Which data is considered least dependent on ARPA processing and frequently used for navigation fixes?

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Using bearing and range cues drawn on the radar screen to plot a position fix relies on simple, manual plotting rather than on the radar’s automatic processing. Electronic Bearing Lines give a bearing from your ship to a target, and the Variable Range Marker creates a circle at a chosen distance from your ship. When you use two bearings to two known points, or a bearing to one point and a range to another, the intersection of those lines provides your position. This method works independently of ARPA’s automatic tracking, so it’s a reliable source for fixes even if ARPA processing is not available or you want to verify its data. ARPA-derived target alerts are just alarms, VRMs by themselves are only range rings without a second line to intersect, and hull speed doesn’t provide positional information. Therefore, EBL/VRM data are the most practical for navigation fixes.