Unmanned aerial vehicle-mounted geological radar system for dam hidden danger detection and inspection method

Abstract

The unmanned aerial vehicle-mounted geological radar system comprises an unmanned aerial vehicle system, the unmanned aerial vehicle system comprises an unmanned aerial vehicle, a sensor holder, a radar holder, a foresight laser range finder and a geological radar, the sensor holder is installed on the unmanned aerial vehicle, and the foresight laser range finder is installed on the sensor holder. A radar holder is installed on the unmanned aerial vehicle on one side of the sensor holder, a geological radar is installed on the radar holder, a variable polarization geological radar antenna array is arranged in the geological radar, the variable polarization geological radar antenna array comprises a substrate, a plurality of groups of orthogonal dual-polarization Vivaldi antenna transmitting sub-arrays and receiving sub-arrays are installed on the substrate, and a plurality of groups of orthogonal dual-polarization Vivaldi antenna receiving sub-arrays are installed on the substrate. A 2 * 2 antenna array is formed by a plurality of groups of orthogonal dual-polarization Vivaldi antenna array elements and a feed network, and electromagnetic waves generated by a plurality of Vivaldi antennas are superposed in time and space phases, so that the gain and directivity of an antenna system are enhanced, and the detection depth of a radar is improved.

Description

technical field [0001] The invention relates to the technical field of unmanned aerial vehicle recording geological radar, in particular to an unmanned aerial vehicle-borne geological radar system and an inspection method for detecting hidden dangers of dams. Background technique [0002] During the long-term service of dams and other infrastructure, there are a large number of hidden dangers such as caves, cracks, leakage, and looseness. These internal hidden dangers directly affect the life of the dam and even cause disasters. Therefore, the use of advanced detection technology to comprehensively detect the hidden dangers of dams is an urgent need to ensure their safe service. Among many geophysical detection technologies, geological radar has become the mainstream method for detecting shallow hidden dangers inside dams due to its rapidity and convenience. The existing geological radars generally use a single polarization mode, and it is difficult to distinguish the elect...

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Problems solved by technology

Among them, the full-polarization geological radar realizes the combination detection mode of multiple polarization modes through the separate arrangement of antenna elements with different polarization directions and time-sharing feeding, but it needs to use the switch to detect time-sharing in the detection process. The measurement completes the combined detection of horizontal-horizontal polarization, horizontal-vertical polarization, vertical-vertical polarization and vertical-horizontal polarization. Circularly polarized waves are received by two antennas with different polarization directions, and the detection results of multiple polarization methods can be obtained in one measurement. However, the above-mentioned systems use different antennas for transmission and reception, and there are inconsistencies in performance and bandwidth.

The small-volume circularly polarized helical antenna suitable for UAVs is suitable for transmitting high-frequency and narrow-band signals. When it is used as a transmitting antenna, there is a performance mismatch with the linearly polarized wide-band receiving antenna, which seriously affects the performance of the antenna.

In addition, a single antenna is used as a transmitting antenna, which limits the antenna gain, thereby affecting the detection depth of ground radar

The geological radar with antenna arrays with multiple polarization characteristics realizes dual-polarization detection through the combination of two single-polarization antenna arrays. This method improves the gain of the geological radar antenna, but the antenna element itself does not have multipoles. The multi-polarization detection relying on the time-sharing feed of the array also requires multiple measurements of the radar on the same survey line, and the radar is large in size and inconvenient for detection;

In addition, in terms of geological radar detection operation methods, conventional geological radar radar work requires people to hold the antenna or use other machinery to assist in the detection work, which is difficult to carry out work in complex environments. A small and constant distance to ensure stable imaging

The radar antenna of the existing UAV-borne geological radar technology has deficiencies in fitting various complex terrains during travel

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