NavCom StarUtil User Manual Rev.E

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NavCom Technology, Inc.

20780 Madrona Avenue
Torrance, CA 90503
USA
Tel: [phone]
Fax: [phone]

[e-mail]
www.navcomtech.com

STARUTIL User Guide Rev. E

Table of Contents

Table of Contents.................................................................................................................ii

Table of Figures ..................................................................................................................iv

Notices .................................................................................................................................vi

Copyright................................................................................................................................................................. vi

Trademarks .............................................................................................................................................................. vi

User Notice .............................................................................................................................................................. vi

Use of this Document............................................................................................................................................... vi

Chapter 1 Introduction.....................................................................................................7

StarUtil Overview......................................................................................................................... 7

Program Initialization................................................................................................................... 7

Output Message Selection........................................................................................................... 7

Receiver Setup Parameters...........................................................................................................7

Receiver Initial Position ................................................................................................................ 8

Viewing Output Messages ...........................................................................................................8

Initiating Data Logging................................................................................................................ 8

Chapter 2 Establishing Communications & Control .....................................................9

Chapter 3 Navigation & Data Output Configuration ................................................11

Solid Earth Tide (SET) Implementation....................................................................................... 15

Receiver Initial Position Setup ....................................................................................................15

Rover / Navigation & Tracking Setup.........................................................................................16

NCT Operating Parameter Displays............................................................................................ 19

Chapter 4 Base Station Setup .......................................................................................21

RTK/dGPS Base Using Internal Radio .......................................................................................... 21

RTK Extend/RTK/dGPS Base Using External Radio....................................................................... 25

Chapter 5 RTK Extend / RTK / dGPS / SBAS Rover Setup .........................................27

RTK/dGPS Rover Internal Radio Setup ........................................................................................ 27

NCT RTK Extend Input............................................................................................................... 27

NCT RTK Input .......................................................................................................................... 28

RTCM RTK Input........................................................................................................................ 28

CMR+/CMR RTK Input............................................................................................................... 28

SBAS .........................................................................................................................................29

StarFire ................................................................................................................................................................. 29

WAAS/EGNOS ......................................................................................................................................................... 29

Chapter 6 NMEA Setup and Output ..............................................................................30

NMEA GGA Station ID Field 14..................................................................................................32

Chapter 7 Data Logging.................................................................................................33

External NCT Binary Logging.....................................................................................................33

Internal NCT Binary Logging ..................................................................................................... 34

Chapter 8 StarFire Specific Operation.......................................................................38

Configure LBM Message Output................................................................................................ 38

Alternate Channel & StarFire™ Frequencies ............................................................................... 41

QuickStart .................................................................................................................................42

StarFire License Installation Using StarUtil................................................................................ 42

Chapter 9 1PPS/Events..................................................................................................43

Chapter 10 Ack/Nacks & General Commands............................................................45

Ack/Nack................................................................................................................................... 45

General Duty Commands .......................................................................................................... 46

Key.......................................................................................................................................................................... 46

Get Almanac ...........................................................................................................................................................46

Get Almanac To File ................................................................................................................................................46

Send Almanac From File .......................................................................................................................................... 46

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STARUTIL User Guide Rev. E

Get Ephemeris.........................................................................................................................................................46

CMR (In) Off ........................................................................................................................................................... 46

Chapter 11 Tools Menu ................................................................................................47

Power Management .................................................................................................................. 47

Save System Configuration ........................................................................................................ 48

Load Software Options .............................................................................................................. 49

Load Software ........................................................................................................................... 51

Appendix A NCT Solid Earth Tide (SET) Message Format .........................................53

Appendix B NCT Station ID NMEA GGA Field 14 Definitions.....................................54

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STARUTIL User Guide Rev. E

Table of Figures

Figure 1: StarUtil Toolbar....................................................................................................................................................9

Figure 2: PC Port Configuration.......................................................................................................................................... 9

Figure 3: PC Port Status Bar ................................................................................................................................................ 9

Figure 4: Unit Port Configuration...................................................................................................................................... 10

Figure 5: StarUtil Main GUI Window ................................................................................................................................. 11

Table 1: NCT Binary Default Output Messages ................................................................................................................. 11

Figure 6: Message Output List Control.............................................................................................................................. 12

Figure 7: NCT-2100/NCT-2000 Message List....................................................................................................................12

Figure 8: NCT Message Choice Added to Output List .......................................................................................................13

Figure 9: NCT Message Logging Port Choice....................................................................................................................13

Figure 10: NCT Message Output Rate Choice ................................................................................................................... 14

Figure 11: NMEA Messages Scheduling Window .............................................................................................................. 14

Figure 12: NCT SET NMEA Sample ................................................................................................................................... 15

Figure 13: Initial Position Location .................................................................................................................................... 15

Figure 14: Set Receiver Position ........................................................................................................................................16

Figure 15: Rover Navigation & Tracking Parameters Setup................................................................................................ 17

Figure 16: Vertical Antenna Bias........................................................................................................................................ 18

Figure 17: View NCT in ASCII Choice................................................................................................................................19

Figure 18: View of Tabbed NCT Messages in ASCII ........................................................................................................... 20

Figure 19: View of Tabbed 0xB1 in ASCII; Independent Window ......................................................................................20

Figure 20: Network Configuration Location ...................................................................................................................... 21

Figure 21: Network Configuration .................................................................................................................................... 22

Figure 22: Base Configuration Window............................................................................................................................. 22

Figure 23: Output Correction Types ................................................................................................................................. 23

Figure 24: Setup Base Location; User Input ....................................................................................................................... 23

Figure 25: Setup Base Location; Self-Survey ...................................................................................................................... 23

Figure 26: Internal Radio Settings Location ....................................................................................................................... 24

Figure 27: Radio Configuration; Operation Mode ............................................................................................................. 24

Figure 28: Radio Configuration; Power Level..................................................................................................................... 25

Figure 29: Corrections Output to Internal Radio Port Configuration.................................................................................. 25

Figure 30: RTK Base Message Output List ......................................................................................................................... 26

Figure 31: L1 SBAS Selection Window............................................................................................................................... 29

Figure 32: NMEA Output Menu Location.......................................................................................................................... 30

Figure 33: NMEA Message Choices & Data Rate ............................................................................................................... 30

Figure 34: NMEA Viewer Menu Location........................................................................................................................... 31

Figure 35: NMEA Viewer & Data Logging......................................................................................................................... 31

Figure 36: NMEA GGA Field 14 Option............................................................................................................................. 32

Figure 37: NCT External Logging Menu Location.............................................................................................................. 33

Figure 38: External Logging Setup.................................................................................................................................... 33

Figure 39: MMC Internal Logging Port Selection ..............................................................................................................34

Figure 40: MMC Internal Logging Control Location.......................................................................................................... 35

Figure 41: MMC Internal Data Logging ............................................................................................................................ 35

Figure 42: More Button Choices ....................................................................................................................................... 36

Figure 43: MMC Format Label .......................................................................................................................................... 36

Figure 44: MMC Open File for Logging ............................................................................................................................36

Figure 45: MMC Download Dialog ................................................................................................................................... 37

Figure 46: MMC Download Progress Bar ..........................................................................................................................37

Figure 47: StarFire™ Specific Menus ................................................................................................................................. 38

Figure 48: LBM Output Message List ................................................................................................................................38

Figure 49: LBM Alternate Channel .................................................................................................................................... 41

Figure 50: LBM Frequency & Channel Status .................................................................................................................... 41

Table 2: StarFire™ Channel Numbers and Satellites .......................................................................................................... 42

Figure 51: RTG QuickStart Initialization............................................................................................................................. 42

Figure 52: StarFire License Upload Location ...................................................................................................................42

Figure 53: LBM License Upload.........................................................................................................................................42

Figure 54: 1 PPS & Events Location................................................................................................................................... 43

Figure 55: 1 PPS & Event Latch Configuration ..................................................................................................................43

Figure 56: Event Latch Output Rate Configuration............................................................................................................44

Figure 57: Select Ack/Nack Logical Ports Location............................................................................................................. 45

Figure 58: Select Ack/Nack Logical Ports........................................................................................................................... 45

Figure 59: General Receiver Commands ........................................................................................................................... 46

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STARUTIL User Guide Rev. E

Figure 60: Tools Commands ............................................................................................................................................. 47

Figure 61: Power Management Control Window .............................................................................................................. 47

Figure 62: System Configuration Dump Window.............................................................................................................. 48

Table 3: Save System Settings Text File Contents .............................................................................................................. 49

Figure 63: Software Options Code Input........................................................................................................................... 49

Figure 64: Options File Opened In NotePad...................................................................................................................... 50

Figure 65: Software Options Sent .....................................................................................................................................50

Figure 66: View Installed Software Options ....................................................................................................................... 50

Figure 67: Load Software .................................................................................................................................................. 51

Figure 68: Software Upload Progress ................................................................................................................................51

Figure 69: Upload Completed Successfully........................................................................................................................ 52

Table A1: NCT Solid Earth Tide (SET) NMEA message ....................................................................................................... 53

Table B1: Beam Selection; ID X.........................................................................................................................................54

Table B2: Navigation Mode; ID YY .................................................................................................................................... 55

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STARUTIL User Guide Rev. E

Notices

StarUtil Engineering Program User Guide

P/N 96-310008-3001

Revision E July 2005

Copyright

 2003 by NavCom Technology, Inc.

All rights reserved. No part of this work or the computer programs described herein may be
reproduced or stored or transmitted by any means, without the written permission of the copyright
holders. Translation in any language is prohibited without the permission of the copyright holders.

Trademarks

The ‘find your way’, ‘NavCom Globe’ and NAVCOM TECHNOLOGY logos are trademarks of
NavCom Technology, Inc.
product and brand names are trademarks or registered trademarks of their respective holders.

StarFire

 is a registered trademark of Deere & Company. All other

User Notice

NAVCOM TECHNOLOGY, INC. SHALL NOT BE RESPONSIBLE FOR ANY INACCURACIES, ERRORS, OR
OMISSIONS IN INFORMATION CONTAINED HEREIN, INCLUDING, BUT NOT LIMITED TO,
INFORMATION OBTAINED FROM THIRD PARTY SOURCES, SUCH AS PUBLICATIONS OF OTHER
COMPANIES, THE PRESS, OR COMPETITIVE DATA ORGANIZATIONS.

THIS PUBLICATION IS MADE AVAILABLE ON AN “AS IS” BASIS AND NAVCOM TECHNOLOGY, INC.
SPECIFICALLY DISCLAIMS ALL ASSOCIATED WARRANTIES, WHETHER EXPRESS OR IMPLIED. IN NO
EVENT WILL NAVCOM TECHNOLOGY, INC. BE LIABLE FOR DIRECT, INDIRECT, SPECIAL,
INCIDENTAL, OR CONSEQUENTIAL DAMAGES IN CONNECTION WITH THE USE OF OR RELIANCE
ON THE MATERIAL CONTAINED IN THIS PUBLICATION, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES. NAVCOM TECHNOLOGY, INC. RESERVES THE RIGHT TO MAKE IMPROVEMENTS
OR CHANGES TO THIS PUBLICATION AND THE PRODUCTS AND SERVICES HEREIN DESCRIBED AT
ANY TIME, WITHOUT NOTICE OR OBLIGATION.

Use of this Document

This User Guide is intended to be used by someone familiar with the concepts of
surveying equipment.

GPS

and satellite

 Note indicates additional information to make better use of the product.

a Indicates a caution, care, and/or safety situation.

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STARUTIL User Guide Rev. E

Chapter 1 Introduction

StarUtil Overview

StarUtil is designed for use as an Engineering/OEM application. This utility is primarily used to assist
in the development of user controller solutions. It is a powerful utility that allows the user to view,
and or configure any of the NavCom Technology, Inc. GPS receivers to any Base or Rover
configuration. It also affords the user the luxury of viewing receiver operations such as Channel
Status, Position Information, Raw Measurements, and many other engineering level receiver
operations, which are not necessarily useful to a user.

StarUtil allows the user to log output data to a file on the computer’s hard drive or to the internal
Memory Module Card (MMC). This data can then be used for post processing or data analysis.

All examples and references in this User Guide are relative to the factory default setup, which is
Rover configuration. In the examples and references to Base setup, NavCom Technology, Inc.
proprietary binary RTK Base configuration is assumed.

Program Initialization

After clicking on the StarUtil Icon, the utility automatically reads the available serial ports (i.e. RS-232
ports) from the Windows
rate for the PC port you have chosen, or you may have the program automatically detect the baud
rate for you.

®

OS registry. You are then given the option to manually choose a baud

Output Message Selection

The NCT-2100/NCT-2000 GPS Engine receiver comes with a default list of messages enabled. In
the case of the NCT binary messages, you will see these messages scrolling upward on the Messages
screen of StarUtil. The Technical Reference Manual (TRM) provides a detailed accounting of all NCT
binary messages that can be output from the receiver, any of which can be included or excluded in
the NCT-2100/NCT-2000 Messages window. The user has the ability to choose the rate at which
the messages are output from the receiver at any of 6-present rates, or by manually entering a value.
The user has the additional option of choosing a message to be output “on change” indicating that
the receiver will not output a particular message until a minimum of 1 bit has changed in the
message. NMEA output messages can be viewed, and logged in their own display screen, while the
output rate is chosen in a similar fashion as the NCT binary.



The NMEA messages GGA, RMC, and VTG follow the outpu rate of the 0xB1 message up to a

rate of 10 HZ, when NMEA output rate for the e messages are set to “On Change”. Setting the

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oxB1 message rate greater than 10 HZ will force the GGA, RMC, and VTG messages to a 1 Hz
output rate.

Receiver Setup Parameters

StarUtil has been designed to allow the user the flexibility of configuring the receiver as a Base or
Rover receiver. Tool bar icons are provided to simplify the process of configuring the receiver for
typical Base or Rover operation (i.e. single button setup). If the user has more specific requirements,

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STARUTIL User Guide Rev. E

they may access additional menu screens that allow setup of such items as the internal radio, or L­Band Module.

Receiver Initial Position

After removing the receiver from the box and powering up, the position first seen may be the
location of the NavCom Technology, Inc. production center. It is recommended that this position
be changed to a position within 500km of your actual location in order to quickly acquire satellites
and receive a new almanac from the GPS system.

Viewing Output Messages

Only a limited number of the many NCT2000D output messages can be viewed within the utility.
These can be found under the "View" menu of the main StarUtil window. When a message is
checked on this menu, a screen with a selection tab will be created in the main workspace window
and displaying for the corresponding message. If you wish, you can remove the screen from the
main workspace window by dragging the tab and placing it anywhere on the Windows
This will make the display a freestanding window. If you wish to put it back, simply drag the
window frame back to the StarUtil main workspace window.

®

desktop.

Initiating Data Logging

You can create a log file of the messages from the receiver by selecting "File\Logging..." from the
main StarUtil window menu. Simply select a folder and enter a file name to begin logging. A folder
named in year, month, day [yymmdd] format will be created under the chosen folder, and the
logged data will be placed there. To stop logging, select "File\Close log" from the main StarUtil
window menu.

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STARUTIL User Guide Rev. E

Chapter 2 Establishing Communications & Control

In order to execute StarUtil double click on the icon. Once StarUtil is active, communications with
the GPS system must be established by pressing the Configure Com Port button on the main
StarUtil window toolbar, see Figure 1. This can also be accomplished via the Menu bar by clicking
PC Port\Configure PC COM Port.

Figure 1: StarUtil Toolbar

A new window will appear as in Figure 2. StarUtil includes an Auto Baud Detect feature that will
allow for quick protocol connection between the PC, and the GPS receiver. You are also given an
opt-out if you choose to manually pick a baud rate. Check the Auto Baud box to initiate automatic
detection, uncheck the box to choose a baud rate from the pop-up window.

StarUtil automatically reads the available serial ports (i.e. RS-232 ports) from the Windows

®

registry,
and displays them in a pop-up window. Choose the Com Port that you will be using to control the
GPS receiver. Typically RTS/DTR and Parity options will remain in the default states unless your
system requires that these options be changed. Once the connection is established the PC COM
Port Status Bar at the bottom of the main StarUtil window will provide connection information as
shown in Figure 3. Information provided is PC COM port baud rate, GPS receiver port baud rate for
both Com Ports, Data Logging Status, and any Input activity. There is also an Auto Baud button,
which only becomes active after the initial connection has been established.

Figure 2: PC Port Configuration

Figure 3: PC Port Status Bar

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Now that PC Port Configuration has been established, the receiver must have its logical ports setup
to meet the specific requirements of the application. At this point you may choose to change the
Control Port to Com 1, elect an output port for NMEA, or an input port for the correction
information being received from an external source. The Unit Port Configuration screen can be
reached by pressing the Ports icon on the Toolbar, or from the Menu Bar pressing
RECEIVER\SETUP\PORTS. Figure 4 shows a typical Unit Port Configuration used for outputting
NMEA data via the Data Port [Port A/Com 1], controlling the receiver via Com 2 [Port B], and
receiving RTK corrections via the *internal radio. The Physical Ports area of Figure 4 displays the
baud rate, and parity at which the port communicates to the Controller Solution.

*

Internal radio option available on the RT-3010 & RT-3020 models only.

Figure 4: Unit Port Configuration

The Default Settings of the Physical Ports is set to 19200. The baud rate can be changed by simply
clicking on the pull-down menu for port A and B and selecting any of the predetermined baud rates
as shown in Figure 4.

The default logical physical mapping places the Control in the Current Port B, and Data, & NMEA,
in the Non-Current Port A. The logical physical mapping of ports can be changed by clicking on any
port and the pull-down menu shown in Figure 4. Logically, there are six ports and physically there
are two, Port A [Com1], and B [Com 2]. The six logical ports are Control, Data, NCT RTK, NMEA,
RTCM, and CMR as shown in Figure 4. Control and NCT RTK are very similar and work with
proprietary messages. The RTCM port receives differential corrections as a rover, and sends out
RTCM 104 corrections if the receiver has been set up as a base station; the CMR port operates in
similar fashion. The NMEA port communicates messages using a protocol for communications
between marine instrumentation. This interface permits flexibility in communication and control of
the various message streams.

The “Apply” button sends the changes to the receiver, and will store the values in NVRam for
recovery after a power cycle. The “Retrieve” button will send a request to the
information stored in NV-Ram pertinent to this particular display. These two buttons operate as

described for each window in which they appear. Checking the Use Defaults box will apply the
factory default configuration for both Physical and Logical Ports.

receiver for the

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STARUTIL User Guide Rev. E

Chapter 3 Navigation & Data Output Configuration

At this point the GPS receiver is ready to be configured for your specific application requirements.
The GPS receiver is factory defaulted to output 7 NCT binary messages via the factory default
control port Com 2. After successfully establishing communications with the receiver, you should
see NCT messages scrolling up in the Messages tab of StarUtil’s main window as seen in Figure 5.

Figure 5: StarUtil Main GUI Window

The messages chosen afford the user the ability to get started viewing, collecting, and analyzing
GPS receiver data immediately. The default messages output from the receiver are shown in Table 1.

Message Rate Description

44

81

86

B0

B1

On Change

On Change

On Change

On Change

On Change

Packed

Almanac

Packed

Ephemeris

Channel

Status

Raw Measurement Data

PVT

Block

A0

AE

On Change

600 Sec

Alerts

Software Versions

Table 1: NCT Binary Default Output Messages

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STARUTIL User Guide Rev. E

The user is allowed to add or delete NCT and/or NMEA message from each format’s output list. This
is established by clicking on RECEIVER\MESSAGES\NCT OUTPUT from the StarUtil Menu bar as
shown in Figure 6.

Figure 6: Message Output List Control

After choosing the message output type [in this case NCT Binary] the window shown in Figure 7 will
appear allowing you to add or delete any of the NCT Binary messages, and schedule the frequency
of their output.

Figure 7: NCT-2100/NCT-2000 Message List

To add messages to the NCT Output List right click in the blank Message ID cell. A list of commonly
used messages will appear; see Figure 8. Click on the message of your choice and it will be added to
the list. Right click on the Port cell to choose where the message will be sent; see Figure 9. Right
click on the Rate cell and you will be given several options as to the frequency of the output for the
message; see Figure 10. Pressing the “Apply” button will send the new list, and scheduling
information to the receiver. If a message you wish to schedule is not in the preset list, choose
“Other” and you will be given the opportunity to manually enter the hex ID of the message you
need.

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There are two check boxes that allow the end user to quickly delete all messages in the NCT­2100/NCT-2000 Message List. By checking the “Turn Off All Other Messages On All Ports” box, and
clicking Apply, all NCT-2100/NCT-2000 messages previously scheduled for output on Control, Data,
or NCT RTK will be deleted from the message list and data output will stop.

By checking the “Turn Off All Other Messages On Only This Port” box, and clicking Apply, all NCT­2100/NCT-2000 messages previously scheduled for output on Control will be deleted from the
message list and data output on the Control Port will stop, leaving any data scheduled for output on
the Data or NCT RTK port to flow freely as scheduled.

Pressing the Clear button will clear the NCT-2100/NCT-2000 messages list on the screen, but will
not affect the output of the receiver.

Deleting a message can be accomplished in one of two ways, either click on the message and press
the Delete key on the keyboard, or Right click on the message, and choose Delete from the popup
menu; see Figure 8.

Figure 8: NCT Message Choice Added to Output List

Figure 9: NCT Message Logging Port Choice

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STARUTIL User Guide Rev. E

Figure 10: NCT Message Output Rate Choice

The NCT messages scheduled should appear scrolling up in the Messages tab of the main StarUtil
window as seen in Figure 5, StarUtil Main GUI Window.

NMEA messages and output rates are chosen in similar fashion via the RECEIVER\NMEA\MESSAGES
menu choice. Additionally, the end user can now have a NCT Proprietary NMEA Type string output
from the NMEA port by choosing NCT SET from the NMEA messages list as shown in Figure 11,
which will provide Solid Earth Tide (SET) correction information.

Figure 11: NMEA Messages Scheduling Window

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STARUTIL User Guide Rev. E

Solid Earth Tide (SET) Implementation

In order to have the SET correction information applied to the position solution there are several
caveats that must be engaged.

1. Navigation MUST be valid.

2. SET Software Option is Enabled.

3. Navigation Mode is set to RTG from the Rover / Tracking & Navigation Setup, Figure 15.

4. SET are applied (“USE”) from the Rover / Tracking & Navigation Setup, Figure 15.

5. SET correctors are valid (minimum of 1 run of the SET algorithm).

Once the criteria above have been met, the SET corrections will be applied to the position solution,
and displayed as North, East, and Up corrections in millimeters on the B1 Solution Window. It will
also be output on the NMEA port. A sample SET message appears in Figure 12, a detailed
description of the NMEA Type message structure can be found in Appendix A Table A1.

$PNCTSET,161625.00,-0.008,0.003,-0.099,,,,,,*47

Figure 12: NCT SET NMEA Sample

Receiver Initial Position Setup

Depending on your Latitude & Longitude, you may be required to enter an initial position in order
to start navigating in the shortest period of time. This is accomplished by clicking on the menu bar
RECEIVER\SETUP\INITIAL POSITION as shown in Figure 13.

Figure 13: Initial Position Location

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The Set Receiver Position screen will appear as shown in Figure 14. The Receiver Position Menu is
comprised of Message Block 0x46 Initial Time and Position.

Figure 14: Set Receiver Position

Click the Set Time box to change the elapsed time since the beginning of the week in seconds if
known. It is not mandatory to set this field since once a satellite is tracked GPS Week Number, and
GPS Week Seconds will automatically update. After the receiver starts tracking satellites, time cannot
be set since the time from the satellite is assumed to be more accurate.

Click the Set Position box in order to change the initial position the receiver will use to track
satellites. Typically a position within 500km will be close enough to pickup satellites and acquire
almanac and ephemeris information. The position can be entered in DDMMSS format, or by use of
the pull down window DDMM format. Similarly the ellipsoidal height can be entered in meters or
feet.

Once the position has been entered, press the “Apply” button and the receiver will use the newly
entered position to locate its first satellite and update almanac and ephemeris information.
Collection of a new almanac requires 12.5 uninterrupted minutes of continuous satellite tracking.

Rover / Navigation & Tracking Setup

Typically the receiver will come from the factory setup as a GPS autonomous rover. Depending on
the options purchased, you may set the receiver up to accept dGPS/RTK/RTG corrections from an
external source. Figure 15 shows the Navigation & Tracking Setup window and the various options
available to the user as a rover. This menu comprises message blocks 0x47 (SV Tracking Control),
and 0x49 (Solution Control). Access this window by clicking RECEIVER/SETUP/ROVER-TRACKING &
NAVIGATION, or click the Rover icon on the main StarUtil toolbar.

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Figure 15: Rover Navigation & Tracking Parameters Setup

The Navigation Elevation Mask selects the elevation angle the receiver starts processing GPS data
from the satellites. The default is set to 7 degrees because GPS measurements of satellites at lower
elevation tend to deteriorate accuracy.

The Navigation Rate is the number of Navigation Solutions per second. The default rate is 1 Hz and
can be increased up to 25 hz as a purchased option.



The Navigation Rate of the 0xB1 message is changed here and NOT on the NCT Message

Output list. Attempting to change the Nav Rate in the NCT Message Output list will delete the
0xB1 message from the output list.

The minimum amount of satellites required for navigation is a user input value =>3. The default is 3
and denotes a 2 dimensional navigation solution. If height solution is needed, an additional satellite
must be manually entered bringing the total to 4. Obviously, the larger the number of satellites
required for navigation, yields a longer period of time before position output

The default setting for Max PDOP is 10. The quality of GPS data is dependent on the geometry
between the receiver and satellites; this includes the number of satellites that can be "seen" by the
receiver and the angle between the receiver and satellites. A satellite near the horizon usually
provides a lower quality signal because of greater atmospheric interference and the increased
likelihood of the signal reflecting from surface features, this is known as "multipath" error. The effect
of geometry on GPS quality is measured by PDOP (position dilution of precision). PDOP is the
overall measure of the precision obtainable with a given satellite geometry. For example, a PDOP of
4 or less yields excellent precision, a PDOP between 5 and 7 is acceptable and a PDOP of 7 or more
is considered poor.

A 2D solution is an altitude hold mode. This typically indicates that the receiver is navigating using
only 3 satellites, and the altitude component is a manually entered valued. This altitude value used
can either be the value entered or the last computed altitude. A 3D solution typically indicates that
the receiver is navigating using 4 or more satellites. When the 2D/3D button is in the Auto mode,

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