ENH: seed sensor measurement noise per instance

CHANGELOG.md

@@ -34,6 +34,7 @@ Attention: The newest changes should be on top -->
 
 - ENH: ENH: Refactor flight.py latitude/longitude to use inverted_haversine [#1055](https://github.com/RocketPy-Team/RocketPy/pull/1055)
 - ENH: TST: Add unit tests for evaluate_reduced_mass and remove TODO [#1051](https://github.com/RocketPy-Team/RocketPy/pull/1051)
+- ENH: seed sensor measurement noise per instance [#1052](https://github.com/RocketPy-Team/RocketPy/pull/1052)
 - ENH: FIX: pre release hardening [#1047](https://github.com/RocketPy-Team/RocketPy/pull/1047)
 - ENH: DEV: Claude Code ruff hooks (auto-format on edit + pre-push lint guard) [#1046](https://github.com/RocketPy-Team/RocketPy/pull/1046)
 - ENH: CI: create a CI for testing docs updates + solve different docs issues [#1045](https://github.com/RocketPy-Team/RocketPy/pull/1045)

rocketpy/sensors/accelerometer.py

@@ -78,6 +78,7 @@ def __init__(
         cross_axis_sensitivity=0,
         consider_gravity=False,
         name="Accelerometer",
+        seed=None,
     ):
         """
         Initialize the accelerometer sensor
@@ -169,6 +170,11 @@ def __init__(
             acceleration. Default is False.
         name : str, optional
             The name of the sensor. Default is "Accelerometer".
+        seed : int, optional
+            Seed for the random number generator that draws the measurement
+            noise. If given, the noise becomes reproducible and independent of
+            the process-global NumPy RNG. Default is None, meaning the noise is
+            seeded from fresh entropy per instance.
 
         Returns
         -------
@@ -193,6 +199,7 @@ def __init__(
             temperature_scale_factor=temperature_scale_factor,
             cross_axis_sensitivity=cross_axis_sensitivity,
             name=name,
+            seed=seed,
         )
         self.consider_gravity = consider_gravity
         self.prints = _InertialSensorPrints(self)
@@ -299,4 +306,5 @@ def from_dict(cls, data):
             cross_axis_sensitivity=data["cross_axis_sensitivity"],
             consider_gravity=data["consider_gravity"],
             name=data["name"],
+            seed=data.get("seed"),
         )

rocketpy/sensors/barometer.py

@@ -62,6 +62,7 @@ def __init__(
         temperature_bias=0,
         temperature_scale_factor=0,
         name="Barometer",
+        seed=None,
     ):
         """
         Initialize the barometer sensor
@@ -110,6 +111,11 @@ def __init__(
             meaning no temperature scale factor is applied.
         name : str, optional
             The name of the sensor. Default is "Barometer".
+        seed : int, optional
+            Seed for the random number generator that draws the measurement
+            noise. If given, the noise becomes reproducible and independent of
+            the process-global NumPy RNG. Default is None, meaning the noise is
+            seeded from fresh entropy per instance.
 
         Returns
         -------
@@ -132,6 +138,7 @@ def __init__(
             temperature_bias=temperature_bias,
             temperature_scale_factor=temperature_scale_factor,
             name=name,
+            seed=seed,
         )
         self.prints = _SensorPrints(self)
 
@@ -206,4 +213,5 @@ def from_dict(cls, data):
             temperature_bias=data["temperature_bias"],
             temperature_scale_factor=data["temperature_scale_factor"],
             name=data["name"],
+            seed=data.get("seed"),
         )

rocketpy/sensors/gnss_receiver.py

@@ -1,7 +1,5 @@
 import math
 
-import numpy as np
-
 from rocketpy.tools import inverted_haversine
 
 from ..mathutils.vector_matrix import Matrix, Vector
@@ -40,6 +38,7 @@ def __init__(
         position_accuracy=0,
         altitude_accuracy=0,
         name="GnssReceiver",
+        seed=None,
     ):
         """Initialize the Gnss Receiver sensor.
 
@@ -55,8 +54,13 @@ def __init__(
             position in meters. Default is 0.
         name : str
             The name of the sensor. Default is "GnssReceiver".
+        seed : int, optional
+            Seed for the random number generator that draws the measurement
+            noise. If given, the noise becomes reproducible and independent of
+            the process-global NumPy RNG. Default is None, meaning the noise is
+            seeded from fresh entropy per instance.
         """
-        super().__init__(sampling_rate=sampling_rate, name=name)
+        super().__init__(sampling_rate=sampling_rate, name=name, seed=seed)
         self.position_accuracy = position_accuracy
         self.altitude_accuracy = altitude_accuracy
 
@@ -90,9 +94,9 @@ def measure(self, time, **kwargs):
         # Get from state u and add relative position
         x, y, z = (Matrix.transformation(u[6:10]) @ relative_position) + Vector(u[0:3])
         # Apply accuracy to the position
-        x = np.random.normal(x, self.position_accuracy)
-        y = np.random.normal(y, self.position_accuracy)
-        altitude = np.random.normal(z, self.altitude_accuracy)
+        x = self._rng.normal(x, self.position_accuracy)
+        y = self._rng.normal(y, self.position_accuracy)
+        altitude = self._rng.normal(z, self.altitude_accuracy)
 
         # Convert x and y to latitude and longitude
         drift = (x**2 + y**2) ** 0.5
@@ -131,6 +135,7 @@ def to_dict(self, **kwargs):
             "position_accuracy": self.position_accuracy,
             "altitude_accuracy": self.altitude_accuracy,
             "name": self.name,
+            "seed": self._seed,
         }
 
     @classmethod
@@ -140,4 +145,5 @@ def from_dict(cls, data):
             position_accuracy=data["position_accuracy"],
             altitude_accuracy=data["altitude_accuracy"],
             name=data["name"],
+            seed=data.get("seed"),
         )

rocketpy/sensors/gyroscope.py

@@ -78,6 +78,7 @@ def __init__(
         cross_axis_sensitivity=0,
         acceleration_sensitivity=0,
         name="Gyroscope",
+        seed=None,
     ):
         """
         Initialize the gyroscope sensor
@@ -169,6 +170,13 @@ def __init__(
             float or int is given, the same sensitivity is applied to all axes.
             The values of each axis can be set individually by passing a list of
             length 3.
+        name : str, optional
+            The name of the sensor. Default is "Gyroscope".
+        seed : int, optional
+            Seed for the random number generator that draws the measurement
+            noise. If given, the noise becomes reproducible and independent of
+            the process-global NumPy RNG. Default is None, meaning the noise is
+            seeded from fresh entropy per instance.
 
         Returns
         -------
@@ -193,6 +201,7 @@ def __init__(
             temperature_scale_factor=temperature_scale_factor,
             cross_axis_sensitivity=cross_axis_sensitivity,
             name=name,
+            seed=seed,
         )
         self.acceleration_sensitivity = self._vectorize_input(
             acceleration_sensitivity, "acceleration_sensitivity"
@@ -320,4 +329,5 @@ def from_dict(cls, data):
             cross_axis_sensitivity=data["cross_axis_sensitivity"],
             acceleration_sensitivity=data["acceleration_sensitivity"],
             name=data["name"],
+            seed=data.get("seed"),
         )

rocketpy/sensors/sensor.py

@@ -62,6 +62,7 @@ def __init__(
         temperature_bias=0,
         temperature_scale_factor=0,
         name="Sensor",
+        seed=None,
     ):
         """
         Initialize the accelerometer sensor
@@ -111,6 +112,11 @@ def __init__(
             meaning no temperature scale factor is applied.
         name : str, optional
             The name of the sensor. Default is "Sensor".
+        seed : int, optional
+            Seed for the random number generator that draws the measurement
+            noise. If given, the noise becomes reproducible and independent of
+            the process-global NumPy RNG. Default is None, meaning the noise is
+            seeded from fresh entropy per instance.
 
         Returns
         -------
@@ -145,6 +151,14 @@ def __init__(
         self._random_walk_drift = 0
         self.normal_vector = Vector([0, 0, 0])
 
+        # Per-instance RNG, seeded deterministically when a seed is given, so
+        # the measurement noise is reproducible and independent of the
+        # process-global NumPy RNG (and therefore safe under parallel or
+        # forked evaluation). seed=None keeps the noise random but still
+        # drawn from this instance's generator.
+        self._seed = seed
+        self._rng = np.random.default_rng(seed)
+
         # handle measurement range
         if isinstance(measurement_range, (tuple, list)):
             if len(measurement_range) != 2:
@@ -291,6 +305,7 @@ def to_dict(self, **kwargs):
             "temperature_bias": self.temperature_bias,
             "temperature_scale_factor": self.temperature_scale_factor,
             "name": self.name,
+            "seed": self._seed,
         }
 
 
@@ -358,6 +373,7 @@ def __init__(
         temperature_scale_factor=0,
         cross_axis_sensitivity=0,
         name="Sensor",
+        seed=None,
     ):
         """
         Initialize the accelerometer sensor
@@ -444,6 +460,11 @@ def __init__(
             no cross-axis sensitivity is applied.
         name : str, optional
             The name of the sensor. Default is "Sensor".
+        seed : int, optional
+            Seed for the random number generator that draws the measurement
+            noise. If given, the noise becomes reproducible and independent of
+            the process-global NumPy RNG. Default is None, meaning the noise is
+            seeded from fresh entropy per instance.
 
         Returns
         -------
@@ -474,6 +495,7 @@ def __init__(
                 temperature_scale_factor, "temperature_scale_factor"
             ),
             name=name,
+            seed=seed,
         )
 
         self.orientation = orientation
@@ -558,12 +580,12 @@ def apply_noise(self, value):
         """
         # white noise
         white_noise = Vector(
-            [np.random.normal(0, self.noise_variance[i] ** 0.5) for i in range(3)]
+            [self._rng.normal(0, self.noise_variance[i] ** 0.5) for i in range(3)]
         ) & (self.noise_density * self.sampling_rate**0.5)
 
         # random walk
         self._random_walk_drift = self._random_walk_drift + Vector(
-            [np.random.normal(0, self.random_walk_variance[i] ** 0.5) for i in range(3)]
+            [self._rng.normal(0, self.random_walk_variance[i] ** 0.5) for i in range(3)]
         ) & (self.random_walk_density / self.sampling_rate**0.5)
 
         # add noise
@@ -660,6 +682,7 @@ def __init__(
         temperature_bias=0,
         temperature_scale_factor=0,
         name="Sensor",
+        seed=None,
     ):
         """
         Initialize the accelerometer sensor
@@ -709,6 +732,11 @@ def __init__(
             meaning no temperature scale factor is applied.
         name : str, optional
             The name of the sensor. Default is "Sensor".
+        seed : int, optional
+            Seed for the random number generator that draws the measurement
+            noise. If given, the noise becomes reproducible and independent of
+            the process-global NumPy RNG. Default is None, meaning the noise is
+            seeded from fresh entropy per instance.
 
         Returns
         -------
@@ -731,6 +759,7 @@ def __init__(
             temperature_bias=temperature_bias,
             temperature_scale_factor=temperature_scale_factor,
             name=name,
+            seed=seed,
         )
 
     def quantize(self, value):
@@ -768,15 +797,15 @@ def apply_noise(self, value):
         """
         # white noise
         white_noise = (
-            np.random.normal(0, self.noise_variance**0.5)
+            self._rng.normal(0, self.noise_variance**0.5)
             * self.noise_density
             * self.sampling_rate**0.5
         )
 
         # random walk
         self._random_walk_drift = (
             self._random_walk_drift
-            + np.random.normal(0, self.random_walk_variance**0.5)
+            + self._rng.normal(0, self.random_walk_variance**0.5)
             * self.random_walk_density
             / self.sampling_rate**0.5
         )

tests/fixtures/sensors/sensors_fixtures.py

@@ -24,6 +24,7 @@ def noisy_rotated_accelerometer():
         cross_axis_sensitivity=0.5,
         consider_gravity=True,
         name="Accelerometer",
+        seed=42,
     )
 
 
@@ -46,6 +47,7 @@ def noisy_rotated_gyroscope():
         cross_axis_sensitivity=0.5,
         acceleration_sensitivity=[0, 0.0008, 0.0017],
         name="Gyroscope",
+        seed=42,
     )
 
 
@@ -62,6 +64,7 @@ def noisy_barometer():
         operating_temperature=25 + 273.15,
         temperature_bias=0.02,
         temperature_scale_factor=0.02,
+        seed=42,
     )
 
 
@@ -71,6 +74,7 @@ def noisy_gnss():
         sampling_rate=1,
         position_accuracy=1,
         altitude_accuracy=1,
+        seed=42,
     )
 
 

tests/unit/sensors/test_sensor.py

@@ -9,15 +9,6 @@
 from rocketpy.tools import euler313_to_quaternions
 
 
-@pytest.fixture(autouse=True)
-def _seed_rng():
-    """Seed NumPy's global RNG before each test so that the noise-based
-    sensor measurements are deterministic. Without this, tests such as
-    ``test_noisy_barometer`` are flaky because the random white noise can
-    occasionally exceed the assertion tolerance."""
-    np.random.seed(42)
-
-
 # calisto standard simulation no wind solution index 200
 TIME = 3.338513236767685
 U = [