.. _program_listing_file_simulations_ephemeris_ephemeris_simulation.h:

Program Listing for File ephemeris_simulation.h
===============================================

|exhale_lsh| :ref:`Return to documentation for file <file_simulations_ephemeris_ephemeris_simulation.h>` (``simulations/ephemeris/ephemeris_simulation.h``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   #pragma once
   
   #include <string>
   #include <vector>
   
   #include "lupnt/conversions/frame_converter.h"
   #include "lupnt/core/constants.h"
   #include "lupnt/simulations/simulation.h"
   
   namespace lupnt {
   
     struct EphemerisOrbitConfig {
       double a_m = 6541.4e3;
       double ecc = 0.6;
       double inc_rad = 56.2 * RAD;
       double raan_rad = 0.0;
       double argp_rad = 90.0 * RAD;
       double m0_rad = 0.0;
   
       Frame coe_frame = Frame::MOON_OP;
     };
   
     struct EphemerisSimulationConfig {
       std::string start_epoch_utc = "2027-01-01T00:00:00";
       EphemerisOrbitConfig orbit;
   
       Frame propagate_frame = Frame::MOON_CI;
   
       double duration_days = 3.0;
       double sample_dt_s = 60.0;
   
       // Force model for the numerically propagated truth trajectory.
       int moon_gravity_degree = 20;
       int moon_gravity_order = 20;
       bool include_earth = true;
       bool include_sun = true;
       bool use_relativity = false;
       double integration_step_s = 30.0;
   
       std::vector<double> fit_window_minutes = {60.0, 120.0, 240.0, 480.0};
   
       int num_windows = 6;
   
       int cartesian_poly_order = 8;
       bool cartesian_use_keplerian_baseline = true;
       int cartesian_num_fourier_terms = 0;
       int almanac_poly_order = 1;
       int almanac_num_fourier_terms = 1;
   
       Frame output_frame = Frame::MOON_CI;
   
       double datasize_precision_m = 0.01;
     };
   
     struct EphemerisWindowResult {
       double fit_window_min = 0.0;
       int num_params = 0;
       int total_bits = 0;
       double pos_rms_m = 0.0;
       double vel_rms_mps = 0.0;
       double pos_p95_m = 0.0;
       double vel_p95_mps = 0.0;
     };
   
     struct EphemerisResults {
       VecXd t_truth_s;  // Elapsed time since start_epoch_utc [s], size [N]
       MatXd rv_truth;   // Truth Cartesian states [N x 6] in output_frame
   
       std::vector<EphemerisWindowResult> cartesian_results;
       std::vector<EphemerisWindowResult> almanac_results;
     };
   
     // The ephemeris/almanac datasize-accuracy study is driven by `EphemerisApp`
     // (applications/ephemeris/ephemeris_app.h) on a thin `EphemerisManager` agent, via
     // `pnt.Simulation(...)`. The `EphemerisSimulationConfig`/`EphemerisResults` structs above
     // are the shared config/result payloads consumed by that app: for each
     // `fit_window_minutes` entry, `num_windows` windows are sampled across a numerically
     // propagated lunar-orbit truth trajectory; each ephemeris/almanac model is fit and
     // evaluated (RMS/95th-percentile RTN position and velocity error) on every window, and the
     // minimum per-parameter broadcast resolution (bit count) needed to keep the position
     // accuracy within `datasize_precision_m` is found by bisection -- mirroring the
     // accuracy/datasize trade-off studies used to size GNSS broadcast ephemeris/almanac
     // message formats.
   
   }  // namespace lupnt