From 08ad7cf3ea141400d582c460092283c369c8985b Mon Sep 17 00:00:00 2001
From: Luc Maisonobe <luc@orekit.org>
Date: Mon, 5 May 2014 11:10:37 +0200
Subject: [PATCH] Slightly changed the intersection refinement in flat-body.
---
.../orekit/rugged/core/ExtendedEllipsoid.java | 24 +++++++++++++++++++
.../core/duvenhage/DuvenhageAlgorithm.java | 5 ++--
.../rugged/core/ExtendedEllipsoidTest.java | 6 +++--
3 files changed, 31 insertions(+), 4 deletions(-)
diff --git a/src/main/java/org/orekit/rugged/core/ExtendedEllipsoid.java b/src/main/java/org/orekit/rugged/core/ExtendedEllipsoid.java
index b64fa130..a6c7dcfb 100644
--- a/src/main/java/org/orekit/rugged/core/ExtendedEllipsoid.java
+++ b/src/main/java/org/orekit/rugged/core/ExtendedEllipsoid.java
@@ -246,4 +246,28 @@ public class ExtendedEllipsoid extends OneAxisEllipsoid {
}
+ /** Convert a line-of-sight from Cartesian to topocentric.
+ * @param primary reference point on the line-of-sight (in body frame and Cartesian coordinates)
+ * @param secondary secondary point on the line-of-sight, only used to define a direction
+ * with respect to the primary point (in body frame and Cartesian coordinates)
+ * @return line-of-sight in topocentric frame (East, North, Zenith) of the point,
+ * scaled to match radians in the horizontal plane and meters along the vertical axis
+ * @exception RuggedException if points cannot be converted to geodetic coordinates
+ */
+ public Vector3D convertLos(final Vector3D primary, final Vector3D secondary)
+ throws RuggedException {
+ try {
+
+ // switch to geodetic coordinates using primary point as reference
+ final GeodeticPoint point = transform(primary, getBodyFrame(), null);
+ final Vector3D los = secondary.subtract(primary);
+
+ // convert line of sight
+ return convertLos(point, los);
+
+ } catch (OrekitException oe) {
+ throw new RuggedException(oe, oe.getSpecifier(), oe.getParts());
+ }
+ }
+
}
diff --git a/src/main/java/org/orekit/rugged/core/duvenhage/DuvenhageAlgorithm.java b/src/main/java/org/orekit/rugged/core/duvenhage/DuvenhageAlgorithm.java
index e128456f..8b9f3097 100644
--- a/src/main/java/org/orekit/rugged/core/duvenhage/DuvenhageAlgorithm.java
+++ b/src/main/java/org/orekit/rugged/core/duvenhage/DuvenhageAlgorithm.java
@@ -154,12 +154,13 @@ public class DuvenhageAlgorithm implements IntersectionAlgorithm {
try {
if (flatBody) {
// under the (bad) flat-body assumption, the reference point must remain
- // at DEM entry, even if we already have a much better close guess :-(
+ // at DEM entry and exit, even if we already have a much better close guess :-(
// this is in order to remain consistent with other systems
final Tile tile = cache.getTile(closeGuess.getLatitude(), closeGuess.getLongitude());
+ final Vector3D exitP = ellipsoid.pointAtAltitude(position, los, tile.getMinElevation());
final Vector3D entryP = ellipsoid.pointAtAltitude(position, los, tile.getMaxElevation());
final GeodeticPoint entry = ellipsoid.transform(entryP, ellipsoid.getBodyFrame(), null);
- return tile.pixelIntersection(entry, ellipsoid.convertLos(entry, los),
+ return tile.pixelIntersection(entry, ellipsoid.convertLos(entryP, exitP),
tile.getLatitudeIndex(closeGuess.getLatitude()),
tile.getLongitudeIndex(closeGuess.getLongitude()));
} else {
diff --git a/src/test/java/org/orekit/rugged/core/ExtendedEllipsoidTest.java b/src/test/java/org/orekit/rugged/core/ExtendedEllipsoidTest.java
index a8fe639d..cefc05a7 100644
--- a/src/test/java/org/orekit/rugged/core/ExtendedEllipsoidTest.java
+++ b/src/test/java/org/orekit/rugged/core/ExtendedEllipsoidTest.java
@@ -226,11 +226,13 @@ public class ExtendedEllipsoidTest {
Vector3D converted = ellipsoid.convertLos(gp, los);
Line line = new Line(p, new Vector3D(1.0, p, 1000, los), 1.0e-10);
- for (double delta = 0; delta < 100.0; delta += 0.1) {
+ for (double delta = 0.1; delta < 100.0; delta += 0.1) {
GeodeticPoint shifted = new GeodeticPoint(gp.getLatitude() + delta * converted.getY(),
gp.getLongitude() + delta * converted.getX(),
gp.getAltitude() + delta * converted.getZ());
- Assert.assertEquals(0.0, line.distance(ellipsoid.transform(shifted)), 1.0e-3);
+ Vector3D converted2 = ellipsoid.convertLos(p, ellipsoid.transform(shifted));
+ Assert.assertEquals(0.0, Vector3D.distance(converted, converted2), 3.0e-5 * converted.getNorm());
+ Assert.assertEquals(0.0, line.distance(ellipsoid.transform(shifted)), 8.0e-4);
}
}
--
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