SAR update reference point (#300)

* Add setting of reference height to Sar Sensor Model

* Update SarTests

src/UsgsAstroSarSensorModel.cpp

@@ -275,6 +275,24 @@ void UsgsAstroSarSensorModel::replaceModelState(const string& argState){
   m_covariance = stateJson["m_covariance"].get<vector<double>>();
   m_sunPosition = stateJson["m_sunPosition"].get<vector<double>>();
   m_sunVelocity = stateJson["m_sunVelocity"].get<vector<double>>();
+
+
+  // If sensor model is being created for the first time, this routine will set the reference point
+  if (m_referencePointXyz.x == 0 && m_referencePointXyz.y == 0 && m_referencePointXyz.z == 0) {
+    MESSAGE_LOG("Updating State")
+
+    double lineCtr = m_nLines / 2.0;
+    double sampCtr = m_nSamples / 2.0;
+    csm::ImageCoord ip(lineCtr, sampCtr);
+    MESSAGE_LOG("updateState: center image coordinate set to {} {}",
+                              lineCtr, sampCtr)
+    
+    double refHeight = 0;
+    m_referencePointXyz = imageToGround(ip, refHeight);
+    MESSAGE_LOG("updateState: reference point (x, y, z) {} {} {}",
+                m_referencePointXyz.x, m_referencePointXyz.y,
+                m_referencePointXyz.z)
+  }
 }
 
 string UsgsAstroSarSensorModel::getModelState() const {

tests/SarTests.cpp

@@ -84,12 +84,12 @@ TEST_F(SarSensorModel, computeGroundPartials) {
   csm::EcefCoord groundPt(1737400.0, 0.0, 0.0);
   std::vector<double> partials = sensorModel->computeGroundPartials(groundPt);
   ASSERT_EQ(partials.size(), 6);
-  EXPECT_NEAR(partials[0], -0.00023385137104424322, 1e-8);
-  EXPECT_NEAR(partials[1], -3.3408269124235446e-05, 1e-8);
-  EXPECT_NEAR(partials[2], -1.0 / 7.5, 1e-8);
-  EXPECT_NEAR(partials[3], -33.057612335589731, 1e-8);
-  EXPECT_NEAR(partials[4], 6.3906252180458977e-05, 1e-8);
-  EXPECT_NEAR(partials[5], 0.0077565105242805047, 1e-8);
+  EXPECT_NEAR(partials[0], 6.5128150576280552e-09, 1e-8);
+  EXPECT_NEAR(partials[1], -5.1810407815840636e-15, 1e-8);
+  EXPECT_NEAR(partials[2], -0.13309947654685725, 1e-8);
+  EXPECT_NEAR(partials[3], -33.057625791698072, 1e-8);
+  EXPECT_NEAR(partials[4], 6.1985123841926308e-05, 1e-8);
+  EXPECT_NEAR(partials[5], 0.007743051337209989, 1e-8);
 }
 
 TEST_F(SarSensorModel, imageToProximateImagingLocus) {