L3Harris Narda SignalShark, User Manual

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SignalShark User Manual
176
The SignalShark simplifies localization of transmitters by autonomously evaluating all the
available bearing results and plotting them on a map. It uses a statistical distribution of
bearing lines that represents the uncertainty in the bearing. The result is a map on which the
possible locations of the transmitter are plotted and color-coded according to their probability.
Red corresponds to a very likely and blue to a very unlikely transmitter position. The
SignalShark also draws an ellipse, which marks the area where the transmitter has a 95%
probability of being located, and its center is the estimated position of the transmitter.
When bearings are taken under non-ideal conditions, such as in an urban environment, the
uncertainty in the bearings is much more dependent on the environment than on the ADFA.
Nevertheless, if enough bearings are taken from enough locations, the localization algorithm
of the SignalShark will generally result in a convergence on the actual location of the
transmitter, even in urban surroundings. To speed up and optimize the localization process,
an ADFA can be attached to the roof of a vehicle to take bearings from random positions in
the suspected area. This allows fast and reliable localizations even in challenging
environments
Automatic Direction Finding step by step
The following recommended steps will lead you through the direction finding process on a
most direct way possible and without too many trial and error.
If you are already familiar with automatic direction finding you can of course skip the
individual steps and make the settings directly in the Bearing view.
Step 1 – Creating an Auto DF task and adding views
Step 2 – Identifying the signal to be localized
Step 3 – Using Spectrum view
Step 4 – Using Bearing view
Step 5 – Using Heat Map Localization
About Automatic Direction Finding
Automatic direction finding with SignalShark and a Narda Automatic Direction Finding
Antenna (ADFA) enables a fully automated localization of RF signals. Proper settings of the
various parameters according to the signal type and surrounding in which the signal is
suspected to be are important prerequisites for fast and reliable results.
Automatic DF measurement and localization
In an ADFA, there are several elements of antenna arrays, an omnidirectional reference
antenna, four phase shifters, a summing stage and a switch matrix. The ADFA translates
signals from several antenna elements into a single-channel DF signal. The SignalShark
controls and synchronizes the switch matrix and determines the bearings automatically,
based on the single-channel DF signals. A complete bearing cycle can be as short as 1.2 ms
for channel bandwidths greater than or equal to 3 MHz.
The DF method used in conjunction with the circular arrays is the correlative interferometer.