m_ephemerisTime should be double (#497)

* m_ephemerisTime should be double

* Changelog entry for m_ephemerisTime

Author: oleg-alexandrov

CHANGELOG.md

@@ -36,6 +36,7 @@ release.
 ## [Unreleased]
 
 ### Fixed
+- Fix a bug in the Frame Sensor Model, the ephemeris time was rounded to it. [#497](https://github.com/DOI-USGS/usgscsm/pull/497)
 - Removed boundary checks for Frame Sensor Model getSensorPosition [#492](https://github.com/DOI-USGS/usgscsm/pull/492)
 - Fixed CAHVOR model optical shifts by removing tolerance check [#488](https://github.com/DOI-USGS/usgscsm/issues/488)
 

src/UsgsAstroFrameSensorModel.cpp

@@ -1534,7 +1534,7 @@ void UsgsAstroFrameSensorModel::replaceModelState(
     m_focalLengthEpsilon = state.at("m_focalLengthEpsilon").get<double>();
     m_nLines = state.at("m_nLines").get<int>();
     m_nSamples = state.at("m_nSamples").get<int>();
-    m_ephemerisTime = state.at("m_ephemerisTime").get<int>();
+    m_ephemerisTime = state.at("m_ephemerisTime").get<double>();
     m_currentParameterValue =
         state.at("m_currentParameterValue").get<std::vector<double>>();
     m_ccdCenter = state.at("m_ccdCenter").get<std::vector<double>>();