GPS World, March 2016
ALTERNATIVE PNT GPS and cellular antennas Universal software radio peripherals USRPs Storage MATRIX LabVIEW Based SDR Tower locations Receiver location GPS SV pseudorange observations EXPERIMENTAL RESULTS A field experiment was conducted using software defined receivers SDRs to demonstrate the reduction of VDOP obtained from including MATLAB Based Filter SOP pseudoranges alongside GPS pseudoranges for estimating the states of a receiver To this end two antennas were mounted on a vehicle to acquire and track multiple GPS signals and three cellular base transceiver stations BTSs whose signals were modulated 28 GPS WORLD WWW GPSWORLD COM MARCH 2016 18 through CDMA The GPS and cellular signals were simultaneously downmixed and synchronously sampled via two universal software radio peripherals USRPs These front ends fed their data to the Multichannel Adaptive TRansceiver Information eXtractor MATRIX SDR developed at the Autonomous Systems Perception Intelligence and Navigation ASPIN Laboratory at the University of California Riverside The LabVIEW based MATRIX SDR produced pseudorange observables from five GPS L1 C A signals in view and the three cellular BTSs FIGURE 4 depicts the experimental hardware setup The p s e u d or ang e s w e r e drawn from a receiver located at r r 106 2430701 4697498 3553099 T expressed in an ECEF frame which was surveyed using a carrier phase differential GPS receiver Five SVs Five SVs three SOPs 0 o 90 o 270 o 180 o 27 22 14 21 0 o 90 o 270 o 180 o 27 22 14 21 FIGURE 4 Experiment hardware setup FIGURE 5 Top Sky plot of GPS SVs 14 21 22 and 27 used for the four SV scenarios Bottom Sky plot of GPS SVs 14 18 21 22 and 27 used for the five SV scenarios The elevation mask el sv min was set to 20 dashed circle FIGURE 6 Top Cellular CDMA SOP tower locations and receiver location Bottom Uncertainty ellipsoid yellow of navigation solution from using pseudoranges from five GPS SVs and uncertainty ellipsoid blue of navigation solution from using pseudoranges from five GPS SVs and three cellular CDMA SOPs
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