Leith Bade

Engineer at Swift Navigation

[Leith Bade @leithbade]

@NASA @NASAArtemis Do you have any special Easter treats like hot cross buns or chocolate eggs?

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#horizonslive why has gravity not been explained by quantum physics?

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@doug_ellison Hopefully they post the raw video files some stage.

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@doug_ellison I was playing with the earlier rover down look frames and the best match with the official JPL video was 3 fps. It seems the images on the raw image page are only every 10th frame, so I wonder why the JPL video appears to be the full 30 fps since the extra frames are missing.

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@GalileoSats We actually saw issues with the satellites clocks starting shortly after 00:00 UTC when looking back at the data after the outage.

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@DCPowerCo Looks like NSW now allows larger residential solar installations - https://t.co/EoICqOSI6G
Might be something worth sharing

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@NSWRFS the link at top of the RFS website for "leave zone areas" is not working

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@coandrei @fgi_nls @Maanmittaus @GNSSfinland @JarkkotKoskinen @EU_GNSS Last satellite E33 to get data was updated an hour ago. All satellites are sending valid ephemeris now.

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@NavSAS @EU_GNSS @fdovis @LinksFoundation @PoliTOnews @AlexMinetto @M_Vannucchi @marionicola75 @MicaelaTrogliaG @G_Povero The SISA value reflects the latest update from GSC that initial recovery steps have been taken but the system is not yet back to full operation.

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@NavSAS @EU_GNSS @fdovis @LinksFoundation @PoliTOnews @AlexMinetto @M_Vannucchi @marionicola75 @MicaelaTrogliaG @G_Povero The broadcast Galileo ephemeris sets the Signal In Space Accuracy field to No Accuracy Prediction Available which the Galileo OS SDD says means the satellites are still unhealthy. It seems some receivers have not correctly implemented this detail

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@GlbGnss @EU_GNSS @GalileoGNSS @GNSSasia @insideGNSS Its surprising it will navigate with the Galileo satellites. The ephemeris data is still setting the SISA field (Signal In Space Accuracy) field to to NAPA (No Accuracy Prediction Available) which Galileo ICD says means the signal is not healthy.

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@GPSGIS_Eric For a start they need to set the health flags on their satellite as unhealthy as soon as an outage starts

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@coandrei @fgi_nls @Maanmittaus @GNSSfinland @GalileoGNSS @esa @EU_GNSS @GNSS_Status @JarkkotKoskinen @GPSBackup @LeoBodnar @LaunchStuff @planet4589 I also noticed satellite E33 has not had new data uploaded yet.

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@coandrei @fgi_nls @Maanmittaus @GNSSfinland @GalileoGNSS @esa @EU_GNSS @GNSS_Status @JarkkotKoskinen @GPSBackup @LeoBodnar @LaunchStuff @planet4589 Another popular brand of reference station receiver however does pick up the satellites are unhealthy.

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@coandrei @fgi_nls @Maanmittaus @GNSSfinland @GalileoGNSS @esa @EU_GNSS @GNSS_Status @JarkkotKoskinen @GPSBackup @LeoBodnar @LaunchStuff @planet4589 Upload rate is back to 10 minute intervals. the SISA value is set to No Accuracy Prediction Available which should stop receivers using the satellites. Health flags still not changed though?

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@coandrei @fgi_nls @Maanmittaus @GNSSfinland @GalileoGNSS @esa @EU_GNSS @GNSS_Status @JarkkotKoskinen @GPSBackup @LeoBodnar @LaunchStuff @planet4589 That looks like a receiver bug. However I noticed that brand of receiver (which I also have access to) was attempting to use Galileo the last few days too but rejected them after the RAIM check failed. They have not properly implemented the health checks!

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@coandrei @fgi_nls @Maanmittaus @GNSSfinland @JarkkotKoskinen @Tiedetuubi @EU_GNSS However unusual behaviour happens during batch 5 (Jul 10 10:30 to 18:38) and there are rumours that there was bad data in this batch. This time also coincides with when the first NAGU 2019025 was sent perhaps in response to reports of problems.

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@coandrei @fgi_nls @Maanmittaus @GNSSfinland @JarkkotKoskinen @Tiedetuubi @EU_GNSS Apparently each Galileo stores in memory 8 batches of data each of which is transmitted for 3 hours but valid for 4 hours. After Jul 10 13:24 it appears that two batches of data were broadcasted. Starting on Jul 11 02:47 all 8 batches are broadcast until the data runs out.

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@coandrei @fgi_nls @Maanmittaus @GNSSfinland @JarkkotKoskinen @Tiedetuubi @EU_GNSS Yes that matches my analysis. The usual ground to satellite update frequency for Galileo is 10 minutes as seen until Jul 10 13:24, it then stop until 17:52, and continues to Jul 11 02:47, and there have been no uploads since.

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@coandrei You should try plotting the IOD nav value for the last week. It shows an interesting sequence of events around the failure time.