Philip G. Mattos

A 56-mW 23-mm/sup 2/ single-chip 180-nm CMOS GPS receiver with 27.2-mW 4.1-mm/sup 2/ radio

A 56-mW 23-mm/sup 2/ GPS receiver with CPU-DSP-64 kRAM-256 kROM and a 27.2-mW 4.1-mm/sup 2/ radio has been integrated in a 180-nm CMOS process. The SoC GPS receiver, connected to an active antenna, provides latitude, longitude, height with 3-m rms precision with no need of external host processor in a [-40, 105]/spl deg/C temperature range. The radio draws 17 mA from a 1.6-1.8-V voltage supply, takes 11 pins of a VFQFPN68 package, and needs just a few passives for input match and a crystal for the reference oscillator. Measured radio performances are NF=4.8 dB, Gp=92 dB, image rejection > 30 dB, -112 dBc/Hz phase noise @ 1 MHz offset from carrier. Though GPS radio linearity and ruggedness have been made compatible with the co-existence of a microprocessor, radio silicon area and power consumption is comparable to state-of-the-art stand-alone GPS radio. The one reported here is the first ever single-chip GPS receiver requiring no external host to achieve satellite tracking and position fix with a total die area of 23 mm/sup 2/ and 56-mW power consumption.

Integrated GPS and dead reckoning for low-cost vehicle navigation and tracking

GPS (global positioning system) for the private car, which spends most of its time in cities, requires augmentation by dead reckoning (DR) sensors. Comparative results are given for GPS alone, loosely coupled with DR, and tightly coupled, based on tests in Paris and England. An implementation is described where GPS, DR, route planning algorithms and map display can all run on a single CPU at minimal cost.<<ETX>>

Correction of pseudorange errors in Galileo and GLONASS caused by biases in group delay

Both Galileo E1 OS and GLONASS L1 signals require a wider pre-correlation bandwidth than GPS C/A. The GLONASS channels are uniformly spaced on a frequency division grid, and occupy some 8MHz in total, whereas Galileo E1 OS has sidebands that are separated by about 2MHz. Being wideband is an advantage because of sharper correlation peak (Galileo) and better interference rejection; however it also exposes distant spectral components of the signal to larger variations of the front-end transfer function. Group delay differences are mostly caused by the analog components like the SAW filter or the integrated analog front-end whereas magnitude can be affected by signal conditioning done in the digital domain, for example by the insertion of recursive filters aimed at interference cancellation. These impairments must be estimated and compensated. The benefits for the consumer multi-constellation receiver are an improved precision and an enriched set of potential applications, including timing.

A BeiDou hardware receiver based on the STA8088 chipset

The recent release, in December 2012, of the complete BeiDou B1I Interface Control Document has boosted new interest and R&D activities in the field. For a manufacturer of GNSS semiconductor devices, the first and logical step in the roadmap toward a full blown BeiDou receiver is the reuse of existing and proven silicon; the new product can blossom and reach the market more quickly, with good overall performance, though not yet optimized in every single aspect. Following this approach, the paper describes a BeiDou receiver implementation, based on the STA8088 “Teseo-II” consumer chip, which was originally designed for GPS, Galileo and GLONASS. Several technical solutions adopted in the receiver are disclosed, including aspects of the RF path, signal processing and higher level software algorithms like GEO velocity computation and ionosphere models. The main difficulty encountered was the generation of the B1I ranging codes, which was accomplished, with some performance trade-offs, by reusing the on-chip Galileo programmable code memory. The final result is a compact, consumer grade BeiDou hardware receiver, suitable for navigation and timing applications. Static positioning plots from real data, collected at a roof antenna are also reported.

Initial signal tracking tests of Galileo IOV and Compass/Beidou satellites

Initial results using Teseo-2 to track both Galileo IOV satellites and Compass MEO satellites are presented showing that the hardware is ready for the full constellations in both cases. Development software under test awaits satellite availability for full field testing. Future plans for other constellations and dual bands are discussed.

Group delay and phase delay in GNSS systems

GNSS signals have previously been modulated using binary phase shift keying but this modulation scheme is being replaced by binary offset carrier (BOC) modulation. Research has considered how the BOC signals might be affected differently when passed through a surface acoustic wave (SAW) filter. The concern has been that because of the split spectrum nature of the BOC signals, the upper and lower side-lobes will be delayed significantly differently. This was suggested because SAW filters have nonlinear phase characteristics and therefore different frequencies are delayed differently. It was suggested that this difference in delay will result in greater distortion of the correlation triangle. A delay magnification effect was also mentioned when analyzing the delay of a BOC signal. It was not understood why the theoretical delay calculations did not match up with the actual results in both hardware and simulation. This paper clarifies some of the confusion and explains why the “delay magnification” applies to phase delay but not group delay. This paper also takes a look at how the code phase delay can vary with frequency and correlator spacing as a result of the SAW filter properties.

GPS-III L1C signal reception demonstrated on QZSS

Consumer Multiconstellation silicon started with GPS-Galileo around 2007 [1], but with Glonass satellites available before Galileo, was first seen publically Teseo-2, STA8088, in 2010/11 [2,3,4]. With QZSS, Compass, GPS-L1C, Glonass-CDMA all expected, the silicon manufacturer must continue the path towards the fully flexible multi constellation receiver, otherwise the number and rate of new required chips would be beyond design and test resource capability. The early availability of the L1C signal on the QZSS satellite helps greatly, and is studied in this paper.

Maximum energy acquisition and tracking of dual component GNSS signals

Dual component systems share energy to optimize tracking and data-down-load, but usually omit acquisition considerations. This paper proposes a new concept that makes all the energy available for pilot, all available for tracking and download, but vastly enhances acquisition sensitivity and TTFF

23mm/sup 2/ single-chip 0.18/spl mu/m CMOS GPS receiver with 28mW-4.1 mm/sup 2/ radio and CPU/DSP/RAM/ROM

A 23 mm/sup 2/ 0.18 /spl mu/m CMOS GPS receiver with ARM7-DSP-64 k RAM-256 k ROM and a 28 mW-4.1 mm/sup 2/ radio has been integrated. The SoC GPS receiver, connected to an active antenna, provides latitude, longitude, height with 3 m rms precision with no need of external host processor in [-20,80]/spl deg/C temperature range. The radio draws 17.5 mA from a 1.6 V-1.8 V supply, takes 11 pins of a VFQFPN68 package and needs just a few passives for input matching and one crystal. Measured radio performances are: NF=4.8 dB, Gp=92 dB, image rejection >30 dB, -112 dBc/Hz @ 1 MHz offset phase noise. Though linearity and ruggedness of the GPS radio have been made compatible with the co-existence of microprocessor, its silicon area and power consumption is aligned with state-of-the-art stand-alone CMOS GPS radio. The one reported here is the first ever radio successfully embedded into a single-chip GPS receiver requiring no external host to achieve satellite tracking and position fix with a total die area of 23 mm/sup 2/.