korving-f / ublox Goto Github PK

Python library for the UBX protocol

License: MIT License

Python 100.00%

ublox's Introduction

UBX Packet Parser

Introduction

This module is able to read from and configure ublox GPS modules through their UBX binary protocol over a serial connection. It can be considered a wrapper around the pyserial module.

A ublox 8 device was used to develop and test this library in combination with the documentation provided by ublox. Many of the messages specified in this document should also be compatible with earlier versions of the device (4/5/6/7) but others might not be backwards compatible.

Test

Move to main directory and issue:

$ python2 -m pytest
$ python3 -m pytest

Supported Messages

Configuration
- CFG-MSG (0x06 0x01)
- CFG-RATE (0x06 0x08)
- CFG-CFG (0x06 0x09)
- CFG-NAV5 (0x06 0x24)
- ...
GPS-Data
- NAV-POSLLH (0x01 0x02)
- NAV-DOP (0x01 0x04)
- NAV-SOL (0x01 0x06)
- NAV-PVT (0x01 0x07)
- ...
Other
- ACK-NAK (0x05 0x00)
- ACK-ACK (0x05 0x01)
- ...

Basic Usage

One would usually create a serial connection to the GPS module and proceed to create an instance of UbxStream through which one reads data and sends configuration messages. The UbxStream class comes with functions to save, load and reset configurations as well as an automated way to disable all enabled-by-default NMEA messages. Of course one can enable/disable specific messages by passing in the documented message class and id. One can auto detect serial ports and set the baudrate for the connection.

Other Issues / Examples

When using the default .read() method the internal message buffer gets cleared, taking in some fresh data first. This seems to have the effect that certain messages are never read while they are activated. One way around this is to read from a loop and check for the message you're interested in:

        >>> while(True):
        ...     y = x.read()
        ...     if(y.ubx_id == '04'):
        ...         break
        ...
        Receiving
        01 02
        Receiving
        01 04
        >>> y
        <ubx.UbxMessage object at 0x7f7a9dcf7be0>

Alternatively one can disable the flushed read as in the following example. NB! since you're reading from a stale buffer you're data will be old unless you read often and/or throw in an occasional flushed .read().

        >>> x.read(reset=False)
        Receiving
        01 07
        <ubx.UbxMessage object at 0x7f7a9dc69438>

For low power consumption use-cases one can increase the time between GNSS measurements. Value given is in milliseconds resulting in a calculated frequency. E.g. 1000ms == 1Hz (This is indicated by u-blox as a good default). Thanks @hankedan000 :)

        >>> x.cfg_rate(1000)
        Receiving
        05 01
        Acknowledged. CLS:0x6 ID:0x8
        <ubx.UbxMessage object at 0x7f8d895ea518

Future Improvements

At the moment only activated messages can be read and there is no support yet for polling specific messages. If any desired messages are not included please create an issue.

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ublox's Issues

Code getting stuck trying to read ubx_id 2

Hey,

Following your tutorial online I tried the following:

ubx_obj = ubx.UbxStream('/dev/serial0')
ubx_obj.enable_message(1,2)
ubx_obj.enable(1,6)

then in a loop i am reading it using
ubx_obj.read()
I then store the data i get depending on which id is being called in your code.
I am encountering this bug where it reads for around 10 to 15 mins or so and then spontaneously stops sending in the data from id 02 but sends in the ecef data from id 06.

Does this bug make any sense to you? Have you dealt with this before?

Bug in a read function

read function compares bytes with string data type for "0xb5" == 'b5' and causes issue in functioning. Please check.

aproblem

hello,here is my problem :
i follow the usage describle in the usage.png
nav_posllh = x.read()
No errors have been found as of now
and then when i go next
nav_posllh.lat
it says that nav_posllh has no attribute 'lat'
nav_posllh.l
it says that nav_posllh has no attribute 'l'
could u help me with that ,thanks

Possible to read multiple messages?

Hi,

Hopefully I am misunderstanding how to use this and this is a simple answer. I'm trying to read the NAV-PVT and NAV-DOP messages from my NEO-M8N (via the EVK-M8N eval kit). When I do x.read(), I only get NAV-PVT. I turned on NAV-PVT and NAV-DOP in U-Center (UBX > CFG > MSG), and when I tried running a while loop like:

while(True):
    print(x.read())

I only get 01 07 (PVT):

>>> while(True):
...     print(x.read())
... 
Receiving
01 07
<ubx.UbxMessage object at 0x7f7f9adfcb70>
Receiving
01 07
<ubx.UbxMessage object at 0x7f7f9adfcb70>
Receiving
01 07

x.enable_message(1,4) does not seem to do anything:

>>> x.enable_message(1,4)
Transmitting
06 01
Receiving
05 01
Acknowledged. CLS:0x6 ID:0x1
<ubx.UbxMessage object at 0x7f7f9b053208>
>>> x.read()
Receiving
01 07

and after running it, if I look in u-center, NAV-DOP was disabled ??
If I go into U-Center again and disable PVT and enable DOP, x.read() will give me the DOP message:

x.read()
Receiving
01 04
<ubx.UbxMessage object at 0x7ff83e846240>

I'm using Python 3.5.3 and the latest ublox library from your git repo. Any ideas? I need to be able to read DOP and PVT as they come in real time. Thank you!

Should disable_NMEA call take ~5min to complete ?

I'm using this call since I only want to get UBX protocol messages at a high rate (5 times a second). I've noticed though that the higher my baudrate that the longer this call takes, sometimes not even completing. When I drilled down into the call, I kept getting a long wait or error when trying to disable 0xF0 0x42.....as soon as I took that out from the list it worked consistently. Is there any reason why this call would fail or take so long compare to the other ones?

RTK capability: (base-station) receive RTCM (1005, 1077 and 1087) corrections

Is it possible to use this library on the UBX M8P for RTK purpose (base-station)?

configure dynamic model
get the RTCM3 corrections (1005, 1077 and 1087)
If not, do you plan on supporting it, is this project open for contributions?

Type Error NAV_PVT

Getting a type error when receiving a NAV_PVT message.
I enable the message with enable_message(1, 7) and then do a read().

Receiving
01 07
Traceback (most recent call last):
File "", line 1, in
File "/home/pi/rocketman/ublox.py", line 130, in disable_message
if(self.__confirmation()):
File "/home/pi/rocketman/ublox.py", line 203, in __confirmation
answer = self.read(reset=False)
File "/home/pi/rocketman/ublox.py", line 114, in read
return UbxMessage(ubx_class, ubx_id, dev=self.dev, version=self._version)
File "/home/pi/rocketman/ublox.py", line 231, in init
messageubx_id
File "/home/pi/rocketman/ublox.py", line 230, in
'07': lambda: self.__ubx_NAV_PVT(kwargs["dev"])}
File "/home/pi/rocketman/ublox.py", line 426, in __ubx_NAV_PVT
self.iTOW, self.year, self.month, self.day, self.hour, self.minute, self.second, self.valid, self.tAcc, self.nano, self.fixType, self.flags, self.flags2, self.numSV, self.lon, self.lat, self.height, self.hMSL, self.hAcc, self.vAcc, self.velN, self.velE, self.velD, self.gSpeed, self.headMot, self.sAcc, self.headAcc, self.pDOP, reserved11, reserved12, reserved13, reserved14, reserved15, reserved16, self.headVeh, self.magDec, self.magAcc = struct.unpack('=LH5BBLlB2BB4l2L5lLLH6BlhH', payload_cpy)
TypeError: a bytes-like object is required, not 'str'

NAV-RELPOSNED

Hi,
Firstly, I want to say thank you for making this libary. It is easy to understand the code but I have problem with reading data.
I would like to get messages from NAV-RELPOSNED but in the libary there are no code for that.
I tried to code it for myself but I faild and you seem a much better programmer than me so please tell me how is it possible te get the position from that. I would be really helpfull for me and also for my half-year homework.
I send you what i have programmed yet but it is not that much :D

I am waiting for your reply and thank you.
import serial
import math

import ubx

x = ubx.UbxStream(serial.Serial(port='COM6', baudrate=19200, timeout=1))
x.enable_message(0x01, 0x3c)
navigation_position = x.read()

print(navigation_position.lat)
#print(navigation_position.clsID)