Improved over-the-horizon radar accuracy for the counter drug mission using coordinate registration enhancements

For the relocatable over the horizon radar (ROTHR) counter-drug radar system accurate knowledge of target position is an important part of the detection and interdiction of drug smuggling aircraft. An improvement in the radar's target track positional accuracy has been obtained by using external reference sources at known locations in the radar coverage area. Tracks formed on these reference sources provide position corrections that are applied to targets for removal of common bias errors due to ionospheric modeling uncertainties. Results from a 1993 R&D study show that such corrections must be applied independently for each propagation mode comprising a track in order to achieve the most improvement in positional accuracy. Additional data taken in 1996 has enabled investigations into the relationship between target distance from the reference source and the amount of positional improvement obtained by correcting a target.