UBX Protocol Parser
Reason this release was yanked:
obsolete
Project description
pyubx2
pyubx2
is an original Python library for the UBX © protocol. UBX is a proprietary binary protocol implemented on u-blox ™ GNSS/GPS receiver modules.
The pyubx2
homepage is located at https://github.com/semuconsulting/pyubx2.
This is an independent project and we have no affiliation whatsoever with u-blox.
FYI There is a companion library pynmeagps, which handles standard NMEA 0183 © GNSS/GPS messages.
Current Status
At time of writing the library implements a comprehensive set of inbound (SET/POLL) and outbound (GET) messages for
u-blox GPS/GNSS devices from generation 6 through generation 10 (NEO-M6*, NEO-M7*, NEO-M8*, NEO-M9*, NEO-D9*, RCB-F9*, ZED-F9*, MAX-M10S, etc.), but is readily extensible. Refer to UBX_MSGIDS
in ubxtypes_core.py for the complete dictionary of messages currently supported. UBX protocol information sourced from u-blox Interface Specifications © 2013-2021, u-blox AG.
Sphinx API Documentation in HTML format is available at https://www.semuconsulting.com/pyubx2.
Contributions welcome - please refer to CONTRIBUTING.MD.
Bug reports and Feature requests - please use the templates provided.
Installation
pyubx2
is compatible with Python 3.6+ and has no third-party library dependencies.
In the following, python
& pip
refer to the Python 3 executables. You may need to type
python3
or pip3
, depending on your particular environment.
The recommended way to install the latest version of pyubx2
is with
pip:
python -m pip install --upgrade pyubx2
If required, pyubx2
can also be installed into a virtual environment, e.g.:
python -m pip install --user --upgrade virtualenv
python -m virtualenv env
source env/bin/activate (or env\Scripts\activate on Windows)
(env) python -m pip install --upgrade pyubx2
...
deactivate
Reading (Streaming)
class pyubx2.ubxreader.UBXReader(stream, *args, **kwargs)
You can create a UBXReader
object by calling the constructor with an active stream object.
The stream object can be any data stream which supports a read(n) -> bytes
method (e.g. File or Serial, with
or without a buffer wrapper).
Individual input UBX messages can then be read using the UBXReader.read()
function, which returns both the raw binary
data (as bytes) and the parsed data (as a UBXMessage
object, via the parse()
method). The function is thread-safe in so far as the incoming data stream object is thread-safe. UBXReader
also implements an iterator.
The constructor accepts the following optional keyword arguments:
ubxonly
: True = raise error if stream contains non-UBX data, False = ignore non-UBX data (default)validate
: VALCKSUM (0x01) = validate checksum (default), VALNONE (0x00) = ignore invalid checksum or lengthmsgmode
: 0 = GET (default), 1 = SET, 2 = POLL
Examples:
- Serial input - this example will ignore any non-UBX data.
>>> from serial import Serial
>>> from pyubx2 import UBXReader
>>> stream = Serial('/dev/tty.usbmodem14101', 9600, timeout=3)
>>> ubr = UBXReader(stream)
>>> (raw_data, parsed_data) = ubr.read()
>>> print(parsed_data)
- File input (using iterator) - this example will produce a
UBXStreamError
if non-UBX data is encountered.
>>> from pyubx2 import UBXReader
>>> stream = open('ubxdata.bin', 'rb')
>>> ubr = UBXReader(stream, ubxonly=True)
>>> for (raw_data, parsed_data) in ubr: print(parsed_data)
...
Parsing
You can parse individual UBX messages using the static UBXReader.parse(data)
function, which takes a bytes array containing a binary UBX message and returns a UBXMessage
object.
The parse()
method accepts the following optional keyword arguments:
validate
: VALCKSUM (0x01) = validate checksum (default), VALNONE (0x00) = ignore invalid checksum or lengthmsgmode
: 0 = GET (default), 1 = SET, 2 = POLL
Attributes within repeating groups are parsed with a two-digit suffix (svid_01, svid_02, etc.).
Example:
>>> from pyubx2 import UBXReader
>>> msg = UBXReader.parse(b'\xb5b\x05\x01\x02\x00\x06\x01\x0f\x38')
>>> print(msg)
<UBX(ACK-ACK, clsID=CFG, msgID=CFG-MSG)>
>>> msg = UBXReader.parse(b'\xb5b\x01\x12$\x000D\n\x18\xfd\xff\xff\xff\xf1\xff\xff\xff\xfc\xff\xff\xff\x10\x00\x00\x00\x0f\x00\x00\x00\x83\xf5\x01\x00A\x00\x00\x00\xf0\xdfz\x00\xd0\xa6')
>>> print(msg)
<UBX(NAV-VELNED, iTOW=16:01:50, velN=-3, velE=-15, velD=-4, speed=16, gSpeed=15, heading=128387, sAcc=65, cAcc=8052720)>
The UBXMessage
object exposes different public properties depending on its message type or 'identity',
e.g. the NAV-POSLLH
message has the following properties:
>>> print(msg)
<UBX(NAV-POSLLH, iTOW=16:01:54, lon=-21601284, lat=526206345, height=86327, hMSL=37844, hAcc=38885, vAcc=16557)>
>>> msg.identity
'NAV-POSLLH'
>>> msg.lat/10**7, msg.lon/10**7
(52.6206345, -2.1601284)
>>> msg.hMSL/10**3
37.844
Generating
(see below for special methods relating to the UBX configuration interface)
class pyubx2.ubxmessage.UBXMessage(ubxClass, ubxID, mode: int, **kwargs)
You can create a UBXMessage
object by calling the constructor with the following parameters:
- message class (must be a valid class from
pyubx2.UBX_CLASSES
) - message id (must be a valid id from
pyubx2.UBX_MSGIDS
) - mode (0=GET, 1=SET, 2=POLL)
- (optional) a series of keyword parameters representing the message payload
The 'message class' and 'message id' parameters may be passed as lookup strings, integers or bytes.
The 'mode' parameter signifies whether the message payload refers to a:
- GET message (i.e. output from the receiver - NB these would normally be generated via the
UBXReader.read()
orUBXReader.parse()
methods but can also be created manually) - SET message (i.e. command input to the receiver)
- POLL message (i.e. query input to the receiver in anticipation of a response back)
The message payload can be defined via keyword parameters in one of three ways:
- A single keyword parameter of
payload
containing the full payload as a sequence of bytes (any other keyword parameters will be ignored). NB thepayload
keyword must be used for message types which have a 'variable by size' repeating group. - One or more keyword parameters corresponding to individual message attributes. Any attributes not explicitly provided as keyword parameters will be set to a nominal value according to their type.
- If no keyword parameters are passed, the payload is assumed to be null.
e.g. to generate a CFG-MSG which polls the 'VTG' NMEA message rate on the current port, any of the following constructor formats will work:
>>> from pyubx2 import UBXMessage, POLL
>>> msg1 = UBXMessage(b'\x06', b'\x01', POLL, payload=b'\xf0\x05')
>>> print(msg1)
<UBX(CFG-MSG, msgClass=NMEA-Standard, msgID=VTG)>
>>> from pyubx2 import UBXMessage, POLL
>>> msg2 = UBXMessage(6, 1, POLL, msgClass=240, msgID=5)
>>> print(msg2)
<UBX(CFG-MSG, msgClass=NMEA-Standard, msgID=VTG)>
>>> from pyubx2 import UBXMessage, POLL
>>> msg3 = UBXMessage('CFG','CFG-MSG', POLL, msgClass=240, msgID=5)
>>> print(msg3)
<UBX(CFG-MSG, msgClass=NMEA-Standard, msgID=VTG)>
NB: Once instantiated, a UBXMessage
object is immutable.
Serializing
The UBXMessage
class implements a serialize()
method to convert a UBXMessage
object to a bytes array suitable for writing to an output stream.
e.g. to create and send a CFG-MSG
message which sets the NMEA GLL message rate to '1' on the receiver's UART1 and USB ports (assuming an output serial stream has been created as serialOut
):
>>> from serial import Serial
>>> serialOut = Serial('COM7', 38400, timeout=5)
>>> from pyubx2 import UBXMessage, SET
>>> msg = UBXMessage('CFG','CFG-MSG', SET, msgClass=240, msgID=1, rateUART1=1, rateUSB=1)
>>> print(msg)
<UBX(CFG-MSG, msgClass=NMEA-Standard, msgID=GLL, rateDDC=0, rateUART1=1, rateUART2=0, rateUSB=1, rateSPI=0, reserved=0)>
>>> output = msg.serialize()
>>> output
b'\xb5b\x06\x01\x08\x00\xf0\x01\x00\x01\x00\x01\x00\x00\x022'
>>> serialOut.write(output)
Configuration Interface
CFG-VALSET, CFG-VALDEL and CFG-VALGET message types
Generation 9 of the UBX protocol introduced the concept of a device configuration interface with configurable parameters being set or unset (del) in the designated memory layer(s) via the CFG-VALSET and CFG-VALDEL message types, or queried via the CFG-VALGET message type. Legacy CFG message types continue to be supported but are now deprecated.
Optionally, batches of CFG-VALSET and CFG-VALDEL messages can be applied transactionally, with the combined configuration only being committed at the end of the transaction.
Individual configuration parameters are designated by keys, which may be in string (keyname) or hexadecimal integer (keyID) format. Keynames and their corresponding hexadecimal keyIDs and data types are defined in ubxtypes_configdb.py as UBX_CONFIG_DATABASE
. Two static helper methods are available to convert keyname to keyID and vice versa - UBXMessage.cfgname2key()
and UBXMessage.cfgkey2name()
.
Dedicated static methods are provided to create these message types - UBXMessage.config_set()
, UBXMessage.config_del()
and UBXMessage.config_poll()
. The following examples assume an output serial stream has been created as serialOut
.
UBXMessage.config_set() (CFG-VALSET)
Sets up to 64 parameters in the designated memory layer(s).
Parameters:
- layers - 1 = Volatile RAM, 2 = Battery-Backed RAM (BBR), 4 = External Flash
- transaction - 0 = None, 1 = Start, 2 = Ongoing, 3 = Commit
- cfgData - an array of up to 64 (key, value) tuples. Keys can be in either keyID (int) or keyname (str) format
>>> from pyubx2 import UBXMessage
>>> layers = 1
>>> transaction = 0
>>> cfgData = [("CFG_UART1_BAUDRATE", 9600), (0x40530001, 115200)]
>>> msg = UBXMessage.config_set(layers, transaction, cfgData)
>>> print(msg)
<UBX(CFG-VALSET, version=0, layers=b'\x01', transaction=0, reserved0=0, cfgData_01=1, cfgData_02=0 ...)>
>>> serialOut.write(msg.serialize())
UBXMessage.config_del() (CFG-VALDEL)
Unsets (deletes) up to 64 parameter settings in the designated non-volatile memory layer(s).
Parameters:
- layers - 2 = Battery-Backed RAM (BBR), 4 = External Flash
- transaction - 0 = None, 1 = Start, 2 = Ongoing, 3 = Commit
- keys - an array of up to 64 keys in either keyID (int) or keyname (str) format
>>> from pyubx2 import UBXMessage
>>> layers = 4
>>> transaction = 0
>>> keys = ["CFG_UART1_BAUDRATE", 0x40530001]
>>> msg = UBXMessage.config_del(layers, transaction, keys)
>>> print(msg)
<UBX(CFG-VALDEL, version=0, layers=b'\x04', transaction=b'\x00', reserved0=0, keys_01=1079115777, keys_02=1079181313)>
>>> serialOut.write(msg.serialize())
UBXMessage.config_poll() (CFG-VALGET)
Polls up to 64 parameters from the designated memory layer.
Parameters:
- layer - 0 = Volatile RAM, 1 = Battery-Backed RAM (BBR), 2 = External Flash, 7 = Default (readonly)
- position - unsigned integer representing number of items to be skipped before returning result (used when number of matches for an individual query exceeds 64)
- keys - an array of up to 64 keys in either keyID (int) or keyname (str) format. keyIDs can use wildcards - see example below and UBX device interface specification for details.
>>> from pyubx2 import UBXMessage
>>> layer = 1
>>> position = 0
>>> keys = ["CFG_UART1_BAUDRATE", 0x40530001]
>>> msg = UBXMessage.config_poll(layer, position, keys)
>>> print(msg)
<UBX(CFG-VALGET, version=0, layer=1, position=0, keys_01=1079115777, keys_02=1079181313)>
>>> serialOut.write(msg.serialize())
Wild card query to retrieve all CFG_MSGOUT (keyID 0x2091*) parameters (set bits 0..15 of the keyID to 0xffff):
>>> from pyubx2 import UBXMessage
>>> layer = 1
>>> position = 0 # retrieve first 64 results
>>> keys = [0x2091ffff]
>>> msg1of3 = UBXMessage.config_poll(layer, position, keys)
>>> print(msg1of3)
<UBX(CFG-VALGET, version=0, layer=1, position=0, keys_01=546439167)>
>>> serialOut.write(msg1of3.serialize())
>>> position = 64 # retrieve next 64 results
>>> msg2of3 = UBXMessage.config_poll(layer, position, keys)
>>> print(msg2of3)
<UBX(CFG-VALGET, version=0, layer=1, position=64, keys_01=546439167)>
>>> serialOut.write(msg2of3.serialize())
>>> position = 128 # retrieve next 64 results
>>> msg3of3 = UBXMessage.config_poll(layer, position, keys)
>>> print(msg3of3)
<UBX(CFG-VALGET, version=0, layer=1, position=128, keys_01=546439167)>
>>> serialOut.write(msg3of3.serialize())
Examples
The following examples can be found in the \examples
folder:
-
ubxstreamer.py
illustrates how to implement a threaded serial reader for UBX messages using pyubx2.UBXReader. -
ubxfile.py
illustrates how to implement a binary file reader for UBX messages using the pyubx2.UBXReader iterator function. -
ubxcfgval.py
illustrates how to invoke the Generation 9 configuration interface via CFG-VALSET, CF-VALDEL and CFG-VALGET messages. -
ubxconfig.py
illustrates how to invoke legacy (pre-Generation 9) configuration messages (CFG-MSG). -
gpxtracker.py
illustrates a simple CLI tool to convert a binary UBX data dump to a*.gpx
track file.
Extensibility
The UBX protocol is principally defined in the modules ubxtypes_*.py
as a series of dictionaries. Message payload definitions must conform to the following rules:
1. attribute names must be unique within each message class
2. attribute types must be one of the valid types (I1, U2, X4, etc.)
3. repeating groups must be defined as a tuple ('numr', {dict}), where:
'numr' is either:
a. an integer representing a fixed number of repeats e.g. 32
b. a string representing the name of a preceding attribute containing the number of repeats e.g. 'numCh'
c. 'None' for a 'variable by size' repeating group. Only one such group is permitted per payload and it must be at the end.
{dict} is the nested dictionary of repeating items
Repeating attribute names are parsed with a two-digit suffix (svid_01, svid_02, etc.). Nested repeating groups are supported. See CFG-VALGET, MON-SPAN, NAV-SAT and RXM-RLM by way of examples.
In most cases, a UBX message's content (payload) is uniquely defined by its class, id and mode; accommodating the message simply requires the addition of an appropriate dictionary entry to the relevant ubxtypes_*.py
module(s).
However, there are a handful of message types which have multiple possible payload definitions for the same class, id and mode, with no consistency as to how to differentiate between them. Under these circumstances, it may be necessary to modify the code in ubxmessage.py
to examine elements of the payload itself in order to determine the appropriate dictionary definition. This currently applies to ESF-MEAS, CFG-NMEA, RXM-PMP, RXM-PMREQ, RXM-RLM and most MGA message types.
Command Line Utility
If pyubx2
is installed using pip, a simple command line utility ubxdump
is automatically installed into the Python 3 scripts (bin) directory. This utility streams the parsed UBX output of a u-blox GNSS device to the terminal.
Assuming the Python 3 scripts (bin) directory is in your PATH, the utility may be invoked thus (all args are optional):
ubxdump port=/dev/ttyACM1 baud=9600 timeout=5 ubxonly=0 validate=1 raw=0
If ubxonly
is set to True (1), streaming will terminate on any non-UBX data (e.g. NMEA).
For help, type:
ubxdump -h
Graphical Client
A python/tkinter graphical GPS client which supports both NMEA and UBX protocols (via pynmeagps and pyubx2 respectively) is available at:
https://github.com/semuconsulting/PyGPSClient
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