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RACELOGIC Support Centre

Record and Replay

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This page contains information about how to record or replay scenario files on LabSat 4 Record & Replay variants.
Recording Operation
Media/Memory

LabSat 4 Record and Replay variants use an internal SSD to record GNSS data.

You can also connect to and use an external USB storage device to record the data. 

Antenna

The placement and setup of the GNSS antenna will depend on the use case. However, if you are using a vehicle to record the scenario file, it is important that the antenna is placed in the ideal location on the vehicle. 

You can read more about antenna placement on a vehicle here.

Setup 

LabSat 4 has 3 RF channels. This gives you the ability to record 1, 2 or 3 frequency bands.

You can configure the recording of the desired constellations, including frequency, bandwidth and quantization, in the Constellation menu on the front panel display or in the Frequency Setup menu in the LabSat 4 Web Server. You can select up to three of the desired constellation groups. 

When you have configured the constellations, you can exit the menu and press the REC button to begin recording. The unit will create a new file each time it starts recording. The file name will be File_001 where the number will be one higher than the highest already saved on the media. 

Note: 
Although you can configure LabSat 4 to have a bandwidth of up to 60 MHz and a quantization of up to 12 for each of the 3 RF channels, the different combinations of these settings may increase the data rate to a level that is incompatible with the unit. You must, therefore, keep this limitation in mind when you configure your unit. You can find more information about the validity of the different configuration possibilities here. 

In most cases, we recommend using a quantization setting of 1-4 bits, as most receivers do not require a resolution greater than this. However, if you are performing special signal analysis and control, you may need to use 8 or 12 bits.  

 

Model Limitations

The available quantization options will differ depending on the LabSat 4 model. 
Battery Life

To maximise battery life during recording, LabSat 4 has a power-save mode enabled by default. You can change this setting in the Setup Menu. The power-save mode recognises when the unit is running from battery power and will dim the display backlight and power down the internal GNSS monitor after 1 minute with no user activity. 

If you are recording from passive antennas, such as the Maxtenna M1516HCT-SMA GPS/GLONASS antenna, enabling the power-save mode will also provide the highest possible sensitivity by ensuring that unused modules in LabSat 4 are switched off.

Recording Example

This is an example of how to record a file to the internal SSD on LabSat 4.

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Antenna to RF-IN.png

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Antenna on roof.png

Connect the antenna to the RF IN port on the rear panel of the LabSat 4 unit.

Place the GNSS antenna in the middle of the vehicle roof, at least 10 cm from any other antennas or objects.
 

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Configure Settings.png

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Rec in progress .png

Press the POWER button to power up the unit. Ensure you have selected the correct recording settings (quantization, bandwidth and frequency).

Press the REC button on the front panel to start the recording. 

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Drive.png

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Rec in completed .png

Drive the desired route for the scenario. 

Press the REC button again to stop the recording. 

Additional Info

During recording, if the SSD becomes full, the recording will stop automatically. 

LabSat 4 contains an onboard GNSS receiver that gives you the ability to monitor the RF signals during record or replay. If you press the OK button while the unit is recording, it will switch the display to show available satellite levels for the different constellations. In this display mode, you can use the UP/DOWN buttons to toggle between the different constellations. Press the OK button in this display mode to open the file status. Press the OK button again to return to the record status display mode.

Note: During recording, while using battery power, the GNSS monitor display will automatically revert to the record display after a short period to conserve battery power. This power save feature can be switched off, but it is recommended to be left active for maximum battery life.
Replaying Operation
Media/Memory

LabSat 4 Record & Replay variants use an internal SSD to replay GNSS data.

You can also connect to and use an external USB storage device or a Network Attached Storage (NAS) device to replay the data. 

Connections

The RF OUT connector on the rear panel of LabSat 4 is a 50 Ω output that can be connected directly to the antenna input of the GNSS receiver under test. The RF OUT connector on your LabSat 4 is DC blocked internally to make it safe to connect almost any device to this port.

Replaying Example

Example of how to replay a scenario file from the SSD.

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Antenna to RF_OUT.png

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FindFile.png

Connect the Device Under Test (DUT) to the RF OUT port on the rear panel on the LabSat 4 unit.

Press the POWER button to power up the unit.

Use the up and down arrow buttons on the front panel to select the relevant scenario file.

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PlayFile.png

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FilePlaying.png

Press the Play button. This will display the Replay Status screen and start the playback of the file. 

The DUT should now be receiving the replayed satellite signal data, making it possible to perform realistic and repeatable tests under controlled conditions.  Press the PAUSE/PLAY button during the replay to stop the replay. The display will return to the File Selection Screen.

Additional Info

LabSat 4 contains an onboard GNSS receiver that gives you the ability to monitor the RF signals during record or replay. If you press the OK button while the unit is replaying, it will switch the display to show available satellite levels for the different constellations. In this display mode, you can use the UP/DOWN buttons to toggle between the different constellations. Press the OK button in this display mode to open the file status. Press the OK button again to return to the replay status display mode.

Note: When you switch between GNSS monitor modes, it will take some time for the internal receiver to re-acquire satellite signal levels. 
Record and Replay External Signals

Model Limitations

LabSat 4 Lite models cannot record or replay external signals. 

In addition to GNSS Signals, you can also record and replay the following data:

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