CONCEPT OF A LOW-ORBIT NAVIGATION AND RADIOCOMMUNICATION EXTENSION (LNRE) TO THE GLONASS SYSTEM

ABSTRACT

The purpose of this article is to analyze the possibilities of a low – orbit extension to the GLONASS system in the case of its construction. The analysis was carried out based on official foreign statements using computer and mathematical modeling. As a result, the main advantages and opportunities of a low-orbit extension are formulated. It is shown that a low-orbit addition to the GLONASS system by minor SPACECRAFT can significantly improve possibilities of the complex as a whole.

Keywords: Glonass, minor sc, lnre, ppp, cluster, low orbit, orbital group.

1 Two approaches to expanding OG

Two fundamentally different approaches to using CDMA signals are possible.

In the first case, there is a build-up of the standard mid-orbital group with correction of orbits, and increasing the number of planes.

In the second case, a new functional addition to the existing OG is created, which in turn continues to be updated with upgraded NSC using CDMA signals.

2 Tasks of the GLONASS’s low-orbit navigation and radiocommunication extension (LNRE)

Tasks of the LNRE are formulated as follows:

1. Continuous monitoring of the GNSS state using RAIM-algorithms and rapid transmission of the unreliability sign globally using inter-satellite radio link (ISRL) for a period of time not exceeding 6 seconds;
2. Providing global high-precision navigation for all types of consumers with a convergence time within 1 minute at cold start;
3. Creating a global space network of unquestioned navigation spacecraft (NSC) GNSS meters to improve the accuracy of GNSS ephemeris-time information (ETI);
4. Increasing global availability and distributing it evenly around the world by expanding the number of navigation signal sources;
5. Increasing resistance to spoofing attacks and attempts to jam the signal.

3 Specificity of ephemeris-time provision (ETP) basic GNSS technology using data from LNRE

• Measurements from the onboard multi-frequency and multi-system receiver of GNSS signals in real time are dump to the the system center management (SCM) of the ground control system (GCS) of the base GNSS via connected channel of the LNRE (using inter-satellite line (ISL));
• SCM of the GCS specifies GNSS ETI SC using the technology of joint processing of unquestioned measurement station (UMS) measurements on the national territory and measurements of navigation signals obtained from GNSS receivers on LNRE satellites. When transmitting ETI via ISL of LNRE channel, global coverage of GNSS satellite trajectory measurements is provided.

4 Specifics of solving problems of high-precision PPP navigation using LNRE signals

• Due to the rapid dynamics of the SC in the field of view, it is possible to quickly accumulate the necessary information to solve the problem of precise point positioning (PPP) using LNRE signals. At the same time PPP corrections are required for satellites LNRE;
• In the case when each LNRE satellite transmits its ETI with centimeter accuracy, the consumer solving the navigation problem using two signals L1 and L5 from LNRE can immediately get centimeter accuracy of its position.

5 Sensitivity to losing 10% of population

Modeling shows that the loss of 10% of the grouping is almost not noticeable for a low-orbit supplement due to the redundancy of its structure. The degradation of accuracy characteristics is not significant at all angles of the site, which is explained by the good geometry of the SC location. In addition, low-orbit groupings, while maintaining 90% of their number, allow navigation in space with high accuracy and with a probability of 0.93 for an altitude of 2000 km, it is still possible to use RAIM algorithms at 25°angles.

6 Group launches of minor space craft (MSC) for LNRE

An important part of reducing the cost of the system is the possibility of group launch of the MSC, including heavy missile when launching the MSC in dozens (the appearance of the heavy missile "Angara-A5" is expected) and the ability to replenish the built grouping using light missiles, including conversion. After separation from the missile, the MSC is brought to the working point by the device's own correction system.

7 Advantage of the low-orbit navigation and radiocommunication extension

• Integrity monitoring with notification up to 6 seconds;
• Reduce the solution convergence time to 1 minute at cold start;
• Increasing global availability;
• Increasing global accuracy;
• Rapid accumulation of information to solve the PPP tasks due to rapid dynamics;
• ETI accuracy (SISRE) is 3-5 cm at any given time;
• Low sensitivity to losing population;
• Ability to build clusters, high flexibility of the system, easy to upgrade;
• Modular production;
• Group launches of SC in dozens.

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