In the paper experimental investigations related with analysis of navigational precision of three chosen GNSS receivers are shown. Used receivers allow for measurement of navigational signals in following modes of operations: receiving signals from single-frequency GPS system, dual-frequency GPS/GLONASS system, and receiving signals from GPS constellation with use of differential measurements. In the last mode the base station and mobile receiver were configured for transmitting/receiving differential corrections by pair of industry-grade radio modems. The most important features and configuration of navigational receivers for conducted experiment are presented. Afterward the features of computer program designed especially for simultaneous acquisition, analysis of quality parameters and archiving of navigational signals are shown. The results of conducted investigations are also shown. For each of the receivers quantity and quality parameters such as maximum and minimum numbers of visible satellites and DOP (dilution of precision) parameters achieved during the experiment are given.
Andrzej Kuranc, Tomasz Słowik, Paweł Krzaczek and Grzegorz Maj
The article presents calculations of unit fumes emission made based on the measurements of the fumes composition during a load test. The test was carried out with the use of a movable dynamometric stand adjusted for testing agricultural tractors by power take-off shaft. Calculations of unit emission were made based on the assumed flow of air sucked by an engine and the measured composition of fumes emitted during the load test. Results of tests and analyses supply information on the mass of particle matter and the selected gas elements emitted by an engine working under the load which was related to simultaneous determination of the exploitation characteristic of an engine. The presented methodology may be helpful at evaluation of impact of farm tractors on the environment within the hazardous fume components emitted by them.