mmHawkeye: Passive UAV Detection with a COTS mmWave Radar

Small Unmanned Aerial Vehicles (UAVs) are becoming potential threats to security-sensitive areas and personal privacy. A UAV can shoot photos at height, but how to detect such an uninvited intruder is an open problem. This paper presents mmHawkeye, a passive approach for UAV detection with a COTS millimeter wave (mmWave) radar. mmHawkeye doesn't require prior knowledge of the type, motions, and flight trajectory of the UAV, while exploiting the signal feature induced by the UAV's periodic micro-motion (PMM) for long-range accurate detection. The design is therefore effective in dealing with low-SNR and uncertain reflected signals from the UAV. mmHawkeye can further track the UAV's position with dynamic programming and particle filtering, and identify it with a Long Short-Term Memory (LSTM) based detector. We implement mmHawkeye on a commercial mmWave radar and evaluate its performance under varied settings. The experimental results show that mmHawkeye has a detection accuracy of 95.8% and can realize detection at a range up to 80m.Comment: 9 pages, 14 figures, IEEE SECON202

AIM : Acoustic Inertial Measurement for Indoor Drone Localization and Tracking

We present Acoustic Inertial Measurement (AIM), a one-of-a-kind technique for indoor drone localization and tracking. Indoor drone localization and tracking are arguably a crucial, yet unsolved challenge: in GPS-denied environments, existing approaches enjoy limited applicability, especially in Non-Line of Sight (NLoS), require extensive environment instrumentation, or demand considerable hardware/software changes on drones. In contrast, AIM exploits the acoustic characteristics of the drones to estimate their location and derive their motion, even in NLoS settings. We tame location estimation errors using a dedicated Kalman filter and the Interquartile Range rule (IQR). We implement AIM using an off-the-shelf microphone array and evaluate its performance with a commercial drone under varied settings. Results indicate that the mean localization error of AIM is 46% lower than commercial UWB-based systems in complex indoor scenarios, where state-of-the-art infrared systems would not even work because of NLoS settings. We further demonstrate that AIM can be extended to support indoor spaces with arbitrary ranges and layouts without loss of accuracy by deploying distributed microphone arrays

Palladium-Catalyzed C(sp²)–H Pyridocarbonylation of <i>N</i>‑Aryl-2-aminopyridines: Dual Function of the Pyridyl Moiety

An efficient synthesis of 11<i>H</i>-pyrido­[2,1-<i>b</i>]­quinazolin-11-one through palladium-catalyzed C­(sp²)–H pyridocarbonylation of <i>N</i>-aryl-2-amino­pyridines has been developed. The pyridyl group acts as an intramolecular nucleophile for the first time in C–H carbonylation reactions

A Metal-Free Tandem Demethylenation/C(sp²)–H Cycloamination Process of <i>N</i>‑Benzyl-2-aminopyridines via C–C and C–N Bond Cleavage

A mild, metal-free synthesis of pyrido[1,2-<i>a</i>]benzimidazoles starting with <i>N</i>-benzyl-2-aminopyridines, which employs PhI(OPiv)₂ as a stoichiometric oxidant, has been developed. The process is initiated by an unusual PhI(OPiv)₂-mediated <i>ipso</i> S_EAr reaction, followed by solvent-assisted C–C and C–N bond cleavage

MicNest : Long-Range Instant Acoustic Localization of Drones in Precise Landing

We present MicNest: an acoustic localization system enabling precise landing of aerial drones. Drone landing is a crucial step in a drone's operation, especially as high-bandwidth wireless networks, such as 5G, enable beyond-line-of-sight operation in a shared airspace and applications such as instant asset delivery with drones gain traction. In MicNest, multiple microphones are deployed on a landing platform in carefully devised configurations. The drone carries a speaker transmitting purposefully-designed acoustic pulses. The drone may be localized as long as the pulses are correctly detected. Doing so is challenging: i) because of limited transmission power, propagation attenuation, background noise, and propeller interference, the Signal-to-Noise Ratio (SNR) of received pulses is intrinsically low; ii) the pulses experience non-linear Doppler distortion due to the physical drone dynamics while airborne; iii) as location information is to be used during landing, the processing latency must be reduced to effectively feed the flight control loop. To tackle these issues, we design a novel pulse detector, Matched Filter Tree (MFT), whose idea is to convert pulse detection to a tree search problem. We further present three practical methods to accelerate tree search jointly. Our real-world experiments show that MicNest is able to localize a drone 120 m away with 0.53% relative localization error at 20 Hz location update frequency

Arylative Cyclization of 2‑Isocyanobiphenyls with Anilines: One-Pot Synthesis of 6‑Arylphenanthridines via Competitive Reaction Pathways

A transition-metal-free method for the synthesis of C6 phenanthridine derivatives by arylative cyclization of 2-isocyanobiphenyls with arylamines in one pot was developed. Mechanistic studies suggest that electrophilic aromatic substitution (S_EAr) of a nitrilium intermediate and homolytic aromatic substitution (HAS) of an imidoyl radical intermediate are two competitive reaction pathways involved in the annulation step

Research on the Development of Rural E-commerce in China

At present, rural e-commerce is characterized by obvious improvement in market prospect, development scale and development momentum, but there are also some problems, such as farmers' low acceptance of e-commerce, lack of promotion and training of rural e-commerce, and lack of rural e-commerce talents. Based on these problems, the government needs to increase financial support for rural e-commerce, improve the distribution logistics system, and strengthen the training of rural e-commerce personnel to promote the sustainable development of rural e-commerce

Reflections on the High-quality Development of Rural Areas in Guangshan County, Xinyang City

The problems faced by the development of Guangshan County were analyzed from the aspects of rural management talents, industrial structure, e-commerce development, and farmers' ideology, and corresponding solutions were proposed to improve the development speed of rural areas in the county and promote the high-quality development of the county as a whole

Research on the Development of Rural E-commerce in China

At present, rural e-commerce is characterized by obvious improvement in market prospect, development scale and development momentum, but there are also some problems, such as farmers' low acceptance of e-commerce, lack of promotion and training of rural e-commerce, and lack of rural e-commerce talents. Based on these problems, the government needs to increase financial support for rural e-commerce, improve the distribution logistics system, and strengthen the training of rural e-commerce personnel to promote the sustainable development of rural e-commerce

Modular Synthesis of 1,2-Benzothiazines and 1,2-Benzothiazine 1‑Imines via Palladium-Catalyzed C–H/C–C Activation Reactions

In this study, a modular approach toward cyclic sulfoximines and sulfondiimines via palladium-catalyzed intramolecular C–H/C-C activation reactions was reported. Various 1,2-benzothiazines including bicyclic, tricyclic, highly fused ones, ones of the seven-membered ring, along with 1,2-benzothiazine 1-imines were accessed in good yields. KIE experiment demonstrated that the C–H bond cleavage at the position ortho to the sulfoximine group is not the rate-determining step in the coupling reaction