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Chapter 1 Introduction
In this chapter, the main goal of FV-25 will be described and then the features of the
FV-25 module will be specified in order that a user can make correct decision about
module selection before proceeding further development. Understanding thoroughly
the pro and con of FV-25 will clear the compatibility of the module with a user’s
system. At the same time, let the users make the best performance out the module.
The main goal of FV-25 is to be used as a part of integrated system, which can be a
simple PVT (Position-Velocity-Time) system, for instance, G-mouse, or complex
wireless systems, such as a system with GSM function, a system with Blue Tooth
function, and a system with GPRS function. The module (FV-25) can be the best
candidate for users’ systems as the users’ systems need the careful consideration on
the performance, power consumption, and/or size of the module. Table 1.1
summarizes the specification of FV-25. It is noticeable that in addition to excellent
start-up times and position accuracy, the updated rate can be up to 4 Hz and the raw
measurements, i.e., pseudoranges and carrier phases, can be output in the format of
UBX binary message.
FV-25 mainly consists of ATR0600 (RF front-end IC), ATR0610 (LNA IC), and
ATR0620 (Baseband IC)
2
as well as 8 Mbit flash memory. Since the low noise
amplifier (LNA: ATR0610) is built in the RF section, the passive and active antennas
are the available options for the module. The Baseband IC (ATR0620) mainly
includes a CPU (ARM7), SRAM, ROM, Battery Backed-up RAM (BBR), and
Real-Time Clock (RTC). To keep running of BBR and RTC after power off, a
backed-up battery, which has voltage in the range of 1.95 V to 3.6 V, is needed. Since
BBR is used to store the updated position, ephemeris, and almanac data, the module
can implement all the start-up modes with the back-up battery. Besides the above
updated data can be saved to BBR, configuration data, which are available at startup,
can be also saved to BBR. In addition, the 8 Mbit flash memory is the other location
to save configuration setting permanently without the support of the backed-up
battery.
Using high performance of software and firmware from u-blox, the module provides
spectacular performance on navigation under static and dynamic conditions in
multipath-trended areas, such as urban skyscrapers and canyons, remarkable
2
ATR 0600, ATR 0610, ATR 0620 are manufactured by Atmel corporation.