# A Fully Integrated Low-Power Multi-Mode RF Receiver for BDS-3/GPS
## 5 Measurement Results
High tracking sensitivity makes code and carrier tracking loops more robust and positioning more reliable in weak signal environments, such as cities and canyons [26]. The tested acquisition sensitivity, tracking sensitivity, position accuracy, velocity accuracy, position update rate, and reacquisition time are \(-148\) dBm, \(-159\) dBm, 0.56 m, 0.025 m/s, 10 Hz, and 1.94 s, respectively. Figure 16: Measured noise figure. Figure 15: Single-ended output power (dBm) versus input power (dBm). After the in-laboratory test, outdoor tests, including the broad road, tunnel road, overpass road, and curve road, were carried out. The measured navigation tracks are compared with the navigation module at the leading level, as shown in Figure 19, where the yellow and blue lines are the tracks of the navigation module and this designed chip, respectively. It should be noted that when the navigation signal is weak, there will be a slight position offset. When the navigation signal is strong with less occlusion, the position is accurate. The trend is consistent with that of the reference navigation module. These results provide convincing evidence that the proposed RF receiver can be well-suited for navigation applications. Figure 17: Measured performance of RC filter calibration. Figure 18: Measured signal and image response. Table 4 summarizes the performance of the proposed receiver that is suitable for both BDS-3 and GPS in the L1 band in comparison to other reported research. In this work, in the on-chip LNA, the source inductor and gate inductor with high Q are realized by a copper bonding wire, improving the in-band noise performance and conserving space. LNA adopts a cascode amplifier structure with the LC resonant network as the load and with reused current, improving the gain and reducing the power consumption. The ACTBA, instead of the traditional passive balun, is adopted to convert the single-ended signal into the differential signal; this not only improves the RF front-end gain but also reduces the gain-realization difficulty of the later-stage circuit, which is conducive to achieving high gain and conserving space throughout the whole system. ACTBA also incorporates current reuse to reduce power consumption. A GMT circuit is modified, which can save the IF DC-blocking capacitors to reduce the insertion loss and area. The specific approach is to advance the DC-blocking capacitor originally located at the input of the CBPF to the output of the Gm so as to use fewer capacitors and a smaller capacitance value, thus conserving space. Image suppression is realized by BPF, and the later circuits only amplify and convert the in-phase path signals, saving nearly half of the IF layout area. Most of the RF front-end gain is realized by the IF PGA, which incorporates an open-loop circuit and has high-gain and low-power characteristics. After convergence, AGC and DCOC shut down automatically, effectively reducing power. A fractional-N phase-locked loop (PLL) as the FS [27] is integrated into the same chip, which is not discussed in this paper. For a fair comparison, the area and current consumption of the FS are included in Table 4, and the area and current of GPS only or BDS only are summarized. This work succeeds in minimizing area, current, and NF. The maximum gain is better, except for [28]. The linearity of this work does not have much advantage over other references, but it is sufficient to meet the system requirements mentioned in Section 3. There is no other interference except for the natural thermal noise or other transmitter leakage noise near the image frequency. This noise power is quite low, so the requirement for IMRR is not strict. Although the IMRR performance of this paper is not superior to other references, it still ensures full compliance with the requirements of navigation specifications [10]. The FOM in Table 4 shows that this work is superior when considering the gain, NF, power, and area. In summary, a compromise is made among power, area, image rejection, and linearity in this work.