Functional Description - ashtech Z-sensor Operation Manual

differential and RTK operation with any other receiver that implements the RTCM
standard.

Functional Description

The receiver is activated when power is applied to the power connector, and (in the
case of the Z-Sensor) the power switch is ON. After self test, the receiver initializes
its 12x3 channels and begins searching for all space vehicles (SV) within the field of
view of the antenna.
The Z-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 coded inside the product. As the Z-receiver acquires (locks onto) each
SV, it notes the time and then collects the ephemeris data about the orbit of that SV,
and almanac data about the orbits of all the SVs in the constellation.
The Z-receiver features 12-parallel channel/12-SV all-in-view operation; each of up
to 12 visible SVs can be assigned to a channel and then continuously tracked. Each
SV broadcasts almanac and ephemeris information every 30 seconds, and the unit
automatically records this information in its non-volatile memory.
The unit has an L1/L2-band radio frequency (RF) port and four RS-232 serial input/
output (I/O) ports. Ports A, B, and C are capable of two-way communication with
external equipment. On the Z-Sensor, port D can only be used with the optional
internal radio. On the Z-Eurocard, port D may be used with an on-board radio or
externally via the DIN64 connector.
The RF circuitry receives satellite data from a GPS antenna and LNA via a coaxial
cable, and can supply +5V to the antenna/LNA by means of that cable. No separate
antenna power cable is required. Typical power consumption is approximately 7.5
watts even when powering an LNA.
The receiver incorporates a red/green LED which lights red to indicate power status
and flashes green to indicate the number of satellites locked.
The Z-receiver collects Coarse Acquisition (C/A) code-phase (pseudo-range) and full
wavelength carrier phase measurement on L1 frequency (1575 MHz), Precise (P)
code phase (pseudo-range) and full wavelength carrier phase on L1 and L2 frequency
(1227 MHz). The Z-receiver permits uninterrupted use even when anti-spoofing (AS)
is turned on. When AS is on, the Z-receiver automatically activates Ashtech's
patented Z-tracking mode that mitigates the effects of AS. The performance when AS
is on is the same as when AS is off.
2 Z-Sensor and Z-Eurocard Operation Manual