improve information on PSDS

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Daniel Micay 2023-03-14 05:58:22 -04:00
parent a68922fba8
commit eaf29c2a5a

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@ -834,12 +834,20 @@
servers. These contain orbits and statuses of satellites, Earth servers. These contain orbits and statuses of satellites, Earth
environmental data and time adjustment information.</p> environmental data and time adjustment information.</p>
<p>Qualcomm Snapdragon SoC devices also use the ntp.org NTP pool from <p>On 6th and 7th generation Pixels (which use a Broadcom GNSS chip),
the GNSS location service implementation when it's enabled as part of almanacs are downloaded from
improving GNSS-based location accuracy. These connections are not used https://broadcom.psds.grapheneos.org/lto2.dat,
to update the system clock. GrapheneOS will likely offer more control https://broadcom.psds.grapheneos.org/rto.dat and
over this in the future, although Pixels moving away from Snapdragon https://broadcom.psds.grapheneos.org/rtistatus.dat which are a cache
has moved this onto the backburner.</p> for Broadcom's data available at
https://gllto.glpals.com/7day/v5/latest/lto2.dat,
https://gllto.glpals.com/rto/v1/latest/rto.dat and
https://gllto.glpals.com/rtistatus4.dat. Alternatively, the standard
servers can be enabled in the Settings app which are
https://agnss.goog/lto2.dat, https://agnss.goog/rto.dat and
https://agnss.goog/rtistatus.dat providing a similar cache of
Broadcom's data currently (as of October 2022) hosted on GCP (Google
Cloud Platform).</p>
<p>On 4th and 5th generation Pixels (which use a Qualcomm baseband <p>On 4th and 5th generation Pixels (which use a Qualcomm baseband
providing cellular, Wi-Fi, Bluetooth and GNSS in separate sandboxes), providing cellular, Wi-Fi, Bluetooth and GNSS in separate sandboxes),
@ -855,20 +863,20 @@
retain the option to use the standard servers to blend in with other retain the option to use the standard servers to blend in with other
devices.</p> devices.</p>
<p>On 6th and 7th generation Pixels (which use a Broadcom GNSS chip), <p>Qualcomm Snapdragon SoC devices also fetch time from
almanacs are downloaded from time.xtracloud.net via NTP rather than using the OS time. Stock Pixel
https://broadcom.psds.grapheneos.org/lto2.dat, OS overrides this to time.google.com but we use the standard server
https://broadcom.psds.grapheneos.org/rto.dat and like other Snapdragon devices. It's technically incorrect to use the
https://broadcom.psds.grapheneos.org/rtistatus.dat which are a cache time.google.com server for this due to non-standard leap second
for Broadcom's data available at smearing not expected by the Qualcomm GNSS implementation. This could
https://gllto.glpals.com/7day/v5/latest/lto2.dat, be avoided by using OS time instead but Qualcomm built it this way to
https://gllto.glpals.com/rto/v1/latest/rto.dat and avoid GNSS-based location being crippled by having time set wrong in
https://gllto.glpals.com/rtistatus4.dat. Alternatively, the standard the OS.</p>
servers can be enabled in the Settings app which are
https://agnss.goog/lto2.dat, https://agnss.goog/rto.dat and <p>We're hosting a similar PSDS cache for Qualcomm PSDS data and plan
https://agnss.goog/rtistatus.dat providing a similar cache of to use it by default once we implement support for switching between
Broadcom's data currently (as of October 2022) hosted on GCP (Google our servers and Qualcomm's servers via the same toggle we use for the
Cloud Platform).</p> newer Broadcomm GNSS Pixels.</p>
</li> </li>
<li> <li>
<p>Connectivity checks designed to mimic a web browser user agent are performed <p>Connectivity checks designed to mimic a web browser user agent are performed