Analyzing the sample signal of your Genetec Patroller™ vehicle’s engine activity - SharpX X1S, X2S, XSU

AutoVu™ Navigator box Technote

series
SharpX X1S, X2S, XSU
revised_modified
2019-02-27

To set the Navigator box's sensitivity to noise, you must analyze the sample signal that you captured by learning how to differentiate between vehicle movement and noise.

What you should know

  • To perform the analysis, you need only the Navigator oscilloscope tool, and access to the .raw data files from your sample capture session
  • You do not have to be connected to the Navigator box to perform the analysis. You can even use another computer with a larger screen if you choose.
  • If the vehicle produces a digital VSS signal, you cannot use this procedure. Use IO services to determine the tick frequency.
  • If the vehicle includes an odometry sensor, you cannot use this procedure. See the instructions for Calibrating the Navigator box for use with an odometry sensor.

Procedure

  1. Double-click Oscilloscope.exe.
    The main window and Login dialog box appear.

  2. Close the Login dialog box.
  3. From the Display X of 64 samples list, select 64.
  4. Go to File > Import capture, and select the .raw file you want to analyze.
    The sample signal appears.

    NOTE: This sample signal is only an example. Your vehicle’s signal may look different.
  5. From the View menu, clear all options except Display analog signal (offset).

    The analog signal represents the vehicle’s engine activity. Displaying the analog signal alone helps you identify noise in the signal.

  6. Zoom in to display the first five or six seconds of the signal.
    This is the best part of the signal to look for noise because you can see when the vehicle first started moving. In this example, the analog signal shows activity at zero seconds even though the vehicle was idle at that point. This represents noise. You want the Navigator box to ignore any part of the analog signal at this voltage.

    A Portions of the analog signal between this “idle zone” are noise, and should be ignored.
    B Vehicle movement starts here, when the analog signal breaks out of the “idle zone” on both sides.

    The vehicle only started moving approximately 1.4 seconds into the capture. That is the point where the analog signal broke out of the “idle zone”.

    Now that you know what part of the signal to ignore (idle zone), you must configure the Navigator box to ignore it.
  7. From the View menu, select Display digital signal, and Display normalized velocity.
    With the digital signal and velocity showing, and the Odometry sensitivity at 116, the sample signal looks like this:

  8. Drag the Odometry sensitivity slider left or right to adjust the starting position of the digital signal (which represents the Navigator box).

    You want the digital signal to start where the analog signal breaks out of the idle zone you identified. You are looking for the highest possible sensitivity setting that satisfies that condition.

    After dragging the slider left and right a few times, you see that a sensitivity setting of 122 is just right for the sample signal used. This is the highest setting you can get, and have the digital signal trigger at the correct break out point of the analog signal.

    Tip: To confirm this setting, you can also perform this procedure using the end of the signal (when the vehicle was slowing down to a complete stop).
    NOTE: Avoid setting the sensitivity too low, as this can make the system capture more noise and give an unstable speed value. Setting a higher sensitivity might create a small deadband at low speed, but this should have a negligible impact on the system if it doesn't go above 5km/h. It is preferable to have a small deadband that to have noise in the signal with large speed fluctuations.
  9. On the in-vehicle computer, open Genetec Patroller™ Config Tool, go to Navigation > Odometry, and enter the sensitivity number in the Sensitivity field.
  10. Click Apply.

Results

The Navigator box is calibrated.