During the last decades, the economic importance of tephritid fruit flies (FF) has increased worldwide because of recurrent invasions and expansions into new areas, and reduced control capabilities of current control systems. Efficient monitoring systems, thus, are required to provide fast information to act promptly. With this aim in mind, we developed two electronic trap (e‐trap) versions for adult FF: one with specific volatiles for male and female adult Ceratitis capitata, and the second, based on the attraction of adult FF to yellow colour, targeting Dacus ciliatus, Rhagoletis cerasi and Bactrocera oleae. In the case of B. oleae, the female pheromone and ammonium bicarbonate were added as synergists. In the two versions, attracted FF were retained in the trap on glued surfaces. Real‐time images of the surfaces were automatically taken and transmitted to a server. We tested the two e‐trap versions in insect‐proof cages, where flies were released and recaptured, and in commercial orchards throughout the Mediterranean: C. capitata in peach orchards in Italy; R. cerasi in cherry orchards in Greece; B. oleae in olive orchards in Spain and in Greece; and D. ciliatus in melons in plastic tunnels in Israel. The e‐trap showed excellent abilities to transmit real‐time images of trapped FF and a high specificity for trapping different FF species. The ability of the entomologist to correctly classify FF from images in the office was >88%. In addition, average number of flies/trap in e‐trap grids did not differ from numbers reported on grids of conventional traps that were operating simultaneously. The e‐traps developed and tested in this study provide the basis for the real‐time monitoring of FF were no olfactory attractants are available, and for the surveillance of alien FF incursions where generic, but not specific, olfactory attractants exists.

Modern agriculture requires technology to give precise measures about relevant parameters such as pest control. Here, we developed a decision support system (DSS) based on semi-automatic pest monitoring for managing the olive fruit fly Bactrocera oleae (Rossi), in Mallorca (Balearic Islands, Spain). The DSS was based on an algorithm that took into account spatial and temporal patterns of olive fruit fly population in an orchard where all trees were georeferenced, thus precise treatments against the pest were conducted through a location aware system (LAS). The olive fruit fly adult population was monitored by using ad hoc off-the-grid autonomous electronic traps.The results were compared with those obtained with conventional methods. For a pilot trial, we selected an olive-producing orchard, where from June to October 2015, three plots using LAS management and three plots under conventional control (NO-LAS plots) were compared. Spray threshold considered both adult population and fruit damage. An additional non-sprayed plot was selected for assessing biological control due to the parasitoid, Psyttalia concolor (Szépligeti). Results showed that the use of DSS reduced by 36.84% the volume of insecticide used in LAS compared to NO-LAS plots. Accordingly, time and distance needed for spraying were also reduced. Adult olive fruit fly population was lower in the LAS plots when compared with the NO-LAS plots; conversely, fruit infestation was higher in LAS compared with NO-LAS. The implementation of LAS and DSS at field level allowed real-time monitoring of adult olive flies, thereby increasing the accuracy and precision of sprays in time and space and decreasing impact on natural enemies.

Bi- and multistatic radar systems have larger sensitivity when compared to the monostatic configuration however, at the expense of increased system complexity. Because the different parts that compose the resulting radar system are not co-located, a synchronisation method for remote nodes is mandatory. For moving platforms, the synchronisation link requires a clock steering algorithm which tolerates ever-changing baselines as well as a method to measure the relative positioning throughout the time between a transmitter-receiver pair. It is intended to research, develop and build a versatile networked radar system which allow moving nodes to take advantage of the fact that its different nodes may adapt their relative geometry to the convenience of the situation. This paper reviews frequency and time transfer methods, and introduce the problematic associated with a dynamic two-way time transfer.

Diverse literature agrees on the advantages that multiple antennas and, thereby, multi-channel diversity brings into a modern radar system. Modern multichannel USRPs are suitable platforms for realisation of diverse radar demonstrators. However, coherency plays an essential role for accurate radar detection and tracking. This paper focuses on determining the stability of multi-channel TwinRX and UBX receiver’s daughterboards within a single and two USRP devices. A common signal generator provides the same signal to all daughterboards and the relative coherency is measured between the received digitised signals. For each daughterboard the modified Allan deviation (MDEV), phase noise and fractional frequency are measured. The measurements show that all selected daughterboards are appropriate for radar applications having MDEV less than 80 fs, phase noise better than -98 dBc/Hz at 1 Hz frequency offset and fractional frequency is in the range of 10 ^-13 .

Time synchronization and positioning of bistatic radar transceivers is required to coordinate and meaningfully merge the measurements made between them. It simultaneously allows the radar transceivers to change their position throughout time. Despite their acknowledged vulnerabilities, Global Navigation Satellite Systems (GNSSs) are the preferred source for Positioning, Navigation and Timing (PNT) services. Because of these vulnerabilities however, research on possible signal sources to obtain alternative positioning, navigation and timing (A-PNT) is of interest. This present work proposes the use of a narrow-band transponder installed on a geostationary (GEO) satellite to be used as one anchor for a future time transfer. A channel calibration is made between the transceiver station and the chosen satellite. Diverse models are used to estimate the channel effects throughout the signal propagation path, estimate the time delay, and correct the measurements, accordingly. The available channel bandwidth on the proposed satellite is 2.7 kHz, limiting the accuracy of the time measurements. After integration of multiple pulses, a time accuracy of approximately 1 μs is obtained. The range measurements are compared against satellite positions propagated from publicly available two-line element sets (TLEs). The obtained results suggest that, after calibration, the expected accuracy and a good repeatability is obtained. Thus, making the QO-100 satellite a suitable anchor for the proposed technique.

Due to their reduced size and usual complex design, detection and tracking of commercial off-the-shelf (COTS) Unmanned Aerial Vehicles (UAVs) is a challenging task. It is often the case that the $UAV$ under test backscatters the impelling radiowave in a different direction than where the transmitter is, thus reducing the received signal strength for the monostatic case. By making use of spatial diversity, for some specific ge-ometries Bistatic radar systems may improve the detection probability by increasing the measured radar cross-section $(RCS)$ of targets with low monostatic $RCS$ signature. This study examines the backscattering properties of a selected COTS UAV for monostatic and bistatic radar configurations. The $RCS$ of the $UAV$ 's airframe components, along with their material properties, was calculated and simulated to estimate their contributions to the overall backscattered energy. Simulations were performed at C- (5.8 GHz) and Ka-band (34 GHz) to evaluate $RCS$ variations across a full azimuthal sweep $(0^{\mathrm{o}}\ to\ 360^{\mathrm{o}})$. The $UAV$ was modeled as both composite and perfect electric conducting $(PEC)$ materi-als. The simulated results were validated by using the monostatic configuration and the theoretical $RCS$,” based on the approximation of canonical shapes of the UAV's diverse airframe components. Results showed a significant $RCS$ enhancement for the selected bistatic geometries, particularly in the forward scatter region. As expected, the forward scatter region showed little to no dependence on the material properties. At 5.8 GHz, $a$ wider forward scatter region was observed due to the longer wavelength. In comparison, a narrower forward scatter region was observed at 34 GHz due to shorter wavelengths while maintaining the same target dimensions.