OSVE Python Wrapper

Introduction

The OSVE Python Wrapper is a Python package that is just a wrapper of the OSVE C++ library and it’s responsible of providing a handy object oriented access to the library’s methods from Python scripting.

So the user only needs to import the “osve” package and get an instance of the “osve” class to start calling available library methods.

The example below just show how to obtain the current OSVE application version:

from osve import osve
sim = osve.osve()
version = sim.get_app_version()
print(version)

The user could also obtain current AGM and EPS versions that are already embed in the OSVE library. For doing this just use the methods: get_agm_version() or get_eps_version()

But of course the main objective of OSVE is to perform simulations to obtain the profile of different parameters of interest for mission planning, or mission analysis.

For running a simulation simply call the method “execute” while passing as parameters the root path of the simulation and the path to the OSVE session file in JSON format:

from osve import osve
test_input_path = "some path with all the resources inside"
test_input_config_path = "path to the JSON session file"
sim = osve.osve()
sim.execute(test_input_path, test_input_config_path)

OSVE will run the simulation and generate the specified outputs at the OSVE JSON session file. A full description of the OSVE session file will be done in another section.

In case any error arises the an error message will be reported by OSVE.

The methods init_step, execute_step, write_files, write_json_log and close are intended to allow the user to run simulations in a step by step controlled way. But for the moment this approach has not been validated and its use is discouraged.

Prerequisites

Operating Systems: Mac Intel, Mac M1, Linux, and Windows.

Python (min v. 3.10)

PIP (Python Package Index)

Installation

OSVE is available from the Python Package Index repository. Install iy by running the following command:

pip install osve

Using the Library

After installing the library can be used with the Python Shell or with its CLI.

Python Shell

A basic test of the library contents can be done as follows:

from osve import osve
sim = osve.osve()
version = sim.get_app_version()
print(version)

Command line Interface

The package has a CLI entry point:

usage: osve [-h] -r ROOTPATH -s SESSIONFILE

JUICE Operations Simulation & Validation Engine (OSVE) command line interface
optional arguments:

-h, --help            show this help message and exit
-r ROOTPATH, --RootPath ROOTPATH
                        Top level path of the scenario file_path to be used to resolve the relative paths
-s SESSIONFILE, --SessionFile SESSIONFILE
                        Location and name of the session file containing all the scenarios files

Usage Examples

There are a number of JUICE SOC tools that make usage of OSVE. The most remarkable public ones are listed hereunder:

PTWrapper Acts as a wrapper to simplify the usage of OSVE to simulate a Pointing Timeline and generate the Attitude as a SPICE CK to assist the Pointing Timeline Harmonisation of the Detailed Scenario process.
juice-phs Exploits and uses the OSVE capabilities to assist the Instrument Timeline Harmonisation of the Detailed Scenario process.

Subscribing to OSVE logs from Python

OSVE provides support to define your custom Python logging implementations by using callbacks. In order to define a your custom Python logger, follow this example:

from osve import osve
from osve_subscriber import OsveLoggerAbstract

class OsveLogger(OsveLoggerAbstract):

    def __init__(self):
        super().__init__("theOsveLogger")

    def onMsgReceived(self, severity, module, time, text):
        print("OsveLogger -> " + str(severity) + " , " + str(module) + " , " + str(time) + " , " + str(text))
        return 0


test_input_path = "SOME_PATH_POINTING_TO_SCENARIO"
test_input_config_path = "SOME_PATH_POINTING_TO_SESSION_FILE"

# First, instantiate the OSVE Simulator
sim = osve.osve()

# Second, register the logger
sim.register_logger(OsveLogger())

# Finally, run simulation
sim.execute(test_input_path, test_input_config_path)

SPICE Kernels usage

Warning

In order to have an error-free run, OSVE needs to have CK coverage for the JUICE S/C reference frame JUICE_SPACECRAFT (-28000), if this were not the case, although OSVE will run logging SPICE Error messages and will generate output, the results should be used with care.