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Hardware Piksi Multi

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Marco Tranzatto edited this page Mar 1, 2018 · 3 revisions

Choose the appropriate section, based on which system you are setting up:

Rover

Hardware (with Piksi Multi)

  • Piksi receiver Multi with FTDI cable.
  • Antenna "Tallysman TW3870E ".
  • Xbee Pro S2C, with RP-SMA connector (allows broadcasting -> we can have one base station and multiple rovers with RTK)
  • SparkFun XBee Explorer Regulated (Used to connect Xbee Pro to Piksi)

System Configuration (pictures taken with Piksi v2.3)

  • GPS antenna & Ground Plane: place them as high as possible and far away from any other electronic device
  • Piksi receiver: put it anywhere you like but try to place it as far as possible from the GPS antenna
  • Xbee: put it anywhere you like but try to place it as far as possible from the GPS antenna. See Xbee Configuration to configure it

HardwareSetup

Hardware (OLD version with Piksi V2.3 - Prefer Piksi Multi!)

(Prefer Piksi Multi!)

  • Piksi receiver v2.3.1 (Swift Navigation will continue to offer customer support for Piksi v2.3.1 untill May 1, 2017).
  • GPS Antenna "ANT-GPS-SH-MX", received with Piksi evaluation kit
  • Xbee Pro S2C, with RP-SMA connector (allows broadcasting -> we can have one base station and multiple rovers with RTK).
  • SparkFun XBee Explorer Regulated (Used to connect Xbee Pro to Piksi).

(Prefer Piksi Multi!)

Connections

  • Prefer UART connection over USB, especially on the robots with moving parts. This could easily solve a "Piksi disconnected" problem that occurs often if USB port is used to connect Piksi and the on-board PC. Look for Piksi Datasheet in the main Wiki Page.

Known Issues

Interference

GPS antenna is quite sensible to interference, especially to the one "close" to 1.5 GHz frequency (which is the GPS carrier frequency).

Behavior:

  • low number of satellites (less than 4 or 5)
  • low Carrier to Noise Density Ratio (C/No), which is the signal strength of the satellite (less than 30 dB-Hz)

Possible Solutions:

  • Place the GPS antenna as far as possible from any other device, such as on-board computer, cameras, Piksi receiver, etc. This is probably the best thing you can do. Increasing the distance of the antenna from everything else really helps you a lot! See even Antenna Placement Guidelines.
  • Avoid using USB 3.0 if possible. See USB 3.0 Radio Frequency Interference. When it is not possible, the Placement of the GPS antenna should also be carefully considered on the platform and be located as far away as possible from a USB 3.0 connector and/or device.
  • Copper tape can help to block noise. You can place it below the cover of your rover.

Piksi Disconnected

Behavior: ROS driver outputs "Piksi disconnected".

Possible Solutions: See "Connections" section in this page.

Base Station

Hardware (with Piksi Multi)

  • Piksi receiver Multi with FTDI calbe.
  • Antenna " L1/L2 GPS/GLN/DBS mini-survey antenna" (bought from Piksi store).
  • Xbee Pro S2C, with RP-SMA connector (allows broadcasting -> we can have one base station and multiple rovers with RTK).
  • SparkFun XBee Explorer Regulated (Used to connect Xbee Pro to Piksi).
  • Upboard.

Hardware (OLD version with Piksi V2.3 - Prefer Piksi Multi!)

(Prefer Piksi Multi!)

  • Piksi receiver v2.3.1 (Swift Navigation will continue to offer customer support for Piksi v2.3.1 untill May 1, 2017)
  • GPS Antenna "TW3100 Permanent Mount GPS L1 Antenna"
  • Xbee Pro S2C, with RP-SMA connector (allows broadcasting -> we can have one base station and multiple rovers with RTK)
  • SparkFun XBee Explorer Regulated (Used to connect Xbee Pro to Piksi)
  • Upboard.

(Prefer Piksi Multi!)

System Configuration

  • GPS antenna: place it as high as possible and far away from any other electronic device
  • Piksi receiver: put it inside the blue box
  • Xbee: put it on top of the blue box. See Xbee Configuration to configure it
  • Upboard: put it as far as possible from the GPS antenna (if you're using a buck converter to power the Upboard, place it as far as possible from the blue box)

Connections

  • The base station is not subject to fast movements and shakes as a robot. Therefore you can use a USB cable to connect Piksi to the Upboard

Known Issues

Low Number Of Satellites

Possible Solutions:

  • Make sure the GPS antenna and Piksi are far away from possible noisy sources (i.e. Upbaord, buck converter, etc)
  • Check how many satellites should be visible in your zone: calsky

Xbee Configuration

Get familiar with Xbee configuration by reading the (short) wiki page in Xbee page. You can use an evaluation XBee board to program your devices . It looks like this (do not plug P8 with a jumper!).

Ready for use configurations, tested successfully in MBZIRC 2017 and ERL 2017, are available in xbee folder. Use XCTU to connect to your Xbee and load these configurations.

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