Systematic errors in VLF direction-finding of whistler ducts. II

Abstract In the previous paper ( Strangeways , 1980) it was shown that the systematic error in the azimuthal bearing due to multipath propagation and incident wave polarisation (when this also constitutes an error) was given by only three different forms for all VLF direction-finders currently used to investigate the position of whistler ducts. In this paper the magnitude of this error is investigated for different ionospheric and ground parameters for these three different systematic error types. By incorporating an ionosphere for which the refractive index is given by the full Appleton-Hartree formula, the variation of the systematic error with ionospheric electron density and latitude and direction of propagation is investigated in addition to the variation with wave frequency, ground conductivity and dielectric constant and distance of propagation. The systematic bearing error is also investigated for the three methods when the azimuthal bearing is averaged over a 2 kHz bandwidth. This is found to lead to a significantly smaller bearing error which, for the crossed-loops goniometer, approximates the bearing error calculated when phase-dependent terms in the receiver response are ignored.

[1]  R. J. Thomson,et al.  Ionospheric whistler propagation , 1978 .

[2]  J. Jespersen,et al.  A numerical study of the excitation, internal reflection and limiting polarization of whistler waves in the lower ionosphere , 1966 .

[3]  D. Page.  Correlated interplanetary and magnetospheric observations , 1974 .

[4]  F. Kelly,et al.  Lower ionosphere effects on the propagation of waves from an elf/vlf source in the magnetosphere , 1976 .

[5]  D. L. Carpenter.  WHISTLER STUDIES OF THE PLASMAPAUSE IN THE MAGNETOSPHERE. 1. TEMPORAL VARIATIONS IN THE POSITION OF THE KNEE AND SOME EVIDENCE ON PLASMA MOTIONS NEAR THE KNEE , 1966 .

[6]  K. Bullough,et al.  VLF goniometer observations at halley bay, Antarctica—II. Magnetospheric structure deduced from whistler observations , 1973 .

[7]  Andy J. Smith,et al.  A semi-automated whistler analyser , 1979 .

[8]  A. Walker,et al.  Bearing error in VLF direction finding , 1975 .

[9]  J. H. Doolittle,et al.  Initial results from a tracking receiver direction finder for whistler mode signals , 1978 .

[10]  Howard H. C. Chang,et al.  Radio waves in the ionosphere , 1962 .

[11]  J. Matthews,et al.  A remote unmanned ELF/VLF goniometer receiver in Antarctica , 1979 .

[12]  K. Tsuruda,et al.  Direction finding technique for elliptically polarized VLF electro-magnetic waves and its application to the low-latitude whistlers , 1975 .

[13]  M. Hayakawa,et al.  The measurement of incident and azimuthal angles and the polarization of whistlers at low latitudes , 1977 .

[14]  D. L. Carpenter,et al.  A model of substorm electric fields in the plasmasphere based on whistler data , 1979 .

[15]  E. Rabe,et al.  Plasmasphere response to the onset of quiet magnetic conditions: Plasma convection patterns , 1977 .

[16]  K. Bullough,et al.  VLF goniometer observations at Halley Bay, Antarctica—I. The equipment and the measurement of signal bearing , 1973 .

[17]  D. Baker,et al.  Spreading of waves emitted from an elf/vlf source in the magnetosphere , 1976 .