diff --git a/src/dynamics/orbit/relative_orbit.hpp b/src/dynamics/orbit/relative_orbit.hpp
index 4377ce5e7..101de90cc 100644
--- a/src/dynamics/orbit/relative_orbit.hpp
+++ b/src/dynamics/orbit/relative_orbit.hpp
@@ -9,6 +9,7 @@
 #include <math_physics/math/ordinary_differential_equation.hpp>
 #include <math_physics/orbit/relative_orbit_models.hpp>
 #include <math_physics/orbit/relative_orbit_yamanaka_ankersen.hpp>
+#include <math_physics/orbit/relative_orbit_carter.hpp>
 #include <simulation/multiple_spacecraft/relative_information.hpp>
 #include <string>
 
@@ -87,7 +88,7 @@ class RelativeOrbit : public Orbit, public math::OrdinaryDifferentialEquation<6>
   orbit::StmModel stm_model_type_;                                          //!< State Transition Matrix model type
   RelativeInformation* relative_information_;                               //!< Relative information
   orbit::RelativeOrbitYamanakaAnkersen* relative_orbit_yamanaka_ankersen_;  //!< Relative Orbit Calcilater with Yamanaka-Ankersen's STM
-  orbit::RelativeOrbitYamanakaCarter* relative_orbit_carter_;               //!< Relative Orbit Calcilater with Carter's STM
+  orbit::RelativeOrbitCarter* relative_orbit_carter_;               //!< Relative Orbit Calcilater with Carter's STM
 
   /**
    * @fn InitializeState
diff --git a/src/library/orbit/relative_orbit_models.cpp b/src/library/orbit/relative_orbit_models.cpp
deleted file mode 100644
index 4c270e6a9..000000000
--- a/src/library/orbit/relative_orbit_models.cpp
+++ /dev/null
@@ -1,226 +0,0 @@
-/**
- * @file relative_orbit_models.cpp
- * @brief Functions for relative orbit
- */
-#include "relative_orbit_models.hpp"
-
-#include <environment/global/physical_constants.hpp>
-#include "../external/sgp4/sgp4unit.h"  // for getgravconst()
-
-libra::Matrix<6, 6> CalcHillSystemMatrix(double orbit_radius_m, double gravity_constant_m3_s2) {
-  libra::Matrix<6, 6> system_matrix;
-
-  double n = sqrt(gravity_constant_m3_s2 / pow(orbit_radius_m, 3));
-  system_matrix[0][0] = 0.0;
-  system_matrix[0][1] = 0.0;
-  system_matrix[0][2] = 0.0;
-  system_matrix[0][3] = 1.0;
-  system_matrix[0][4] = 0.0;
-  system_matrix[0][5] = 0.0;
-  system_matrix[1][0] = 0.0;
-  system_matrix[1][1] = 0.0;
-  system_matrix[1][2] = 0.0;
-  system_matrix[1][3] = 0.0;
-  system_matrix[1][4] = 1.0;
-  system_matrix[1][5] = 0.0;
-  system_matrix[2][0] = 0.0;
-  system_matrix[2][1] = 0.0;
-  system_matrix[2][2] = 0.0;
-  system_matrix[2][3] = 0.0;
-  system_matrix[2][4] = 0.0;
-  system_matrix[2][5] = 1.0;
-  system_matrix[3][0] = 3.0 * n * n;
-  system_matrix[3][1] = 0.0;
-  system_matrix[3][2] = 0.0;
-  system_matrix[3][3] = 0.0;
-  system_matrix[3][4] = 2.0 * n;
-  system_matrix[3][5] = 0.0;
-  system_matrix[4][0] = 0.0;
-  system_matrix[4][1] = 0.0;
-  system_matrix[4][2] = 0.0;
-  system_matrix[4][3] = -2.0 * n;
-  system_matrix[4][4] = 0.0;
-  system_matrix[4][5] = 0.0;
-  system_matrix[5][0] = 0.0;
-  system_matrix[5][1] = 0.0;
-  system_matrix[5][2] = -n * n;
-  system_matrix[5][3] = 0.0;
-  system_matrix[5][4] = 0.0;
-  system_matrix[5][5] = 0.0;
-
-  return system_matrix;
-}
-
-libra::Matrix<6, 6> CalcHcwStm(double orbit_radius_m, double gravity_constant_m3_s2, double elapsed_time_s) {
-  libra::Matrix<6, 6> stm;
-
-  double n = sqrt(gravity_constant_m3_s2 / pow(orbit_radius_m, 3));
-  double t = elapsed_time_s;
-  stm[0][0] = 4.0 - 3.0 * cos(n * t);
-  stm[0][1] = 0.0;
-  stm[0][2] = 0.0;
-  stm[0][3] = sin(n * t) / n;
-  stm[0][4] = 2.0 / n - 2.0 * cos(n * t) / n;
-  stm[0][5] = 0.0;
-  stm[1][0] = -6.0 * n * t + 6 * sin(n * t);
-  stm[1][1] = 1.0;
-  stm[1][2] = 0.0;
-  stm[1][3] = -2.0 / n + 2.0 * cos(n * t) / n;
-  stm[1][4] = 4.0 * sin(n * t) / n - 3.0 * t;
-  stm[1][5] = 0.0;
-  stm[2][0] = 0.0;
-  stm[2][1] = 0.0;
-  stm[2][2] = cos(n * t);
-  stm[2][3] = 0.0;
-  stm[2][4] = 0.0;
-  stm[2][5] = sin(n * t) / n;
-  stm[3][0] = 3.0 * n * sin(n * t);
-  stm[3][1] = 0.0;
-  stm[3][2] = 0.0;
-  stm[3][3] = cos(n * t);
-  stm[3][4] = 2 * sin(n * t);
-  stm[3][5] = 0.0;
-  stm[4][0] = -6.0 * n + 6.0 * n * cos(n * t);
-  stm[4][1] = 0.0;
-  stm[4][2] = 0.0;
-  stm[4][3] = -2.0 * sin(n * t);
-  stm[4][4] = -3.0 + 4.0 * cos(n * t);
-  stm[4][5] = 0.0;
-  stm[5][0] = 0.0;
-  stm[5][1] = 0.0;
-  stm[5][2] = -n * sin(n * t);
-  stm[5][3] = 0.0;
-  stm[5][4] = 0.0;
-  stm[5][5] = cos(n * t);
-  return stm;
-}
-
-// 定数やreferenceの軌道要素は以下のように取得できます
-// gravconsttype whichconst = wgs72;
-// double mu_km3_s2, radius_earth_km, tumin, xke, j2, j3, j4, j3oj2;
-// getgravconst(whichconst, tumin, mu_km3_s2, radius_earth_km, xke, j2, j3, j4, j3oj2);
-// double semi_major_axis_m = reference_oe->GetSemiMajorAxis_m();
-// double eccentricity = reference_oe->GetEccentricity();
-
-libra::Matrix<6, 6> CalcMeltonStm(double orbit_radius_m, double gravity_constant_m3_s2, double elapsed_time_s, OrbitalElements* reference_oe) {
-  libra::Matrix<6, 6> stm;
-  // ここでstmを計算してください
-  return stm;
-}
-
-libra::Matrix<6, 6> CalcSsStm(double orbit_radius_m, double gravity_constant_m3_s2, double elapsed_time_s, OrbitalElements* reference_oe) {
-  libra::Matrix<6, 6> stm;
-  // ここでstmを計算してください
-  return stm;
-}
-
-libra::Matrix<6, 6> CalcSabatiniStm(double orbit_radius_m, double gravity_constant_m3_s2, double elapsed_time_s, OrbitalElements* reference_oe) {
-  libra::Matrix<6, 6> stm;
-  // ここでstmを計算してください
-  return stm;
-}
-
-libra::Matrix<6, 6> CalcCarterStm(double orbit_radius_m, double gravity_constant_m3_s2, double f_ref_rad, double f_ref_0_rad, OrbitalElements* reference_oe){
-  libra::Matrix<6, 6> stm;
-  libra::Matrix<6, 6> stm_inv;
-  // ここでstmを計算してください
-  double n = sqrt(gravity_constant_m3_s2 / pow(orbit_radius_m, 3));
-  double e = reference_oe->GetEccentricity();
-  double E_rad = 2 * atan(sqrt((1 - e) / (1 + e)) * tan(f_ref_rad / 2));
-  double k = e * cos(f_ref_rad) + 1;
-  double K1 = pow(1 - e * e, -2.5) * (-1.5 * e * E_rad + (1 + e * e) * sin(E_rad) - e * sin(2. * E_rad) / 4.);
-  double K2 = pow(1 - e * e, -2.5) * (0.5 * E_rad - 0.25 * sin(2 * E_rad) - e * pow(sin(E_rad), 3) / 3.);
-  double phi1 = sin(f_ref_rad) * k;
-  double phi2 = 2 * e * phi1 * (sin(f_ref_rad) / pow(k, 3) - K2) - cos(f_ref_rad) / k;
-  double phi3 = (6 * e * phi1 * K2 - (2 * pow(sin(f_ref_rad), 2) / pow(k, 2)) - (pow(cos(f_ref_rad), 2) / k) - pow(cos(f_ref_rad), 2));
-  double phi1_prime = cos(f_ref_rad) * k - e * pow(sin(f_ref_rad), 2);
-  double sigma4 = atan(tan(f_ref_rad / 2) * sqrt(-(e - 1) / (e + 1)));
-  double term1_phi2_prime = sin(f_ref_rad) / k;
-  double term2_phi2_prime = 2 * e * sin(f_ref_rad) * k * (cos(f_ref_rad) / pow(k, 3)) - (cos(f_ref_rad) / pow(1 - pow(e, 2), 5.0 / 2.0));
-  double phi2_prime = term1_phi2_prime + term2_phi2_prime;
-  double phi3_prime = k - 4 * e * pow(sin(f_ref_rad), 3) / pow(E_rad / 2., 3) + 2 * cos(f_ref_rad) * sin(f_ref_rad) / pow(E_rad / 2., 2) - 6 * e * cos(f_ref_rad) * E_rad / 2. / pow(1 - pow(e, 2), 5.0 / 2.0);
-  double S1 = -cos(f_ref_rad) - (e / 2.0) * pow(cos(f_ref_rad), 2);
-  double S2 = 3 * e * k * k * K2 - (sin(f_ref_rad) / k);
-  double S3 = -6 * k * k * K2 - ((2 + k) / (2 * k)) * sin(2 * f_ref_rad); 
-  stm[0][0] = phi1;
-  stm[0][1] = phi2;
-  stm[0][2] = phi3;
-  stm[0][3] = 0.0;
-  stm[0][4] = 0.0;
-  stm[0][5] = 0.0;
-  stm[1][0] = phi1_prime;
-  stm[1][1] = phi2_prime;
-  stm[1][2] = phi3_prime;
-  stm[1][3] = 0.0;
-  stm[1][4] = 0.0;
-  stm[1][5] = 0.0;
-  stm[2][0] = -2*S1;
-  stm[2][1] = -2*S2;
-  stm[2][2] = -S3;
-  stm[2][3] = -1;
-  stm[2][4] = 0.0;
-  stm[2][5] = 0.0;
-  stm[3][0] = -2*phi1;
-  stm[3][1] = -2*phi2;
-  stm[3][2] = -(2*phi3 + 1);
-  stm[3][3] = 0.0;
-  stm[3][4] = 0.0;
-  stm[3][5] = 0.0;
-  stm[4][0] = 0.0;
-  stm[4][1] = 0.0;
-  stm[4][2] = 0.0;
-  stm[4][3] = 0.0;
-  stm[4][4] = cos(f_ref_rad);
-  stm[4][5] = sin(f_ref_rad);
-  stm[5][0] = 0.0;
-  stm[5][1] = 0.0;
-  stm[5][2] = 0.0;
-  stm[5][3] = 0.0;
-  stm[5][4] = -sin(f_ref_rad);
-  stm[5][5] = cos(f_ref_rad);
-
-  stm_inv[0][0] = 4*S2 + phi2_prime;
-  stm_inv[0][1] = -phi2;
-  stm_inv[0][2] = 0.0;
-  stm_inv[0][3] = 2*S2;
-  stm_inv[0][4] = 0.0;
-  stm_inv[0][5] = 0.0;
-  stm_inv[1][0] = -(4*S1 + phi1_prime);
-  stm_inv[1][1] = phi1;
-  stm_inv[1][2] = 0.0;
-  stm_inv[1][3] = -2*S1;
-  stm_inv[1][4] = 0.0;
-  stm_inv[1][5] = 0.0;
-  stm_inv[2][0] = -2;
-  stm_inv[2][1] = 0.0;
-  stm_inv[2][2] = 0.0;
-  stm_inv[2][3] = -1;
-  stm_inv[2][4] = 0.0;
-  stm_inv[2][5] = 0.0;
-  stm_inv[3][0] = 2*S3 + phi3_prime;
-  stm_inv[3][1] = -phi3;
-  stm_inv[3][2] = -1;
-  stm_inv[3][3] = S3;
-  stm_inv[3][4] = 0.0;
-  stm_inv[3][5] = 0.0;
-  stm_inv[4][0] = 0.0;
-  stm_inv[4][1] = 0.0;
-  stm_inv[4][2] = 0.0;
-  stm_inv[4][3] = 0.0;
-  stm_inv[4][4] = cos(f_ref_rad);
-  stm_inv[4][5] = -sin(f_ref_rad);
-  stm_inv[5][0] = 0.0;
-  stm_inv[5][1] = 0.0;
-  stm_inv[5][2] = 0.0;
-  stm_inv[5][3] = 0.0;
-  stm_inv[5][4] = sin(f_ref_rad);
-  stm_inv[5][5] = cos(f_ref_rad);
-
-  return stm;
-}
-
-libra::Matrix<6, 6> CalcYamakawaAnkersenStm(double orbit_radius_m, double gravity_constant_m3_s2, double f_ref_rad, OrbitalElements* reference_oe){
-  libra::Matrix<6, 6> stm;
-  // ここでstmを計算してください
-  return stm;
-}
diff --git a/src/math_physics/orbit/relative_orbit_carter.cpp b/src/math_physics/orbit/relative_orbit_carter.cpp
index ab125fe1e..ffb9fe32c 100644
--- a/src/math_physics/orbit/relative_orbit_carter.cpp
+++ b/src/math_physics/orbit/relative_orbit_carter.cpp
@@ -1,6 +1,6 @@
 /**
- * @file relative_orbit_models.cpp
- * @brief Functions to calculate Yamanaka-ANkersen STM for relative orbit
+ * @file relative_orbit_carter.cpp
+ * @brief Functions to calculate Carter's STM for relative orbit
  */
 #include "relative_orbit_carter.hpp"
 
@@ -16,17 +16,17 @@ RelativeOrbitCarter::~RelativeOrbitCarter() {}
 
 void RelativeOrbitCarter::CalculateInitialInverseMatrix(double orbit_radius_m, double gravity_constant_m3_s2, double f_ref_rad,
                                                                   OrbitalElements* reference_oe) {
-  double n = sqrt(gravity_constant_m3_s2 / pow(orbit_radius_m, 3));
+  // double n = sqrt(gravity_constant_m3_s2 / pow(orbit_radius_m, 3));
   double e = reference_oe->GetEccentricity();
   double E_rad = 2 * atan(sqrt((1 - e) / (1 + e)) * tan(f_ref_rad / 2));
   double k = e * cos(f_ref_rad) + 1;
-  double K1 = pow(1 - e * e, -2.5) * (-1.5 * e * E_rad + (1 + e * e) * sin(E_rad) - e * sin(2. * E_rad) / 4.);
+  // double K1 = pow(1 - e * e, -2.5) * (-1.5 * e * E_rad + (1 + e * e) * sin(E_rad) - e * sin(2. * E_rad) / 4.);
   double K2 = pow(1 - e * e, -2.5) * (0.5 * E_rad - 0.25 * sin(2 * E_rad) - e * pow(sin(E_rad), 3) / 3.);
   double phi1 = sin(f_ref_rad) * k;
   double phi2 = 2 * e * phi1 * (sin(f_ref_rad) / pow(k, 3) - K2) - cos(f_ref_rad) / k;
   double phi3 = (6 * e * phi1 * K2 - (2 * pow(sin(f_ref_rad), 2) / pow(k, 2)) - (pow(cos(f_ref_rad), 2) / k) - pow(cos(f_ref_rad), 2));
   double phi1_prime = cos(f_ref_rad) * k - e * pow(sin(f_ref_rad), 2);
-  double sigma4 = atan(tan(f_ref_rad / 2) * sqrt(-(e - 1) / (e + 1)));
+  // double sigma4 = atan(tan(f_ref_rad / 2) * sqrt(-(e - 1) / (e + 1)));
   double term1_phi2_prime = sin(f_ref_rad) / k;
   double term2_phi2_prime = 2 * e * sin(f_ref_rad) * k * (cos(f_ref_rad) / pow(k, 3)) - (cos(f_ref_rad) / pow(1 - pow(e, 2), 5.0 / 2.0));
   double phi2_prime = term1_phi2_prime + term2_phi2_prime;
diff --git a/src/math_physics/orbit/relative_orbit_carter.hpp b/src/math_physics/orbit/relative_orbit_carter.hpp
index 9bcee57f1..5aaa05b1c 100644
--- a/src/math_physics/orbit/relative_orbit_carter.hpp
+++ b/src/math_physics/orbit/relative_orbit_carter.hpp
@@ -1,10 +1,10 @@
 /**
- * @file relative_orbit_yamanaka_ankersen.hpp
- * @brief Functions to calculate Yamanaka-ANkersen STM for relative orbit
+ * @file relative_orbit_carter.hpp
+ * @brief Functions to calculate Carter's STM for relative orbit
  */
 
-#ifndef S2E_LIBRARY_ORBIT_RELATIVE_ORBIT_YAMANAKA_ANKERSEN_HPP_
-#define S2E_LIBRARY_ORBIT_RELATIVE_ORBIT_YAMANAKA_ANKERSEN_HPP_
+#ifndef S2E_LIBRARY_ORBIT_RELATIVE_ORBIT_CARTER_HPP_
+#define S2E_LIBRARY_ORBIT_RELATIVE_ORBIT_CARTER_HPP_
 
 #include "../math/matrix.hpp"
 #include "./orbital_elements.hpp"