P.A. Lopardin1, D.S. Feoktistov2, V.F. Garifullin3, V.N. Bondarenko4, A.I. Zuevskaya5

1-4 Engineering Physics and Radioelectronics Institute of the Siberian Federal University (Krasnoyarsk, Russia)

5 SPE JSC ‘‘Radiosvyaz’’ (Krasnoyarsk, Russia)

Phase-based marine radio-geodesic systems are highly accurate. One of the possible ways to implement the measurement of distances or the distances differences for navigation needs is to measure only the fractional part of the metric frequency period.  To expand the distance measurement limits, several values of discrete metric frequencies are used, which are interconnected by the coupling coefficients of metric frequencies. The consistent application of mathematical operations to eliminate ambiguity for the restored full phase cycles from low metric frequencies to high metric frequencies allows us to obtain the result of the multi-frequency navigation signals delay in the form of whole and fractional phase cycles parts of the highest metric frequency. The possibilities of restoring the exact number of the whole phase cycles part are limited by the total measurement errors of the fractional phase cycles parts. A significant contribution to the total error is made by the error caused by multipath propagation of navigation signals.

In this paper, the ratio magnitude influence of the total reflected signal amplitude to the magnitude of the direct signal on the resulting maximum possible distortion of the direct signal phase is analytically considered. The permissible value of this error is determined from the point of view of restoring the exact number of the whole phase cycles part, depending on the magnitude of the ambiguity elimination coefficient. Thus, a direct relationship has been analytically established between the chosen coefficient of ambiguity elimination and the permissible ratio of the total reflected signal amplitude to direct signal the magnitude. Besides, the real contribution of the hardware error to the total error is taken into account. All specified dependencies are shown in tabular form.

As the result of the conducted research, in order to reliably restore the exact number of the whole part of the phase cycles, it is proposed to reduce the ratio of the neighboring metric frequencies values. If we take into account that the mass-produced RGC operates on the high seas without failures, then the proposed addition of a reserve in terms of the reflected signal in relation to the direct signal value of more than 16 dB should allow its operation even in the presence of local items. This will increase the reliability of navigation and expand the scope of the RGC on land.

Lopardin P.A., Feoktistov D.S., Garifullin V.F., Bondarenko V.N., Zuevskaya A.I. The impact of simple navigation signals multipath propagation on the effectiveness of eliminating the phase measurements ambiguity. Radiotekhnika. 2022. V. 86. № 8. P. 29−36. DOI: https://doi.org/10.18127/j00338486-202208-03 (In Russian)

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