FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W1489674722> ?p ?o ?g. }

• W1489674722 abstract "This paper focuses on particular aspects of customised GPS receivers for radio occultation: occultation management and open-loop tracking. The two aspects are closely related because open-loop tracking requires a-priori geometric information about the occultation events. The simplest way to perform this task is to let the receiver to autonomously compute in quasi real-time all the needed parameters. Alenia Spazio-Laben is the designer and manufacturer of the ROSA instrument, a space-based, geodetic-quality radio occultation receiver commissioned by the Italian Space Agency (ASI), which features velocity and anti-velocity antennas in addition to the navigation one [1]. ROSA is an evolution of the LAGRANGE dual-frequency navigation receiver that will fly on Radarsat-2, GOCE and COSMO satellites. Handling of the occultations seen by the velocity antenna (rising occultations) is the novel aspect with respect to currently flying occultation receivers (like those onboard the CHAMP, SAC-C and GRACE missions). Rising events require special attention in order to acquire the signal in the low troposphere as soon as possible and the special techniques described hereafter are implemented in ROSA. Open-loop tracking (raw-sampling) is nowadays seen as a reliable technique to have information about the atmospheric parameters in the low troposphere from occultation signals, the closed-loop carrier phase tracking may be challenging because of the weakness and blinking nature of the signal. This is particularly true for rising occultations, the signal suddenly exits from the Earth mask and the receiver must be internally instructed exactly when, where and how to search. To this aim a simple atmospheric model that provides the atmospheric excess doppler must be available on-board, in order to let the received signal to be centred as near as possible to the correct frequency of the incoming GPS signal. Relatively high sampling rate (i.e. up to 100 Hz) will then help the users to reconstruct the signal characteristic without loss of information [3]. When these customised algorithms/models are ported to a target (in our case the ADSP 21020) performance issues rise, mainly related to numerical inaccuracies introduced by the native 40-bit architecture of the DSP. Another important issue that may be a driver in the receiver design is the average number of floating point operations needed for the preparation of open-loop data related to a single occultation event, that translates in computational load and overhead for the target processor. This paper will present the ideas behind the occultation manager and its performances connected to the open-loop tracking (i.e. real-time, on-board predictions accuracy of LEO and GPS SV). In particular the required accuracy of LEO ephemerides forward predictions was analysed. Different methods were tried, but at the end it was found that using the Navigation Kalman Filter (NKF) state and covariance predictions, always available inside the receiver and obtained with minimum effort from navigation receiver operations, provide the required accuracy for the needs of occultation handling. The absolute performances of the excess-doppler prediction technique and of the selected on-board atmospheric model are presented in other papers and validated against CHAMP real data [8], [9]. In this paper numerical accuracies in the computation of open-loop data using available real-time information are compared to an ideal double precision architecture. To this aim simulations were run on an ADSP 21020 PC simulator and the results were compared with Matlab truth results. Analyses were carried out in order to assess the sensitivity of computed parameters like the geometric impact parameter, tangent height and excess doppler to numerical and navigation errors" @default.
• W1489674722 created "2016-06-24" @default.
• W1489674722 creator A5021702538 @default.
• W1489674722 creator A5037932458 @default.
• W1489674722 creator A5057029665 @default.
• W1489674722 creator A5085093024 @default.
• W1489674722 date "2004-01-01" @default.
• W1489674722 modified "2023-09-24" @default.
• W1489674722 title "Gnss Radio Occultation From Leo: Occultation Management And Open-Loop Tracking Aspects" @default.
• W1489674722 hasPublicationYear "2004" @default.
• W1489674722 type Work @default.
• W1489674722 sameAs 1489674722 @default.
• W1489674722 citedByCount "3" @default.
• W1489674722 countsByYear W14896747222012 @default.
• W1489674722 countsByYear W14896747222013 @default.
• W1489674722 crossrefType "journal-article" @default.
• W1489674722 hasAuthorship W1489674722A5021702538 @default.
• W1489674722 hasAuthorship W1489674722A5037932458 @default.
• W1489674722 hasAuthorship W1489674722A5057029665 @default.
• W1489674722 hasAuthorship W1489674722A5085093024 @default.
• W1489674722 hasConcept C121332964 @default.
• W1489674722 hasConcept C127313418 @default.
• W1489674722 hasConcept C1276947 @default.
• W1489674722 hasConcept C12957241 @default.
• W1489674722 hasConcept C131040042 @default.
• W1489674722 hasConcept C14279187 @default.
• W1489674722 hasConcept C198613851 @default.
• W1489674722 hasConcept C199360897 @default.
• W1489674722 hasConcept C2777034083 @default.
• W1489674722 hasConcept C2779843651 @default.
• W1489674722 hasConcept C41008148 @default.
• W1489674722 hasConcept C60229501 @default.
• W1489674722 hasConcept C62649853 @default.
• W1489674722 hasConcept C76155785 @default.
• W1489674722 hasConceptScore W1489674722C121332964 @default.
• W1489674722 hasConceptScore W1489674722C127313418 @default.
• W1489674722 hasConceptScore W1489674722C1276947 @default.
• W1489674722 hasConceptScore W1489674722C12957241 @default.
• W1489674722 hasConceptScore W1489674722C131040042 @default.
• W1489674722 hasConceptScore W1489674722C14279187 @default.
• W1489674722 hasConceptScore W1489674722C198613851 @default.
• W1489674722 hasConceptScore W1489674722C199360897 @default.
• W1489674722 hasConceptScore W1489674722C2777034083 @default.
• W1489674722 hasConceptScore W1489674722C2779843651 @default.
• W1489674722 hasConceptScore W1489674722C41008148 @default.
• W1489674722 hasConceptScore W1489674722C60229501 @default.
• W1489674722 hasConceptScore W1489674722C62649853 @default.
• W1489674722 hasConceptScore W1489674722C76155785 @default.
• W1489674722 hasLocation W14896747221 @default.
• W1489674722 hasOpenAccess W1489674722 @default.
• W1489674722 hasPrimaryLocation W14896747221 @default.
• W1489674722 hasRelatedWork W106338036 @default.
• W1489674722 hasRelatedWork W1605473168 @default.
• W1489674722 hasRelatedWork W1635060425 @default.
• W1489674722 hasRelatedWork W2053497319 @default.
• W1489674722 hasRelatedWork W206853854 @default.
• W1489674722 hasRelatedWork W2141987836 @default.
• W1489674722 hasRelatedWork W2185862955 @default.
• W1489674722 hasRelatedWork W2209019548 @default.
• W1489674722 hasRelatedWork W2219083734 @default.
• W1489674722 hasRelatedWork W2285012650 @default.
• W1489674722 hasRelatedWork W239548879 @default.
• W1489674722 hasRelatedWork W2607087493 @default.
• W1489674722 hasRelatedWork W2735440983 @default.
• W1489674722 hasRelatedWork W2751032923 @default.
• W1489674722 hasRelatedWork W2774238557 @default.
• W1489674722 hasRelatedWork W2886737074 @default.
• W1489674722 hasRelatedWork W2945870534 @default.
• W1489674722 hasRelatedWork W2968340171 @default.
• W1489674722 hasRelatedWork W746722582 @default.
• W1489674722 hasRelatedWork W811002122 @default.
• W1489674722 hasVolume "180" @default.
• W1489674722 isParatext "false" @default.
• W1489674722 isRetracted "false" @default.
• W1489674722 magId "1489674722" @default.
• W1489674722 workType "article" @default.