.. _program_listing_file_agents_gnss_yaw_steering.h:

Program Listing for File gnss_yaw_steering.h
============================================

|exhale_lsh| :ref:`Return to documentation for file <file_agents_gnss_yaw_steering.h>` (``agents/gnss_yaw_steering.h``)

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

.. code-block:: cpp

   
   #pragma once
   
   #include "lupnt/core/definitions.h"
   
   namespace lupnt {
   
     class GnssYawSteering {
     public:
       GnssYawSteering() = delete;
   
       // ---- Satellite-Sun-Earth geometry --------------------------------------
   
       static Real BetaAngle(const Vec3& r_sat, const Vec3& v_sat, const Vec3& r_sun);
   
       static Real OrbitAngle(const Vec3& r_sat, const Vec3& v_sat, const Vec3& r_sun);
   
       static Real OrbitNoonAngle(Real mu);
   
       // ---- Nominal yaw-attitude model (Kouba, 2009), Eq. (1)-(2) --------------
   
       static Real NominalYawAngle(Real beta, Real mu);
   
       static Real NominalYawRate(Real beta, Real mu, Real mu_dot);
   
       // ---- GPS Block IIF -------------------------------------------------------
       // (Kuang et al., 2017)
   
       static Real GpsIIFShadowYawAngle(Real t, Real ts, Real te, Real phi_ts, Real phi_te);
   
       static Real GpsIIFNoonTurnYawAngle(Real t, Real ts, Real phi_ts, Real beta);
   
       // ---- GPS Block IIR -------------------------------------------------------
       // (Kouba, 2017)
   
       static Real GpsIIRMidnightTurnYawAngle(Real t, Real ts, Real phi_ts, Real beta);
   
       static Real GpsIIRNoonTurnYawAngle(Real t, Real ts, Real phi_ts, Real beta);
   
       // ---- GPS Block III -------------------------------------------------------
       // (Montenbruck et al., 2026)
       //
       // No manufacturer-published yaw-steering model exists for GPS Block III;
       // IGS analysis centers currently substitute the nominal, GPS IIR, or
       // GPS IIF laws, none of which match the attitude quaternions distributed
       // by JPL (believed to reflect the true on-board model) particularly well.
       // Montenbruck et al. (2026) instead adapt the Galileo-IOV-type "smoothed
       // yaw steering" law (cf. `GalileoIovEclipseYawAngle`) to GPS III's wider
       // collinearity zone and lower peak yaw rate (~0.09 deg/s, vs. ~0.20 deg/s
       // for IIR and ~0.11 deg/s for IIF), finding it to give the closest overall
       // approximation (RMS yaw-angle error 1.9-3.5 deg) of the JPL quaternions
       // among the candidate models considered -- and recommend it as a
       // transitional standard for OD/PPP processing of GPS III satellites.
   
       static Vec3 Gps3SunVector(Real beta, Real mu);
   
       static Real Gps3EclipseYawAngle(Real beta, Real mu, Real phi_nom);
   
       // ---- Galileo IOV ---------------------------------------------------------
       // (EGSC, 2017)
   
       static Vec3 GalileoSunVector(Real eta, Real beta);
   
       static Real GalileoIovNominalYawAngle(Real eta, Real beta);
   
       static Real GalileoIovEclipseYawAngle(Real eta, Real beta, Real phi_nom);
   
       // ---- Galileo FOC ---------------------------------------------------------
       // (EGSC, 2017)
   
       static Real GalileoFocYawAngle(Real t, Real ts, Real phi_s);
   
       // ---- BDS-3 CAST (WHU model) ----------------------------------------------
       // (Wang et al., 2018)
   
       static Real Bds3CastIgsoYawAngle(Real t, Real ts, Real phi_s);
   
       static Real Bds3CastMeoYawAngle(Real t, Real ts, Real phi_s);
   
       // ---- BDS-3 SECM (CSNO / MCSNO models) ------------------------------------
       // (CSNO, 2019; Xia et al., 2018; Yang et al., 2023)
   
       static Real Bds3SecmCsnoYawAngle(Real beta, Real mu);
   
       static Real Bds3SecmMcsnoYawAngle(Real t, Real t0, Real ts, Real te, Real beta, Real beta_dot,
                                         Real mu, Real mu_ts, Real mu_dot, Real phi_ts);
   
       // ---- FORTRAN-style helper -------------------------------------------------
   
       static Real Sign(Real a, Real b);
   
     private:
       static Real CosineTransitionYawAngle(Real t, Real ts, Real phi_s, double period_s);
     };
   
   }  // namespace lupnt