eclipse-sailing-analytics/sailing-analytics
1
0
Fork 0
mirror of https://github.com/eclipse-sailing-analytics/sailing-analytics.git synced 2026-09-25 06:58:39 +00:00
Code Activity

bug 2086: avoid NPE by no trying to correct declination with a null position when the Wind fix wouldn't be constructed anyway

Browse Source
This commit is contained in:
Axel Uhl
2014-07-23 22:41:54 +02:00
parent 080be4d5be
commit 26fff28560
1 changed files with 41 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files
java/com.sap.sailing.domain.igtimiadapter/src/com/sap/sailing/domain/igtimiadapter/shared/IgtimiWindReceiver.java
+41 -36
View File
@@ -185,42 +185,47 @@ public class IgtimiWindReceiver implements BulkFixReceiver {
Speed aws = getAWS(timePoint, awsPair);
com.sap.sse.common.Util.Pair<GpsLatLong, GpsLatLong> gpsPair = getSurroundingFixes(getGpsTrack(deviceSerialNumber), timePoint);
Position pos = getPosition(timePoint, gpsPair);
com.sap.sse.common.Util.Pair<HDG, HDG> hdgPair = getSurroundingFixes(getHdgTrack(deviceSerialNumber), timePoint);
com.sap.sse.common.Util.Pair<HDGM, HDGM> hdgmPair = getSurroundingFixes(getHdgmTrack(deviceSerialNumber), timePoint);
Bearing heading = getHeading(timePoint, hdgPair, hdgmPair, pos);
if (awa != null && aws != null && pos != null && heading != null) {
Bearing apparentWindDirection = heading.add(awa);
SpeedWithBearing apparentWindSpeedWithDirection = new KnotSpeedWithBearingImpl(aws.getKnots(), apparentWindDirection);
/*
* Hint from Brent Russell from Igtimi, at 2013-12-05 on the question whether to use GpsLatLong to improve
* precision of boat speed / coarse over SOG/COG measurements:
*
* "Personally I would use COG/SOG exclusively, and if unhappy with the result add a small amount of
* smoothing and consider dropping samples as outliers if they cause a SOG discontinuity. The latter might
* happen as a satellite is dropped/acquired - and I'd expect to see a time correlated position jump as
* well. Probably not though a direction/speed correlation :)
*
* All our GPS systems are using Doppler to calculate COG/SOG and this should be the most accurate measure.
* I don't believe that delta position really adds any more "truth" to the measurement of physical reality,
* if that makes sense. I'd trust d-p even less at low speeds, where you'll see the most disagreement. Also
* there is a significant quantisation noise error in the d-p calculations from the GPS resolution too, so
* you'd have to smooth it before averaging - possibly in a speed dependent way.
*
* Remember that Doppler COG/SOG is using the same raw satellite measurements that are being used to
* calculate position, just the algorithm is different. I suspect that merging the two might be, in
* practice, just a slightly indirect way of averaging. If you like the central limit theorem in action over
* the set of algorithms!
*
* So again, my personal preference would be to work with the data that should be the most accurate
* (COG/SOG) and consider algorithms that handle smoothing of that data best."
*/
com.sap.sse.common.Util.Pair<SOG, SOG> sogPair = getSurroundingFixes(getSogTrack(deviceSerialNumber), timePoint);
Speed sog = getSOG(timePoint, sogPair);
com.sap.sse.common.Util.Pair<COG, COG> cogPair = getSurroundingFixes(getCogTrack(deviceSerialNumber), timePoint);
Bearing cog = getCOG(timePoint, cogPair);
SpeedWithBearing sogCog = new KnotSpeedWithBearingImpl(sog.getKnots(), cog);
SpeedWithBearing trueWindSpeedAndDirection = apparentWindSpeedWithDirection.add(sogCog);
result = new WindImpl(pos, timePoint, trueWindSpeedAndDirection);
if (pos != null) {
com.sap.sse.common.Util.Pair<HDG, HDG> hdgPair = getSurroundingFixes(getHdgTrack(deviceSerialNumber), timePoint);
com.sap.sse.common.Util.Pair<HDGM, HDGM> hdgmPair = getSurroundingFixes(getHdgmTrack(deviceSerialNumber), timePoint);
Bearing heading = getHeading(timePoint, hdgPair, hdgmPair, pos);
if (awa != null && aws != null && heading != null) {
Bearing apparentWindDirection = heading.add(awa);
SpeedWithBearing apparentWindSpeedWithDirection = new KnotSpeedWithBearingImpl(aws.getKnots(), apparentWindDirection);
/*
* Hint from Brent Russell from Igtimi, at 2013-12-05 on the question whether to use GpsLatLong to
* improve precision of boat speed / coarse over SOG/COG measurements:
*
* "Personally I would use COG/SOG exclusively, and if unhappy with the result add a small amount of
* smoothing and consider dropping samples as outliers if they cause a SOG discontinuity. The latter
* might happen as a satellite is dropped/acquired - and I'd expect to see a time correlated position
* jump as well. Probably not though a direction/speed correlation :)
*
* All our GPS systems are using Doppler to calculate COG/SOG and this should be the most accurate
* measure. I don't believe that delta position really adds any more "truth" to the measurement of
* physical reality, if that makes sense. I'd trust d-p even less at low speeds, where you'll see the
* most disagreement. Also there is a significant quantisation noise error in the d-p calculations from
* the GPS resolution too, so you'd have to smooth it before averaging - possibly in a speed dependent
* way.
*
* Remember that Doppler COG/SOG is using the same raw satellite measurements that are being used to
* calculate position, just the algorithm is different. I suspect that merging the two might be, in
* practice, just a slightly indirect way of averaging. If you like the central limit theorem in action
* over the set of algorithms!
*
* So again, my personal preference would be to work with the data that should be the most accurate
* (COG/SOG) and consider algorithms that handle smoothing of that data best."
*/
com.sap.sse.common.Util.Pair<SOG, SOG> sogPair = getSurroundingFixes(getSogTrack(deviceSerialNumber), timePoint);
Speed sog = getSOG(timePoint, sogPair);
com.sap.sse.common.Util.Pair<COG, COG> cogPair = getSurroundingFixes(getCogTrack(deviceSerialNumber), timePoint);
Bearing cog = getCOG(timePoint, cogPair);
SpeedWithBearing sogCog = new KnotSpeedWithBearingImpl(sog.getKnots(), cog);
SpeedWithBearing trueWindSpeedAndDirection = apparentWindSpeedWithDirection.add(sogCog);
result = new WindImpl(pos, timePoint, trueWindSpeedAndDirection);
} else {
result = null;
}
} else {
result = null;
}