FSUE «VNIIFTRI» Moscow region, Mendeleevo
Al’manac of Modern Metrology № 4 (24) 2020, pages 161–172
In difficult conditions for receiving signals from the GLONASS system, for example, such as urban canyons, the availability of measurements of four navigation satellites (NS), necessary for solving a navigation task, is reduced. To provide navigation on the signals of only three NS, additional information is required on the exact time scale of the receiver and / or the height of the object.
Currently, FSUE “VNIIFTRI” has developed a subminiature rubidium frequency standard (SRFC) based on the effect of coherent population trapping. SRFC has frequency instability no worse than 10-11 and a volume of up to several tens of cubic centimeters, which allows you to integrate this standard into the design of navigation receiver (NR).
In order to assess the possibility of determining the coordinates and altitude in the NR using the signals of only three of the NS, mathematical modeling of navigation sessions was carried out with a time scale forecast using the frequency stability characteristics of real reference oscillators: quartz — type GK-99 and SRFS. The results of modeling estimates of coordinate and altitude errors for stationary and dynamic objects showed the advantages of using the SRFS to navigate the signals of only three NS for at least 30 minutes.
Key words: navigation receiver, global navigation satellite systems, subminiature rubidium frequency standard, coordinate error.
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