Program Listing for File ephemeris_simulation.h

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#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