Feat/system4 antenna

sharc/antenna/antenna_factory.py

@@ -60,6 +60,12 @@ def create_antenna(
                     azimuth,
                     elevation
                 )
+            case "Antenna System 4":
+                # Handled in station_factory.py since it requires two antennas
+                raise NotImplementedError(
+                    "Antenna System 4 requires two antenna instances and "
+                    "should be created in station_factory.py"
+                )
             case _:
                 raise ValueError(
                     f"Antenna factory does not support pattern {

sharc/antenna/antenna_s1528.py

@@ -175,12 +175,18 @@ def __init__(self, param: ParametersAntennaS1528):
         # the system design
         self.l_s = param.antenna_l_s
 
+        # far-out side-lobe level [dBi]
+        if param.far_out_side_lobe is None:
+            self.l_f = 0
+        else:
+            self.l_f = param.far_out_side_lobe
+
         # for elliptical antennas, this is the ratio major axis/minor axis
         # we assume circular antennas, so z = 1
-        self.z = 1
-
-        # far-out side-lobe level [dBi]
-        self.l_f = 0
+        if param.major_minor_axis_ratio is None:
+            self.z = 1
+        else:
+            self.z = param.major_minor_axis_ratio
 
         # back-lobe level
         self.l_b = np.maximum(
@@ -190,19 +196,22 @@ def __init__(self, param: ParametersAntennaS1528):
         # one-half the 3 dB beamwidth in the plane of interest
         self.psi_b = param.antenna_3_dB_bw / 2
 
-        if self.l_s == -15:
-            self.a = 2.58 * math.sqrt(1 - 1.4 * math.log10(self.z))
-        elif self.l_s == -20:
-            self.a = 2.58 * math.sqrt(1 - 1.0 * math.log10(self.z))
-        elif self.l_s == -25:
-            self.a = 2.58 * math.sqrt(1 - 0.6 * math.log10(self.z))
-        elif self.l_s == -30:
-            self.a = 2.58 * math.sqrt(1 - 0.4 * math.log10(self.z))
+        if math.isclose(self.z, 1.0):
+            self.a = 2.58
         else:
-            sys.stderr.write(
-                "ERROR\nInvalid AntennaS1528 L_s parameter: " + str(self.l_s),
-            )
-            sys.exit(1)
+            if self.l_s == -15:
+                self.a = 2.58 * math.sqrt(1 - 1.4 * math.log10(self.z))
+            elif self.l_s == -20:
+                self.a = 2.58 * math.sqrt(1 - 1.0 * math.log10(self.z))
+            elif self.l_s == -25:
+                self.a = 2.58 * math.sqrt(1 - 0.6 * math.log10(self.z))
+            elif self.l_s == -30:
+                self.a = 2.58 * math.sqrt(1 - 0.4 * math.log10(self.z))
+            else:
+                sys.stderr.write(
+                    f"ERROR\nInvalid AntennaS1528 L_s parameter {self.l_s} for z={self.z}"
+                )
+                sys.exit(1)
 
         self.b = 6.32
         self.alpha = 1.5

sharc/parameters/antenna/parameters_antenna_s1528.py

@@ -37,6 +37,14 @@ class ParametersAntennaS1528(ParametersBase):
     l_r: float = None
     l_t: float = None
 
+    # Recommends 1.2 only
+    # For elliptical antennas, this is the ratio major axis/minor axis
+    # we assume circular antennas, so z = 1
+    major_minor_axis_ratio: float = None
+
+    # Far-out side-lobe level
+    far_out_side_lobe: float = None
+
     def load_parameters_from_file(self, config_file: str):
         """Load the parameters from file an run a sanity check.
 

sharc/parameters/antenna/parameters_antenna_system4.py

@@ -0,0 +1,48 @@
+# Implementation of ParametersAntennaSystem4 class
+# The System 4 antenna was defined in WP4C Working Document 4C/356 from October 2025
+# The antenna is based on S.1528 recommends 1.2
+# It defines two sets of parameters for high elevation and low elevation beams
+from dataclasses import dataclass, field
+
+from sharc.parameters.parameters_base import ParametersBase
+from sharc.parameters.antenna.parameters_antenna_s1528 import ParametersAntennaS1528
+
+
+@dataclass
+class ParametersAntennaSystem4(ParametersBase):
+    """Dataclass containing the Antenna System 4 parameters for the simulator.
+    """
+    section_name: str = "Antenna System 4"
+
+    # Parameters for high elevation beams
+    antenna_parameters_high: ParametersAntennaS1528 = field(
+        # we don't care about frequency and bandwidth here. Just to make validation work.
+        default_factory=lambda: ParametersAntennaS1528(
+            frequency=-1,
+            bandwidth=-1
+        )
+    )
+
+    # Parameters for low elevation beams
+    antenna_parameters_low: ParametersAntennaS1528 = field(
+        # we don't care about frequency and bandwidth here. Just to make validation work.
+        default_factory=lambda: ParametersAntennaS1528(
+            frequency=-1,
+            bandwidth=-1
+        )
+    )
+
+    def load_parameters_from_file(self, config_file: str):
+        """Load the parameters from file an run a sanity check.
+
+        Parameters
+        ----------
+        file_name : str
+            the path to the configuration file
+
+        Raises
+        ------
+        ValueError
+            if a parameter is not valid
+        """
+        super().load_parameters_from_file(config_file)

sharc/parameters/imt/parameters_grid.py

@@ -339,6 +339,9 @@ class ParametersSatelliteWithServiceGrid(ParametersTerrestrialGrid):
 
     beam_radius: float = None
 
+    # [deg]
+    minimum_service_angle: float = 5.0
+
     def validate(self, ctx):
         """Validates instance parameters.
         Parameters
@@ -353,6 +356,9 @@ def validate(self, ctx):
             )
         self.cell_radius = self.beam_radius
 
+        if self.minimum_service_angle < 0. or self.minimum_service_angle > 90:
+            raise ValueError(f"{ctx}.minimum_service_angle should be in [0, 90]")
+
         if not isinstance(
                 self.eligible_sats_margin_from_border,
                 float) and not isinstance(

sharc/parameters/parameters_antenna.py

@@ -5,6 +5,7 @@
 from sharc.parameters.antenna.parameters_antenna_s672 import ParametersAntennaS672
 from sharc.parameters.antenna.parameters_antenna_with_freq import ParametersAntennaWithFreq
 from sharc.parameters.imt.parameters_antenna_imt import ParametersAntennaImt
+from sharc.parameters.antenna.parameters_antenna_system4 import ParametersAntennaSystem4
 
 from dataclasses import dataclass, field
 import typing
@@ -29,7 +30,8 @@ class ParametersAntenna(ParametersBase):
         "ITU-R-S.1528-Taylor",
         "ITU-R-S.1528-Section1.2",
         "ITU-R-S.1528-LEO",
-        "MSS Adjacent"]
+        "MSS Adjacent",
+        "Antenna System 4"]
 
     # chosen antenna radiation pattern
     pattern: typing.Literal["OMNI",
@@ -44,7 +46,8 @@ class ParametersAntenna(ParametersBase):
                             "ITU-R-S.1528-Taylor",
                             "ITU-R-S.1528-Section1.2",
                             "ITU-R-S.1528-LEO",
-                            "MSS Adjacent"] = None
+                            "MSS Adjacent",
+                            "Antenna System 4"] = None
 
     # antenna gain [dBi]
     gain: float = None
@@ -94,6 +97,10 @@ class ParametersAntenna(ParametersBase):
         default_factory=ParametersAntennaS672,
     )
 
+    antenna_system_4: ParametersAntennaSystem4 = field(
+        default_factory=ParametersAntennaSystem4,
+    )
+
     def set_external_parameters(self, **kwargs):
         """
         Set external parameters for all sub-parameters of the antenna.
@@ -198,6 +205,8 @@ def validate(self, ctx):
                 self.itu_r_s_672.validate(f"{ctx}.itu_r_s_672")
             case "MSS Adjacent":
                 self.mss_adjacent.validate(f"{ctx}.mss_adjacent")
+            case "Antenna System 4":
+                self.antenna_system_4.validate(f"{ctx}.antenna_system_4")
             case _:
                 raise NotImplementedError(
                     "ParametersAntenna.validate does not implement this antenna validation!", )

sharc/propagation/atmosphere.py

@@ -385,6 +385,9 @@ def get_reference_atmosphere_p835(
         """
 
         h_km = altitude / 1000
+        season = season.lower()
+        if season not in ['winter', 'summer']:
+            raise ValueError(f"Invalid season name f{season}.")
 
         if latitude <= 22:
             # low latitude

sharc/station_factory.py

@@ -1752,6 +1752,7 @@ def generate_mss_d2d(
         z = mss_d2d_values["sat_z"]
         elev = mss_d2d_values["sat_antenna_elev"]
         azim = mss_d2d_values["sat_antenna_azim"]
+        beams_ground_elev = mss_d2d_values["beams_ground_elev"]
         mss_d2d.geom.set_global_coords(
             x, y, z,
             azim, elev,
@@ -1783,11 +1784,21 @@ def generate_mss_d2d(
             antenna_pattern = AntennaS1528Taylor(params.antenna.itu_r_s_1528)
         elif params.antenna.pattern == "MSS Adjacent":
             antenna_pattern = AntennaMSSAdjacent(params.frequency)
+        elif params.antenna.pattern == "Antenna System 4":
+            antenna_pattern_high = AntennaS1528(params.antenna.antenna_system_4.antenna_parameters_high)
+            antenna_pattern_low = AntennaS1528(params.antenna.antenna_system_4.antenna_parameters_low)
+
         else:
             raise ValueError(
                 f"generate_mss_ss: Invalid antenna type: {params.antenna.pattern}")
 
         for i in range(mss_d2d.num_stations):
+            if params.antenna.pattern == "Satellite Beamforming":
+                if beams_ground_elev[i] >= 50:
+                    antenna_pattern = antenna_pattern_high
+                else:
+                    antenna_pattern = antenna_pattern_low
+
             mss_d2d.antenna[i] = antenna_pattern
 
         return mss_d2d  # Return the configured StationManager