Vision™ MX280001A Software Help : TDoA Locate (Option 401) : Using TDoA : Correlation Results
 
Correlation Results
View the correlation results, the I/Q pair count, samples per second data, as well as correlation data for each monitor. The correlation ratio is a number that relates to how strongly the algorithm was able to find the correct time alignment and offsets (expressed in meters). The correlation peaks at the position where the two sets of IQ data are aligned in time. If this peak is very pronounced, then you can have confidence in the time alignment. If it is not so pronounced, then the data is suspect. Basically, the correlation ratio is the peak amplitude divided by the average value of the correlation function. A value less than 20 means you should not trust the results at all while a value above 100 is usually a strong indication that the correlation is good. This area provides you the option of selecting Averaging and setting the averaging count used in the calculation above. The Correlation Results section is shown in Figure: Correlation Results.
Correlation Results
The TDoA Correlation Results section are described in Table: Correlation Results
Correlation Results
Icon
Description
I/Q Pair Count
Displays the I/Q Pair Count.
Samples/Sec
Displays the number of samples per second.
 
Correlation Offset (meters)
The values shown in the Averages look different. For example: The yellow box averaging display of –236 (3). The first number is the averaged value taken from the Correlation Offset (meters) field above. The number in parenthesis is the count of values used in the average. This can be a different number for each monitor pair, depending on the Correlation Ratios from each measurement.
 
Correlation Ratio
The Correlation Ratio is the peak amplitude divided by the average value of the correlation function. A value less than 20 means you should not trust the results at all, while a value above 100 is usually a strong indication that the correlation is good.
Averaging
Click the Averaging check box to initiate averaging for each time a TDoA I/Q capture is done. Type or select the amount of averages. The measured distance is averaged with previous measurements. The average values are used when drawing the arcs on the map and locating the RF source. If the check box is clear, then the most recent measurement values will be used on the map, rather than the average values.
Monitor Block
The monitor combinations blocks and the numeric boxes are colored for quick visual separation.
Yellow, dark green, blue for each monitor combination corresponds to the hyperbolic lines drawn on the map.
Lighter green background in the numeric boxes indicate the measurement is good.
Lighter red in the numeric boxes indicate the correlation ratio is too low (<5) or if the monitor correlation is greater than the monitor separation.
Any number of the numeric boxes can be either green background or red background, depending on the value it displays.