" Received Data Spk " ts Signal Acquisition fD Carrier Wipe Off Correlator Sek Slk Carrier Phase Discrim. PLL Loop Filter Code Phase Discrim. DLL Loop Filter " " Sync and Paging Channel Decoding ts PN Generator ts 1 ωc NCO NCO Tracking 16 0 ×1 19 15.2 7.6 3.8 .4 10 0.8 2 ts ( 2 31. .6 µs 41 52 ) 80 120 20 40 60 0 10 1 -2 160 00 -1 0 -6 0 |S |2 11.4 0 fD z) (H 200 240 280 320 360 400 440 480 512 FIGURE 3. A cellular CDMA SDR architecture and LabVIEW front panel showing internal signals: code error; phase error; Doppler frequency; early, prompt, and late correlations; pseudorange; and in-phase and quadrature components of the correlation function. crossing a known landmark [11]. Other methods rely on monitoring stations or synchronized reference receivers to account for the clock bias of the transmitter [12], [31]. In this article, a navigation framework based on a mapping receiver and a navigating receiver is adopted. Each receiver is 116 equipped with the proposed cellular CDMA SDR. The mapping receiver is assumed to have knowledge of its own position and clock error states (by having access to GNSS signals, for example), to have knowledge of the position of the BTSs, and to be estimating the clock error states of the BTSs. The mapper IEEE SIGNAL PROCESSING MAGAZINE | September 2017 |