spac_kit.parser

The parser module provides tools for parsing CCSDS binary files and converting them to structured data formats.

spac_kit.parser

Generic code to parse a downlink binary file encoded using CCSDS.

spac_kit.parser.parse_ccsds_downlink

CCSDS parser for binary file with multiple APIDs.

exception spac_kit.parser.parse_ccsds_downlink.CCSDSParsingException

Bases: Exception

CCSDS packet parsing Exception.

exception spac_kit.parser.parse_ccsds_downlink.CRCNotCalculatedError

Bases: Exception

CRC Calculation exception.

class spac_kit.parser.parse_ccsds_downlink.CalculatedChecksum

Bases: Converter

Converter which calculates a CRC checksum from a parsed packet and compare it with the one found in the packet.

TODO: make something better, by supporting any packets as input…

CRC

alias of Crc16Ibm3740

JUMBO_CRC

alias of Crc32Mpeg2

JUMBO_TLM_PKT_LEN_BYTES = 4089

__init__()

Initialization.

classmethod calculate_crc(ccsds_version_number, ccsds_packet_type, ccsds_secondary_flag, ccsds_apid, ccsds_sequence_flag, ccsds_sequence_count, ccsds_packet_length, body)

Calculate one CRC from the parsed fields of one packet.

Parsed fields must be the CCSDS header and one body excluding the CRC at the end of the packet.

convert(ccsds_version_number_array, ccsds_packet_type_array, ccsds_secondary_flag_array, ccsds_apid_array, ccsds_sequence_flag_array, ccsds_sequence_count_array, ccsds_packet_length_array, body_array)

Converter to add a calculated CRC to the parsed packets.

Parameters:

• ccsds_version_number_array – from the CCSDS header

• ccsds_packet_type_array – from the CCSDS header

• ccsds_secondary_flag_array – from the CCSDS header

• ccsds_apid_array – from the CCSDS header

• ccsds_sequence_flag_array – from the CCSDS header

• ccsds_sequence_count_array – from the CCSDS header

• ccsds_packet_length_array – from the CCSDS header

• body_array – body of the packet, without the trailing CRC.

Returns:

The array of calculated CRCs.

spac_kit.parser.parse_ccsds_downlink.calculate_crc(f, crc_size_bytes=2)

Calculate a CRC for each packet so to compare it with the CRC sent at the end of the packets.

spac_kit.parser.parse_ccsds_downlink.cast_to_list(d)

Casts any multidimensional arrays to lists.

spac_kit.parser.parse_ccsds_downlink.distribute_packets(keyss, stream1)

Distribute binary stream into multiple binary stream with consistent sub-packet structures.

Used when single APID does not have consistent packet structure.

spac_kit.parser.parse_ccsds_downlink.get_packet_definitions()

Select packet definitions which will be parsed in the first round or second round, as a refinement for some APIDs.

First round parsing: object instances of _BasePackets which have an apid but no sub_apid Second round parsing: object instances of _BasePackets which have an apid and a sub_apid

spac_kit.parser.parse_ccsds_downlink.get_sub_packet_keys(parsed_apids, sub_apid: dict)

Identify sub-packet keys when single APId does not have consistent packet structures.

spac_kit.parser.parse_ccsds_downlink.get_tab_name(apid, pkt_def, existing_names)

Proposes a tab name for each APID or sub-packet structure of an APID.

The tab name can be used as keys in the dictionary of DataFrames or as tab names in the Excel spreadsheet.

Parameters:

• apid – APID

• pkt_def – current packet definition. Preferably, the packet definition has a “name” property which will be used to name the tab. If not available the name of the class implementing the packet structure definition is used.

• existing_names – already used names, to avoid duplicates. A counter is added to duplicate names.

Returns:

A unique tab name for the current APID and packet structure definition.

spac_kit.parser.parse_ccsds_downlink.parse_ccsds_file(ccsds_file: str, do_calculate_crc: bool = False)

Parse a pure CCSDS binary file (only CCSDS packets).

spac_kit.parser.downlink_to_excel

Utility to convert a downlink CCSDS binary file to excel.

spac_kit.parser.downlink_to_excel.add_tab_to_xlsx(dfs, writer, name='')

Add tab to excel writer from a dictionary, recursively.

Only use the name in the leaf of the dictionary tree.

Parameters:

• dfs – dictionary (of dictionary) of pandas dataframes or single pandas dataframe

• writer – pandas.ExcelWriter

• name – name of the tab to be used, optional

spac_kit.parser.downlink_to_excel.export_ccsds_to_excel(ccsds_file, output_filename, do_calculate_crc)

Export a binary file of CCSDS packets into an Excel file.

spac_kit.parser.downlink_to_excel.export_dfs_to_xlsx(dfs, filename1)

Export a dictionnary of pandas dataframes to an Excel file.

spac_kit.parser.downlink_to_excel.get_parser()

Parser for the command line utility.

spac_kit.parser.downlink_to_excel.main()

Command line interface to parse downlink binary file and export to Excel file.

spac_kit.parser.Packets

CCSDSpy packet specialized for configurable APID parsing.

class spac_kit.parser.Packets.ParserSubAPIDPacket(fields: list[PacketField], name: str, apid: int, sub_apid: int)

Bases: SimpleAPIDPacket

Packet definition associated to a specific flavor of structure within a single APID.

__init__(fields: list[PacketField], name: str, apid: int, sub_apid: int)

Constructor.

class spac_kit.parser.Packets.PreParserAPIDPacket(fields: list[~ccsdspy.packet_fields.PacketField], name: str, apid: int, decision_field: str = None, decision_fun: ~typing.Callable = <function PreParserAPIDPacket.<lambda>>)

Bases: SimpleAPIDPacket

Packet definition used to pre-parse packets.

This is used when the structure vary for a single APID depending on one field in this packet.

__init__(fields: list[~ccsdspy.packet_fields.PacketField], name: str, apid: int, decision_field: str = None, decision_fun: ~typing.Callable = <function PreParserAPIDPacket.<lambda>>)

Constructor.

class spac_kit.parser.Packets.SimpleAPIDPacket(fields: list[PacketField], name: str, apid: int)

Bases: VariableLength

Simple Packet definition, with name and associated APID.

__init__(fields: list[PacketField], name: str, apid: int)

Constructor.

spac_kit.parser.util

Utilities shared.

spac_kit.parser.util.import_ccsds_packet_packages()

Import subpackages of ccsds.packets containing CCSDSpy definitions.

Stolen from https://packaging.python.org/en/latest/guides/ creating-and-discovering-plugins/#using-namespace-packages

Returns:

‘packet’ (the packet object), ‘variable_name’, ‘module_path’

Return type:

List of dictionaries with keys

spac_kit.parser.remove_non_ccsds_headers

Remove non CCSDS binary code from input streams.

spac_kit.parser.remove_non_ccsds_headers.remove_bdsem(f)

Remove BDSEM headers.

spac_kit.parser.remove_non_ccsds_headers.remove_bdsem_and_message_headers(f)

Removes extra headers provided by the BDSEM data generation.

Parameters:

f – file handler

Returns:

File handler

spac_kit.parser.remove_non_ccsds_headers.remove_mise_and_headers(f)

Remove packet markers from Raw mode file.

spac_kit.parser.remove_non_ccsds_headers.start_sequence(seq)

Returns True if seq is on the beginning of a marker between CCSDS packets.

spac_kit.parser.remove_non_ccsds_headers.strip_non_ccsds_headers(file_handler, is_bdsem: bool = False, has_pkt_header: bool = False, has_json_header: bool = False)

Remove all cases of non CCSDS headers which can occur in Europa-Clipper SDS inputs.

Mostly used in test cases.

Parameters:

• file_handler – input binary file handler

• is_bdsem – file coming from BDSEM, else RAW

• has_pkt_header – whether the file has packet headers

• has_json_header – whether the file has a JSON header

Returns:

The file handler where the CCSDS packets start

spac_kit.parser.spac_ls

Command line utility to list available CCSDS packet packages.

spac_kit.parser.spac_ls.format_packet_info(packet_info, long_format=False)

Format packet information into a row for display.

Parameters:

• packet_info – Either a dict with ‘packet’, ‘variable_name’, ‘module_path’ keys, or a packet object for backward compatibility

• long_format – If True, include additional fields like packet type and field count

spac_kit.parser.spac_ls.get_parser()

Parser for the command line utility.

spac_kit.parser.spac_ls.list_packages(delimiter=None, long_format=False)

List all available CCSDS packet packages.

Parameters:

• delimiter – If specified, output as delimited format (e.g., ‘,’ for CSV, ‘ ‘ for TSV)

• long_format – If True, display additional fields like packet type and field information

spac_kit.parser.spac_ls.main()

Command line interface to list CCSDS packet packages.

spac_kit.parser.test_utils

Utilities to test the packet parsing.

spac_kit.parser.test_utils.compare(local_dir: str, is_bdsem: bool = False, has_pkt_header: bool = False, has_json_header: bool = False, create_output: bool = False, create_spreadsheet: bool = False)

Run parsing and compare results with a reference.

Parameters:

• local_dir – local directory containing input file

• is_bdsem – whether file is from BDSEM

• has_pkt_header – whether file has packet headers

• has_json_header – whether file has JSON header

• create_output – whether to create output pickle file

• create_spreadsheet – whether to create Excel spreadsheet

spac_kit.parser.test_utils.recursive_compare(dfs, dfs_expected)

Compare embedded dictionary of dictionaries of pandas dataframes.

Compare the keys and the actual dataframes. None should be missing and all should match.

Parameters:

• dfs – dictionary of dictionaries of dataframes

• dfs_expected – expected dictionary of dictionaries

Returns:

True if the pandas dataframes are identical at the same location