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In this paper, we present a design and first proof-of-concept test results of a distributed radio-localization system for tracking of moving targets with a swarm of drones. In particular, we develop and test a software framework that uses bistatic ranges to follow a target in-flight. We conduct full-system flight test with up to two drones in the a...
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... main goal of the swarming logic is to ensure that the UAVs are maintaining a pre-defined formation while moving along with the target. To facilitate accurate location estimation, the UAVs form a 10m×10m square with the TX UAV in the centre and 4 RX UAVs positioned at equal distances from it, as shown in Fig. 4. As a safety precaution, the swarming subsystem must also ensure that the UAVs do not come within 3m of each another. Further, the UAVs must be prevented from moving to an unreasonable location in case of erroneous target location estimates, i.e., when the current target location is outside a pre-defined area, or further than a certain ...
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Road traffic delay and urban overcrowding are increasing rapidly all over the world. As a result, several companies have proposed the use of small unmanned aerial vehicles (sUAVs) as an alternative to road-based transportation. These small autonomous drones are expected to operate within a thin airspace band (Very Low Level) in high traffic densiti...
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... These technologies try to address the overall lack of abundance data on insect populations [1,2] and hold potential for applications in agriculture, where pest monitoring and the decline of pollinators are critical, and in public health, for vector control strategies. Among these new Insects 2024, 15, 342 2 of 12 methods are various optical sensors [3][4][5][6][7][8][9][10][11][12][13], including entomological lidars [7,9,[14][15][16][17][18][19][20][21] and radars [22][23][24][25][26][27][28][29][30][31], as well as acoustic sensing [32][33][34]. Smart traps, imaging technologies, and computer vision [35][36][37][38][39][40][41][42] also offer alternative ways to track and evaluate insect abundance, while some instruments coupled these observations with lethal lasers to directly eliminate pests [43][44][45][46][47][48][49][50][51]. ...
This study examines the relationship between the wingbeat frequency of flying insects and ambient temperature, leveraging data from over 302,000 insect observations obtained using a near-infrared optical sensor during an eight-month field experiment. By measuring the wingbeat frequency as well as wing and body optical cross-sections of each insect in conjunction with the ambient temperature, we identified five clusters of insects and analyzed how their average wingbeat frequencies evolved over temperatures ranging from 10 °C to 38 °C. Our findings reveal a positive correlation between temperature and wingbeat frequency, with a more pronounced increase observed at higher wingbeat frequencies. Frequencies increased on average by 2.02 Hz/°C at 50 Hz, and up to 9.63 Hz/°C at 525 Hz, and a general model is proposed. This model offers a valuable tool for correcting wingbeat frequencies with temperature, enhancing the accuracy of insect clustering by optical and acoustic sensors. While this approach does not account for species-specific responses to temperature changes, our research provides a general insight, based on all species present during the field experiment, into the intricate dynamics of insect flight behavior in relation to environmental factors.
... Future studies should include all pastures within an area, implement traps on transects between pastures including forested areas and suburban settlements, sample in shorter intervals, e.g., each month after 24, 72, and 120 h. It would also be interesting to track the dispersal of individual tagged beetles, e.g., by drone-assisted harmonic radar tracking (Lavrenko et al. 2021, Woodgate et al. 2021 and relocate beetles from one pasture to another to see if there are any homing tendencies. uable advice on calculating and interpreting the population estimates in MARK and FSA. ...
Until now, little is known about the population structure and mobility of temperate dung beetles including the rainbow scarab, Phanaeus vindex (MacLeay 1819), although this knowledge is essential for their conservation as pastures become increasingly rare and the landscape fragmented by monocultures and urbanization. Here, we estimated population size, longevity, and dispersal within and between pastures. For 3 yr, we life-trapped beetles every week on 2 adjacent farms in SE Michigan, determined their sex, male morph, and size, and marked their elytra with individual tattoo patterns before releasing them. We marked a total of 470 rainbow scarabs of which 14 were recaptured once and 2 were recaptured twice. The sex ratio was not significantly sex-biased but fluctuated between months with no apparent uniformity between years. While the minor to major male ratios were unbiased in 2019 and 2020, they were marginally minor-biased in 2021. The gross population estimates for the 2 farms were 458-491 and 217 rainbow scarabs, respectively. Beetles traveled distances of up to 178 m within farms. No beetles dispersed between farms. One large female was recaptured after 338 days documenting the first cold hardiness and long lifespan of a cold-temperate dung beetle species in the wild. The low population estimates on both farms indicate 2 vulnerable populations with no or extremely limited connectivity. Supplementary funding for the land stewardship of small-scale cattle farmers could stabilize populations of native dung beetles and maintain their ecosystem services.
... To the best of our knowledge, this unique property of HR has not been addressed so far. In a practical system, it can be used to increase system's coverage, or signal-to-noise ratio (SNR), e.g., by having a HR transmitter and a receiver placed on a mobile platform such as UAVs for instance [7]. ...
Harmonic radar systems are used to interrogate, or track a location of, passive nonlinear targets in highly cluttered environments, and they are notorious for their poor power efficiency and low detection ranges. Due to harmonic operation, the received signal power close to maximum range becomes inversely proportional to the fourth power of the forward distance (from the radar transmitter to the harmonic target), compared against the inverse second power law for the return distance (from the harmonic target back to the radar receiver). This difference provides additional degrees of freedom for system design when a harmonic radar transmitter and receiver can be positioned at different distances to the target. This paper investigates the effect this has on detection range in harmonic radar.
... As for the RN antenna gain G tx , it is often assumed to be relatively large to enable tag localization (hence α 1 or α ≈ 1 if helper antenna gains are also high). On the other hand, in a system that solely relies on ranging and multilateration for tag localization, such as in [30] for instance, the RN antennas can be more broadbeam (α ≈ 1). A combination of multiple RNs with pointing and multilateration is also possible. ...
... r If there are multiple RNs, allow them to report their ranging information to some central point for processing. We note that even for a conventional (non-helper) HR system with more than one RN, a protocol for coordinating the RNs and reporting of measurements would be similar [30]. ...
In harmonic radar (HR), the transmitter illuminates a nonlinear target (the tag), causing the return signal to consist of harmonics at multiples of the transmitted carrier frequency. Of them, the second harmonic is usually the strongest and the one to which the receiver is tuned. This frequency difference distinguishes the tag reflection from environmental clutter, which remains at the illuminating frequency. However, the passive nature of HR tags severely limits the reflected power, and therefore the operational range of a HR system. We propose to increase the range and/or signal to noise ratio (SNR) by novel restructuring at the physical and signal levels. For this, we accompany the original transmitter with auxiliary transmitters able to send simple tones that are synchronized to arrive at the tag in phase, and we design the receiver to detect an intermodulation component. The resulting range and SNR are much greater than those of the original, conventional HR system, even if the original system were to transmit with power equal to the aggregate power of the proposed system. Achieving mutually coherent, (in phase), arrival of the tones at the tag is the focus of the present paper. We provide a system framework that models the tag, then present the adaptive phase coherence algorithm and analyze the probabilistic growth of the output signal power. We also account for the effects of frequency shifts due to transmitter mobility and the frequency offset errors in the transmitter local oscillators.
Sustainable and effective means to control flying insect vectors are critically needed, especially with widespread insecticide resistance and global climate change. Understanding and controlling vectors requires accurate information about their movement and activity, which is often lacking. The Photonic Fence (PF) is an optical system that uses machine vision, infrared light, and lasers to identify, track, and interdict vectors in flight. The PF examines an insect’s outline, flight speed, and other flight parameters and if these match those of a targeted vector species, then a low-power, retina-safe laser kills it. We report on proof-of-concept tests of a large, field-sized PF (30 mL × 3 mH) conducted with Aedes aegypti, a mosquito that transmits dangerous arboviruses, and Diaphorina citri, a psyllid which transmits the fatal huanglongbing disease of citrus. In tests with the laser engaged, < 1% and 3% of A. aegypti and D. citri, respectfully, were recovered versus a 38% and 19% recovery when the lacer was silenced. The PF tracked, but did not intercept the orchid bee, Euglossa dilemma. The system effectively intercepted flying vectors, but not bees, at a distance of 30 m, heralding the use of photonic energy, rather than chemicals, to control flying vectors.
In distributed radio localisation systems based on
time-of-flight measurements accuracy of time synchronisation
between radio nodes places limits on the achievable performance.
In this work, we evaluate feasibility of using pulse-per-second
reference signals provided by off-the-shelf timing GNSS modules
as a means for wireless synchronisation of distributed softwaredefines
radio nodes. Our experimental results indicate that it is
possible to achieve sub-nanosecond level synchronisation required
for accurate time-of-flight estimation. This, however, requires
post-processing and firmware modifications in order to remove
the influence of instability of the timing reference signals.
