A positioning method based on shortwave time difference of arrival in near-vertical propagation
In order to further reduce the influence of terrain restrictions and obstacle shielding,the paper studied the shortwave communication positioning technology with ionospheric near-vertical propagation mode,and proposed a time difference positioning model combining the approximation of the flat ionosphere and the spherical group path ground distance(PD)transformation:the characteristics of the near-vertical propagation virtual height of the ionosphere with the variation of ground distance under different frequency conditions were analyzed;and based on the relationship between the working frequency and the critical frequency of the ionosphere,the flat ionosphere approximation or spherical PD transformation positioning method was adaptively selected;then,the geometric accuracy factor of the positioning model was analyzed to provide a basis for the positioning system layout.Simulational result showed that the proposed model could achieve high positioning accuracy.
near-vertical propagationtime difference of arrival positioningionosphereshortwavegeometric dilution of precision
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