Influence of Characteristics of Crystals on Performance Of Tracking Loops

A significant challenge has been existed concerning the relationship between the manufacturing costs and the high performance of the handheld GNSS terminals. The crystals of the oscillators represent one the most expensive component in the terminals even, the crystals used in them, can often be called rubbish ones. The work is pending to develop a method including a mathematical / software procedure to estimate the expected performance of the tracking loops (or other closed loop systems having crystal oscillators) in the terminals. The future creates more new challenges since e.g. the indoor -and the poor conditions -navigation will have the more and more important role because, for example, the number and transmitted power of the satellite signals are expected to increase. The theoretical studies of Nokia Technology Platform and MIKES have concentrated on the knowledge available in the existing literature to build up a model comprising of the most essential noise processes and characterizing parameters of tracking loop(s), as noise bandwidth, gain(s), attenuation, etc. The tool will include mathematical algorithms and the final target is to compute for desired tracking loops an optimized solution subject to certain required restriction(s), term(s) or / and conditions. In the case of the simplest solutions, the analytical ones can be derived and the functionality of the tool can be verified by these cases. Experimental computations have been carried out to study the functionality in the more complicated cases and the output of the tool has been observed to be a relevant one. The procedure can be carried out by different spread sheet programs or e.g. by Matlab.