The algorithms of GNSS signal processing based on the generalized maximum likelihood criterion for attitude determination are discussed in the paper. The likelihood function is determined by multidimensional samples of processes observed directly on array elements. The comparative analysis of attitude estimation accuracy was accomplished for optimal and suboptimal algorithms. An optimal algorithm provides potential attitude accuracy, on the other hand, suboptimal algorithms are characterized by comparative ease of implementation. To maximize objective functions the reference phase differences are used for all developed algorithms.

Algorithms of GNSS signal processing based on the generalized maximum likelihood criterion for attitude determination

The following paper discusses a conducted synthesis and assessment of the effectiveness of control algorithms for null formation in the radiation pattern of a flat phased antenna array according to two coordinates; the procedure is performed by adjusting the amplitude distribution in rows and columns.

Algorithms for adaptive processing of signals in a flat phased antenna array

Global navigation satellite systems are widely used across the world because of their continuous/all-weather, global coverage, and high precision positioning. But, three-dimensional positioning acc...

https://journals.sagepub.com/doi/pdf/10.1177/0020294019827329

Time synchronization requirement of global navigation satellite system augmentation system based on pseudolite

Currently, lots of work is being done to improve the accuracy of navigation systems both from the hardware point of view [1-6] and from the software [7-11]. No less important issue is development of a single system within hardware and software complexes [12-14]. In this article we reveal the issues solving the navigation-temporal tasks in different coordinate systems. When creating multichannel GNSS receivers that implement interferometric methods for measuring spatial orientation on GLONASS and GPS signals, it is extremely important to solve navigation and time problems, especially in order to optimize the solution with missing satellite data.The article also presents proposals for the improvement of multichannel GNSS receivers in order to solve the problems of positioning in conditions of uncertainty and incompleteness of data.

https://iopscience.iop.org/article/10.1088/1757-899X/450/2/022029/pdf

Solving navigation-temporal tasks in different coordinate systems

Currently, a growing number of satellite communication systems developers and manufacturers pay attention to the adaptive multibeam antenna systems. These systems allow you to implement flexible traffic management by forming a multi-beam patterns within the service area. In addition, they have such an important property, as the high noise immunity when exposed as a deliberate and industrial noise provided by the use of spatial filtering methods for interference. The adaptive multibeam antenna can be built on the basis of a phased antenna arrays with scanning beams and multibeam antennas are constructed on the basis of hybrid reflector antennas [1]. The main control element of such antennas is a block adaptation that implements control algorithms and individual beams beamforming. A block adaptation is a processor based on the adaptive signal processor, and the adaptation is made on the program level. In [2] made

/pdf/methods-of-assessing-the-characteristics-of-the-4alldcj3rd.pdf

Methods of Assessing the Characteristics of the Multiprocessor Computer System Adaptation Unit

Hybrid-reflector multibeam antennas employed in satellite navigation systems transform adopted accelerated spatial filtering algorithms. In order to accelerate the algorithm, the adaptive system selects an amplitude-phase distribution from a set of precalculated distributions for various interference signaling environments in the beam where the interference signal affects the radiation pattern of the main lobe. Specification of the weighted coefficients is performed after the most appropriate amplitude-phase distribution has been selected. Data from the weighted coefficients calculations is used for null formation in radiation patterns of beams where interference affects the side lobes.

Spatial filtering algorithms in adaptive multi-beam hybrid reflector antennas

This paper discusses phase methods for measuring the spatial orientation of objects using satellite navigation equipment. An analysis of methods for resolving phase ambiguity is presented in the paper. The effectiveness and applicability of the single-step methods are discussed in detail. The authors have shown that applying the exhaustive method requires a constellation of 5 - 6 visible satellites. The measurement of signals, having a base length of 1 m transmitted from 8 satellites, demonstrates that an unambiguous solution is achieved practically in all cases.

https://iopscience.iop.org/article/10.1088/1757-899X/94/1/012022/pdf

Phase methods for measuring the spatial orientation of objects using satellite navigation equipment

This paper reviews adaptation algorithms influenced by active interferences in satellite communication systems. A multi-beam antenna is suggested as an adaptive system; it is built on the basis of a hybrid reflector antenna with a 19-element array feed element, which incorporates a modified algorithm for radiation pattern synthesis used for suppressing targeted interferences. As a criterion for this synthesis, antenna gains are used at fixed points. As a result, the size of the objective function and time required for the synthesis can be significantly limited.

https://iopscience.iop.org/article/10.1088/1757-899X/94/1/012010/pdf

Adaptation algorithms for satellite communication systems equipped with hybrid reflector antennas

This article discusses the main approaches to the designs of systems for determining location and spatial attitude based on satellite navigation equipment. The article describes possible solutions for constructing an angular attitude measurement system capable of spatial interference selection on the basis of a single antenna system.

https://iopscience.iop.org/article/10.1088/1757-899X/122/1/012035/pdf

Using GLONASS for precise determination of navigation parameters under interference from various sources

This article discusses the application of user navigation equipment of satellite radionavigation systems (GLONASS/GPS) for measuring the inclination of the aerial axis of rotation. The authors have demonstrated that the required accuracy of the angular inclination is achieved only in a relative phase mode, which is not always feasible. The application of filtering for measured parameters of navigation equipment has namely been used for planimetric coordinates. Filtering is performed using the second order Kalman filter. It has significant effect; thus, even at a speed of 1 rpm, there is no disruption in the autonomous coded mode; for the relative phase mode, the required accuracy is achieved at 3 rpm.

http://iopscience.iop.org/article/10.1088/1757-899X/155/1/012020/pdf

A E Goncharov

Papers

Spatial filtering algorithms in adaptive multi-beam hybrid reflector antennas

Phase methods for measuring the spatial orientation of objects using satellite navigation equipment

Adaptation algorithms for satellite communication systems equipped with hybrid reflector antennas

Using GLONASS for precise determination of navigation parameters under interference from various sources

Applying filtering for determining the angular orientation of spinning objects during interference