R
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GGPPSS PPrroodduuccttss
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NavCom Technology, Inc.
20780 Madrona Avenue
Torrance, CA 90503
USA
Tel: +1 310.381.2000
Fax: +1 310.381.2001
sales@navcomtech.com
www.navcomtech.com
RT-3020 User Guide - Rev. E
Table of Contents
Table of Contents................................................. i
Notices.................................................................. ii
Chapter 1 Introduction.................................... 7
System Overview..................................................... 7
Applications .......................................................... 11
Unique Features .................................................... 11
Chapter 2 Interfacing..................................... 13
Electrical Power ..................................................... 13
Communication Ports............................................15
Indicator Panel ......................................................17
1 PPS..................................................................... 20
CAN Bus/Event...................................................... 20
Chapter 3 Installation .................................... 22
Tri-Mode Antenna ................................................. 22
GPS Sensor............................................................ 24
Communication Ports............................................27
GPS Antenna Connector........................................ 28
Chapter 4 Configuration................................ 30
Factory Default Settings.........................................30
Advanced Configuration Settings........................... 33
Chapter 5 Safety Instructions ........................ 34
FCC Notice............................................................ 34
Transport .............................................................. 34
Maintenance ......................................................... 35
External Power Source ........................................... 35
Safety First............................................................. 35
A
GPS
Sensor Technical Specifications ......... 37
RT-3020S and RT-3020M ...................................... 37
B GPS Antenna Technical Specifications ...... 43
L1+L, L2 GPS Antenna ......................................... 43
C Event Input Configuration ......................... 45
Glossary............................................................. 47
i
RT-3020 User Guide - Rev. E
Notices
RT-3020
P/N
Revision E August 2005
Serial Number:
Date Delivered:
GPS
Products User Guide
96-310005-3001
Copyright
2002 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.
Deere & Company. All other product and brand names
are trademarks or registered trademarks of their
respective holders.
StarFire
is a registered trademark of
FCC Notice
This device complies with Part 15 of the FCC Rules.
Operation is subject to the following two conditions:
ii
RT-3020 User Guide - Rev. E
(1) this device may not cause harmful interference, and
(2) this device must accept any interference received,
including interference that may cause undesired
operation.
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.
Limited Warranty
NavCom Technology, Inc., warrants that its products
will be free from defects in workmanship at the time of
delivery. Under this limited warranty parts found to be
defective or defects in workmanship will be repaired or
replaced at the discretion of NavCom Technology, Inc.,
iii
RT-3020 User Guide - Rev. E
at no cost to the Buyer, provided that the Buyer returns
the defective product to NavCom Technology, Inc. in
the original supplied packaging and pays all
transportation charges, duties, and taxes associated
with the return of the product. Parts replaced during
the warranty period do not extend the period of the
basic limited warranty.
This provision does not extend to any NavCom
Technology, Inc. products, which have been subjected
to misuse, accident or improper installation,
maintenance or application, nor does it extend to
products repaired or altered outside the NavCom
Technology, Inc. production facility unless authorized in
writing by NavCom Technology, Inc.
THIS PROVISION IS EXPRESSLY ACCEPTED BY THE
BUYER IN LIEU OF ANY OR ALL OTHER AGREEMENTS,
STATEMENTS OR REPRESENTATIONS, EXPRESSED OR
IMPLIED, IN FACT OR IN LAW, INCLUDING THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE AND OF ALL
DUTIES OR LIABILITIES OF NAVCOM TECHNOLOGY,
INC. TO THE BUYER ARISING OUT OF THE USE OF THE
GOODS, AND NO AGREEMENT OR UNDERSTANDING
VARYING OR EXTENDING THE SAME WILL BE BINDING
UPON NAVCOM TECHNOLOGY, INC. UNLESS IN
WRITING, SIGNED BY A DULY-AUTHORIZED OFFICER
OF NAVCOM TECHNOLOGY, INC.
This limited warranty period is one (1) year from date of
purchase.
iv
RT-3020 User Guide - Rev. E
USG FAR
Technical Data Declaration (Jan 1997)
The Contractor, NavCom Technology, Inc., hereby
declares that, to the best of its knowledge and belief,
the technical data delivered herewith under
Government contract (and subcontracts, if appropriate)
are complete, accurate, and comply with the
requirements of the contract concerning such technical
data.
Global Positioning System
Selective availability (S/A
2000 at 04:05
stated that present
The US Government may at any time end or change
operation of these satellites without warning.
The U.S. Department of Commerce Limits
Requirements state that all exportable
contain performance limitations so that they cannot be
used to threaten the security of the United States.
Access to satellite measurements and navigation results
will be limited from display and recordable output
when predetermined values of velocity and
exceeded. These threshold values are far in excess of
the normal and expected operational parameters of the
RT-3020
GPS
UTC
sensor.
code) was disabled on 2nd May
. The United States government has
GPS
users do so at their own risk.
GPS
products
altitude
are
Use of this Document
This User Guide is intended to be used by someone
GPS
familiar with the concepts of
equipment.
and satellite surveying
v
RT-3020 User Guide - Rev. E
Note indicates additional information to make
better use of the product.
a Indicates a caution, care, and/or safety situation.
0 Warning indicates potentially harmful situations.
Items that have been
acronym that can be found in the Glossary.
Revisions to this User Guide can be obtained in a digital
format from
support.navcomtech.com
ITALICIZED
indicate a term or
vi
RT-3020 User Guide - Rev. E
Chapter 1 Introduction
The RT-3020
to the precise positioning community who need a
cost-effective, high performance
unique receiver can transmit or receive corrections via
an onboard
GPS
sensor delivers unmatched accuracy
GPS
sensor. This
Spread Spectrum Radio (SSR)
.
System Overview
GPS
Sensor
The RT-3020 sensor consists of a 24-channel dual
GPS
frequency precision
channels for receiving
System (SBAS)
proprietary raw data as fast as 50Hz (optional) and
signals. The sensor can output
Position Velocity Time (PVT)
(optional) through two 115
software provides fast initialization. Testing shows that
the system resolves ambiguities at start-up or on
reacquisition of satellites typically within two seconds.
receiver with two additional
Satellite Based Augmentation
data as fast as 25Hz
kbps
serial ports. The
RTK
The RT-3020 has a built-in
providing an immediate solution for the system
integrator and real time surveyor. Utilizing the built in
radio for
communicate using NavCom’s highly efficient
proprietary
RTCM
simultaneously accept corrections for
(
WAAS/EGNOS
The RT-3020S is packaged for mobility. It can be used
for construction stakeout, boundary surveys, high order
control surveys and topographic surveys in rough
RTK
measurements, the receivers
RTK
format or other
and CMR. Additionally, the receivers
) assuring seamless position output.
Spread Spectrum Radio
RTK
formats, such as
DGPS
1-7
RT-3020 User Guide - Rev. E
terrain. The sensor can be carried in a backpack with
the antenna either pole-mounted from the backpack or
on a survey pole with a single cable connection.
The RT-3020M is a
specifically designed for machine control applications in
construction, agriculture, mining and many other fields.
It is equipped with additional features allowing
interconnectivity with a wide variety of antennas,
vehicle data buses and other instrumentation to suit
specific applications and configurations. The RT-3020M
also has a 1
Bus
interface port.
GPS
Antenna
Our compact
performance and a stable
L2
. The robust housing assembly features a standard
BSW
5/8”
pole, tripod, or mast and is certified to 70,000’ feet.
PPS
thread for mounting directly to a surveyor’s
real-time kinematic (RTK
output port and a combined Event/
GPS
antenna with excellent tracking
phase center
for
) sensor
GPS L1
Although rated to 70K feet, this antenna is not
designed for aircraft installations. E-Mail
sales@navcomtech.com
for aircraft solutions.
CAN
and
Controller
GPS
The RT-3020
external c
serial
This may be accomplished using an IBM compatible PC,
Tablet PC or
software program which implements the rich control
language defined for NavCom
User’s Guide of your
information.
COM
ontroller
ports.
sensor is designed for use with an
solution connected via one of two
Personal Digital Assistant (PDA
GPS
products.
Controller
Solution for further
) and a
See
1-8
the
RT-3020 User Guide - Rev. E
Included Items
Figure 1: RT-3020 Supplied Equipment
X RT-3020
(RT-3020S
(RT-3020M
Y Compact
(
P/N
Z
GPS
GPS
sensor
P/N
92-310054-3001)
P/N
92-310054-3002)
L1/L2 GPS
82-001002-3002)
Antenna Cable (
Antenna
P/N
94-310058-3012)
1-9
RT-3020 User Guide - Rev. E
[
SSR
\
2.4GHz Radio Antenna (
LEMO
(
7 Pin to DB9S Data Communications Cable
P/N
94-310059-3006)
P/N
82-001000-0003)
] CD-Rom (
Guides to NavCom Technology, Inc. product line,
brochures, software utilities, and technical papers.
^
LEMO
12vdc 2 amp (
P/N
96-310006-3001) containing User
4-Pin Univerasal AC/DC Power Adapter
P/N
82-020002-5001)
_ RT-3020 User’s Guide {Not Shown}
P/N
(Hard Copy
96-310005-3001)
` Ruggedized Travel Case {Not Shown}
(
P/N
79-100100-0002)
a
SSR
Antenna Adapter {Not Shown}
(
P/N
91-310020-3001
11 American 2-Pin AC power Cord {Not Shown}
1-10
RT-3020 User Guide - Rev. E
Applications
The RT-3020
number of applications including, but not limited to:
Land Survey / GIS
Asset Location
Hydrographic Survey
Photogrammetric Survey
Machine Control
Railway, Ship and Aircraft Precise Location
GPS
sensors meets the needs of a large
Unique Features
The RT-3020
Positioning Flexibility
The RT-3020 is capable of using two internal
Based Augmentation System
provide
European Geostationary Navigation Overlay Service
(EGNOS)
itself to use the most suitable correction source available
and changes as the survey dictates.
GPS
sensors have many unique features:
Satellite
(
SBAS
) channels that
Wide Area Augmentation System (WAAS)
code corrections. The RT-3020 configures
or
1-11
RT-3020 User Guide - Rev. E
Data Sampling
GPS L1
configuration and as an optional upgrade as fast as 10,
25, and 50Hz via either of the two serial ports. The
(Position, Time, & Velocity)
standard configuration and as an optional upgrade as
fast as 10, and 25Hz for high dynamic applications.
GPS
The NCT-2100
incorporates several patented innovations. The receiver
provides more than 50% signal to noise ratio advantage
over competing technologies. The benefit to the user is
improved real time positioning. Independent tests have
proven the NCT-2100 to be the best receiver when
facing various
Rugged Design
The rugged design of the RT-3020 system components
provides protection against the harsh environments
common to areas such as construction sites, offshore
vessels, and mines.
and L2 raw data is 1 to 5Hz in the standard
data is also 1 to 5Hz in the
Performance
GPS
engine at the heart of the RT-3020
multipath
environments.
PVT
Units have been tested to conform to MIL-STD-810F for
low pressure, solar radiation, rain, humidity, salt-fog,
sand, and dust.
1-12
RT-3020 User Guide - Rev. E
Chapter 2 Interfacing
This chapter details the RT-3020
connectors and status display. Appropriate sources of
electrical power, and how to interface the
communication ports.
GPS
sensor
Electrical Power
Electrical power is input thru a 4-pin
connector located on the front panel of the RT-3020,
and labeled ‘DC PWR.’ The pin designations are shown
in Table 1; see Figure 2 for pin rotation on unit.
Pin Description
1
2
3
Power Input 10 to 30 VDC
Return
LEMO
female
4
Table 1: External Power Cable Pin-Out
Pins 1 and 2 are connected together inside the RT-3020
GPS
sensor. Pins 3 and 4 are connected together inside
the
GPS
sensor.
When using an external power cable longer
than 5m (15ft), it is recommended that positive voltage
2-13
RT-3020 User Guide - Rev. E
DC be applied on both pins 3 and 4, and return on
both pins 1 and 2.
Navcom P/N 82-020002-5001 Universal AC/DC 12 V 2
Amp Power Adapter comes standard with the RT3020S/M GPS receivers. An optional external power
cable, NavCom
unterminated power cable fitted with a
(Mfr.
P/N
FGG.1K.304.CLAC50Z) and red strain relief, is
suitable for supplying power to the RT-3020
sensor. The wiring color code and pin designations are
labeled on this optional cable assembly.
The
GPS
sensor is protected from reverse polarity by an
inline diode. It will operate on any DC voltage between
10 and 30 VDC, capable of supplying the required
current, typically. Power Consumption of the RT-3020 is
typically 5 Watts Maximum.
P/N
94-310060-3010 a 3m (10ft)
LEMO
plug type
GPS
Voltages less than 10VDC will shut the unit down.
When power is restored, the ON switch will need to be
held down for more than 3 seconds.
0 Voltages in excess of 30VDC will damage the unit. It
is extremely important to ensure that the power
supply is well conditioned with surge protection. This
is especially true for vehicular electrical systems, which
can create voltage spikes far in excess of 30VDC.
2-14
RT-3020 User Guide - Rev. E
Communication Ports
The RT-3020
LEMO
connector communication ports labeled
and
COM
sensor as shown in Figure 2. Each conforms to the EIA
RS232 standard with data speeds between 1200
and 115.2kbps. The pin-outs for these connectors are
described in Table 2. An interface data cable (P/N 94310059-3006) is supplied with the RT-3020 for easy
startup. The cable construction is described in Figure 4.
LEMO
Pins
1 CTS___Clear To Send 8
2 RD____Receive Data 2
3 TD____Transmit Data 3
4 DTR___Data Terminal Ready 4
GPS
sensor is fitted with two 7-pin female
2 located at the bottom front of the
Signal Nomenclature
DCE
w/respect to
[
DB9S
]
COM
GPS
bps
DB9S
Pins
1
5 RTN___Return [Ground] 5
6 DSR___Data Set Ready 6
7 RTS___Request To Send 7
Table 2: Serial Cable Pin-Outs
2-15
RT-3020 User Guide - Rev. E
2-16
Figure 2: RT-3020 Front View
Figure 3: RT-3020M Only Back View
RT-3020 User Guide - Rev. E
Figure 4: NavCom Serial Cable 94-310059-3006
Pin 5 should connect to shield of cable at both ends.
Indicator Panel
Figure 5 RT-3020 Indicator Panel
The Indicator Panel provides the on/off (I/O) switch and
a quick view of the status of the RT-3020
corrections source & type, and radio signal strength.
Each of the three indicators has three
depict status as detailed in the following tables.
GPS
sensor,
LED
s, which
2-17
RT-3020 User Guide - Rev. E
To power the unit on or off, the I/O switch must be
depressed for more than 3 seconds. During power up of
GPS
the
seconds.
Link LEDs
sensor, all
LED
s will be on for a period of 3-5
The Link lights are software configurable via the
appropriate NavCom
the numerous scenarios available for the Link light, only
the factory default configuration [
discussed.
LINK Status
Command Mode
Rapidly repeating Red to Amber to Green
indicates Searching for base radio signal.
proprietary command
Rover
Mode] is
. Because of
Strong Signal Strength from the base radio.
Medium Signal Strength from base radio.
Weak Signal Strength from base radio.
Table 3: Link Light Indication
Base LEDs
If the RT-3020 has been configured as a
LED
the
produced. Where the color of the
format of the correction, the blink rate indicates
specifically which message is being sent. Table 4
s indicate the type of
RTK
corrections being
Base Station
LED
will indicate the
2-18
,
RT-3020 User Guide - Rev. E
n
illustrates the color, format, message, and blink rate of
the
LED
s for the type of corrections being output.
BASE Status Blink Rate
Rover mode N/A
NCT Proprietary 1Hz
CMR 1Hz
GPS LEDs
GPS
Status
Power is off.
Power is on. No satellites tracked.
Tracking satellites,
Non-differential positioning.
Code based differential positioning.
Dual frequency
RTCM
Table 4:
20,21=5Hz; 18,19=1Hz
Base statio
Phase positioning.
Indication
position
not available yet.
Table 5:
GPS
Light Indication
2-19
RT-3020 User Guide - Rev. E
The
GPS LED
selected.
s will blink at the positioning rate
1 PPS
The RT-3020M has the ability to output a precise pulse
every second that can be used for a variety of Time/
Mark applications where precise timing is critical.
Specifications:
- 12.5ns relative accuracy.
- Better than 100ns absolute accuracy.
- 50 Ohm, TTL level.
- Pulse width, default 100mS, range 10 – 999mS
- Pulse delay, default 0mS, range 0 – 999mS.
- Rising or Falling Edge Synchronization.
Connecting the 1
BNC male connector, NavCom
0.9m (3ft) long, BNC male to BNC male cable
PPS
output requires a cable with a
P/N
94-310050-3003
CAN Bus/Event
The RT-3020M also employs a balanced (differential) 2wire
CAN Bus
compliant. The
transmission scheme employing serial binary
interchange and is widely used in the automotive
industry. The data rate is defined as 250K
maximum with Termination resistors used at each end
of the cable. This port/connector is shared with the
Even
t Input.
technology interface, ISO11898 -24V
CAN
interface uses an asynchronous
bps
2-20
RT-3020 User Guide - Rev. E
As CAN Bus specifications are diverse, drivers for the
existing hardware must be tailored to the specific
manufacturer’s equipment being interfaced to. For
further information, e-mail NavCom Customer Support
at
customersupport@navcomtech.com
Event
The RT-3020M also can utilize an event input pulse to
synchronize any external incident that requires precise
GPS
time tagging, such as aerial photography. In this
case, the action of a camera’s aperture would output a
pulse to the
position and time information relative to when the
photograph was taken.
Specifications:
Event
port and have the receiver output
- 50 Ohm input impedance
- 3Vdc > Input Voltage, High < 6Vdc
.
- 0Vdc < Input Voltage, Low < 1.2Vdc
- Minimum pulse width, 100nsec
- Rising or Falling edge Synchronization
Connecting the shared EVT MKR/CAN BUS port
requires a five core, 5mm diameter, cable fitted with a
LEMO
plug, type FGG.0K.305.CLAC50Z, plus strain
relief, NavCom P/N 94-310062-3003.
Detailed specifications of the
cable wiring and how to configure the Event input may
be found in Appendix C of this User Guide
Event
Input and
2-21
RT-3020 User Guide - Rev. E
Chapter 3 Installation
This chapter provides guidance on hardware should be
installation for optimum performance.
Tri-Mode Antenna
The antenna is fitted with a 5/8” BSW threaded mount
with a depth of 16mm (0.63”). This should be used as
the primary means of mounting the antenna.
It is possible to remove the 5/8” BSW threaded alloy
insert to reveal the secondary means of mounting the
antenna which consists of a 1-14UNS-2B thread with a
depth of 16mm (0.63”) typically used in the marine
industry for navigation antenna.
Figure 6: Tri-Mode
GPS
Antenna
The eight Phillips screws on the base of the antenna
should NOT be loosened or used for mounting the
antenna as this will VOID the warranty and compromise
the environmental seal of the antenna, and lead to
internal damage.
3-22
RT-3020 User Guide - Rev. E
There should be an unobstructed view of the sky above
a 10-degree
visibility for
horizon should be mapped using a compass and
clinometer and used in satellite prediction software with
a recent satellite
satellite visibility at that location. Potential sources of
interference should also be avoided where possible.
Examples of interference sources include overhead
power lines, radio transmitters and nearby electrical
equipment.
elevation mask
RTK
use. Any obstructions above the
almanac
for optimum
to assess the impact on
GPS
satellite
3-23
RT-3020 User Guide - Rev. E
GPS Sensor
The RT-3020
surface using four screws spaced as per the following
diagram of the base plate. In environments with high
vibration, shock absorbers suitable for 1.8kg (4lbs)
should be considered.
Figure 7: RT-3020 Base Plate Dimensions
GPS
sensor can be mounted to a flat
The RT-3020S can be installed in a backpack for mobile
surveying applications.
The sensor should not be placed in a confined space or
where it may be exposed to excessive heat, moisture, or
humidity.
There are no user serviceable parts inside the RT-3020
GPS
sensor. Undoing the four screws, which secure the
front end plate, and the four securing the rear end plate
will void the equipment warranty.
3-24
RT-3020 User Guide - Rev. E
Basics of RTK Surveying
The idea behind
quality, low ambiguity accuracy of post-processed
position fixes, in a real time environment. In order to
accomplish this task, the
roving sensor must have its error sources inherent to
GPS
corrected as much as possible. These errors will be
accounted for virtually instantaneously; thus the Real
Time in
Setting up a
errors in a roving
would be set up on a known surveyed location, with
this position locked in. It would then transmit its code,
clock, and
the roving sensor. The roving sensor would use this
information to correct each
receives.
In the RT-3020 this link between the
and the
RTK
rover
Spectrum Radio
SSR
was designed specifically with
has built in interference rejection so any extraneous
radio signals will not interfere with the transmission of
the correction data.
RTK
surveys is to achieve the high
GPS
data collected at the
.
Reference (Base) Station
GPS
sensor. The reference
reference station
coordinate information to
GPS
can minimize
measurement it
reference station
is achieved via a 2-way, 2.4GHz
(
SSR
) integrated into the RT-3020. This
GPS RTK
GPS
GPS
sensor
Spread
in mind. It
The RT-3020 when configured as a
can transmit corrections to any number of
receivers
decoding one of the three
[
RTCM
2.4Ghz, data being broadcast via modulated radio
carrier frequency is limited to line of sight for error free
reception. However, the signal can be received in less
than ideal environments, though some data loss could
occur. The
sight range up to a maximum of 10km.
capable of picking up the radio signal and
GPS
, CMR, or NavCom proprietary] transmitted. At
SSR
integrated into the RT-3020 has a line of
reference sta ion
t
roving
correction formats
3-25
RT-3020 User Guide - Rev. E
When setting up the reference sensor, it is best to have
the
reference station
sensors since radio signals of such high frequency tend
to travel a shorter distance than their lower frequency
counterparts, and are apt not to penetrate obstructions
as well over distance. This also affords the reference
sensor to transmit to all
minimal obstruction. Figure 8 & 9 illustrates a proper
and improper
RTK reference station
sensor elevated above the roving
rove s
in all directions with
r
installation.
3-26
Figure 8: Good Line of Sight
Figure 9: Poor Line of Sight
RTK
RTK
setu
setup
p
RT-3020 User Guide - Rev. E
Communication Ports
Connect the supplied
serial cable (NavCom
(factory default Control Port) connector of the RT-3020.
Connect the
that some devices may require an additional adaptor, as
the receiver is configured as a DCE device.
DB9S
By factory default
the RT-3020.
control port by using the appropriate NavCom
proprietary commands
types, such as NMEA messages, cannot output on the
Control Port
COM 1
LEMO
7-Pin end of the NavCom
P/N
94-310059-3006) to
end to your controlling device. Note
COM 2
can be designated as the
. NOTE: Some output data
is the control port for
COM 2
Figure 10: Communication Port Connections
3-27
RT-3020 User Guide - Rev. E
GPS Antenna Connector
The connector used on the RT-3020 is a TNC female,
labeled “GPS ANT” on the front panel of the sensor as
shown in Figure 2.
The center pin of the TNC connector carries a voltage
of nominally 4.6 VDC, which is used to power the
GPS
preamplifier in the
powered on, the antenna cable should not be
disconnected.
The cable length between the RT-3020 and the TriMode antenna should not exceed more than 10dB loss
at 1.5GHz. Examples are:
Cable Type Maximum Length
RG58/U 13.7m (45ft)
LMR400 59.7m (196ft)
antenna. When the
GPS
unit is
NavCom cable P/N 94-310058-3012 provides a 3.6m
(12ft) length of RG58/U cable with a right angle male
TNC connector to a straight male TNC connector
GPS
suitable for connecting the RT-3020
Tri-Mode antenna.
In-line amplifiers suitable for all
used to increase the length of the antenna cable but
care should be exercised that tracking performance is
not degraded due to multiple connections and possible
ingress of moisture and dust.
GPS
sensor to the
frequencies may be
The antenna cable can degrade signal quality if
incorrectly installed, or the cable loss exceeds NavCom
specifications. Care should be taken not to kink, stretch
or damage the antenna cable. Do not place the cable
adjacent to cables carrying electrical power or radio
frequencies.
3-28
RT-3020 User Guide - Rev. E
0 Where the
electromagnetic discharge such as lightning, an in-line
electrical surge suppressor, properly grounded, should
be considered between the
Such installations should comply with local regulatory
codes and practices.
GPS
antenna is exposed to sources of
GPS
sensor and antenna.
3-29
RT-3020 User Guide - Rev. E
Chapter 4 Configuration
The RT-3020
detailed control language, which allows each unit to
be tailored specifically to the required application.
GPS
sensor has a rich interface and
Factory Default Settings
COM1
Configuration - Data port
Rate – 19.2Kbps
Output of NMEA messages GGA & VTG
scheduled @ 1Hz rate
COM2
Configuration - Control Port
Rate – 19.2Kbps
Input/output of Navcom Proprietary messages
used for Navigation and receiver setup. Table 6
describes the default messages that provide the
user the best opportunity to initiate surveying
with minimal effort.
The user has full control over the types of messages
utilized and their associated rates by using either
Navcom Technologies StarUtil or a third party
software/Utility.
4-30
RT-3020 User Guide - Rev. E
Message Rate Description
44
81
86
A0
AE
B0
B1
On
Change
On
Change
On
Change
On
Change
600
Seconds
On
Change
On
Change
Packed
Packed
Channel
Alert Text Message
Identification Block
Raw Measurement Data
Almanac
Ephemeris
Status
PVT
Block
COM
Table 6: Factory Setup Proprietary Messages
2
The term “On Change” indicates that the RT-3020 will
output the specified message only when the
information in the message changes. Thus in some
cases, there may be an
output.
44 Packed
corresponding to each satellite in the
constellation. This information includes
number of
Almanac
almanac
4-31
epoch
without a message block
: This message provides data
GPS
GPS
Week
collected,
GPS
Time of week [in
RT-3020 User Guide - Rev. E
seconds] that
reference week,
source,
4 & 5.
almanac
almanac
was collected,
almanac
health, pages 1-25, and subframes
reference time,
almanac
almanac
81 Packed
information as it relates to individual satellites
tracked, including
collected,
ephemeris
2, & 3 data.
86
A0 Alert Text Message: Details if a message has
AE Identification Block: Details the receiver software
B0 Raw Measurement Data: Raw Measurement Data
Channel
information and contains the
of Week, NCT-2100 Engine status, solution status,
number of satellites being tracked and the number
and identity of satellites used in solution,
the satellite
been properly received and processed.
versions.
Block that contains the
Week, Time Slew Indicator, Status,
CA
Pseudorange
Pseudorange
CA
repeated for any additional satellite.
Ephemeris
GPS
Time of week [in seconds] that
was collected, IODC, and Sub-frame 1,
Status: Provides receiver
PRN
: This message provides
GPS
Week number of
GPS
week,
.
GPS
Week,
, L1 Phase, P1-CA
, and L1 Phase. This data stream is
ephemeris
channel
GPS
status
Time
PDOP
GPS
Time of
Channel
Status,
Pseudorange
and
, P2-
B1
PVT
: Provides
latitude, longitude, navigation mode, and
information.
GPS
Week number, satellites used,
4-32
DOP
RT-3020 User Guide - Rev. E
Advanced Configuration Settings
If a third party
your RT-3020
manual/user’s guide.
Controller
GPS
sensor, please refer to that
solution was provided with
4-33
RT-3020 User Guide - Rev. E
Chapter 5 Safety Instructions
The RT-3020
navigation and positioning using the
Positioning System
of portable
these safety instructions prior to use of this equipment.
GPS
sensor is designed for precise
Global
. Users must be familiar with the use
GPS
equipment, the limitations thereof and
FCC Notice
This device complies with Part 15 of the FCC Rules.
Operation is subject to the following two conditions:
(1) this device may not cause harmful interference, and
(2) this device must accept any interference received,
including interference that may cause undesired
operation.
Transport
The NavCom equipment should always be carried in its
case. The case must be secured whilst in transit to
minimize shock and vibration.
All original packaging should be used when
transporting via rail, ship, or air.
5-34
RT-3020 User Guide - Rev. E
Maintenance
The NavCom equipment may be cleaned using a new
lint free cloth moistened with pure alcohol.
Connectors must be inspected, and if necessary cleaned
before use. Always use the provided connector
protective caps to minimize moisture and dirt ingress.
Cables should be regularly inspected for kinks and cuts
as these may cause interference and equipment failure.
Damp equipment must be dried at a temperature less
than +40C (104F), but greater than 5C (41F) at the
earliest opportunity.
External Power Source
The RT-3020 is supplied with an external power cable
(
P/N
94-310060-3010). This must be connected to the
chosen external power solution in accordance with
Chapter 2 Interfacing\Electrical Power. It is important
that the external power source allow sufficient current
draw for proper operation. Insufficient supplied current
will cause damage to your external power source.
If your chosen external power source is a disposable
battery, please dispose of the battery in accordance
with your local regulations.
Safety First
The owner of this equipment must ensure that all users
are properly trained prior to using the equipment and
are aware of the potential hazards and how to avoid
them.
5-35
RT-3020 User Guide - Rev. E
Other manufacturer’s equipment must be used in
accordance with the safety instructions issued by that
manufacturer. This includes other manufacturer’s
equipment that may be attached to NavCom
Technology Inc manufactured equipment.
The equipment should always be used in accordance
with local regulatory practices for safety and health at
work.
There are no user serviceable parts inside the RT-3020
GPS
sensor. Accessing the inside of the equipment will
void the equipment warranty.
Typically the RT-3020 may be mounted in a backpack,
the crew cab of construction machinery, or if
configured as a reference station on a building top.
Care should be taken to ensure that the RT-3020 does
not come into contact with electrical power
installations, the unit is securely fastened and there is
protection against electromagnetic discharge in
accordance with local regulations.
The
GPS
sensor has been tested in accordance with FCC
regulations for electromagnetic interference. This does
not guarantee non-interference with other equipment.
Additionally, the
by nearby sources of electromagnetic radiation.
Global Positioning System
The
the United States Air Force. Operation of the
satellites may be changed at any time and without
warning.
GPS
sensor may be adversely affected
is under the control of
GPS
5-36
RT-3020 User Guide - Rev. E
A
The technical specifications of this unit are detailed
below. NavCom Technology, Inc. is constantly
improving, and updating our technology. For the latest
technical specifications for all products go to:
GPS
Sensor Technical Specifications
support.navcomtech.com
RT-3020S and RT-3020M
These
coin cell used to maintain
removed from the unit. This allows faster satellite
acquisition upon unit power up. The cell has been
designed to meet over 10 years of service life before
requiring replacement at a NavCom approved
maintenance facility.
GPS
sensors are fitted with an internal Lithium
GPS
time when power is
Features
• “All-in-view" tracking with 26 channels
(12 L1 GPS + 12 L2 GPS + 2 SBAS)
• L1 &
• C/A, P1 & P2 code tracking
• Proprietary RTK processing with on-the-fly
initialization
• Fast ambiguity resolution
• Units are user configurable as base or rover
• User programmable output rates
• Built-in Spread Spectrum Radio (SSR)
• External 12VDC power
• 64 MB internal memory to record field data
• NavCom compact RTK format or standard RTCM v2.2
• Output format NMEA 0183 or NavCom binary format
L2
full wavelength carrier phase tracking
or CMR formats
A-37
RT-3020 User Guide - Rev. E
• Superior interference suppression (both in-band &
out-of-band)
• Patented multipath rejection
• 2 separate WAAS/EGNOS channels
• Self-survey mode (position averaging)
• Compact Physical Size
• CAN bus interface (RT-3020M Only)
• 1PPS output (RT-3020M Only)
• Event Marker input (RT-3020M Only)
Physical and Environmental
• Size (L x W x H): 8.18” x 5.67” x 3.06”
• Weight: 4lbs. (1.81 kg)
• External Power:
Input Voltage: 12 VDC nominal
(10VDC to 30VDC)
Consumption: 5 W
• Connectors
I/O Ports: 2 x 7-pin LEMO
DC Power: 4-pin LEMO
SSR Antenna: BNC
GPS Antenna TNC
(with 5 VDC bias for external/LNA)
CAN bus/Event Marker: 5-pin LEMO
(RT-3020M Only)
1PPS Output: BNC
(RT-3020M Only)
• Temperature (ambient)
Operating: -40º C to +55º C
Storage: -40º C to +85º C
• Humidity: 95% non-condensing
A-38
RT-3020 User Guide - Rev. E
Measurement Performance
GPS Receiver Performance
• RTK Accuracy (RMS)*
Position (H): < 1 cm + 1ppm
Position (V): < 2 cm + 1ppm
• Pseudo-range Measurement Precision (RMS):
Raw C/A code : 20cm @ 42 dB-Hz
Raw carrier phase noise: L1: 0.95 mm @ 42 dB-Hz
L2: 0.85 mm @ 42 dB-Hz
• Real-time DGPS (code) Accuracy** (RMS):
Position (H): 12 cm + 2ppm
Position (V): 25 cm + 2ppm
Velocity: 0.01 m/s
• User programmable output rates:
RT-3020S
PVT: 1, 2, 5Hz Standard
Optional, 10 & 25Hz
Raw data: 1, 2, 5Hz Standard
Optional, 10, 25, & 50Hz
RT-3020M
PVT: 1, 2, 5, 10Hz Standard
Optional, 25Hz
Raw data: 1, 2, 5, 10, 25Hz Standard
Optional, 50Hz
• Data Latency:
PVT: < 20 ms at all nav rates
Raw data: < 20 ms at all rates
• Time-to-first-fix:
Cold Start
Satellite Acquisition: < 60 Seconds (typical)
A-39
RT-3020 User Guide - Rev. E
Satellite Reacquisition: < 1 Second
• Dynamics:
Acceleration: up to 6g
Speed: < 515 m/s*
Altitude: < 60,000 ft*
• 1PPS Accuracy: 12.5nS (Relative; User Configurable)
(RT-3020M Only)
*Restricted by export laws
* Up to 10 km if using receivers as base & rover.
* * Up to 200 km if using receivers as base station &
mobile.
Built in Radio Performance
• Frequency Band: 2.400GHz - 2.485GHz
• Modulation: Frequency Hopping
Spread Spectrum ¿
• Data Rate: 9600bps (configurable)
• Transmit Power: 1-Watt max
• Receiver Sensitivity: -105dBm
• Range @ Max. Power: 10km Line of Sight
• Maximum EIRP: 6dBW***
• Optional Pole-Mount Antenna: 3db gain
*** Using high gain antenna
¿EIRP and hopping bandwidth restrictions vary
depending on local regions. Contact NavCom
Technology, Inc. for regulations in your local area.
A-40
RT-3020 User Guide - Rev. E
Connector Assignments
•Data Interfaces:
2 serial ports; from 1200 bps to 115.2 kbps
CAN Bus I/F (RT-3020M Only)
Event Marker I/P (RT-3020M Only)
1PPS (RT-3020M Only)
• Com Port Functions
NCT Proprietary Control, Data
Input/Output Data Messages
• NCT Proprietary Data: PVT
Raw Measurement
Satellite Messages
Nav Quality
Receiver Commands
• NMEA Messages ALM, GGA, GLL, GSA,
(Output Only): GSV, RMC, VTG, ZDA, GST
Proprietary NMEA Type SET
(Output Only)
• Code Corrections: RTCM 1 or 9
WAAS/EGNOS
• RTK Correction Data: NCT Proprietary
RTCM 18/19 or 20/21
CMR+/CMR (Msg. 0, 1, 2)
LED Display Functions (Default)
Link: Base Signal Strength
Base: Type of Correction/Rate
Rover; = N/A
GPS: Position Quality
A-41
RT-3020 User Guide - Rev. E
Satellite Based Augmentation System Signals
• WAAS/EGNOS
A-42
RT-3020 User Guide - Rev. E
B GPS Antenna Technical Specifications
The standard antenna supplied with the RT-3020
sensor is capable of Tri-Mode reception.
GPS
L1+L, L2 GPS Antenna
1525-1585 MHz GPS L1 plus Inmarsat L Band
1217-1237 MHz GPS L2
L1 Phase Centre 58.7mm
Polarization Right Hand Circular (RHCP)
Finish Fluid resistant Ultem, UV stable
Cable Connector TNC Female
Pre–Amplifier 39dB gain (+/-2)
Input Voltage 4.2 to 15.0 VDC
Impedance 50 Ohms
VSWR 2.0:1
Band Rejection 20 dB @ 250MHz
Power Handling 1 Watt
Operating Temp -55C to +85C
Altitude 70,000’
NavCom
mount antenna, also rated to 70,000 feet.
P/N
82-001002-3001 is an optional aircraft
Designed to DO-160D Standard
B-43
RT-3020 User Guide - Rev. E
Figure B1: Tri-Mode Antenna Dimensions
In order to achieve the greatest level of accuracy, the
absolute
into your processing. For
the Tri-Mode Antenna go to
phase center
Navcomtech.com/support.cfm
B-44
values must be incorporated
phase center
information for
RT-3020 User Guide - Rev. E
C Event Input Configuration
Figure D1 details the wiring of the Event/Can cable
assembly NavCom part number P/N 94-310062-3003.
Refer to Chapter 2, Event for detailed electrical
specifications.
Table D1 details the wiring configuration required for
Event-Hi, and Event-Lo pulse sensing.
Figure C1: Event Cable Wiring Diagram
Pin #
1 Event Lo Tie Event-Hi to Ground
2 Event Hi Tie Event-Lo to Ground
3 Ground N/A
Once the cable is wired to correspond with the event
pulse requirements, the receiver must be configured to
output the message containing a time mark, referenced
to the time kept within the receiver, indicating when
the event is sensed.
Signal
Name
Table C1: Event Wiring Connections
Event Sync Wiring
C-45
RT-3020 User Guide - Rev. E
The Event Input can be triggered on the Rising or
Falling edge of the input pulse. Configuration is
possible thru Navcoms StarUtil program. Figure D2
shows a screen capture of the programs PPS & Event
Latch window.
Figure C2: PPS & Event Latch Configuration
Next, the Event Latch message (0xB4) must be enabled
in the NCT 2000 Message Output list. The Message
Rate for the 0xB4 must be set to “On Trigger”. This is
carried out by Right- Clicking on the Rate area adjacent
to the B4 Message ID, and following the menus as seen
in Figure C3. Once configured. t
he Event Latch
Message 0xB4 will only be output when the chosen
pulse edge of the incoming event is sensed by the
receiver.
Figure C3: Event Latch Output Rate Configuration
C-46
RT-3020 User Guide - Rev. E
Glossary
.yym files see meteorological files (where yy = two digit
year data was collected).
.yyn files see navigation files (where yy = two digit year
data was collected).
.yyo files see observation files (where yy = two digit
year data was collected).
almanac files an almanac file contains orbit
information, clock corrections, and atmospheric delay
parameters for all satellites tracked. It is transmitted to a
receiver from a satellite and is used by mission planning
software.
alt see
altitude vertical distance above the
is always stored as height above
receiver but can be displayed as height above
(HAE) or height above
antenna phase center (APC) The point in an antenna
where the
height above ground of the APC must be measured
accurately to ensure accurate
height can be calculated by adding the height to an
easily measured point, such as the base of the antenna
mount, to the known distance between this point and
the APC.
APC see
Autonomous positioning (
in which a
time from satellite data alone, without reference to data
altitude
.
ellipsoid
ellipsoid
mean sea level (MSL
GPS
signal from the satellites is received. The
GPS
readings. The APC
in the
).
antenna phase center or phase center
GPS
) a mode of operation
GPS
receiver computes
position
fixes in real
or
geoid
GPS
ellipsoid
.
. It
Glossary-47
RT-3020 User Guide - Rev. E
supplied by a
corrections.
least precise positioning procedure a
perform, yielding
meters with Selective Availability on, and 30 meters
with S/A off.
azimuth the
the angle between the
in a clockwise direction from the north branch of the
meridian
base station see
baud rate (
received each second. For example, a
means there is a data flow of 9600 bits each second.
One character roughly equals 10 bits.
bits per second see
bps see
reference station
Autonomous positioning
position
azimu h
t
fixes that are precise to 100
of a line is its direction as given by
meridian
.
reference station
bits per second
) the number of bits sent or
baud rate.
baud rate
.
or orbital clock
is typically the
GPS
receiver can
and the line measured
.
baud rate
of 9600
BSW (British Standard Whitworth) a type of coarse
BSW
screw thread. A 5/8” diameter
mount for survey instruments.
C/A code see
CAN BUS a balanced (differential) 2-wire interface that
uses an asynchronous transmission scheme. Often used
for communications in vehicular applications.
channel a
circuitry necessary to receive the signal for a single
satellite.
civilian code see
Coarse Acquisition code (C/A or
Coarse Acquisition code
channel
of a
GPS
receiver consists of the
Coarse Acquisition code
is the standard
.
.
Civilian code
GPS
)
Glossary-48
RT-3020 User Guide - Rev. E
the pseudo-random code generated by
is intended for civilian use and the accuracy of readings
using this code can be degraded if
(
S/A
) is introduced by the US Department of Defense.
COM# shortened form of the word Communications.
Indicated a data communications port to/from the
sensor to a
controller a device consisting of hardware and software
used to communicate and manipulate the I/O functions
of the
Compact Measurement Record (CMR) a standard
format for
corrections from a
data files files that contain Proprietary,
RTCM,
datum A reference datum is a known and constant
surface which can be used to describe the location of
unknown points. Geodetic datums define the size and
shape of the earth and the origin and orientation of the
coordinate systems used to map the earth.
DB9P a type of electrical connector containing 9
contacts. The P indicates a plug pin (male).
DB9S a type of electrical connector containing 9
contacts. The S indicates a slot pin (female).
DGPS see
Differential
uses two receivers, a
a
reference s ation
reference station
GPS
controller
sensor.
DGPS
or data collection device.
corrections used to transmit
reference station
or any type of data logged from a
Differential GPS
GPS (DGPS
at a known, fixed location. The
t
computes corrections based on the
.
) a positioning procedure that
rover
at an unknown location and
GPS
satellites. It
selective availability
GPS
to
rover
sensors.
GPS
, NMEA,
GPS
receiver.
Glossary-49
RT-3020 User Guide - Rev. E
actual and observed ranges to the satellites being
tracked. The coordinates of the unknown location can
be computed with sub-meter level precision by
applying these corrections to the satellite data received
by the
Dilution of Precision (
magnitude of error in
orientation of the
receiver. There are several
components of the error. Note: this is a unitless value.
see also
DOP see
dual-frequency a type of
L1 and L2 signals from
receiver can compute more precise position fixes over
longer distances and under more adverse conditions
because it compensates for ionospheric delays. The RT3020 is a dual frequency receiver.
dynamic mode when a
dynamic mode
certain algorithms for
order to calculate a tighter
EGNOS (European Geostationary Navigation Overlay
Service) a European satellite system used to augment
the two military satellite navigation systems now
operating, the US
elevation distance above or below Local Vertical
Datum.
elevation mask the lowest
which a receiver can track a satellite. Measured from
the horizon to zenith, 0º to 90º.
rover
.
DOP
GPS position
GPS
satellites with respect to the
PDOP
.
Dilution of Precision
GPS
, it assumes that it is in motion and
GPS position
GPS
and Russian GLONASS systems.
) a class of measures of the
fixes due to the
DOP
s to measure different
.
GPS
receiver that uses both
satellites. A
GPS
receiver operates in
position
elevation
dual-frequency
fixing are enabled in
fix.
, in degrees, at
GPS
Glossary-50
RT-3020 User Guide - Rev. E
ellipsoid a mathematical figure approximating the
earth’s surface, generated by rotating an ellipse on its
GPS
minor axis.
WGS-84
which does not match the earth’s geoidal surface
closely, so
large vertical error component. Conventionally surveyed
positions usually reference a
undulating surface and approximates the earth’s surface
more closely to minimize
epoch literally a period of time. This period of time is
defined by the length of the said period.
geoid the gravity-equipotential surface that best
approximates
the earth. The surface of a
for
ellipsoid
geoid
calculating the distance between the
ellipsoid
ellipsoid
GPS
readings, which are measured relative to an
. Conventionally surveyed positions reference a
. More accurate
at each
GPS altitude
positions are computed relative to the
. An
ellipsoid
GPS altitude
measurements can contain a
mean sea level
GPS
position
measurement.
has a smooth surface,
geoid
, which has an
altitude
geoid
readings can be obtained by
and subtracting this from the
errors.
over the entire surface of
is too irregular to use
geoid
and
GIS (Geographical Information Systems) a computer
system capable of assembling, storing, manipulating,
updating, analyzing and displaying geographically
referenced information, i.e. data identified according to
their locations. GIS technology can be used for scientific
investigations, resource management, and
development planning. GIS software is used to display,
edit, query and analyze all the graphical objects and
their associated information.
Global Positioning System (GPS) geometrically, there
can only be one point in space, which is the correct
distance from each of four known points.
the distance from a point to at least four satellites from
GPS
measures
Glossary-51
RT-3020 User Guide - Rev. E
a constellation of 24 NAVSTAR satellites orbiting the
earth at a very high
to calculate the point’s
GMT see Greenwich Mean Time.
GPS see
GPS time a measure of time.
UTC
correct for changes in the earth’s period of rotation. As
of September 2002
UTC
Greenwich Mean Time (
meridian
HAE see
JPL Jet Propulsion Laboratory.
Global Positioning System
, but does not add periodic ‘leap seconds’ to
.
passing through Greenwich, England.
altitude
altitude
GPS
, and
. These distances are used
position
time is 13 seconds ahead of
ellipsoid
.
.
GPS
time is based on
GMT
) the local time of the 0°
.
Kbps kilobits per second.
L-Band the group of radio frequencies
extending from approximately 400MHz to
approximately 1600MHz. The
frequencies L1 (1575.4MHz) and L2 (1227.6
MHz) are in the
L1 carrier frequency the primary
by
GPS
satellites to transmit satellite data. The
frequency is 1575.42MHz. It is modulated by
P-code or Y-code, and a 50 bit/second navigation
message.
L2 carrier frequency the secondary
GPS
by
frequency is 1227.6MHz. It is modulated by
Y-code, and a 50 bit/second navigation message.
satellites to transmit satellite data. The
L-Band
range.
GPS
carrier
L-Band
L-Band
carrier used
C/A code
carrier used
P-code
Glossary-52
,
or
RT-3020 User Guide - Rev. E
lat see latitude.
latitude (lat) the north/south component of the
coordinate of a point on the surface on the earth;
expressed in angular measurement from the plane of
the equator to a line from the center of the earth to the
point of interest. Often abbreviated as Lat.
LED acronym for Light Emitting Diode.
LEMO a type of connector.
LES Land Earth Station the point on the earth’s surface
where data is up linked to a satellite.
logging interval the frequency at which positions
generated by the receiver are logged to
long see longitude.
longitude (
coordinate of a point on the surface of the earth;
expressed as an angular measurement from the plane
that passes through the earth’s axis of rotation and the
0°
meridian
of rotation and the point of interest. Often abbreviated
Long
as
Mean Sea Level (
sea level.
meridian one of the lines joining the north and south
poles at right angles to the equator, designated by
degrees of longitude, from 0° at Greenwich to 180°.
meteorological (.YYm) files one of the three file types
that make up the
the last two digits of the year the data was collected. A
meteorological file contains atmospheric information.
long
) the east/west component of the
and the plane that passes through the axis
.
MSL
) a vertical surface that represents
RINEX
file format. Where YY indicates
data files.
Glossary-53
RT-3020 User Guide - Rev. E
MSL see
multipath error a positioning error resulting from
interference between radio waves that has traveled
between the transmitter and the receiver by two paths
of different electrical lengths.
navigation (.YYn) files one of the three file types that
make up the
last two digits of the year the data was collected. A
navigation file contains satellite
information.
observation (.YYo) files one of the three file types that
make up the
last two digits of the year the data was collected. An
observation file contains raw
P/N Part Number.
P-code the extremely long pseudo-random code
generated by a
by the U.S. military, so it can be encrypted to Y-code
deny unauthorized users access.
parity a method of detecting communication errors by
adding an extra parity bit to a group of bits. The parity
bit can be a 0 or 1 value so that every byte will add up
to an odd or even number (depending on whether odd
or even parity is chosen).
PDA Personal Digital Assistant.
Mean sea level.
RINEX
RINEX
file format. Where YY indicates the
file format. Where YY indicates the
GPS
satellite. It is intended for use only
position
and time
GPS position
information.
PDOP see
PDOP mask the highest
computes positions.
Position Dilution of Precision
Glossary-54
.
PDOP
value at which a receiver
RT-3020 User Guide - Rev. E
phase center the point in an antenna where the
signal from the satellites is received. The height above
ground of the
accurately to ensure accurate
center
height can be calculated by adding the height to
an easily measured point, such as the base of the
antenna mount, to the known distance between this
point and the
Position the latitude, longitude, and
An estimate of error is often associated with a
Position Dilution of Precision (PDOP) a measure of
the magnitude of Dilution of Position (
the x, y, and z coordinates.
Post-processing a method of differential data
correction, which compares data logged from a known
reference point to data logged by a
the same period of time. Variations in the
reported by the
the positions logged by the
processing is performed after you have collected the
data and returned to the office, rather than in real time
as you log the data, so it can use complex, calculations
to achieve greater accuracy.
Precise code see
PRN (Uppercase) typically indicates a
number sequence from 1 – 32.
prn (Lower Case) see Pseudorandom Noise.
Protected code
Proprietary commands those messages sent to and
received from
Technology, Inc. own copyrighted binary language.
phase center
phase center
reference station
P-code
see
P-code
GPS
equipment produced by NavCom
must be measured
GPS
readings. The
.
altitude
DOP
roving receiver
can be used to correct
roving receiver
.
GPS
.
) errors in
position
. Post-
satellite
GPS
phase
of a point.
position
.
over
Glossary-55
RT-3020 User Guide - Rev. E
pseudo-random noise (
appears to be randomly distributed but can be exactly
reproduced. Each
in its signals.
lock onto satellites and to compute their pseudoranges.
Pseudorange the apparent distance from the
station
the time the signal takes to reach the antenna by the
speed of light (radio waves travel at the speed of light).
The actual distance, or
because various factors cause errors in the
measurement.
PVT
in the NCT proprietary message format.
Radio Technical Commission for Maritime Services
range the distance between a satellite and a
receiver’s antenna. The
the
atmospheric conditions which slow down the radio
waves, clock errors, irregularities in the satellite’s orbit,
and other factors. A
determined if you know the ranges from the receiver to
at least four
be one point in space, which is the correct distance
from each of four known points.
RCP a NavCom Technology, Inc. proprietary processing
technique in which carrier phase measurements, free of
Ionospheric and Troposphere effects are used for
navigation.
’s antenna to a satellite, calculated by multiplying
GPS
information depicting Position, Velocity, Time
see
RTCM
pseudorange
GPS
GPS
receivers use
.
. However, errors can be introduced by
GPS
satellites. Geometrically, there can only
prn
) a sequence of data that
satellite transmits a unique
PRN
s to identify and
range
, is not exactly the same
range
is approximately equal to
GPS
receiver’s location can be
PRN
reference
GPS
Real-Time Kinematic (
very accurate 3D
The
base station
position
transmits its
Glossary-56
RTK
) a
GPS
system that yields
fixes immediately in real-time.
GPS position
to
roving
RT-3020 User Guide - Rev. E
receivers
receivers
correct their own positions. Accuracies of a few
centimeters in all three dimensions are possible.
requires
radio modems.
reference station a
for a fixed, known location. Some of the errors in the
GPS
positions recorded at the same time by
which are relatively close to the
reference station
accuracy of
RHCP Right Hand Circular Polarization used to
discriminate satellite signals.
RINEX (Receiver Independent Exchange) is a file set
of standard definitions and formats designed to be
receiver or software manufacturer independent and to
promote the free exchange of
format consists of separate files, the three most
commonly used are: the observation
(.YYo) file, the navigation (.YYn) file, and the
meteorological (.YYm) files; where YY indicates the last
two digits of the year the data was collected.
rover any mobile
collecting data in the field. A
can be differentially corrected relative to a stationary
reference
corrections from a
roving receiver see
as the receiver generates them, and the
use the
dual frequency GPS
positions for this location can be applied to
base station
readings to differentially
receivers and high speed
reference station
collects
GPS
roving receivers
reference station
is used to improve the quality and
GPS
data collected by
GPS
receiver and field computer
roving receive s. r
GPS
signals are RHCP.
GPS
data. The
RINEX
roving receiver’s position
GPS
receiver or by using
SBAS
such as StarFire.
rover
.
GPS
orbit and clock
roving
RTK
data
. A
file
Glossary-57
RT-3020 User Guide - Rev. E
RTCM
(Radio Technical Commission for Maritime Services)
a standard format for
to transmit corrections from a
RTCM allows both
collection and post-processed differential data
collection. RTCM SC-104 (RTCM Special Committee
104) is the most commonly used version of RTCM
message.
RTK see
RTG Real Time GIPSY, a processing technique
developed by NASA’s Jet Propulsion Laboratory to
provide a single set of real time global corrections for
the
S/A see
SBAS (Satellite Based Augmentation System) this is
a more general term, which encompasses
StarFire
Real-time kinematic
GPS
satellites.
Selective availability
and
EGNOS
Differential GPS
base station
real-time kinematic (RTK
.
.
type corrections.
corrections used
to
rovers
.
) data
WAAS
,
Selective Availability (S/A) deliberate degradation of
GPS
the
Department of Defense uses
errors, which can cause positions to be inaccurate by as
much as 100 meters.
Signal-to-Noise Ratio (
signal strength.
single-frequency a type of receiver that only uses the
L1
effects.
SNR see
signal by encrypting the
SNR
GPS
signal. There is no compensation for ionospheric
signal-to-noise
Ratio.
P-code
S/A
, the signal contains
) a measure of a satellite’s
. When the US
Glossary-58
RT-3020 User Guide - Rev. E
StarFire a set of real-time global orbit and clock
corrections for
receivers are capable of real-time decimeter positioning
(see Appendix B).
Spread Spectrum Radio (SSR) a radio that uses wide
band, noise like (pseudo-noise) signals that are hard to
detect, intercept, jam, or demodulate making any data
transmitted secure. Because spread spectrum signals are
so wide, they can be transmitted at much lower spectral
power density (Watts per Hertz), than narrow band
transmitters.
SV (Space Vehicle) a
Universal Time Coordinated (
maintained by the US Naval Observatory, based on
local solar mean time at the Greenwich
time is based on
UTC see
WAAS (Wide Area Augmentation System) a set of
corrections for the
Americas region. They incorporate satellite orbit and
clock corrections.
GPS
satellites. StarFire equipped
GPS
satellite.
UTC
UTC
.
Universal time coordinated
GPS
satellites, which are valid for the
) a time standard
meridian. GPS
.
WAD
GPS (Wide Area Differential GPS
GPS
corrections for the
wide geographic area.
WGS-84 (World Geodetic System 1984) the current
standard datum for global positioning and surveying.
The WGS-84 is based on the GRS-80
Y-code the name given to encrypted
U.S. Department of Defense uses
satellites, which are valid for a
) a set of
ellipsoid
P-code
.
when the
selective availability.
Glossary-59
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