Welcome to GNSS_visualization_tools’ documentation!¶

Scenarios already define¶

6 scenarios have been defined for you to test your devices:

- test_1: This is the static case, for a minute, data are taken from your simulator and/or your receiver(s).

- test_2: This is the temporal square test, the simulator run a path representing a square at constant speed , each section last a minute. It basically test if the receiver(s) is well responding to a brutal change of direction.

- test_3: This is the temporal circle test, the simulator run a path representing a circle at constant speed, during 2 minutes.

- test_4: This is the test of constant acceleration in straight line.

- test_5: This is the sensitivity test, staying static, the C/N0 is increased. The goal is to see until which C/N0 it is still possible to receive something

- test_6: This is the Free to Urban space test. The goal is to test if the receiver can keep its reliability when passing from a free space to a urban space.

Create your scenario¶

You can also create your own scenario, let’s explain that with an example.

Let’s imagine you want to go from the point A to C passing by B.

- 1st step:

Create a new .ini file and use this template:

[START]
LAT:
LONG:
ALT:
Duration:
Heading:
Speed:
Acceleration:
Rateheading:
Turnrate:
Turnradius:
Cn0:
Propagation:
Antenna:
Tropo:
Iono:
keepalt:
ECEFpos:
Multipath:
SpeedOverGround:
Verticalspeed:
Enuvel:
Ecefvel:
VerticalAcceleration:
ENUAccel:
ECEFAccel:
PRYattitude:
DPRYattitude:
Kepler:
[SECTION 1]
LAT:
LONG:
ALT:
Duration:
Heading:
Speed:
Acceleration:
Rateheading:
Turnrate:
Turnradius:
Cn0:
Propagation:
Antenna:
Tropo:
Iono:
keepalt:
signaltype:
ECEFpos:
Multipath:
SpeedOverGround:
Verticalspeed:
Enuvel:
Ecefvel:
VerticalAcceleration:
ENUAccel:
ECEFAccel:
PRYattitude:
DPRYattitude:
Kepler:
[END]

In our case the [START] section will look like:

[START]
LAT: latitude of A in decimal degrees
LONG: longitude of A in decimal degrees
ALT: altitude of A in meters
Duration:
Heading:
Speed:
Acceleration:
Rateheading:
Turnrate:
Turnradius:
Cn0:
Propagation:
Antenna:
Tropo:
Iono:
keepalt:
ECEFpos:
Multipath:
SpeedOverGround:
Verticalspeed:
Enuvel:
Ecefvel:
VerticalAcceleration:
ENUAccel:
ECEFAccel:
PRYattitude:
DPRYattitude:
Kepler:

- 2nd step:

Copy/Paste the number of [SECTION] needed. In our example, there is two sections:

• Section 1 between A and B
• Section 2 between B and C

For each section, you can now fill all parameters you need but pay attention:

• Either fill a position information or a duration and a heading, not both
• fill LAT, LONG, ALT or ECEFpos not both
• fill ENUvel or ECEFvel or Speed or SpeedOverGround not four of them
• fill ENUaccel or ECEFaccel or Acceleration not three of them
• fill PRYattitude or DPRYattitude not both

For our example:

We know latitude, longitude and altitude of point A and B, and we want to put this 4 parameters (acceleration, antenna model, ionosperic model and tropospheric model).

Then our [SECTION1] will look like:

[SECTION1]
LAT: latitude of B in decimal degrees
LONG: longitude of B in decimal degrees
ALT: altitude of B in meters
Duration:
Heading:
Speed:
Acceleration: 5.0
Rateheading:
Turnrate:
Turnradius:
Cn0:
Propagation:
Antenna: Patch
Tropo: Saastamoinen
Iono: ON
keepalt:
ECEFpos:
Multipath:
SpeedOverGround:
Verticalspeed:
Enuvel:
Ecefvel:
VerticalAcceleration:
ENUAccel:
ECEFAccel:
PRYattitude:
DPRYattitude:
Kepler:

Now, to reach C from B, we have to head South West for a minute. During this second section, we want to set 4 other parameters (speed, propagation model, antenna model and tropospheric model).

Then our [SECTION2] will look like:

[SECTION2]
LAT:
LONG:
ALT:
Duration: 00:00:01:00
Heading: 220
Speed: 10.0
Acceleration:
Rateheading:
Turnrate:
Turnradius:
Cn0:
Propagation: URBAN,25.0,10.0,0.5
Antenna: Zero model
Tropo: black
Iono:
keepalt:
ECEFpos:
Multipath:
SpeedOverGround:
Verticalspeed:
Enuvel:
Ecefvel:
VerticalAcceleration:
ENUAccel:
ECEFAccel:
PRYattitude:
DPRYattitude:
Kepler:

- 3rd step

Now you just have to put a [END] at the end of the file!

Choose your scenario¶

Once you have create your own scenario, or if you want to run a pre-defined scenario, in the main file fill the argument of tools.read_scen() with the name of your scenario like this for example:

scenario = tools.read_scen('data/scenariotest/test_2.ini')

Ublox initialisation¶

There is different steps to configure the receiver(s):

• First of all, fill the COM port like this:

  ubloxcnx = Ublox(com='COM6')
  

• Then you have to choose which reset you want to make between Cold RST, Warm RST or Hot RST, like this:

  ubloxcnx.reset(command='Cold RST')
  

• Then you have to enable and disable which message you want or don’t want to receive from the receiver, you can:

  enable:

  • ephemerides message thanks to ‘EPH’
  • ionospheric messages thanks to ‘HUI’
  • pseudo-range messages thanks to ‘RAW’
  • if you want all the UBX data just put ‘UBX’
  • position messages thanks to ‘GGA’
  • if you want all the NMEA data just put ‘NMEA’

  disable:

  • all NMEA message thanks to ‘NMEA’
  • all UBX message thanks to ‘UBX’

Here is an example of how to enable/disable message:

ubloxcnx.enable(command='NMEA')
ubloxcnx.disable(command='UBX')

Spectracom initialisation¶

To make the connexion with the Spectracom, you need to fill the argument of Spectracom(), like this for example:

spectracomcnx = Spectracom('USB0::0x14EB::0x0060::200448::INSTR')

You can if you want get the almanach data and/or the latest observation file by uncomment line 84 and/or 87 in the main file:

# Get almanach of Spectracom
spectracomcnx.get_almanach()

# Get latest observation file
spectracomcnx.get_latest()

Launch the application¶

First of all, you have to run the flask.py file. You can find it in GNSS_visualization_tools > GNSSTools > visualisation > flaskr. This will launch the server on http://127.0.0.1:5000. Then, if you want to get the home page, just go to http://127.0.0.1:5000/home.

Play a scenario¶

Six scenarios are already stored in the database : Circle, Square, Static, Acceleration, Sensivity and Free to urban tests. You can choose to run any of these in order to visualize the trajectory. You just have to select it in the list, then click on the “Run” button.

A map appears on the screen, centered on the coordinates where the scenario is played.

There are two differents trajectories for each scenario :

• The blue one represents the estimated position calculated by the receiver
• The red one represents the true position generated by the generator

Avalaible data of the trajectory¶

You can have a sight of the Root Mean Square Error of the estimated trajectory. This information is avalaible :

• in 1D : RMS errors in altitude, longitude and altitude
• in 2D : RMS error in the plan latitude-longitude
• in 3D : RMS error in the space latitude-longitude-altitude

You just have to click on the corresponding button, below the map.

Avalaible data for each point¶

You can have a sight of several data of any point of the trajectory. You just have to click on the point you want. Then a first popup appears, giving two pieces of information :

• The coordinates of the point
• The time when the receiver was at that point
• The latitude and longitude errors of positionning

If you want to learn more, you need to click on th “More” button at the bottom of the popup. A alert window will appear and you will be given many data :

• The velocity of the receiver at that point
• The ID, elevation, azimuth and C/N0 of any satelite involved in the positionning at that point

How to run your own files¶

For the moment, there is a esay way to avoid this issue.

You may have remarked there is a “Test” choice in the list of the scenarios. There are likewise two files in the database : stest_ublox.txt and stest_spectracom.txt. These two files are empty, and dedicated to your own files. Let’s remind that all the stored files have the .txt format and their names begin with a “s”.

Thus you have two solutions :

• You can copy/paste the content of your nmea files in these two ones
• You can save your files with the same name “stest_ublox(spectracom).txt” in data > database and erase the empty ones

Don’t forget to refresh the web application. Now you can select the “Test” scenario and visualize it on the map.