摘要:
A method and system for estimating velocity of an aircraft is provided. The method comprises transmitting a beam toward a surface from the aircraft using a Doppler beam sharpened radar altimeter, receiving a plurality of reflected signals that correspond to portions of the transmitted beam that are reflected by the surface, and forming a plurality of Doppler beams by filtering the received signals. A complex-valued array of range bin is computed with respect to frequency of the Doppler beams from at least one antenna aperture of the radar altimeter, and a range for each of the Doppler beams is estimated. A velocity vector magnitude for the aircraft is estimated by a curve fit of the range with respect to the frequency of the Doppler beams.
摘要:
Systems and methods for measuring velocity with a radar altimeter are provided. In at least one embodiment a method for measuring velocity magnitude of a platform in relation to a surface comprises transmitting a radar beam, wherein the radar beam is aimed toward a surface; receiving a plurality of reflected signals, wherein the plurality of reflected signals correspond to portions of the transmitted radar beam that are reflected by a plurality of portions of the surface; and applying Doppler filtering to the plurality of signals to form at least one Doppler beam. The method also comprises identifying range measurements within each Doppler beam in the at least one Doppler beam; and calculating the velocity magnitude based on the range measurements of the at least one Doppler beam.
摘要:
Es werden ein Verfahren und eine Vorrichtung (10) zur berührungslosen Bestimmung von Ortsgrößen eines Objekts vorgestellt, indem das Objekt mit einem Signal abgetastet wird, wobei die Beschaffenheit einer Oberfläche des Objekts ausgenutzt wird.
摘要:
L'invention concerne un procédé de construction de systèmes micro-ondes et de traitement du signal par corrélation. Elle trouvera notamment son application en cinémométrie, télémétrie, asservissement de direction et de poursuite, détection d'hétérogénéité et de discontinuité dans un matériau à partir de capteurs fonctionnant au contact ou sans contact. Selon le procédé de l'invention, qui utilise le rayonnement micro-onde, des antennes de réception des micro-ondes et au moins un corrélateur, on réalise au moins les étapes suivantes:
- on émet un rayonnement micro-onde (1) unique à l'aide d'une source micro-onde (2) dont les caractéristiques sont déterminées et d'une antenne d'émission A, - on capte à l'aide d'antennes de réception A1, A2 situées en différents points, le rayonnement micro-onde émis, - on dirige les signaux perçus par les antenes de réception A1 et A2 vers un ou plusieurs corrélateurs (3), - on analyse le spectre de fréquence du signal de sortie du ou des corrélateurs.
Selon l'invention, l'analyse du spectre de fréquence du signal de sortie s'effectue par transformée de Fourier (FFT) ou par tout dispositif permettant d'extraire le fondamental du signal de sortie ou de mesurer l'intervalle de temps séparant deux passages au zéro du dit signal de sortie.
摘要:
A method and system for estimating velocity of an aircraft is provided. The method comprises transmitting a beam toward a surface from the aircraft using a Doppler beam sharpened radar altimeter, receiving a plurality of reflected signals that correspond to portions of the transmitted beam that are reflected by the surface, and forming a plurality of Doppler beams by filtering the received signals. A complex-valued array of range bin is computed with respect to frequency of the Doppler beams from at least one antenna aperture of the radar altimeter, and a range for each of the Doppler beams is estimated. A velocity vector magnitude for the aircraft is estimated by a curve fit of the range with respect to the frequency of the Doppler beams.
摘要:
A measuring apparatus is provided in one of two objects moving relatively to each other. The apparatus includes a circuit (18, 20) for effecting a direct spread modulation with respect to a transmission carrier signal (f₀) using modulation codes (MA1, MB1); an antenna unit (22, 24) for transmitting the modulated carrier signal toward the other of the two objects and for receiving a reflection wave therefrom; a circuit (30, 32) for demodulating the received reflection wave signal using the transmission carrier signal; a circuit (42, 44) for making correlation between the demodulated output signal (IF1, IF2) and a signal (MA2, MB2) having the same code as that of the modulation code and having a phase delayed by a predetermined time; a unit (46, 48) for extracting a Doppler frequency component contained in a signal which has been propagated through a propagation path existing in a specified distance range; and a circuit (60) for properly processing the extracted Doppler frequency component. By the constitution, it is possible to precisely measure a speed and/or direction angle of one object relative to the other of the two objects, without being subject to an influence by a reflection in the close neighborhood, or an influence by interference of a transmission signal or interference signal in a receiving channel of the apparatus.
摘要:
An apparatus for measuring speed with respect to an object comprises first to Nth sensors (13) sensitive to energy received from first to Nth consecutive regions, respectively, of the object. Signal delay means (21-27) are provided to delay the signals from the second to Nth sensors, the delay increasing with sensor number. A subtractor (16) is provided to form the difference between the sum of the signals of the even-numbered sensors and the sum of the signals of the odd-numbered sensors.
摘要:
An apparatus for measuring speed with respect to an object comprises first to Nth sensors (13) sensitive to energy received from first to Nth consecutive regions, respectively, of the object. Signal delay means (21-27) are provided to delay the signals from the second to Nth sensors, the delay increasing with sensor number. A subtractor (16) is provided to form the difference between the sum of the signals of the even-numbered sensors and the sum of the signals of the odd-numbered sensors.