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RACELOGIC Support Centre

Playing Simulations

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This page contains information about how to play scenario simulations with SatGen 4.

Real Time Simulations

LabSat 4 Realtime

The SatGen 4 software can generate a live signal stream to a LabSat 4 Realtime unit, converting the RF data from digital to analogue with less than 1 second’s latency. 

Once you have specified your route, you can proceed to connect to the network and create the simulation. 

You can either connect directly to the PC or via a network. When using a network, you can either use the internal Ethernet (LAN1) or a UGreen USB to Ethernet Adapter (LAN2).

Note: Using an isolated network or direct connection is recommended to ensure that the performance is not hindered by other network traffic.

Connect:
  1. Select LabSat 4 Realtime as your Format. 
 RealTime_Format_LabSat4_400px.svg
  1. Select the Mode you wish to use:
  • Current Time (Today - Now) 
    When selecting this, the simulation will start at the next whole minute.
     
  • Start at [Date] [Time] 
    The start time of the route.
    When selecting this, the simulation will start instantly.
 RealTime_Format_LabSat4_Time.svg
  1. Click on the Device dropdown to see a list of all LabSat 4 units on the network (Units must be Enabled for Ethernet Streaming to be discoverable).
  2. Select the required LabSat 4 unit from the list of serial numbers. 
     

    Notes:

    • If you cannot see the required serial number in the list, select Custom from the Device dropdown list and enter the IP address of the LabSat 4 unit into the IP Address field. 

      SatGen 4 will search for the unit and select it when it discovers it. 
       
    • You cannot select a unit marked with the Busy label, as this unit is already performing a simulation. 

    You can read more about using multiple LabSat Realtime units with the same computer system here.
     
  3. Tick the Use Timeline Events box to include the timeline events in the simulation. 

RealTime_Format_LabSat4_Device_Discovered.svg

 

RealTime_Format_LabSat4_Device_Custom.svg
  1. Select the required GNSS signals for the simulation from the list of available signals.
  2. Select the required quantisation level and whether you want to apply attenuation. 
 SatGen _CreateTab_LabSat4Format_Signals.svg
  1. Click the Simulate button to confirm the output format. This will open the Live Output tab next to the Create tab.
Note: When you want to run real-time simulations, we recommend that you disable all background activity in Windows, pause Windows Updates, etc.
  1. Select the live output mode you wish to use and check relevant settings for the selected mode.
  2. You can use the attenuation sliders to add attenuation to the individual satellites in your simulation.
  3. You can stop the simulation by clicking the Stop button in the top right-hand corner of the Live Output tab. 
  
LabSat Realtime

The SatGen software can generate a live signal stream to a LabSat Realtime unit that can convert the RF data from digital to analogue with less than 1 second’s latency.

Real Time is an output format in SatGen 4. There are two variations of this feature:

  • Current Time: You can create a live signal output for the current time.
  • User Time: You can create a live signal output for a specified time and date.

Once you have specified your desired route, you can proceed to create the scenario:

  1. Make sure that your LabSat Realtime unit is connected to your computer.  
  2. Select LabSat Realtime as your Format. 
 RealTime_Format_LabSatRealtime.svg
  1. Select the Mode you wish to use: Real Time (Current Time) or Real Time (User Time). 

Note:

  • Real Time - Current Time will always start the simulation at the next whole minute.
  • Real Time - User Time will start the simulation instantly.
  1. The Serial Number box will auto-fill with the serial number of your connected unit.

    If you have more than one LabSat Realtime unit connected to your computer, you must make sure that you have the correct serial number selected for your simulation.

    You can read more about using multiple LabSat Realtime units with the same computer system here.
  1. Select the Reference Clock you wish to use from the following options:
  • OXCO
  • TCXO
  • External 10MHz
  • External 16.368MHz
  1. You can also choose 1- or 2-bit quantisation and whether you want to attenuate the signal-to-noise ratio. 
  1. Click the Simulate button to confirm the output format. This will open the Live Output tab next to the Create tab.
Note: When you want to run real-time simulations, we recommend that you disable all background activity in Windows, pause Windows Updates, etc.
  1. Select the live output mode you wish to use and check relevant settings for the set mode.
  2. You can use the attenuation sliders to add attenuation to the individual satellites in your simulation.
  3. You can stop the simulation by clicking the Stop button in the top right-hand corner. 
  
Live Output
Status Indicators

You will also see a new status indication area at the top of the Live Output Tab. 

Live Output Streaming.gif

Transmitting

The Transmitting indicator will display yellow when the simulation first starts and the time is being synchronised. It will display green when live signals are being transmitted.

Overloads

The Overloads indicator makes it easy to see how many times the software has encountered an overload during the simulation.

Buffer Level

The Buffer Level indicator 

If too many satellites are present, the indicator will briefly display red to symbolise an overload and reduce the number of satellites until it is able to transmit successfully again.

To make it quick and easy for you to gauge the buffer usage, it will use colours to identify the following ranges of usage: 

  • Green - 50% to 100%
  • Amber - 33% to 49%
  • Red - 0% to 32%

CPU Usage

The CPU usage indicator will display the current CPU usage throughout the simulation.

To make it quick and easy for you to gauge the CPU usage, it will use colours to identify the following ranges of usage: 

  • Green - 0% to 64%
  • Amber - 65% to 79%
  • Red - 80% to 100%

Stop Output

Click on the Stop Output button to stop the simulation stream. 
Auto

This mode will use the total number of satellites as restricted to the value in the Total Satellites setting. 

If a buffer under-run occurs (indicating that the computing power required to simulate that many satellites exceeds the capabilities of the computer), SatGen 4 will reduce the total number of satellites by 1. 

This makes it safer to run a real-time simulation on a slower machine, as the number of satellites will keep dropping one by one until there are no more buffer under-runs and the simulation is stable. 

That final number of satellites is then remembered between sessions to avoid buffer under-runs the next time you run a real-time simulation. 

Reset

Click the Reset button to set the number of Total Satellites to the default value of 999.

If a buffer under-run occurs, (indicating that the computing power required to simulate that many satellites exceeds the capabilities of the computer), SatGen 4 will attempt to simulate the specified number of satellites even if the machine is not capable of sustaining it.

Note: The simulated satellites are chosen by an algorithm that promotes the satellites that are going to stay in view longer.
RealTime_Mode_Auto.svg
Constellation 

The number of satellites is limited separately for each constellation.  You can, for example, select 8 GPS satellites and 5 Galileo satellites.

Constellation Satellite number

You can select the number of satellites you wish to simulate from each available constellation. The available constellations will depend on your system. 

Note: The simulated satellites are chosen by an algorithm that promotes the satellites that are going to stay in view longer.
RealTime_Mode_Constellation.svg
Total

This mode will use the total number of satellites as restricted to the value in the Total Satellites setting. 

Total Satellites

This setting defines the maximum number of satellites SatGen can use in the simulation.

Use the up and down arrows to adjust the number of satellites. 

Reset

Click the Reset button to set the number of Total Satellites to the default value of 999.

If a buffer under-run occurs, (indicating that the computing power required to simulate that many satellites exceeds the capabilities of the computer), SatGen 4 will attempt to simulate the specified number of satellites even if the machine is not capable of sustaining it.

Note: The simulated satellites are chosen by an algorithm that promotes the satellites that are going to stay in view longer.
RealTime_Mode_Total.svg
No Limit

The number of satellites is not limited in any way.  All satellites in view will be simulated whether the PC can process the simulation or not.

 RealTime_Mode_NoLimit.svg
Manual

You can select the satellites you wish to simulate manually from the list of visible satellites.

Unlike in the Constellation, Auto and Total modes, where you select the number of satellites but not which satellites in each available constellation, you have full control over which satellites are simulated in Manual mode. 

 RealTime_Mode_Manual.svg
Attenuation Sliders

You can use the attenuation sliders to add attenuation to the individual satellites. Alternatively, you can link the attenuation sliders to apply the same level of attenuation to the entire constellation.

Note: Due to the Automatic Gain Control always amplifying the signal to fully utilise the 1- or 2-bit output range, reducing the level of all satellites will not affect the signal. You can reduce the level of 1 or 2 satellites in relation to the others, but the total signal power will always remain constant. 

 

 RealTime_Mode_Attenuation.svg

NMEA Streaming

Once you are satisfied with your route, go to the Create options to specify the output options for your scenario.

  1. Set the Format to NMEA.
  2. Set the Mode to RS232 Stream.
  3. Select the required Update Rate.
  4. Select the relevant COM port that you want to output the NMEA stream through. 
  5. Select the required Baud Rate.
  6. Tick the VTG and/or RMC boxes to add these messages to the output stream if required.
  7. Select the required Output Speed.
  8. Tick the Repeat box if you want SatGen 4 to loop the simulation. 

NMEA_Output.svg
When you are happy with the configuration of the output format, click the Simulate button to make SatGen 4 start the NMEA stream on the selected output. Simulate_Button.svg
Live Output

The Live Output tab will display the start date and start time in the simulation, along with the counter for the actual simulation.  It will also display the selected Output Rate, Output Speed, if it is repeating or not, and if it includes VTG or RMC messages. 

NMEA Streaming_Live Output.svg

Pause/Resume

Click Pause to pause the simulation. The button will change to Resume. 

Click Resume to continue playing the simulation. 

NMEA Streaming_Live Output_Pause.svg       NMEA Streaming_Live Output_Resume.svg

Reset

Click the Reset button to play the simulation from the start again. 

 NMEA Streaming_Live Output_Reset.svg

Stop Button

Click the Stop button to stop the simulation.

 NMEA Streaming_Live Output_Stop.svg
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