This wiki documents Piksi v2.3.1 which was discontinued April 1st, 2017.
Visit support.swiftnav.com for newer products including Piksi Multi.

New Getting Started Guide

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THIS DOCUMENT IS DEPRECATED. THE UPDATED GUIDE IS HERE.



Note: This guide was tested on:

  • Windows XP (SP3)
  • OS X (10.8.5)
  • Ubuntu Linux (12.10 32-bit, kernel version 3.5.0-17)

Welcome to the getting started guide for the Swift Navigation Piksi GPS Receiver! This guide provides first time Piksi users an overview of how to set up Piksi, download the required software, connect to Piksi, and use Piksi to acquire position solutions.

By the end of this guide, you will be able to acquire a fixed RTK solution using two Piksis. Performing the five major steps listed below should take you about an hour and you will need to perform the last two steps outdoors:

  1. Piksi RTK Kit Contents
  2. Installing the Piksi Console
  3. Simulation Mode
  4. Single Point Position
  5. RTK Baseline

If you are a developer and want to set up the toolchain to build firmware for Piksi, see the Piksi Developer Getting Started Guide. If anything in this guide is incorrect or unclear, please contact us through our forum and give us your feedback!

Piksi RTK Kit Contents

The items below are included in the Piksi RTK Kit. On the right is a description of Piksi connectors. The Piksi Datasheet provides a more detailed description of Piksi hardware.

PiksiBoxMedium.png

RTK Kit Contents Piksi Components
A) Two (2) micro USB cables I) External GPS antenna connector
B) Four (4) single-sided UART cables J) UART A serial connector
C) Two (2) Linx Technologies external GPS antennas K) UART B serial connector
D) Two (2) 3DR radio antennas L) Debug and expansion header
E) Two (2) radio cables M) JTAG serial connector
F) Two (2) ground planes N) Micro USB connector
G) Two (2) 3DR radios (either 433 or 915 MHz)
H) Two (2) Piksi OEM boards

Installing the Piksi Console

Caution: Running the Piksi Console on a virtual machine (e.g. VMWare, VirtualBox, Parallels) is strongly discouraged. This is due to imperfections in the USB passthrough functionality, which can lead to symptoms such as freezing during firmware updates and glitches in regular operation. We suggest that you use the native console for your platform.

This step can be done indoors and requires an Internet connection. The Piksi Console is a GUI that runs on your computer and allows you to connect to Piksi. It displays the position and other status information. To run the Piksi console, you need to first install the Piksi USB drivers and download the Piksi Console Installer.

Installing the Piksi USB drivers

Windows and Mac OS X

Caution: The FTDI site offers two drivers, VCP and D2XX. You only need the VCP driver. Do not follow the instructions for installing D2XX drivers.

If running Windows or Mac OS X, you must install FTDI's VCP drivers to communicate with Piksi over USB. Download them from FTDI's website and install them:

http://www.ftdichip.com/Drivers/VCP.htm

Mac OS X

In addition to the above, if you are running Mac OS X 10.9 (Mavericks) or later versions, you must install the official driver from the FTDI website. The built-in Apple driver is buggy and won't work with Piksi. You must choose FTDI driver version 2.2.18, not version 2.3. After installing the FTDI VCP driver, you must forcibly unload the Apple driver and load the FTDI driver by running the following commands from the Terminal application:

$ sudo kextunload /System/Library/Extensions/IOUSBFamily.kext/Contents/PlugIns/AppleUSBFTDI.kext
$ sudo kextload /System/Library/Extensions/FTDIUSBSerialDriver.kext

After unloading the Apple driver, you might get the message below in your command window.

(kernel) Kext com.apple.driver.AppleUSBFTDI not found for unload request.
Failed to unload com.apple.driver.AppleUSBFTDI (libkern/kext) not found.

Ignore this message and load the FTDI driver. The Piksi console will still work as it should.

Linux

Recent versions of Linux (kernel > 3.0) have built-in native kernel support for the FTDI devices and do not require the above drivers.

Getting the Piksi Console Installer

OS X Note: Be sure to drag the Piksi Console application into your Applications folder. Later when you try to run the console, launch it from the Piksi Console icon located in your Applications Folder.

Windows and Mac OS X

Download the installer for Windows and Mac OS X from the link below. Look for the Console with the highest version number and click the link to download it:

http://downloads.swiftnav.com/piksi_console/

Linux

If you want to run the Piksi Console on Linux, follow the instructions at HOW-TO: Running the Piksi Console from source.

Simulation Mode

This test can be done indoors and requires an Internet connection.

Goal

With the Piksi Console and FTDI driver installed, the first thing you should try is the Piksi Simulation Mode. This will give you some familiarity with the Piksi Console before testing outside with Piksi receiving actual GPS signals. In the simulation mode, Piksi will output simulated position solutions, status information, and differential corrections as if Piksi was mounted on a vehicle flying in a large circle.

Hardware Setup

  1. Plug Piksi into your computer via the micro-USB cable.

Piksi connected to a computer via USB cable.

Running the Console Software

With the Piksi connected to your computer, launch the Piksi Console using the installed icon. When the console starts, it will prompt you to select which port to use. Simply select the port that corresponds to Piksi from the drop down menu:

PiksiSelection2a.png

Updating Piksi Firmware

Periodically, Swift Navigation will release a new version of the Piksi firmware. Launching the Console after plugging Piksi into your laptop via USB will cause the system to automatically check for an update. The Console will detect out of date firmware and open an update dialog box like the one below:

Firmware-update-dialog.png

Whether or not you see this dialog box, navigate to the Firmware Update tab of the Console and check for updates.

  1. Check to see if you have the latest version of the Console. The versions in these boxes should match. If they don't, close the Console and follow the instructions above to install the latest Console.
  2. Check to see if you have the latest NAP firmware. The versions in these boxes should match.
  3. Check to see if you have the latest STM firmware. The versions in these boxes should match.
  4. If new STM or NAP versions are needed, click the Download Newest Firmware Files button. This may take a few seconds. Wait until the Update Status dialog box has two messages, one for STM and one for NAP, reading "Saved file to... .hex"
  5. Click Update Piksi Firmware and wait until all the updates are installed. This may take a few minutes. Wait until you see the confirmation stating all updates are installed in the Update Status box.
  6. Repeat Steps 2-5 for each Piksi you own! Always update all of your Piksis when new firmware is available.

FirmwareUpdate3.png

Enabling Simulation Mode

Go to the Settings tab and do the following:

  1. Under the Simulator tab, you will see a value for enabled set equal to False. Click on this.
  2. Change this value of enabled to True by selecting True on the selection at the right part of the tab.

Enabling1.png

Your hardware will now be running Simulation Mode. If you view the tracking, solution, and baseline tabs, you can now see the simulated output.

Viewing Position Solutions

In this simulated set of solutions, the simulated rover is traveling counter-clockwise around the simulated base station in a 100 meter radius circle. The way to view these results are through three primary screens in the Piksi Console. You can also read additional documentation that gives a complete overview of the Piksi Console. The key tabs you should examine for this test are below.

Tracking Tab

This tab shows the number of satellites Piksi is tracking. Each satellite is represented by a colored line on the graph, and the line's position on the graph represents the strength of the satellite's signal over time. The x axis is the last 200 messages that Piksi sent to the Console and the y axis is Carrier to Noise Density Ratio (C/No), in dB-Hz, which is the signal strength of the satellite. The most recent time is on the right hand side and scrolls to the left. This simulation shows that you are tracking 8 satellites; you know this because you will see consistent C/No of over 33 dB-Hz.

Solution Tab

This tab shows Piksi's Single Point Position, a standard GPS position solution with an absolute position accuracy of several meters. The Latitude parameter graphed on the vertical axis describes the angular distance north or south of the Earth's equator, in decimal degrees. The Longitude parameter graphed on the horizontal axis describes the angular distance east or west of the Prime Meridian, in decimal degrees. Here you will see blue dots (single point solution) and an orange line (RTK solution). The blue dots will have less precise positions and therefore will appear as a noisy cluster around the orange RTK line.

Baseline Tab

This tab shows Piksi's RTK Baseline, a high precision GPS position solution, with a relative position accuracy of several centimeters. This data visualization will show the base station as a red cross, the rover as an orange cross, and the path of the rover as blue dots. Note that, in the Piksi Console, the Piksi that is connected to the Console is always the Rover and the unit not connected to the console is always the Base. Also, the base is always considered to be at coordinate [0,0]. The rover position data is a relative vector between the base and the rover, given as a distance North (graphed on the vertical axis, in meters), East (graphed on the horizontal axis, in meters), and Down (not graphed). Here you will notice that the rover path is the same exact circle as shown in the Solution tab, but it is much more precise than the path shown by the Single Point Position solution.

Disabling Simulation Mode

Now, disable simulation mode by changing the enabled value back to False on the Settings tab.

EnableFalse.png

Single Point Position

Note: A Single Point Position solution is a standard GPS position solution, with an accuracy of several meters. This is an absolute position and only one Piksi is required to calculate the position.

This test must be performed outdoors and does not require an Internet connection.

Goal

In this section, you will set up Piksi to display a Single Point Position on the Piksi Console.

Antenna Guidelines

For this test you need to go outdoors and find a spot that meets the requirements for positioning of the external antenna. The Piksi comes with an internal antenna and an external antenna. For all testing in this guide, you must use the external antenna and a ground plane. Place the external antenna on top of the ground plane, indicated by the blue marker, at a spot with a sky view that is unobstructed above 30 degrees up from the horizon in every direction. Piksi's high precision GPS antenna is sensitive to its environment. Since Piksi needs to track carrier phase information from GPS satellites, it is much more sensitive to obstructions than standard consumer GPS of the type found in, for example, smartphones. Thus, the external Piksi antenna must be kept away from any obstructions to its sky view.

Antenna1.png

  • Do use the external antenna.
  • Do place the ground plane underneath the external antenna.
  • Do not test inside a building.
  • Do not place the external antenna near buildings.
  • Do not place the external antenna near trees and other cover.
  • Do not stand near the antenna or put your hand over the antenna during testing.
  • Do not place an open laptop near the antenna so that the laptop itself is blocking sky view.

Hardware Setup

  1. Screw the external Linx GPS antenna onto the Piksi and place the antenna on a ground plane.
  2. Plug Piksi into your computer via the micro-USB cable.
  3. Follow the antenna guidelines, above.

Piksi connected to an external antenna

Running the Console Software

  1. Launch the Piksi Console using the installed icon as described in the previous section.
  2. Ensure that you have disabled simulation mode, per the instructions from the previous section.

Checking Satellite Signals

Navigate to the Tracking tab. In the text area at the bottom you will see messages printed as Piksi tries to acquire different satellites in turn. If a satellite has successfully been acquired, it will be assigned to a tracking channel and transitioned to tracking. In the Tracking tab you will see a line added to the plot indicating the signal strength of that satellite. Wait until 4 satellites are tracking with signal strengths above 33 db-Hz, as indicated by the red line in the image below.


Tracking3.png

Viewing Position Solutions

Once 4 satellites are tracking, the green LED light on Piksi will start flashing, as described in the Piksi LED Lighting Overview page. The green LED light will flash the number of satellites Piksi has successfully tracked, then pause and repeat. Piksi will begin to download the data it needs from the satellites to perform the position solution. This is called the ephemeris and takes approximately 30 seconds. When the ephemeris has been downloaded, the message "New ephemeris for PRN x" will be displayed in the text area of the Tracking tab. Navigate to the Solution tab and you should see Piksi outputting position solutions represented as a cloud of blue points on the graph.

Solutions2.png

RTK Baseline

Note: An RTK Position Solution is a high precision GPS position solution, with an accuracy of several centimeters. This is a relative position between two Piksis, which are both required in order to calculate the solution.

This test must be performed outdoors and does not require an Internet connection.

Goal

In this section, you will setup two Piksis outdoors and be able to display an RTK position solution on the Piksi Console. Be sure to follow the guidelines for external antenna positioning for outdoor testing. You should also have run through the simpler Single Point Position test before moving on to this test.

Hardware Setup

Note: Ensure the UART serial connector on the 3DR radio is fully seated: it may need an extra push.

  1. Screw the external Linx GPS antennas onto the Piksi and place the antennas on ground planes.
  2. Screw the two radio antennas onto the circular connectors of the 3DR radios.
  3. Use the radio cables to connect the UART ports on the radios to the UART A receiving ports on the Piksi boards.
  4. Connect the Piksis to your computer with the USB cables. You may connect both Piksis to the same computer or connect them each to different computers.
  5. Follow the antenna guidelines, above.

RTKSetup.png

Running the Console Software

Load up the console software as for the single point position solution. If both Piksis are connected to the same computer, open two windows, one for each Piksi. You will have to specify the port used by each of the two Piksis when running the console command, specifying one port when you open the first console window and the second port when you open the second console window. If you have connected the two Piksis to each their computers, you only need to open one console for the Piksi connected to each computer.

Note for Mac OS X Users: In order to have a separate console window for each Piksi connected to the same computer, your computer will need to have two copies of the Piksi Console application (ie, "Piksi Console 1" and "Piksi Console 2"). To do this, right click on the Piksi console and choose Duplicate.

Checking Satellite Signals

Navigate to the Tracking tab. Wait until 5 satellites have signal strengths above 33 dB-Hz for the Piksis to acquire position solutions. The green LED light on each Piksi will flash slowly once it has a Single Point Position solution.

Tracking3.png

Checking Communication Between Piksis

Once the Piksis have position solutions, they will transmit the raw GPS observations over the radios. The red LED light on Piksi will flash when it correctly receives an observation packet from the other Piksi, as described on the Piksi LED Lighting Overview page. If you navigate to the Observations tab on one of the console, you will see the observations being sent by that Piksi in the upper Rover table, and the corrections that have been received over the radio from the other Piksi in the lower Base table. Recall that the Rover is the Piksi that is connected to the Console and the Base is the other Piksi. Wait until you can see 5 satellites in common between the Rover and Base windows in the Observations tab.

Observations3.png

Viewing Position Solutions

Once 5 satellites are in common between the Rover and Base windows in the Observations tab, Piksi will start producing differential solutions. Navigate to the Baseline tab and you will begin to see differential solutions being outputted. Initially Piksi will begin in Float mode and will eventually change to Fixed. This transition should take about 10 minutes, but the exact time to get to Fixed should vary between a few minutes, up to 15 minutes. When this happens, your Piksi has a fixed RTK lock. You should now see a centimeter accurate distance between your base Piksi and rover Piksi, visualized on the Baseline tab, like the example shown below.

Baseline3.png


Congratulations, you now know how to use Piksi! To learn more, visit the rest of the Piksi documentation.