength of the survey prism detected with the relative location change movement of the drone,
wherein
the photography information for positioning further includes photographing time information,
the surveying device includes a plurality of surveying devices disposed at a plurality of preset locations at which GNSS signals are received, and
the one or more memory devices stores instructions operable when executed by the processor to further perform processing synchronization correction of the photographing time information using a preset weight matrix table for each location range by bundle block adjustment according to a relative coordinate relationship between the plurality of surveying devices,
the preset weight matrix table comprises pre-calculated weight values for each bundle block, and
the photographing time is a data acquisition time of survey data, and the data acquisition time is corrected based on the pre-calculated weight values.
8 . The computing device according to claim 7 , wherein the survey prism is formed to allow for reflection of light at 360° in all directions by collimation of the surveying device, and is attached to a specific location of the drone, and
wherein the specific location corresponds to any one of a top, a bottom or a side of the drone.
9 . The computing device according to claim 7 , wherein the photography information for positioning includes at least one of a photography image of the target object or an orthomosaic image formed based on the photography image.
10 . The computing device according to claim 9 , wherein the photography information for positioning further includes photographing time information, and
wherein the photographing time information includes GNSS based time information synchronized with GNSS time information of the surveying device.
11 . The computing device according to claim 9 , wherein the photography information for positioning further includes photographing time information, and the photographing time information is unsynchronized with the surveying device, and
wherein the one or more memory devices stores instructions operable when executed by the processor to further perform comparing a plurality of first survey data by the reflective metering of the survey prism acquired according to a preset data acquisition time cycle with second survey data acquired according to the photographing time information, and as a result of the comparison, calculates the absolute coordinates of the target object using the survey data in which the time information is close within a threshold.