First, is the low-accuracy pulse radar units, now these are only “low accuracy” when compared to units designed for servo tank gauge. These are excellent general purpose radar units, but they are limited in use to materials with dielectric coefficients greater than about 8 or so. It generally rules them out for low viscosity hydrocarbons.
Second is the various radar-by-wire designs, such as Alliant(Bindicator-Celtek) and Magnetrol, etc. These are mostly used for solids, but could be used in hydrocarbons. They are also relatively inexpensive.
Next are the FMCW units, these are moderately high accuracy, and can be used in gauging fluids with a dielectric of 3-5 or so. The compromises made in the designs of these units in order to make them look through small (4″<100 mm> to 6″ <150 mm>) vessel ports reduces the accuracy and the ability of these units to see lower dielectric constants. These are designed as process servo tank gauges, not tank farm designs.
The highest level of accuracy are the units designed specifically for Tank Farm Gauging, they were designed to compete specifically with servo tank gauges and with hydrostatic level gauging and are designed to be used specifically for tank farms. These servo tank gauges consistently outperform their competition but are very expensive.
This article comes from control edit released