ON THE DERIVATION OF AN IMPROVED PARAMETER CONFIGURATION FOR THE DYNASONDE

The inherent precision and ambiguity in the measurement of ionospheric ally reflected echoes by digital ionosondes, which utilize interferome tric receiving arrays, depends on the transmitted pulse set pattern, t he receiving array configuration, and the data analysis scheme. Buildi ng on earlier work carried out for the National Oceanic and Atmospheri c Administration HF radar [Grubb, 19791 by Pitteway and Wright [1992], we use six phase parameters (PHI(o), PHI(x), PHI(y), PHI(l), PHI(p), and PHI(f)) to derive echo location, Doppler shift, and wave polarizat ion. We have applied the method of least squares to determine the prec ision and a ''zero-freedom'' technique to derive the ambiguity associa ted with each of the phase parameters. Three criteria can be specified which lead to an optimum design of the system parameters: (1) the pha se parameters must have aliasing values equal to 2pi; (2) the relative confidence limit factors of the derived phase parameters should be as small as possible; and (3) there must be no aliasing of echo location . By varying the array configuration, frequency pattern, the number of pulses per pulse set, and the number of parallel receivers and receiv ing dipoles, various designs have been analyzed, and an improved confi guration has been obtained. We have shown that various arrangements of the four-pulse, two-receiver configuration can reduce the sum of the relative uncertainties in the phase parameters found for the WERPOL ar ray by up to 33% and improve the ambiguity in each of the derived phas e parameters to 2pi.