ns-level time transfer over a microwave link using the PTP-WR protocol

Today it is possible to achieve sub-ns level time synchronization on a wireline network while only us-level synchronization can be achieved on a wireless (microwave) link. In this paper we will, first, study the performances of different time synchronization wireline based protocols, such as Precision Time Protocol (PTP), Synchronous Ethernet (SyncE) and PTP White Rabbit (PTP-WR). And then, we will present our results using a wireless link, and determine which radio technology can achieve ns range time synchronization. Our motivation is to qualify a time transfer process operating over microwave link and offering secured GNSS-like time performance

Calibration of the GNSS Signal Amplitudes in the Interference Pattern Technique for Altimetry

Global Navigation Satellite Systems signals can be used in bi-static radar systems in order to get altimetric measurements. With a single classic GNSS ground-based receiver processing the combination of the signals coming directly and after one reflection to the receiving antennas, the Interference Pattern Technique allows the computation of the height of the reflecting surface. In this case, the observed parameter is the Signal to Noise Ratio of the received composite signal, which oscillates at a frequency proportional to this height. However, the signal recordings are generally very long since the accuracy of the SNR frequency estimation is proportional to the variation of the satellite elevation during the observation interval. In this article, we propose a calibration technique that allows reducing the observation duration while keeping a centimeter accuracy performance. The proposed technique is tested on both synthetic and real data

RoSe: A sub-GHz wireless sensor platform with housing integrated overmolded antenna

A wireless sensor platform for use in ultralow-power wireless sensor networks (WSNs) is presented. The proposed round sensor (RoSe) node is physically robust, is resistant to humidity, and has a housing that can be in direct contact with food. These characteristics are achieved via injection molding technology which is investigated at both the component and the system levels. The results of injection molding tests on the node's electronic components are reported, while a housing-integrated overmolded antenna is conceived and realized. The radiator, operating in the subgigahertz industrial, scientific, and medical (ISM) band (ISM 868 or 915 MHz), has been characterized, and a good correspondence with theoretical predictions is observed. The proposed system enables industrialized mass production and results in a generic platform for wireless monitoring applications. In this paper, we present the RoSe node with a temperature sensor for use in food cold chain management, i.e., for use at temperatures down to -30 °C and in frequent contact with water due to condensation or cleaning. Its ultralow-power characteristics are demonstrated by the analysis of the charge consumption when the node performs specific tasks both in a test case and operating in a WSN. Long-term battery lifetime results while running a demo WSN are also presented

Normalized GNSS Interference Pattern Technique

It is well known that water level and snow height can be monitored with the ground reflectometry GNSS-R approach [1, 2]. In this approach the antenna situated on a mast, receives a direct GNSS signal coming from the satellite and a nadir signal reflected by the observed surface. Assuming that the antenna position is known we can compute the position of the surface of reflection. For water level monitoring and snow determination, this approach provides precise localization and dating of the measures that allows to process spatio-temporal comparison of water level and snow cover, respectively. These parameters are very important for flood monitoring, avalanche prevention, as well as for hydroelectic companies. Furthermore the approach is noninvasive and can be easily implemented on a portable instrument and embedded in a vehicle with a mast. The Interference Pattern Technique considers the behavior of the SNR of the received GNSS signal as a function of the satellite elevation [1]. The received signal is indeed the integration by the antenna of the direct and nadir reflected GNSS signals. Due to their different phase variations, the SNR oscillates at a rate proportional to the height between the antenna and the surface of specular reflection. Unfortunately the measurement is typically very long because it needs to process the SNR for high satellite elevation variations. We indeed need to observe a sufficient number of SNR oscillations to estimate the frequency and derive the surface height. In order to reduce the estimation time to a fraction of one period of the SNR variation, we propose to normalize the measures. The normalization consists in varying the antenna height of a value dh in order to read the minimum and maximum value of SNR for a given satellite elevation, and then in processing with these values the SNR measured for different satellite elevations. We show in this paper that the normalization allows to compute the cosine of the phase delay between the direct and reflected signals and to estimate the signal frequency on a fraction of a period. We also derive the minimum antenna variation range dh as a function of the satellite elevation. We deduce from this function the minimum time of observation as a function of the satellite elevation rate. We derive the exact evolution of the SNR as a function of the signals parameters (Doppler frequency, code delay, CN0) of the visible satellites [3]. The proposed method is assessed on real and synthetic signals

Universal-SBAS: A worldwide multimodal standard

This paper describes a generalisation of the aeronautical GNSS Space Based Augmentation System (SBAS) air interface, in a true worldwide multimodal standard named Universal S-BAS. Examples of usages of this multifrequency future standard are presented in the area of science and precise positioning, timing, security, robust positioning, maritime and reflectometry applications

Fatty-Acid Preference Changes during Development in Drosophila melanogaster

Fatty-acids (FAs) are required in the diet of many animals throughout their life. However, the mechanisms involved in the perception of and preferences for dietary saturated and unsaturated FAs (SFAs and UFAs, respectively) remain poorly explored, especially in insects. Using the model species Drosophila melanogaster, we measured the responses of wild-type larvae and adults to pure SFAs (14, 16, and 18 carbons) and UFAs (C18 with 1, 2, or 3 double-bonds). Individual and group behavioral tests revealed different preferences in larvae and adults. Larvae preferred UFAs whereas SFAs tended to induce both a strong aversion and a persistent aggregation behavior. Adults generally preferred SFAs, and laid more eggs and had a longer life span when ingesting these substances as compared to UFAs. Our data suggest that insects can discriminate long-chain dietary FAs. The developmental change in preference shown by this species might reflect functional variation in use of FAs or stage-specific nutritional requirements, and may be fundamental for insect use of these major dietary components

Les glandes exocrines mâle et femelle de Pseudaletia unipuncta Haw. (Lepidoptera, Noctuidae) et leur rôle dans le comportement précopulatoire des deux sexes

International audienc

Caractérisation de protéines de surface chez la blatte Leucophaea maderae (Blaberidae, Oxyhaloinae)

Chez L. maderae, les femelles et les mâles sécrètent un mélange de protéines sur toute la surface de l'abdomen. Les sternites du mâle produisent également la phéromone sexuelle alors que les sécrétions tergales sont léchées et ingérées par la femelle au cours du comportement sexuel. Les sécrétions sont composées de quatre protéines majoritaires de 18 (Lma-p18), 22 (Lma-p22), 54 (Lma-p54) et 72 kDa (Lma-p72). Lma-p18, Lma-p22 et Lma-p72 sont des protéines spécifiques du mâle. Les deux premières sont présentes uniquement dans les sécrétions tergales alors que Lma-p72 est plus abondante au niveau des sternites. Lma-p54 est présente chez les deux sexes. L'obtention de microséquences peptidiques a permis la détermination des séquences complètes des ADNc correspondant à ces protéines en utilisant des stratégies de RT-PCR et RACE-PCR. Lma-p18, comme Lma-p22, appartiendrait à la superfamille des calycines qui sont des protéines de transport pour des molécules hydrophobes. Ces protéines pourraient donc avoir comme ligands des composés volatils de la phéromone sexuelle mâle. La localisation du transcrit de Lma-p18 dans une région glandulaire exposée uniquement lors du comportement précopulatoire appuie cette hypothèse...DIJON-BU Sciences Economie (212312102) / SudocSudocFranceF