Move ground station to its own module for maintainability

data/tests/config/one_ground_station.yaml

@@ -19,4 +19,5 @@ doppler_noise_km_s:
 light_time_correction: false
 measurement_types:
     - Range
-    - Doppler
+    - Doppler
+integration_time: 1 min

src/od/ground_station/builtin.rs

@@ -0,0 +1,96 @@
+/*
+    Nyx, blazing fast astrodynamics
+    Copyright (C) 2018-onwards Christopher Rabotin <[email protected]>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published
+    by the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+use super::*;
+
+impl GroundStation {
+    pub fn dss65_madrid(
+        elevation_mask: f64,
+        range_noise_km: StochasticNoise,
+        doppler_noise_km_s: StochasticNoise,
+        iau_earth: Frame,
+    ) -> Self {
+        let mut measurement_types = IndexSet::new();
+        measurement_types.insert(MeasurementType::Range);
+        measurement_types.insert(MeasurementType::Doppler);
+        Self {
+            name: "Madrid".to_string(),
+            elevation_mask_deg: elevation_mask,
+            latitude_deg: 40.427_222,
+            longitude_deg: 4.250_556,
+            height_km: 0.834_939,
+            frame: iau_earth,
+            measurement_types,
+            integration_time: None,
+            light_time_correction: false,
+            timestamp_noise_s: None,
+            range_noise_km: Some(range_noise_km),
+            doppler_noise_km_s: Some(doppler_noise_km_s),
+        }
+    }
+
+    pub fn dss34_canberra(
+        elevation_mask: f64,
+        range_noise_km: StochasticNoise,
+        doppler_noise_km_s: StochasticNoise,
+        iau_earth: Frame,
+    ) -> Self {
+        let mut measurement_types = IndexSet::new();
+        measurement_types.insert(MeasurementType::Range);
+        measurement_types.insert(MeasurementType::Doppler);
+        Self {
+            name: "Canberra".to_string(),
+            elevation_mask_deg: elevation_mask,
+            latitude_deg: -35.398_333,
+            longitude_deg: 148.981_944,
+            height_km: 0.691_750,
+            frame: iau_earth,
+            measurement_types,
+            integration_time: None,
+            light_time_correction: false,
+            timestamp_noise_s: None,
+            range_noise_km: Some(range_noise_km),
+            doppler_noise_km_s: Some(doppler_noise_km_s),
+        }
+    }
+
+    pub fn dss13_goldstone(
+        elevation_mask: f64,
+        range_noise_km: StochasticNoise,
+        doppler_noise_km_s: StochasticNoise,
+        iau_earth: Frame,
+    ) -> Self {
+        let mut measurement_types = IndexSet::new();
+        measurement_types.insert(MeasurementType::Range);
+        measurement_types.insert(MeasurementType::Doppler);
+        Self {
+            name: "Goldstone".to_string(),
+            elevation_mask_deg: elevation_mask,
+            latitude_deg: 35.247_164,
+            longitude_deg: 243.205,
+            height_km: 1.071_149_04,
+            frame: iau_earth,
+            measurement_types,
+            integration_time: None,
+            light_time_correction: false,
+            timestamp_noise_s: None,
+            range_noise_km: Some(range_noise_km),
+            doppler_noise_km_s: Some(doppler_noise_km_s),
+        }
+    }
+}

src/od/ground_station/event.rs

@@ -0,0 +1,75 @@
+/*
+    Nyx, blazing fast astrodynamics
+    Copyright (C) 2018-onwards Christopher Rabotin <[email protected]>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published
+    by the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+use super::GroundStation;
+use crate::md::EventEvaluator;
+use crate::{errors::EventError, md::prelude::Interpolatable};
+use anise::prelude::Almanac;
+use hifitime::{Duration, Unit};
+use nalgebra::{allocator::Allocator, DefaultAllocator};
+use std::sync::Arc;
+
+impl<S: Interpolatable> EventEvaluator<S> for &GroundStation
+where
+    DefaultAllocator: Allocator<S::Size> + Allocator<S::Size, S::Size> + Allocator<S::VecLength>,
+{
+    /// Compute the elevation in the SEZ frame. This call will panic if the frame of the input state does not match that of the ground station.
+    fn eval(&self, rx_gs_frame: &S, almanac: Arc<Almanac>) -> Result<f64, EventError> {
+        let dt = rx_gs_frame.epoch();
+        // Then, compute the rotation matrix from the body fixed frame of the ground station to its topocentric frame SEZ.
+        let tx_gs_frame = self.to_orbit(dt, &almanac).unwrap();
+
+        let from = tx_gs_frame.frame.orientation_id * 1_000 + 1;
+        let dcm_topo2fixed = tx_gs_frame
+            .dcm_from_topocentric_to_body_fixed(from)
+            .unwrap()
+            .transpose();
+
+        // Now, rotate the spacecraft in the SEZ frame to compute its elevation as seen from the ground station.
+        // We transpose the DCM so that it's the fixed to topocentric rotation.
+        let rx_sez = (dcm_topo2fixed * rx_gs_frame.orbit()).unwrap();
+        let tx_sez = (dcm_topo2fixed * tx_gs_frame).unwrap();
+        // Now, let's compute the range ρ.
+        let rho_sez = (rx_sez - tx_sez).unwrap();
+
+        // Finally, compute the elevation (math is the same as declination)
+        // Source: Vallado, section 4.4.3
+        // Only the sine is needed as per Vallado, and the formula is the same as the declination
+        // because we're in the SEZ frame.
+        Ok(rho_sez.declination_deg() - self.elevation_mask_deg)
+    }
+
+    fn eval_string(&self, state: &S, almanac: Arc<Almanac>) -> Result<String, EventError> {
+        Ok(format!(
+            "Elevation from {} is {:.6} deg on {}",
+            self.name,
+            self.eval(state, almanac)? + self.elevation_mask_deg,
+            state.epoch()
+        ))
+    }
+
+    /// Epoch precision of the election evaluator is 1 ms
+    fn epoch_precision(&self) -> Duration {
+        1 * Unit::Second
+    }
+
+    /// Angle precision of the elevation evaluator is 1 millidegree.
+    fn value_precision(&self) -> f64 {
+        1e-3
+    }
+}