GPS World, February 2014
Ubiquitous Positioning SIGNAL PROCESSING be extended to include cases where the relative navigation parameters are completely unknown For such cases MUSTER implements an adjustment VHDUFK WR QG WKH YDOXHV RI FRGH SKDVH DQG RSSOHU VKLIW IRU HDFK supplemental receiver that maximize the overall signal energy Adjustment search must be LPSOHPHQWHG LI 0867 5 supplemental relative states are FRPSOHWHO XQNQRZQ RU LI WKHLU DFFXUDF LV LQVXI FLHQW WR HQDEOH GLUHFW DFFXPXODWLRQ RI PXOWL SODWIRUP HQHUJ IRU H DPSOH ZKHQ the relative range accuracy is worse than 150 meters and an energy loss RI DW OHDVW G LV LQWURGXFHG WR the signal accumulation process For each code phase Doppler and FDUULHU SKDVH LI FRKHUHQW LQWHJUDWLRQ LV SHUIRUPHG IURP WKH DGMXVWPHQW VHDUFK VSDFH D VXSSOHPHQWDO PV IXQFWLRQ LV DGMXVWHG DFFRUGLQJO and then added to the MUSTER IXQFWLRQ 0XOWLSOH 36 VLJQDO images are constructed and the image with the maximum accumulated energy is applied to initialize relative navigation parameters code phase DQG RSSOHU VKLIW DGMXVWPHQWV YDOXHV IURP WKH DGMXVWPHQW VHDUFK VSDFH WKDW correspond to the energy peak serve DV DSSUR LPDWH HVWLPDWHV RI UHODWLYH range and Doppler 7KH DFFXUDF RI WKHVH HVWLPDWHV LV GH QHG E WKH UHVROXWLRQ RI WKH adjustment search which would be generally kept quite coarse in order to minimize the search space For LQVWDQFH D PHWHU VHDUFK JULG LV FXUUHQWO LPSOHPHQWHG IRU WKH FRGH phase which enables the resolution RI UHODWLYH UDQJHV ZLWKLQ PHWHUV RQO HQFH WR PLWLJDWH WKH LQÀXHQFH RI UHODWLYH VWDWH XQFHUWDLQWLHV RQ the tracking quality a correction algorithm is applied as described in our earlier paper FIGURE 3 shows the overall system architecture The architecture keeps all the previously developed system components and adds the adjustment search capability red block in LJXUH WR LQFRUSRUDWH FDVHV RI XQNQRZQ 0867 5 VXSSOHPHQWDO receivers relative navigation states To minimize the computational load DGMXVWPHQW VHDUFK LV SHUIRUPHG RQO IRU WKH UVW WUDFNLQJ HSRFK 6HDUFK results are applied to initialize the HVWLPDWHV RI 0867 5 VXSSOHPHQWDO range and Doppler which are WKHQ UH QHG DW HDFK VXEVHTXHQW measurement epoch using a combined ELDVHG QRLV WUDFNLQJ VFKHPH The updated architecture can VXSSRUW FDVHV RI FRPSOHWHO XQNQRZQ relative states as well as those cases Choose one for your high precision applications ComNav Technology Ltd Tel 86 21 6405 6796 Email sales@ comnavtech com www comnavtech com K508 GPS L1 L2 L5 GLONASS L1 L2 BeiDou B1 B2 B3 support K500 GPS L1 GLONASS L1 BeiDou B1 K501G GPS L1 L2 GLONASS L1 L2 K501 GPS L1 L2 BeiDou B1 B2 B3 support www gpsworld com February 2014 GPS World 29
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