Overview; Functional Description - ashtech Z-Xtreme Operations & Reference Manual

application-specific packages to work directly with the receiver. The Z-Xtreme
receiver works with a wide choice of controller software and data collectors,and
provides a full range of accessories to make surveying simple and efficient.
Incorporating an integrated, optimized keyboard/display, the system supports
collection and post-processing of static, rapid static, and kinematic data without the
need for an external handheld display/controller . The unit functions as a base station
and/or rover for real-time code and code/carrier RTCM differential GPS usage. To
support the requirement for real-time centimeter-level surveying solutions, an optional
UHF or spread spectrum radio is incorporated into the receiver, providing a
configured portable and integrated real-time GPS surveying system. The receiver can
be configured as a continuous operating reference station (CORS) for surveying,
GIS, geological, or other scientific monitoring applications.

Overview

The Z-Xtreme processes signals from the GPS satellite constellation, deriving real-
time position, velocity, and time measurements. Twelve dedicated separate and
parallel channels extract Coarse/Acquisition (C/A) code-phase, and carrier-phase
measurement on the L1 (1575 MHz) band, and Precise (P) code phase and carrier
phase measurement on the L1 and L2 (1227 MHz) bands.
The Z-Xtreme receives satellite signals via an L-band antenna and low-noise
amplifier (LNA). The receiver operates stand-alone and as a base (reference) station
or remote (rover) station providing real-time differential GPS operation for code, and
real-time kinematic (RTK) operation for carrier phase. The unit implements the RTCM
SC 104 V2.2 standard for differential and RTK operation. These features allow the Z-
Xtreme to achieve centimeter accuracy while being compatible for differential and
RTK operation with any other receiver that implements the RTCM standard.

Functional Description

The receiver is activated when either an internal battery has been inserted, or an
external power supply has been connected to the power connector, and the power
push-button is pushed to ON. After self-test, the receiver initializes its 12 channels
and begins searching for all space vehicles (SV) within the field of view of the
antenna. The receiver can track all Block I and Block II GPS SVs. All 32 PRN
numbers as specified in Navstar GPS Space Segment/Navigation User Interfaces,
ICD-GPS-200, Revision B are internally coded. As the receiver acquires (locks onto)
each SV, it notes the time and collects the ephemeris data about the orbit of that SV,
and almanac data about the orbits of all the SVs in the constellation.
2 Z-Xtreme Operations and Reference Manual