Results 1 to 10 of about 16,923 (143)
Multi-Constellation Software-Defined Receiver for Doppler Positioning with LEO Satellites [PDF]
Sensors, 2020 A Multi-Constellation Software-Defined Receiver (MC-SDR) is designed and implemented to extract the Doppler measurements of Low Earth Orbit (LEO) satellite’s downlink signals, such as Orbcomm, Iridium-Next, Globalstar, Starlink, OneWeb, SpaceX, etc.
Farzan Farhangian, René Landry
doaj +2 more sources
A Decoupled Doppler Positioning Algorithm for Dynamic Receivers Using LEO Constellation Signals [PDF]
SensorsThe advancement of low-earth-orbit (LEO) communication constellations has revitalized interest in Doppler-based positioning. However, conventional Doppler positioning algorithms struggle with dynamic receivers under unknown initial states due to the ...
Tianqi Liu +6 more
doaj +2 more sources
Doppler Positioning Performance of LEO Mega Constellation
天地一体化信息网络This paper proposed a Doppler-only point-solution algorithm and analyzed the Doppler positioning performance based on the Starlink constellation.The Doppler positioning accuracy was about 3～6 m.To achieve the meter-level positioning accuracy, the ...
Yulu ZHANG +3 more
doaj +3 more sources
How maternal position affects umbilical and middle cerebral artery Doppler indices: insights from a scoping review [PDF]
Revista Brasileira de Ginecologia e ObstetríciaBackground: During pregnancy, the maternal supine position may reduce uterine and placental perfusion due to compression of the aorta and inferior vena cava by the gravid uterus, potentially impairing maternal and fetal oxygenation.
Larissa Raso Hammes +2 more
doaj +2 more sources
Instantaneous velocity determination and positioning using Doppler shift from a LEO constellation
Satellite Navigation, 2023 To provide backup and supplementation for the Global Navigation Satellite System (GNSS), Doppler shift from Low Earth Orbit (LEO) satellites can be used as signals of opportunity to provide positioning, navigation, and timing service.
Fei Guo +5 more
doaj +1 more source
Doppler-Aided Positioning for Fused LEO Navigation Systems
Aerospace, 2023 Fused LEO navigation systems have been proposed as a low-cost means of supplementing and backing up global navigation satellite system (GNSS) navigation services based on low-earth orbit (LEO) constellations, which means broadcasting navigation signals ...
Weiwei Wang +5 more
doaj +1 more source
Results in Physics, 2020 With the wide civil applications of low-cost Global Navigation Satellite System (GNSS) receiver, precise positioning based on low-cost receiver attracted extensive attention.
Houxiang Zhou +5 more
doaj +1 more source
Applied Sciences, 2021 This work proposes a proof-of-concept ultrasound blood-flow-monitoring circuit system using a single-element transducer. The circuit system consists of a single-element ultrasonic transducer, an analog interface circuit, and a field-programmable gate ...
Hyun-Tae Park, Ji-Yong Um
doaj +1 more source
Semi-dynamical Doppler satellite positioning
Bulletin Géodésique, 1976 In semi-dynamical satellite geodesy, the satellite orbit is determined beforehand by dynamical methods, and tracking station coordinates are determined geometrically from satellite observations and the accepted satellite coordinates. This paper analyzes the use of the U.S.
J. Kouba, D. E. Wells
openaire +2 more sources
Position finding using simple Doppler sensors [PDF]
Advances in Radio Science, 2007 Abstract. An increasing number of modern applications and services is based on the knowledge of the users actual position. Depending on the application a rough position estimate is sufficient, e. g. services in cellular networks that use the information about the users actual cell. Other applications, e. g.
S. Schelkshorn, J. Detlefsen
openaire +2 more sources