Search

The results of the work on the improvement of programs and methods for the joint processing (combining) of measurement results of various types (radio-interferometry with extra-long bases, satellite laser ranging, measurements based on the results of receiving signals from global navigation satellite systems) at the Main Metrology Center of the State Service for Time, Frequency, and Earth’s Rotation Parameters Evaluation are described. Methods of combining the results of various measurements at the measurement levels and time series level are considered. The accuracy of determining universal time was improved by the post-correlation- processing of measurement results obtained from new 13-meter antennas of a two-element radio interferometer at the colocation assemblies of the Institute of Applied Astronomy of the Russian Academy of Sciences. The accuracy of determining the combined values of the Earth’s rotation parameters was increased due to the following: improvement in the accuracy of the individual series obtained by processing various measurements determined by different data processing and analysis centers and improvement of combination algorithms.

The development of methods and means of measurement for the National Service for Time, Frequency, and Determination of the Parameters of the Earth’s Rotation is discussed.

A new approach to defining universal time in terms of observed intervals of pulsar time and measured parameters of the earth’s rotation is proposed. The identity of pulsar scales of universal time UT1 determined from equivalent parameters of the earth’s rotation is demonstrated. Computational relationships are derived for determining the parameters of pulsar scales of universal time and evaluating their errors.

A new method is proposed for predicting universal time based on constructing a general harmonic model for the earth’s rotation and using a modified autoregression technique. A comparison of the predictions made at the Siberian State Research Institute of Metrology (SNIIM) and the International Earth Rotation and Reference Systems Service (IERS) during 2008–2009 shows that the former are more accurate. The efficiency of the new prediction technique for time support of the GLONASS system is demonstrated.

The state and future outlook of research to determine the Earth’s orbital parameters, i.e., Universal Time and the coordinates of the pole, carried out by the State Time and Frequency Service and in calculations of the Earth’s orbital parameters are described.

A report is given on the development and initial results of tests of a specialized GPS system for receiving time signals. The system is designed mainly for highly accurate comparison of remote metrological-class time scales and frequency standards. The fact that the method of operation of the system and the format of the output data conform to CCTF requirements ensures high-precision access to the time scales of any time laboratories which participate in the formation of the International Atomic Time (TAI) scale and the Universal Time (Coordinated) (UTC) scale.

The authors discuss reproducing the universal time scale UT1 by the joint use of two types of measurement: satellite and traditional astro-optic ones, with the first in essence providing high accuracy and resolving power and the second long-time stability in the systematic error.

In this article a new time scale is proposed, that of pulsar time PT which is based on the regular sequence of time intervals between pulses of a pulsar's radio emissions. In discussing variations in the arrival times of pulsar radio emissions, three kinds of variations in the radiation periods are described. PSR 0834 + 06 is used as the basic reference pulsar. Time scales are also determined for reference pulsars PSR 0905 + 08 and 1919 + 21. The initial parameters for the three reference pulsars needed for managing a PT scale are presented. The basic PT scale is defined as the continuous sequence of time intervals between radio-emission pulses of the basic reference pulsar.

1. The system for transmitting time information along television channels provides most of the Soviet Union with exact time signals and information as to the current time by using transmission systems already in existence; as well as ensuring the high-accuracy matching of spatially-separated clocks, this leads to great economic efficiency. 2. The apparatus for transmitting information regarding the current time may be used without serious changes in both short and longwave radio stations using present-day precision “second” signals, without interrupting the normal operation of the systems providing information as to the difference between the UT1 and UTC time scales (UT=universal time).

One of the specifications for universal-time scales is stability, i.e., constancy in the residual systematic error. It is difficult to meet this specification on account of the specific form of measurement used, namely astronomical observations, which are subject to considerable interference from external factors: cloud cover prevents regular execution of the observations, while the results obtained with different astronomical instruments by different observers are distorted by different systematic errors (SE), which vary in time. Therefore, the elimination of systematic errors and the provision of a stable system of universal time involves correcting for the changes in SE relative to the assumed initial values.