Библиографическое описание:Особенности построения и современное развитие глобальных навигационных спутниковых систем ГЛОНАСС и GPS : научное издание / Е. Н. Гарин, В. А. Копылов, В. Н. Ратушняк. - Текст : непосредственный // Успехи современной радиоэлектроники. - 2017. - № 12. - С. 22-25. - ISSN 2070-0784. Перевод заглавия: Features of construction and modern development of GNSS GLONASS and GPS
Аннотация:Рассмотрена история развития, структура и основы построения навигационных систем ГЛОНАСС и GPS. Отражены ключевые характеристики и тенденции развития новых навигационных сигналов в современных навигационных космических аппаратах. Приведены отличительные особенности, достоинства и недостатки ГЛОНАСС и GPS, включая навигационную аппаратуру потребителей, а также пути их дальнейшего совершенствования.
Global Navigation Satellite Systems (GNSS): American NAVSTAR and Russian GLONASS are used to determine the position and spatial orientation of objects, currently. Globality of Satellite Systems is ensured by the functioning in near-earth orbits of artificial satellites, which continuously transmit high-precision measuring signals and thus create an information coordinate-time field around our planet [1,2]. The main difference from the GPS system is that the GLONASS satellites in their orbital motion have no resonance with the gravitational field of the Earth and the centrifugal force caused by its daily rotation, which provides them greater stability. Thus, the satellites GLONASS grouping does not require additional adjustments during the whole period of active existence. However, the lifetime of GLONASS satellites as they are upgraded is less by 5-7 years than for NKA GPS. The structure of the navigation message GLONASS and GPS is also different due to the fact that in GLONASS the duration of the superframe consisting of 5 frames of 30 seconds is 2,5 minutes, and in GPS the superframe consists of 25 frames of 30 seconds and its duration is 12,5 mines. Therefore, in GLONASS, unlike GPS, there is a faster update of the almanac. Comparing the methods of signal separation, the advantages of code division of signals in comparison with the frequency one include the absence of the effect of the unevenness of the group delay time of the radio-frequency path on the accuracy of coordinate determinations, the lower power consumption of navigation receivers. At the same time, the frequency method of signal separation has a higher degree of distinguishability of navigation signals, which provides better search characteristics, and less vulnerability to narrowband interference. To improve the accuracy of the GPS time-co-ordinate determinations, GPS has a widely developed network of differential and zero-point GPS base stations located around the globe that allows minimizing ephemeris, ionospheric and tropospheric measurement errors practically anywhere in the world. On the territory of the USA, Canada, Japan, China, the European Union and India there are stations transmitting corrections for the differential mode, which allows reducing the error to 1-2 meters in these countries, and using more complex differential regimes, 10 cm [4]. The ephemerides of the GLONASS system are determined from the requested measurements of the distances of three command measurement systems (CMS) (St. Petersburg, Yeniseysk, Komsomolsk-on-Amur), and the position of the SC time scales for single-stage, non-interrogative and interrogation measurements. The control system, measurement and control (Moscow), tied to the central synchronizer (CS) of the system. The main element of the non-interrogative technology of ephemeris-time provision is the use of an non-interrogating measuring station network. Thus, as a result of constant confrontation in the «navigational war» between Russia and the US, the following trends have evolved: GNSS, GLONASS, GPS: the use of new navigation crypto-signals; formation of special anti-noise navigation zones for special consumers; extending the service life of the satellites in orbit; the introduction of new onboard 'highly stable time standards, the use of antennas with flexible control of its directional pattern; increase the accuracy of the definition of the ephemerides of the satellites and the autonomy of the satellite constellation; The use of satellites in highly elliptical and geostationary orbits.
