Raven INVICTA 115, Инструкция по установке и обслуживанию

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INTRODUCTION
The Raven Invicta 115 GPS receiver provides highly accurate and reliable DGPS navigation using
WAAS satellite based DGPS corrections. This receiver is ideal for GIS, precision farming or any other
application where a high performance, rugged, and simple to operate receiver is required.
FUNCTIONAL DESCRIPTION
The Raven Invicta 115 is a 10 channel high-performance GPS receiver with a built-in DGPS correction
receiver. Built-in WAAS receiver can be selected for DGPS corrections.
DGPS corrections are needed to improve the accuracy of standard GPS. If operated without DGPS
corrections, the accuracy will be about 4 meters RMS. This means the receiver would have an accu-
racy of about 12 feet in any direction 67% of the time, or about 24 feet 95% of the time. Prior to the
government turning off Selective Availability (SA), this error was 100 meters RMS. With DGPS correc-
tions, the receiver can give positions with a RMS accuracy of 1.4 meters, about 4 feet.
Accuracy depends on many factors including the correction method and the range from source.
Primary concern with WAAS is that the Invicta 115 is designed to use this as the only source of DGPS
corrections. Considering that today there is a limited number of WAAS reference stations, the accu-
racy will vary from about 1 meter to 1.4 meters RMS depending on location.
In addition to improved accuracy, DGPS corrections keep the calculated position from jumping around
when the receiver loses or picks up a new satellite. Without DGPS these common occurrences will
cause the position to suddenly jump to a new point. Applications such as crop guidance will see
accuracies of about 0.75 feet RMS swath to swath when in WAAS DGPS. In this application the DGPS
correction source is critical, so the position won’t jump around while spraying a field.
For the functional description the Invicta 115 can be broken into several parts. Each is described in the
following sections.
GPS RECEIVER
The Invicta 115 GPS receiver can generate real-time position solutions at a rate of 5 solutions per
second. An option that enables the Invicta 115 to output up to 10 solutions per second can be pur-
chased. Position solutions are output via RS232 in NMEA format messages.
The Invicta 115 has two RS232 ports and can communicate at 1200, 2400, 4800, 9600, 19.2k, or
38.4k BPS on either/both port(s). The baud rate and the desired output messages can be configured
via the serial port using configuration messages.
NMEA format messages are standard for most GPS receivers and therefore should be compatible
with almost any software or hardware application designed to work with GPS.
The receiver comes from the factory with message settings that should be compatible with most
applications. Refer to the connecting equipment manuals for information about what message types
and serial settings they require. By default, the Invicta 115 will output GGA and VTG messages on
both ports. On port A these messages are output at 19.2k BPS with 5 solutions per second. This is the
optimum setting for connecting a guidance smart bar such as the Raven LB-5. Port B will output GGA,
VTG and RMC at 4800 BPS with 1 solutions per second. This is optimum for applications such as GIS
or yield monitors.
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