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This study is aimed at evaluating the trade-off between Global Positioning System (GPS) accuracy and power saving from reduction of number of channels. The study is conducted for number of GPS receiver channels of 4 to 12 for two scenarios: (1) normal scenario with full range of available GPS satellites and (2) obstruction scenario with GPS satellite elevation cutoff of 20°. It is observed that increase of power saving from reducing the number of channels causes increase of probable error values. This is due to increasing position dilution of precision (PDOP) of the reducing number of GPS satellites tracked. However, reduction of number of channels to match the number of available GPS satellites does not cause degradation of accuracy, as there is no reduction in number of trackable GPS satellites. For the obstruction scenario, with significantly fewer available GPS satellites due to the GPS satellite elevation cutoff, significant power saving can be achieved without degradation of accuracy. An effective power saving system would require the management of minimum number of channels required to achieve the user’s minimum required accuracy.

This study is aimed at evaluating the trade-off between Global Positioning System (GPS) accuracy and power saving from reduction of number of channels. The study is conducted for number of GPS receiver channels of 4 to 12 for two scenarios: 1) Normal scenario with full range of available GPS satellites; 2) Obstruction scenario with GPS satellite elevation cutoff of 20°. It is observed that increase of power saving from reducing the number of channels causes increase of probable error values, due to increasing position dilution of precision (PDOP) of the reducing number of GPS satellites tracked. However, reduction of number of channels to match the number of available GPS satellites does not cause degradation of accuracy, as there is no reduction in number of trackable GPS satellites. For the obstruction scenario, with significantly fewer available GPS satellites due to the GPS satellite elevation cutoff, significant power saving can be achieved without degradation of accuracy. An effective power saving system would require the management of minimum number of channels required to achieve the user's minimum required accuracy.

This study is aimed at evaluating the effect of Global Positioning System (GPS) satellite clock error using GPS simulation. Two conditions of tests are used; Case 1: All the GPS satellites have clock errors within the normal range of 0 to 7 ns, corresponding to pseudorange error range of 0 to 2.1 m; Case 2: One GPS satellite suffers from critical failure, resulting in clock error in the pseudorange of up to 1 km. It is found that increase of GPS satellite clock error causes increase of average positional error due to increase of pseudorange error in the GPS satellite signals, which results in increasing error in the coordinates computed by the GPS receiver. Varying average positional error patterns are observed for the each of the readings. This is due to the GPS satellite constellation being dynamic, causing varying GPS satellite geometry over location and time, resulting in GPS accuracy being location / time dependent. For Case 1, in general, the highest average positional error values are observed for readings with the highest PDOP values, while the lowest average positional error values are observed for readings with the lowest PDOP values. For Case 2, no correlation is observed between the average positional error values and PDOP, indicating that the error generated is random.