China’s navigation satellite system BeiDou is developed according to a three step strategy [1]. The first step construction begun in 1994 and ended in 2000, as the BeiDou Navigation Demonstration System, as known as BeiDou I, provided radio determination satellite service (RDSS). The second step covers from 2004 to 2012, and is to construct the BeiDou navigation satellite System (BDS, also call...

We develop a comprehensive approach to the evaluation of the uncertainty of a primary frequency standard. Indirect, model-dependent means are employed for the evaluation of all known biases. This approach leads to a lower combined standard uncertainty (CSU) and leaves frequency measurements under altered conditions as a powerful search technique for unknown biases. We report the results of this...

Frequency shifts of the (199)Hg(+) 5d (10)6s (2)S1/2 (F = 0, MF = 0) to 5d (9)6s (2 2)D5/2 (F = 2, MF = 0) electric-quadrupole transition at 282 nm due to external fields are calculated, based on a combination of measured atomic parameters and ab initio calculations. This transition is under investigation as an optical frequency standard. The perturbations calculated are the quadratic Zeeman sh...

High frequency models of large power transformers are required for analysis of transient interaction phenomena between transformers and the power system. Fast transient overvoltages may lead to transformer dielectric failures. Deeper understanding of the mechanisms may help to take actions against possible damages. This paper describes the simulation principle of transient interaction in matter...

In Cs frequency standards a zone of highly uniform magnetic flus density, lower in value of 0.1 T, is required The magnetic homogeneity value is tied to the overall accuracy of the standard and, for an accuracy of a design value 1 p.p.m. is required. For this purpose a resistive solenoid 700 mm long with a bore radius of 32.5 mm has been designed and built. This paper reports the design process...

Calibration laboratories can choose from a variety of frequency standards, including quartz oscillators, atomic oscillators, and oscillators disciplined to agree with reference signals from the Global Positioning System (GPS) satellites or other sources. The frequency calibration and measurement capability of a laboratory is largely determined by the type of primary frequency standard* that is ...

The develpoment of smart antennas for mobile phones has recently recevied much interest due to compact size of multimode phones and requirements to keep the amount of RF power absorbed by a user below a certain level. In this paper a new Yagi Uda shaped frequency reconfigurable antenna for multimode mobile applications has been presented. The proposed fabricated antenna have return loss better ...

We propose an approach to all-optical frequency standard design, based on a counterintuitive combination of the coherent population trapping effect and signal discrimination at the maximum of absorption for the probe radiation. The short-term stability of such a standard can achieve the level of 10−14/ . The physics beyond this approach is a dark resonance splitting caused by the interaction of...

We describe an optically pumped cesium-beam frequency standard under development for deployment on the GPS-III satellite constellation. The objective of the project is to demonstrate the feasibility of a space quulifikd optically pumped cesium-beam frequency standard exhibiting a short-term stability of cry (r < 6 x f-ln with lifetime and reliability comparable to that of the current GPS-IIF ce...

The design process and the magnetic measurements 011 a permanent magnet asymmetric dipole to be used for magnetic selection in a Cs beam frequency standard is presented Tbe design target is to create a magnetic induction gradient of 50 Tlm in a zone extending 10 mm in width and 50 mm in length. The computer aided design process is outlined and design predictions are compared with measurements o...