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improve correctness of GNSS datetime handling #6502

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improve correctness of GNSS datetime handling #6502

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5874f3a
improve correctness of GNSS datetime handline
edgecase14 Jul 29, 2025
9543d52
forgot another pre-commit hook
edgecase14 Jul 29, 2025
70d1283
commit-hook for real this time
edgecase14 Jul 29, 2025
2c7cebc
Merge branch 'opengisch:master' into null-gnss-time
edgecase14 Aug 13, 2025
0bdbd7d
add comment to trigger MacOS build
edgecase14 Aug 14, 2025
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2 changes: 1 addition & 1 deletion src/core/positioning/internalgnssreceiver.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -177,7 +177,7 @@ void InternalGnssReceiver::handleSatellitesInUseUpdated( const QList<QGeoSatelli
mSatellitesInfo, 0, 0, 0,
mLastGnssPositionInformation.hacc(),
mLastGnssPositionInformation.vacc(),
mLastGnssPositionInformation.utcDateTime(),
mLastGnssPositionInformation.utcDateTime().isValid() ? mLastGnssPositionInformation.utcDateTime() : QDateTime::currentDateTimeUtc(),
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This code is repeated a bunch of times. That makes me wonder:

  • should it be a procedure?
  • why check if datetime is not valid, but use hacc/vacc unconditionally? Is there really a situation with vllid accuracy but not valid time?

It seems clear something tricky is going on, but I don't understand it from the comments you didn't add, and I don't understand it from the commit message. Maybe GNSS data should not be used at all if the associated datetime is not valid, and that's the real bug.

QChar(), 0, -1, static_cast<int>( mSatellitesID.size() ), QChar( 'A' ), mSatellitesID, mSatelliteInformationValid,
mLastGnssPositionInformation.verticalSpeed(),
mLastGnssPositionInformation.magneticVariation(),
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2 changes: 1 addition & 1 deletion src/core/positioning/positioningsource.cpp
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Expand Up @@ -326,7 +326,7 @@ void PositioningSource::lastGnssPositionInformationChanged( const GnssPositionIn
lastGnssPositionInformation.vdop(),
lastGnssPositionInformation.hacc(),
lastGnssPositionInformation.vacc(),
lastGnssPositionInformation.utcDateTime().isValid() ? lastGnssPositionInformation.utcDateTime() : QDateTime::currentDateTimeUtc(),
lastGnssPositionInformation.utcDateTime(),
lastGnssPositionInformation.fixMode(),
lastGnssPositionInformation.fixType(),
lastGnssPositionInformation.quality(),
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7 changes: 4 additions & 3 deletions src/core/tracker.cpp
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Expand Up @@ -306,16 +306,17 @@ void Tracker::processPositionInformation( const GnssPositionInformation &positio
if ( !mIsActive && !mIsReplaying )
return;

mLastDevicePositionTimestampMSecsSinceEpoch = positionInformation.utcDateTime().toMSecsSinceEpoch();
mLastDevicePositionTimestampMSecsSinceEpoch = positionInformation.utcDateTime().isValid() ? positionInformation.utcDateTime().toMSecsSinceEpoch() : QDateTime::currentDateTimeUtc().toMSecsSinceEpoch();

double measureValue = 0.0;
switch ( mMeasureType )
{
case Tracker::SecondsSinceStart:
measureValue = positionInformation.utcDateTime().toSecsSinceEpoch() - mStartPositionTimestamp.toSecsSinceEpoch();
if ( positionInformation.utcDateTime().isValid() && mStartPositionTimestamp.isValid() )
measureValue = positionInformation.utcDateTime().toSecsSinceEpoch() - mStartPositionTimestamp.toSecsSinceEpoch();
break;
case Tracker::Timestamp:
measureValue = positionInformation.utcDateTime().toSecsSinceEpoch();
measureValue = positionInformation.utcDateTime().isValid() ? positionInformation.utcDateTime().toSecsSinceEpoch() : QDateTime::currentDateTimeUtc().toSecsSinceEpoch();
break;
case Tracker::GroundSpeed:
measureValue = positionInformation.speed();
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4 changes: 3 additions & 1 deletion src/core/utils/expressioncontextutils.cpp
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Expand Up @@ -44,7 +44,9 @@ QgsExpressionContextScope *ExpressionContextUtils::positionScope( const GnssPosi
const QgsGeometry point = QgsGeometry( new QgsPoint( positionInformation.longitude(), positionInformation.latitude(), positionInformation.elevation() ) );

addPositionVariable( scope, QStringLiteral( "coordinate" ), QVariant::fromValue<QgsGeometry>( point ), positionLocked );
addPositionVariable( scope, QStringLiteral( "timestamp" ), positionInformation.utcDateTime(), positionLocked );
addPositionVariable( scope, QStringLiteral( "timestamp" ),
positionInformation.utcDateTime().isValid() ? positionInformation.utcDateTime() : QDateTime::currentDateTimeUtc(),
positionLocked );
addPositionVariable( scope, QStringLiteral( "direction" ), positionInformation.direction(), positionLocked ); // Speed direction
addPositionVariable( scope, QStringLiteral( "ground_speed" ), positionInformation.speed(), positionLocked );
addPositionVariable( scope, QStringLiteral( "orientation" ), positionInformation.orientation(), positionLocked ); // Compass/magnetometer orientation
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8 changes: 6 additions & 2 deletions src/core/utils/fileutils.cpp
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Expand Up @@ -373,8 +373,12 @@ void FileUtils::addImageMetadata( const QString &imagePath, const GnssPositionIn
metadata["Exif.GPSInfo.GPSSpeedRef"] = "K";
}

metadata["Exif.GPSInfo.GPSDateStamp"] = positionInformation.utcDateTime().date();
metadata["Exif.GPSInfo.GPSTimeStamp"] = positionInformation.utcDateTime().time();
// slight change in behaviour, but more correct
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I prefer to see changes in commit messages, and comments in the code describe how it is. I find "slight change in behavior" unhelpful, and it will not age well. Change from when? Why? What actual change?

if ( positionInformation.utcDateTime().isValid() )
{
metadata["Exif.GPSInfo.GPSDateStamp"] = positionInformation.utcDateTime().date();
metadata["Exif.GPSInfo.GPSTimeStamp"] = positionInformation.utcDateTime().time();
}
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I see what you're doing, but elsewhere you are using system time instead of gnss time if gnss time is not valid. Why is this different? I'm not saying you don't have a reason but that reason is what should be in the comment.

Are you finding that there is a valid position but not valid time in gnss data?


metadata["Exif.GPSInfo.GPSSatellites"] = QString::number( positionInformation.satellitesUsed() ).rightJustified( 2, '0' );

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2 changes: 1 addition & 1 deletion src/core/utils/positioningutils.cpp
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Expand Up @@ -74,7 +74,7 @@ GnssPositionInformation PositioningUtils::averagedPositionInformation( const QLi
double verticalSpeed = std::numeric_limits<double>::quiet_NaN();
double magneticVariation = std::numeric_limits<double>::quiet_NaN();

QDateTime utcDateTime = positionsInformation.last().utcDateTime();
QDateTime utcDateTime = positionsInformation.last().utcDateTime().isValid() ? positionsInformation.last().utcDateTime() : QDateTime::currentDateTimeUtc();

QList<QgsSatelliteInfo> satellitesInView = positionsInformation.at( 0 ).satellitesInView();
int satellitesUsed = satellitesInView.size();
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