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Automating electronic data sheets CCSDS Spring 2013

Automating electronic data sheets CCSDS Spring 2013. Sam Price. Navigator Background. Missions GPM MMS – High Altitude 12Re Hubble servicing mission Reflected GPS signals Embedded orbit propagator Geons 3 rd Party software 3 rd party commands/telemetry 45 commands

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Automating electronic data sheets CCSDS Spring 2013

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  1. Automating electronic data sheetsCCSDS Spring 2013 Sam Price

  2. Navigator Background • Missions • GPM • MMS – High Altitude 12Re • Hubble servicing mission • Reflected GPS signals • Embedded orbit propagator • Geons • 3rd Party software • 3rd party commands/telemetry • 45 commands • 43 telemetry messages

  3. Navigator Electronic Documents for Command / Telemetry

  4. Multiple documents are expensive $$$$ • 15 different electronic versions, • manually created • Same data across all of the documents • 5+ different people maintaining separate documents. • Changes propagate slowly throughout documents ($$$) • Errors occur from manual changes.($$$$) • Naming conventions are not the same

  5. A streamlined approach 3rd party C Headers Some tools • C/C++ • Endianess conversion routines • Command validation • Header files • Human readable Interface Control Document • Latex • HTML • Maybe MS Word … • Ground system definitions • Bandwidth spreadsheet • Ada mockup of telemetry for testing. • Logging tools • CSV Logging • Matlab import • Database logging C++ headers Telemetry/ Commands XML Database Why C/C++ as starting point • Widespread existence • All of my Telemetry is in C • More people know C • Machine readable • Exactly what is implemented • 3rd party libraries are in C • Many more reasons

  6. Workflow Convert C/C++ to XML 3rd party C Headers Latex ICD xml_to_latex.py Asist C++ headers Telemetry/ Commands XML xml_to_asist.py Asist RDLS XML Database Python xml_to_ctypes.py Python CTypes

  7. What does it take to mimic C/C++ in XML • No child / parents / inheritance • No templates • C/C++ can have alignment/padding problems • Metadata stored in doxygen style comments • Units, Polynomials, warning ranges, etc • Bit fields defined in comments • No C bitfield yet… • Basic Types • bools • integers -- Use stdint.h • int8_t,int16_t,int32_t, int64_t • unsigned Integers • uint8_t,uint16_t,uint32_t, uint64_t • floating point memory • float, double, long double • strings • char arrays • Arrays • Multidimensional • void pointer, pointers (16,32,64) sizes • Structures/classes • unions • enums

  8. Use a compiler for parsing • Clang/llvm • C/C++ Compiler similar to GCC • Cross platform compatible(Windows,Linux,Mac) • LibClang • Pass arguments to change C/C++ structure padding. • -m32 , -m64 • Cross platform compatible (Linux, Mac, Windows) • Apple uses it in their developer tools for code completion, syntax highlighting, etc… • Use it to find comments, structures, types, padding in structure, etc. • http://clang.llvm.org/docs/Tooling.html • http://clang.llvm.org/get_started.html • https://github.com/trolldbois/clang <- padding/size info

  9. C Example CCSDS Header /*! * @brief CCSDS Telemetry Header * @TelemetryPacketHeader * */ typedefstructCCSDS_Telemetry_Header { /*! * @brief Destination address */ charp_sp_dest; /*! * @brief Protocol ID * @default 0xf2 */ charp_sp_prot; /*! *@bitarraymsbf * @bits 3 * @name packet_version_number * @brief Pacet Version Number * @default 0 * @bits 1 * @name packet_type * @brief Packet type * @enum ENUM_PACKET_TYPE * @bits 1 * @name secondary_header_present * @brief Secondary Header flag * @detailed The Secondary Header Flag shall indicate the presence or absence of the Packet Secondary Header within this Space Packet. * It shall be 1 if a Packet Secondary Header is present; it shall be 0 if a Packet Secondary Header is not present. * @enumCCSDS_Secondary_Header * @bits 11 * @name apid * @brief Application Process Identifier (APID) * @detailed via 135.0-b-1 application ID's 2040- 2047 are reserved and should not be used. * The APID (possibly in conjunction with the optional APID Qualifier that * identifies the naming domain for the APID) shall provide the naming mechanism for the LDP. */ uint16_t p_ident; /*! . . . . */ uint16_t p_seq_cont; /*! . . . . */ uint16_t p_data_len; /*! . . . . */ uint64_t s_time; } CCSDS_Telemetry_Header; Doxygen comments start with @marker_name marker value Indented comments belong to parent comment Could have used C bitfields (See backup slides)

  10. C/C++ -> clang_to_json.py -> json_to_xml.py-> XML • Current status • 500 lines of code to go from C Header to XML • Need to add enums, meta data, bit fields. • Implemented structures, unions, bit structures, arrays, padding bytes, integers, unsigned integers, floating point numbers, pointers, comment parsing. • https://github.com/nasa/SOIS-CCSDS-XML • NonNasa Contact for access, currently private project until XML format is well defined. • NASA: fill out a NAMS/IDMAX request

  11. C Example p_ident /*! *@bitarraymsbf * @bits 3 * @name packet_version_number * @brief Pacet Version Number * @default 0 * @bits 1 * @name packet_type * @brief Packet type * @bits 1 * @name secondary_header_present * @brief Secondary Header flag * @detailed The Secondary Header Flag shall indicate the presence or absence of the Packet Secondary Header within this Space Packet. * It shall be 1 if a Packet Secondary Header is present; it shall be 0 if a Packet Secondary Header is not present. * @bits 11 * @name apid * @brief Application Process Identifier (APID) * @detailed via 135.0-b-1 application ID's 2040- 2047 are reserved and should not be used. * The APID (possibly in conjunction with the optional APID Qualifier that * identifies the naming domain for the APID) shall provide the naming mechanism for the LDP. */ uint16_t p_ident;

  12. Clang to JSON Output for p_ident ….. {'array': [], 'basetype': 'uint16_t', 'basetype_name': None, 'bitarray': True, 'data': <clang.cindex.Cursor object at 0x10a7969e0>, 'is_pointer': False, 'kind': CursorKind.FIELD_DECL, 'name': 'p_ident', 'offset': 16, 'size': 2L, 'comments': [{'bitarray': 'msbf', 'children': [{'bits': '3', 'children': ['name': 'packet_version_number'}, {'brief': 'Pacet Version Number’}, {'default': '0'} ] }, ], …. More Member Comments ….. ] 'members': [{'array': [], 'basetype_name': None, 'bitarray': False, 'bits': 3, 'comments': [{'name': 'packet_version_number'}, {'brief': 'Pacet Version Number’}, {'default': '0'}], 'data': None, 'is_pointer': False, 'kind': None, 'members': [], 'name': 'packet_version_number', 'size': -1}, … More Members..], }, > python clang_to_json.py../examples/src_cpp/ccsds.h -m32 –I../examples/src_cpp • Offset, Sizes include padding information. • Clang object used for further processing if needed. • Bit arrays become children for bitstructs.

  13. XML Layout <TypeDatabase> <typeInt/> <typeFloat/> <typeBitStruct> <Members> <variable/> </Members> <typeBitStruct\> <typeStruct> <Members> <variable/> </Members> <typeStruct/> </TypeDatabase> <Telemetry> </Telemetry> <Commands> </Commands> • Type database • Basic types • Integers, floats • Structures • Unions • Bit structures • Telemetry database • Similar to structures • Command database • Similar to structures

  14. C Example /*! * @brief CCSDS Telemetry Header * @TelemetryPacketHeader * */ typedefstructCCSDS_Telemetry_Header { /*! * @brief Destination address */ charp_sp_dest; /*! * @brief Protocol ID * @default 0xf2 */ charp_sp_prot; /*! *@bitarraymsbf * @bits 3 * @name packet_version_number * @brief Pacet Version Number * @default 0 * @bits 1 * @name packet_type * @brief Packet type * @enum ENUM_PACKET_TYPE * @bits 1 * @name secondary_header_present * @brief Secondary Header flag * @detailed The Secondary Header Flag shall indicate the presence or absence of the Packet Secondary Header within this Space Packet. * It shall be 1 if a Packet Secondary Header is present; it shall be 0 if a Packet Secondary Header is not present. * @enumCCSDS_Secondary_Header * @bits 11 * @name apid * @brief Application Process Identifier (APID) * @detailed via 135.0-b-1 application ID's 2040- 2047 are reserved and should not be used. * The APID (possibly in conjunction with the optional APID Qualifier that * identifies the naming domain for the APID) shall provide the naming mechanism for the LDP. */ uint16_t p_ident; /*! . . . . */ uint16_t p_seq_cont; /*! . . . . */ uint16_t p_data_len; /*! . . . . */ uint64_t s_time; } CCSDS_Telemetry_Header;

  15. Generated XML <TypeDatabase> <typeIntbits="3"endianess="bigEndian"name="int3_be"signed="true"/> …. More small types for int1, int11, int8, int16 .. etc …. <typeBitStructname="CCSDS_Telemetry_Header_p_ident"type="uint16_be"> <Members> <variablename="packet_version_number"type="int3_be"/> <variablename="packet_type"type="int1_be"/> <variablename="secondary_header_present"type="int1_be"/> <variablename="apid"type="int11_be"/> </Members> </typeBitStruct> …. More typeBitStruct for p_seq_cont, s_time …. <typeStructname="CCSDS_Telemetry_Header"> <Members> <variablebits="8"name="p_sp_dest"offset="0"type="int8_be"/> <variablebits="8"name="p_sp_prot"offset="8"type="int8_be"/> <variablebits="16"name="p_ident"offset="16"type="CCSDS_Telemetry_Header_p_ident"/> <variablebits="16"name="p_seq_cont"offset="32"type="CCSDS_Telemetry_Header_p_seq_cont"/> <variablebits="16"name="p_data_len"offset="48"type="uint16_be"/> <variablebits="64"name="s_time"offset="64"type="CCSDS_Telemetry_Header_s_time"/> </Members> </typeStruct> </TypeDatabase> > python json_to_xml.py../examples/src_cpp/messages.h -m32 –I../examples/src_cpp

  16. Writing XML with python fromxml.etree.ElementTreeimportElement fromxml.etree.ElementTreeimportElementTree parent_node= Element('EDS') Messages = Element('Telemetry') parent_node.append(Messages) #All attributes/text must text Messages.attrib['Count'] = str(5) Messages.text = “Hello” document = ElementTree(parent_node) #See json_to_xml for prettify function print prettify(document.getroot())

  17. XML Output <?xml version="1.0" ?> <EDS> <Telemetry Count="5"> Hello </Telemetry> </EDS> Or Root = document.getroot() print xml.etree.ElementTree.tostring(Root,'utf-8') '<EDS><Telemetry Count="5">Hello</Telemetry></EDS>'

  18. XML to Python CTypes • Decode telemetry/send commands json_to_xml.py clang_to_json.py 3rd party C Headers xml_to_ctypes.py Python XML C++ headers Telemetry/ Commands Python CTypes

  19. Reading XML with python importxml.etree.ElementTreeas ET doc = ET.parse(filename) root = doc.getroot() for node inroot.findall('TypeDatabase/typeStruct'): print node.attrib['name’] print node.text See xml_to_ctypes.py for complete listing 200 lines of code to convert from XML to python ctypes Or http://docs.python.org/2/library/xml.etree.elementtree.html

  20. Python ctypes example importctypes classCCSDS_Telemetry_Header_p_ident(ctypes.LittleEndianStructure): """""" #_packed_ _fields_=[("apid",ctypes.c_uint16,11), ("secondary_header_present”,ctypes.c_uint16,1), ("packet_type",ctypes.c_uint16,1), ("packet_version_number",ctypes.c_uint16,3)] classCCSDS_Telemetry_Header(ctypes.LittleEndianStructure): ""”This is a comment about the CCSDS Packet Header""" _pack_=1 _fields_=[("p_sp_dest",ctypes.c_int8 ), ("p_sp_prot",ctypes.c_int8 ), ("p_ident",CCSDS_Telemetry_Header_p_ident), ("p_seq_cont",CCSDS_Telemetry_Header_p_seq_cont), ("p_data_len”,ctypes.c_int16), ("s_time",CCSDS_Telemetry_Header_s_time)] • python xml_to_ctypes.pytest.xml > test_ctypes.py • 205 lines of code

  21. Using python ctypes to decode / encode data importtest_ctypesastc fid=open('log.raw’) #Buffer big enough to hold any command / telemetry data big_buffer=bytearray(1024*10) write_buffer=memoryview(big_buffer) #header data directly into the buffer. 8bytes. fid.readinto(write_buffer[0:8]) #big_buffer[0:8] #bytearray(b'\x00\xf2E\n\x00\xc0\x17\x00\') header=tc.CCSDS_Telemetry_Header.from_buffer(big_buffer) #Read in the rest of the CCSDS packet. fid.readinto(write_buffer[8:(header.p_data_len+1)]) print"Apid is %d decode it."%header.p_ident.apid #changing ctypes changes the binary data. Good for commanding header.p_sp_dest=5 #big_buffer[0:8] #bytearray(b'\x05\xf2E\n\x00\xc0\x17\x00') fid.close()

  22. ctypescont… classCCSDS_Telemetry_Header(ctypes.LittleEndianStructure): "””Documentation about CCSDS Telemetry Header""" _pack_=1 _fields_=[("p_sp_dest",ctypes.c_int8), ("p_sp_prot",ctypes.c_int8), ("p_ident",CCSDS_Telemetry_Header_p_ident), ("p_seq_cont",CCSDS_Telemetry_Header_p_seq_cont), ("_p_data_len",ctypes.c_int16), ("s_time",CCSDS_Telemetry_Header_s_time)] @property defp_data_len(self): “””More Documentation””” returnself._p_data_len+1 @p_data_len.setter defp_data_len(self,new_len): self._p_data_len=new_len–1 h = CCSDS_Telemetry_Header h.p_data_len = 8 print h._p_data_len 7 print h.p_data_len 8 CCSDS data length is 1 minus actual length of the message. Provide documentation via docstring on telemetry value. Telemetry: Polynomials, conversions, etc Commanding: limit values, throw errors if not within ranges.

  23. Lessoned learned • Provide all of the standard C/C++ types • As listed on “mimic C/C++ in XML” slide • Standardized naming of Integers, floats, bools, pointers. (int32,int16,int8, …) • Allows for creating dictionary mappings between XML and desired language • Mimic the structure of existing languages. • Makes mapping from XML to existing language more strait forward • Keep it simple • Develop tools with XML standard • Kept having to change scheme while making tools to make processing easier

  24. Backup slides

  25. C bit field example(Not supporting, yet …) structCCSDS_Telemetry_header_p_ident { uint16_t apid:11; uint16_t secondary_header_present:1; uint16_t packet_type:1; uint16_t packet_version_number:1; }; http://msdn.microsoft.com/en-us/library/ewwyfdbe(v=vs.71).aspx Least significant field first

  26. C Example cont /*! * @ingroup MESSAGES * @brief An example message for Power point. * @apid 135 */ typedefstructBasic_M{ CCSDS_Telemetry_Headerpacket_header; //CCSDS Packet Header /*! * @brief Temp of the baseplate the cpu is attached to. * @polynomial [1566.7676,-18.85822,-.17372, 0.00229, 0.00001] * @unitfahrenheit * @modenominal * @red_limit [-Inf,-20), (120,Inf] * @yellow_limit [-20,-15), (115,120] */ int32_t cpu_temp; /*! * @brief Receiver Position * @coordinate_frame ECEF * @unitmeter */ doubleposition[3]; }; Doxygen comments start with @marker_name marker value Indented comments belong to parent comment

  27. Example basic example <Telemetry> <Messagename="Basic_M"> <Members> <variablebits="128"name="packet_header"offset="0"type="CCSDS_Telemetry_Header"/> <variablebits="32"name="cpu_temp"offset="128"type="int32_be"/> <variablebits="192"name="position"offset="192"type="float64_be"> <array> <size> 3 </size> </array> </variable> </Members> </Message> </Telemetry>

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