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Zubax GNSS positioning module - GPS/GLONASS + Compass + Barometer + CAN

Posted by Zubax Robotics on September 26, 2014 at 12:43pm

Hi everyone,3689619101?profile=original


Today we present our first product - Zubax GNSS. It is a high-performance open source positioning module for outdoor environments with doubly redundant UAVCAN bus interface. It's the right choice for any UAV or robotic application where safety, positioning accuracy and cost efficiency are paramount.

Being UAVCAN-interfaced, Zubax GNSS can be used out of the box with any UAVCAN-enabled controller, such as Pixhawk. Detailed instructions about how to configure Pixhawk for use with Zubax GNSS can be found at our documentation portal (see the links below). At the moment, the native PX4 stack already has complete UAVCAN support implemented in the stable branch. The APM stack doesn't have support for UAVCAN at the moment, but there were some successful experiments with it earlier so it will be there soon as well. By the way, any cooperation from the APM developer community is highly welcome!

Features

Sensors

  • High performance concurrent GPS/GLONASS receiver u-blox MAX-M83689619120?profile=original
    • Full RF shielding of the GNSS circuits ensures reliable operation in high-EMI environments
    • 35 mm high gain patch antenna with large ground plane for reliable reception even in urban canyons
    • Analog front end with LNA and SAW ensures high noise resilience
    • Rechargeable backup battery enables low time-to-first-fix (a few seconds)
    • Up to 15 Hz update rate
  • High precision digital barometer Measurement Specialties MS5611
    • Altitude resolution 10 cm
  • 3-axis digital compass Honeywell HMC5883L

Interfaces

  • Doubly redundant UAVCAN with standard connectors
    • Sensor measurements at configurable rates
    • Continuous self diagnostic and failure detection outputs
    • Configuration
    • CAN bus bitrate up to 1 Mbps
    • Can be used in non-redundant mode as well (one interface will be inactive)
  • Auxiliary serial port
    • Direct access to the u-blox module
    • Firmware update
    • Diagnostics and configuration via command-line interface

General

  • 3689619043?profile=originalExtensive, continuous self diagnostics and failure detection make Zubax GNSS a favorable choice for safety-critical applications
  • Multiple redundant units can be used concurrently on the same UAVCAN bus
  • Sources are open and freely available for everyone:
    • Firmware sources
    • Schematics
    • 3D printable models of protective case and mounts
  • Low cost

Performance

The image below shows the performance of Zubax GNSS in comparison with another popular GPS receiver (u-blox LEA-6H with 25 mm patch antenna). Notice the deviation map, position accuracy estimates and SNR. This was captured in a shallow urban canyon of a large city. Zubax GNSS is on the left (click to enlarge):

3689619210?profile=original

This video features a highly precise, fully automatic landing of a Pixhawk-powered quadrotor with Zubax GNSS:

Links


P.S. Stay tuned for more UAVCAN-interfaced avionics. UAVCAN-enabled ESC and a UAVCAN-enabled something-quite-important are on their way to the market. Developers, please consider moving towards UAVCAN-centered ecosystem by supporting this protocol in your projects - learn more at uavcan.org.

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Comments

  • Francis German November 28, 2014 at 7:04pm

    I will not buy it in the near future for the following reasons:

    1. Not yet supported by Ardupilot and no “old” connection options
    2. The form factor is too big for the rest of my installation
    3. There is the “old” mag sensor on it, the HMC5983 has temperature compensation
    4. Sadly there is no mini/micro usb connector on it, instead you sell a pretty expensive UART Adapter with a special plug (there would be enough space)
    5. You have to cover the baro yourself(why not sell a mass produced clip-in hood with it?)
    6. According to http://www.u-blox.com/images/downloads/Product_Docs/GNSS-module-sel... the M8N is far better than the inbuilt M8C signal reception wise and can be firmware updated

    Do not get me wrong this board looks promising, but in my opinion it is 85% of the ideal board.

    Maybe you will take this comment into account fo a second revision.

  • Zubax Robotics November 22, 2014 at 12:17am

    Hi Craig,

    As it is stated at the article, the APM firmware does not officially support UAVCAN at the moment. Your options are:

    A similar case was discussed on our product forums. We'd appreciate if you posted your future questions directly to this forum.

    Thanks!

  • Craig Defleming November 21, 2014 at 5:04pm

    Hi, I purchased a Zubax, and it came today. There is no documentation anywhere that states how to turn on the UAVCAN bus on the pixhawk. There is no parameter named UAVCAN-anything. Even in the CLI in MP it says there is no parameter called UAVCAN or any way to use the CAN bus. The zubax documentation is not that clear either. Please help me! I want to unlock the power of zubax and spread the word! I have a very high end hexacopter with long flight times which is already next level stuff. but with the zubax, i can only imagine the power of this bird. PLEASE help me enable this for use on the pixhawk!!!

  • Zubax Robotics November 19, 2014 at 3:23am

    Thanks Alex,

    Some feedback and relevant discussion can be found on the dd mailing list here: https://groups.google.com/forum/#!topic/drones-discuss/P5MqTgdF8N4

    Google Groups
    Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.
  • Alex November 18, 2014 at 6:34am

    Interesting product, I will buy one for testing as well.

    Can brothers who also bought and tested this unit provide any positive/negative feedback? Would be really appreciated to see it.

    To ZR Team, wonderful work! One suggestion: if you can provide more tested data, it would be significantly enhance our confidence to buy your products!

  • Zubax Robotics October 1, 2014 at 10:00am

    Considering the initial feedback, we decided to lower the price of Zubax GNSS to $109. We have contacted everyone who has purchased Zubax GNSS for its initial price to refund the extra $40 they paid.

    Also, it seems like the question #1 we're receiving so far is "What is the accuracy of your product, as compared to 3DR uBlox GPS?". The short answer was provided on the 4-th comment to this post:

    If you take a look at the screenshot from u-center linked from the article you may notice significant difference in performance between Zubax GNSS and a competitor (and yes, the competitor is 3DR GPS, so called another popular GPS receiver):

    • Peak deviation (~5 vs. ~25 meters)
    • Number of SVs available (18 vs. 9)
    • SNR
    • 3D accuracy estimate (1.45 vs. 6.9 meters)

    Also, we have special discounts for resellers - feel free to reach us via info@zubax.com.

  • Zubax Robotics September 29, 2014 at 9:29pm

    Sadly, no, but PDF is available: https://github.com/Zubax/zubax_gnss/blob/master/hardware/pcb/GNSS.PDF

  • naish September 29, 2014 at 9:26pm

    Hi there is any chance on getting the .sch file of the board? 

    Thanks 

  • Zubax Robotics September 29, 2014 at 1:02pm

    This is a replacement.

    For instance, the copter on the video did not have any GPS or compass onboard except Zubax GNSS.

    Whether the external barometer will be preferred over the internal one depends on the configuration of your autopilot. For instance, PX4 stack always prefers a UAVCAN-interfaced barometer over the internal one, if such external barometer is present.

  • Craig Defleming September 29, 2014 at 12:48pm

    does this module act along side the 3rd compass/gps? or is it a replacement? Also, is it a replacement for the barometer? or is does it act along side the one on pixhawk?

This reply was deleted.