Improving the Performance of Galileo E1-OS by Optimizing the I/NAV Navigation Message

Paonni, Matteo; Anghileri, Marco; Burger, Thomas; Ries, Lionel; Schlotzer, Susanne; Schotsch, Birgit; Ouedraogo, Mahamoudou; Damy, Sophie; Châtre, Eric; Jeannot, M.; Godet, Jeremie; Hayes, Dominic

doi:10.33012/2019.17048

Cited by 4 publications

(3 citation statements)

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“…The inclusion of Reduced CED (hereafter RedCED) word 16 and Outer Forward Error Correction (FEC2) based on Reed-Solomon (hereafter RS) words 17-20 [2,3] was proposed in order to improve the conditions of CED information retrieval. The RedCED word 16 contains the information of legacy words 1-4 compressed in a single word with reduced bits (and, therefore, reduced accuracy), while RS words 17-20 complement words 1-4 with information protected via the FEC2 RS algorithm that will complement words 1-4, as shown in Table 1.…”

Section: Introductionmentioning

confidence: 99%

“…The introduction of the Secondary Synchronization Pattern (hereafter SSP) [2] is intended to improve the time needed for time convergence when a coarse estimate is available (within +/− 3 s), as it will resolve the ambiguity when the receiver retrieves SSP bits pattern every 2 s among three possible patterns. The SSP information is present on the raw navigation data bits with no need to decode further data.…”

Section: Introductionmentioning

confidence: 99%

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Galileo Receiver Performance Analysis with New I/NAV Improvements Live Data

Nunes,

Ouedraogo,

Schlötzer

et al. 2023

Enc 2023

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Galileo Receiver Performance Analysis with New I/NAV Improvements Live Data

Nunes,

Ouedraogo,

Schlötzer

et al. 2023

Enc 2023

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show abstract

“…Delayed disclosure protocols for GNSS have several advantages, but the main disadvantages are that they require an external loose time reference, and that they purposely delay the disclosure of the cryptographic key required for the authentication verification, which increases the Time To First Authenticated Fix (TTFAF) with respect to TTFF [12]. For Galileo, TTFF has been typically in the order of 30-60 seconds, although some recent improvements (the so-called I/NAV improvements) in the navigation message will bring it to even lower values [13].…”

Section: Introductionmentioning

confidence: 99%

OSNMAlib: An Open Python Library for Galileo OSNMA

Galan¹,

Fernández‐Hernández

Cucchi

2022

2022 10th Workshop on Satellite Navigation Technology (NAVITEC)

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Galileo is the first global navigation satellite system to authenticate their civilian signals through the Open Service Galileo Message Authentication (OSNMA) protocol. However, OSNMA adds a delay in the time to obtain a first position and time fix, the so-called Time To First Authentication Fix (TTFAF). Reducing the TTFAF as much as possible is crucial to integrate the technology seamlessly into the current products. In the cases where the receiver already has cryptographic data available, the so-called hot start mode and focus of this article, the currently available implementations achieve an average TTFAF of around 100 seconds in ideal environments. In this work, we dissect the TTFAF process, propose two main optimizations to reduce the TTFAF, and benchmark these optimizations in three distinct scenarios (open-sky, soft urban, and hard urban) with recorded real data. Moreover, we also evaluate the optimizations using the synthetic scenario from the official OSNMA test vectors. The first block of optimizations centers on extracting as much information as possible from broken sub-frames by processing them at page level and combining redundant data from multiple satellites. The second block of optimizations aims to reconstruct missed navigation data by the intelligent use of fields in the authentication tags belonging to the same sub-frame as the authentication key. Combining both optimization ideas improves the TTFAF substantially for all considered scenarios. We obtain an average TTFAF of 60.9 and 68.8 seconds for the test vectors and the open-sky scenario, respectively, with a best-case of 44.0 seconds in both. Likewise, the urban scenarios see a drastic reduction of the average TTFAF between the non-optimized and optimized cases, from 127.5 to 87.5 seconds in the soft urban scenario and from 266.1 to 146.1 seconds in the hard urban scenario. These optimizations have been made available as part of the open-source OSNMAlib library on GitHub.

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LEO-PNT Mega-Constellations: a New Design Driver for the Next Generation MEO GNSS Space Service Volume and Spaceborne Receivers

Menzione

Paonni

2023

2023 IEEE/ION Position, Location and Navigation Symposium (PLANS)

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Improving the Performance of Galileo E1-OS by Optimizing the I/NAV Navigation Message

Cited by 4 publications

References 0 publications

Galileo Receiver Performance Analysis with New I/NAV Improvements Live Data

Galileo Receiver Performance Analysis with New I/NAV Improvements Live Data

OSNMAlib: An Open Python Library for Galileo OSNMA

LEO-PNT Mega-Constellations: a New Design Driver for the Next Generation MEO GNSS Space Service Volume and Spaceborne Receivers

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