NavCom SF-2050 User Manual Rev.D

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NavCom Technology, Inc.

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

[e-mail]
www.navcomtech.com

SF-2050 User Guide - Rev. D

Table of Contents

Table of Contents ................................................. i

Notices................................................................. iii

Chapter 1 Introduction.................................... 9

System Overview..................................................... 9

Applications .......................................................... 13

Unique Features .................................................... 13

Chapter 2 Interfacing..................................... 15

Electrical Power ..................................................... 15

Communication Ports............................................ 17

Indicator Panel ......................................................19

1 PPS..................................................................... 22

CAN Bus/Event...................................................... 22

Chapter 3 Installation .................................... 24

Tri-Mode Antenna ................................................. 24

GPS Sensor............................................................ 26

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

SF-2050G and SF-2050M ...................................... 37

LED Display Functions (Default)............................. 40

B GPS Antenna Technical Specifications ...... 41

L1+L, L2 GPS Antenna ......................................... 41

C StarFire ..................................................... 43

Description............................................................ 43

How to Access the

D Event Input Configuration ......................... 49

StarFire

 Service...................... 46

i

SF-2050 User Guide - Rev. D

Glossary .............................................................. 51

ii

SF-2050 User Guide - Rev. D

Notices

SF-2050

P/N

Revision D April 2005

Serial Number:

Date Delivered:

GPS

Products User Guide

96-310002-3001

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

iii

SF-2050 User Guide - Rev. D

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.

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.

iv

SF-2050 User Guide - Rev. D

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.,
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.

v

SF-2050 User Guide - Rev. D

This limited warranty period is one (1) year from date of
purchase.

StarFire

The
be purchased in order to access the service. Licenses are
non-transferable, and are subject to the terms of the

StarFire

on the
and conditions visit
email inquiry to

 Licensing

StarFire

 signal requires a subscription that must

™ Signal License agreement. For further details

StarFire

™ Signal Network, its capabilities, terms

www.navcomtech.com

or send an

[e-mail]

USG FAR

Technical Data Declaration (Jan 1997)

vi

SF-2050 User Guide - Rev. D

Global Positioning System

Selective availability (S/A

GPS

UTC

Sensor.

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
SF-2050

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
familiar with the concepts of
equipment.

GPS

and satellite surveying

 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.

vii

SF-2050 User Guide - Rev. D

Items that have been

ITALICIZED

indicate a term or

acronym that can be found in the Glossary.

Revisions to this User Guide can be obtained in a digital
format from

support.navcomtech.com

viii

SF-2050 User Guide - Rev. D

Chapter 1 Introduction

The SF-2050
to the precise positioning community who need a
cost-effective, high performance
unique receivers use the
worldwide

position

anytime.

GPS

sensor delivers unmatched accuracy

GPS

sensor. These

StarFire

SBAS

system, for instant decimeter level

accuracy, virtually anywhere in the world,

 Network, NavCom’s

System Overview



GPS

Sensor

The SF-2050 sensor consists of a 10-

frequency

channels for receiving

System (SBAS)

reception of NavCom’s
service, for instant decimeter-level position accuracy,
anywhere in the world, anytime. The sensor can output
proprietary raw data as fast as 50Hz (optional) and

Position Velocity Time (PVT

(optional) through two 115kbps serial ports. NavCom's
SF-2050 model sensors deliver unmatched positioning
accuracy to system integrators needing a cost-effective,
high performance differential

precision

signals and an

GPS

sensor with two additional

Satellite Based Augmentation

L-Band

StarFire

) data as fast as 25Hz

GPS

channel dual

demodulator for

 Network correction

sensor.

The SF-2050 has a built-in
reception of NavCom’s
service giving an immediate solution for the system
integrator. Additionally, the sensor simultaneously
accepts corrections for
seamless position output.

L-Band

StarFire

demodulator for

 Network correction

DGPS (WAAS/EGNOS)

assuring

1-9

SF-2050 User Guide - Rev. D

The SF-2050G is packaged for mobility. It can be used
for

Geographical Information System (GIS),

hydrographic surveying, and

frequency

backpack with the antenna either pole-mounted from
the backpack or on a survey pole with a single cable
connection.

The SF-2050M is ideal for vehicle mounting to suit a
wide variety of machine guidance and control
applications in agriculture, mining, aerial, and
hydrographic surveying. It is equipped with additional
features allowing interconnectivity with a wide variety
of antennas, vehicle data busses and other
instrumentation to suit specific applications and
configurations. The SF-2050M also has a 1
port and a combined

Both SF-2050 models can output proprietary raw data
as fast as 50Hz (optional) and
(

PVT

115kbps serial ports with less than 20ms latency. The
horizontal accuracy of 1 cm or better and the vertical
accuracy of 2 cm or better are maintained as each
output is independently calculated based on an actual

GPS

position measurement, as opposed to an

extrapolation between 1Hz measurements.

surveys. The sensor can be carried in a

Event/CAN Bus

) data as fast as 25Hz (optional) through two

post-processed dual

interface port.

Position Velocity Time

aerial and

-

PPS

output

 Integrated

The all-in-one housing incorporates our compact
antenna with excellent tracking performance and a
stable phase center for
housing assembly features a standard 5/8”
for mounting directly to a surveyor’s pole, tripod, or
mast and is certified to 70,000 feet.

GPS

and Inmarsat Band Antenna

GPS

L1 and L2. The robust

BSW

1-10

GPS

thread

SF-2050 User Guide - Rev. D

 Although rated to 70K feet, this antenna is not

designed for aircraft installations. E-Mail

[e-mail]

 Controller

for aircraft solutions.

The SF-2050
external Controller Solution connected via one of the
two

COM

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 Controller Solution for further
information.

 Included Items

GPS

sensor is designed for use with an

ports.

Personal Digital Assistant (PDA

GPS

products. see the

) and a

Figure 1: SF-2050 Supplied Equipment

1-11

SF-2050 User Guide - Rev. D

X SF-2050

(SF-2050G
(SF-2050M

Y Compact L1/L2 Tri-Mode

(

P/N

Z

GPS

[

LEMO

P/N

(

\

LEMO

P/N

(

] CD-Rom (

Guides to NavCom Technology, Inc. product line,
brochures, software utilities, and technical papers.

GPS

Sensor

P/N

92-310059-3001)

P/N

93-310059-3002)

GPS

Antenna

82-001000-0004)

Antenna Cable (

4-Pin External Power Cable

94-310060-3010)

7 Pin to

94-310059-3006)

P/N

96-310006-3001) containing User

P/N

94-310058-3012)

DB9S

Data Communications Cable

^ SF-2050 User’s Guide {Not Shown}

P/N

96-310002-3001)

_

1-12

(Hard Copy

Ruggedized Travel Case {Not Shown}

P/N

79-100100-0002)

(

SF-2050 User Guide - Rev. D

Applications

The SF-2050
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 meet the needs of a large

Unique Features

The SF-2050

StarFire



The ability to receive NavCom’s unique
correction service is fully integrated within each unit.
No additional equipment is required. A single set of
corrections can be used globally enabling a user to
achieve decimeter level positioning accuracy without
the need to deploy a separate
time and capital expenditure.

GPS

sensor has many unique features:

 [Subscription Required]

base station

StarFire

. Thus saving



 Positioning Flexibility

The SF-2050 is capable of using two internal

Based Augmentation System

provide

Wide Area Augmentation System (WAAS)
European Geostationary Navigation Overlay Service
(EGNOS)

code corrections. The SF-2050 self configures

(

SBAS

) channels that

Satellite

1-13

or

SF-2050 User Guide - Rev. D

itself to use the most suitable correction source available
and changes as the survey dictates.

 Data Sampling

GPS

L1 and L2 raw data is 1 to 5Hz in the standard
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



Performance

data is also 1 to5 Hz in the

PVT

The NCT-2000D
2050 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-2000D to be the best
receiver when facing various

 Rugged Design

The rugged design of the SF-2050 system components
provides protection against the harsh environments
common to areas such as construction sites, offshore
vessels, and mines.

Units have been tested to conform to MIL-STD-810F for
low pressure, solar radiation, rain, humidity, salt-fog,
sand, and dust.

GPS

engine at the heart of the SF-

multipath

environments.

1-14

SF-2050 User Guide - Rev. D

Chapter 2 Interfacing

This chapter details the SF-2050
and status display. Appropriate sources of electrical
power, and how to interface the communication ports.

GPS

sensor connectors

Electrical Power

The electrical power input comprises of a 4-pin
female connector located on the bottom front panel of
the SF-2050, and is labeled ‘DC PWR’ as shown in
Figure 2. The pin designations of this connector are
shown in Table 1; see Figure 2 for pin rotation on unit.

Pin Description

1 Return

2 Return

3 Power Input 10 to 30 VDC

LEMO

4 Power Input 10 to 30 VDC

Table 1: External Power Cable Pin-Out

 Pins 1 and 2 are connected together inside the SF-2050

GPS

sensor. Pins 3 and 4 are connected together inside

the

GPS

sensor.

2-15

SF-2050 User Guide - Rev. D

 When using an external power cable longer than

5m(15ft), it is recommended that positive voltage DC
be supplied on both pins 3 and 4, and return on both
pins 1 and 2.

NavCom
unterminated power cable fitted with a
(Mfr.
suitable for supplying power to the SF-2050
This cable is supplied with the SF-2050 series
sensors. The wiring color code and pin designations are
labeled on the cable.

The
inline diode. It will operate on any DC voltage between
10 and 30 VDC, which is capable of supplying the
required current. The sensor typically uses:

P/N

94-310060-3010 a 3m (10ft)

LEMO

plug type

P/N

FGG.1K.304.CLAC50Z) and red strain relief, is

GPS

GPS

GPS

sensor is protected from reverse polarity by an

0.87 Amps at 12VDC (10.4 Watts)

0.45 Amps at 24VDC (10.8 Watts)

0.38 Amps at 30VDC (11.4 Watts)

sensor.

 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.

2-16

SF-2050 User Guide - Rev. D

Communication Ports

The SF-2050

LEMO

connector communication ports labeled

and

COM

sensor as shown in Figure 2. Each conforms to the
RS232 standard with data speeds between 1200 bps
and 115.2kbps. The pin-outs for these connectors are
described in Table 2. An interface data cable (NavCom
P/N 94-310059-3006) is supplied with the SF-2050 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

[

DB9

]

COM

GPS

DB9S

Pins

EIA

1

5 RTN Return [Ground] 5

6 DSR Data Set Ready 6

7 RTS Request To Send 7

Table 2: Serial Cable Pin-Outs

2-17

SF-2050 User Guide - Rev. D

2-18

Figure 2: SF-2050 Front View

Figure 3: SF-2050M Only Back View

SF-2050 User Guide - Rev. D

Figure 4: NavCom Serial Cable

P/N

94-310059-3006

 Pin 5 should connect to shield of cable at both ends.

Indicator Panel

Figure 5: SF-2050 Indicator Panel

The Indicator Panel provides the on/off (I/O) switch and
a quick view of the status of the SF-2050
corrections source & type, and StarFire signal
strength. Each of the three indicators has three LEDs,
which depict status as detailed in the following tables.

GPS

sensor,

2-19

SF-2050 User Guide - Rev. D

To power the unit on or off, the on/off (I/O) switch
must be depressed for more than 3 seconds. During

GPS

power up of the
period of 3-5 seconds.

 Link LEDs

sensor, all LEDs will be on for a

 The Link lights are software configurable via the

appropriate NavCom proprietary command. Because of
the numerous scenarios available for the Link light, only
the factory default configuration [Rover Mode] is
discussed.

LINK Status

Command Mode

2-20

Repeating Red to Amber to Green indicates
Searching

Strong Signal Strength from

Medium Signal Strength

Weak Signal Strength

Table 3: Link Light Indication

StarFire

 signal

StarFire

StarFire

StarFire







SF-2050 User Guide - Rev. D

 Base LEDs

BASE Status

The BASE LEDs are not utilized in the

SF-2050

Table 4:



GPS LED

GPS

Power is off

Power is on, No satellites tracked

Tracking satellites,

Non-differential positioning

Code based differential positioning

s

Status

Dual frequency

GPS

sensor

Base station

position

Phase positioning

Indication

not available yet

 The

GPS

selected (1, 2, 5, 10 and 25 Hz).

Table 5:

LEDs will blink at the

GPS

Light Indication

PVT

positioning rate

2-21

SF-2050 User Guide - Rev. D

1 PPS

The SF-2050M has the ability to output a precise pulse
every second with a relative accuracy to within 12.5ns,
and an absolute accuracy better than 100ns. The 1
is 50 Ohm, TTL level. By using the appropriate NavCom

PPS

proprietary command, the 1
configurable between 0.01 and 0.50 seconds, with the
default width set to 0.10 seconds. The delay default is
set to 0.0 seconds from the
is configurable between 0.0 seconds and 0.999
seconds. This precise pulse can be used for a variety of
time mark applications where precise timing is a must.
The 1

PPS

pulse is user configurable to sync on the rising
or falling edge of the pulse. Connecting the 1
output requires a cable with a BNC male connector.

P/N

NavCom
long BNC male to BNC male connection.

94-310050-3003 provides a 0.9m (3ft)

pulse width is user

GPS

zero second mark and

PPS

PPS

CAN Bus/Event

The SF-2050M also employs
bus is a balanced (differential) 2-wire interface, and is
ISO11898 -24V compliant. The
asynchronous transmission scheme. This interface
employs a serial binary interchange and is widely used
in the automotive industry. The data rate for the SF­2050M
Termination resistors are used at each end of the cable.
This port/connector is shared with the

CAN Bus

is defined as 250K

CAN Bus

CAN

interface uses an

bps

technology.

maximum.

Even

t Input.

CAN

 As CAN Bus specifications are diverse, drivers for the

existing hardware must be tailored to the specific
manufacturer’s equipment being interfaced. For further
information on interfacing with the SF-2050M CAN Bus
hardware e-mail NavCom Customer Support at

[e-mail]

2-22

.

SF-2050 User Guide - Rev. D

The SF-2050M also can utilize an event input. This
input pulse can be used to synchronize any external

GPS

incident that requires precise
aerial photography. The action of a camera’s aperture
could send a pulse to the
and have it output position information relative to the
time the photograph was taken. It requires input
impedance of 50 Ohms, a minimum High Level Input of
3V (not exceeds 6V), and a minimum Low Level Input
of 1.2V. The minimum pulse width is 100nsec. The
Event Input latch can be configured to sync on the
rising, or falling edge of the event input pulse by using
the appropriate NavCom proprietary command.
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. This is available as NavCom P/N 94-310062-

3003. Detailed specifications of the
cable wiring can be found in Appendix D of this User
Guide.

Event

time tagging, such as

port of the SF-2050M

Event

Input and

2-23

SF-2050 User Guide - Rev. D

Chapter 3 Installation

This chapter provides guidance on how the hardware
should be installed for optimum performance.

Tri-Mode Antenna

The antenna is fitted with a 5/8 inch
mount with a depth of 16mm (0.63 inch). This should
be used as the primary means of mounting the
antenna.

It is possible to remove the 5/8 inch
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 inch) typically used in the marine
industry for navigation antennas.

BSW

threaded

BSW

threaded alloy

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. This will compromise the environmental seal

3-24

SF-2050 User Guide - Rev. D

of the antenna, may lead to internal damage and will
void the equipment warranty.

There should be an unobstructed view of the sky above
a 7-degree
visibility. Any obstructions above the horizon should be
mapped using a compass and clinometer and used in
satellite prediction software with a recent satellite

almanac

location. Potential sources of interference should be
avoided where possible. Example interference sources
include overhead power lines, radio transmitters and
nearby electrical equipment.

elevation mask

to assess the impact on satellite visibility at that

for optimum

GPS

satellite

To take full advantage of the
needs to be a clear line of sight between the antenna
and the local Inmarsat satellite. Inmarsat satellites are
geo-synchronized 35,768kms above the Equator
currently at Longitudes 098West, 025East, and
109East.

StarFire

 service, there

3-25

SF-2050 User Guide - Rev. D

GPS Sensor

The SF-2050
surface using the four screw slots shown in Figure 7. In
environments with high vibration, shock absorbers
suitable for 1.8kg (4lbs) should be considered.

GPS

sensor can be mounted to a flat

Figure 7: SF-2050 Base Plate Dimensions

The SF-2050G 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 SF-2050

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.

3-26

SF-2050 User Guide - Rev. D

Communication Ports

Connect the supplied
serial cable (NavCom
(factory default control port) connector of the SF-2050.
Connect the
that some devices may require an additional adaptor.

DB9S

 By factory default

port for the SF-2050.
control port by using the appropriate NavCom

proprietary commands

types cannot output on the controlling port.

LEMO

7-Pin end of the NavCom

P/N

94-310059-3006) to

end to your controlling device. Note

COM 2

is designated as the control

COM 1

can be designated as the

. Although some output data

COM 2

Figure 8: Communication Port Connections

3-27

SF-2050 User Guide - Rev. D

GPS Antenna Connector

The connector used on the SF-2050 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 4.4 VDC (nominally), which is used to power the

GPS

preamplifier in the
powered on, the antenna cable should not be
disconnected.

The cable length between the SF-2050 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. This

GPS

is suitable for connecting the SF-2050
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, noise from
the amplifier, and possible ingress of moisture and dust.

GPS

frequencies may be

sensor to the

 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

SF-2050 User Guide - Rev. D

0 Where the

electromagnetic discharge such as lightning, an in-line
electrical surge suppressor should be considered
between the
should comply with local regulatory codes and
practices.

GPS

antenna is exposed to sources of

GPS

sensor and antenna. Such installations

3-29

SF-2050 User Guide - Rev. D

Chapter 4 Configuration

The SF-2050
detailed control language, which allows each unit to
be tailored specifically to the required application.

GPS

sensors have a rich interface and

Factory Default Settings

By factory default,
Port. The Control Port manages the full functionality of
the SF-2050.
as the Data Port. By factory default this port handles the
non-NavCom proprietary messages that are input
and/or output to/from the receiver. By factory default,

NMEA
COM 1
COM 2

Baud. This baud rate can be changed to accommodate
faster data rates.

The standard factory configuration for the SF-2050
allows for the basic operation of the system. The factory
default for NavCom Proprietary Control Port Message
Block output is described in Table 6. These message
blocks afford the novice or seasoned
opportunity to get up and surveying in a minimal
period of time.

message GGA data is scheduled for output from

at 1Hz. The
communicate is factory defaulted to 19.2k

COM 2

COM 1

is designated as the Control

, by factory default, is designated

baud rate

at which

GPS

COM 1

and

user the best

The output data rate for the factory default message
blocks is described in Table 6 and will remain at that
rate until the user specifies otherwise by issuing the
appropriate NavCom Proprietary command.

4-30

SF-2050 User Guide - Rev. D

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

Table 6: Factory Setup Proprietary Messages COM 2

 44 Packed

corresponding to each satellite in the
constellation. This information includes
number of
seconds] that
reference week,
source,
4 & 5.

 81 Packed

information as it relates to individual satellites

Almanac

almanac

almanac

Ephemeris

: This message provides data

GPS

GPS

Week

collected,

almanac

was collected,

almanac

health, pages 1-25, and subframes

: This message provides

GPS

Time of week [in

almanac

reference time,

almanac

4-31

SF-2050 User Guide - Rev. D

tracked. This information includes
number of
[in seconds] that
and Sub-frame 1, 2, & 3 data.

ephemeris

ephemeris

collected,

was collected, IODC,

GPS

Week

GPS

Time of week

 86 Channel Status: Provides receiver

information and contains the
of Week, NCT-2000D Engine status, solution status,
number of satellites being tracked and the number
and identity of satellites used in solution,
the satellite

 A0 Alert Text Message: Details if a message has

been properly received and processed.

 AE Identification Block: Details the receiver software

versions.

 B0 Raw Measurement Data: Raw Measurement Data

Block that contains the
Week, Time Slew Indicator and Status. Information
included is
Phase, P1-CA
and L1 Phase. This data stream is repeated for any
additional satellite.

 B1

PVT

latitude, longitude, navigation mode, and
information.

PRN

Channel

Pseudorange

: Provides

.

GPS

Status, CA

GPS

Week number, satellites used,

GPS

Week,

, P2-CA

channel

week,

GPS

PDOP

GPS

Time of

Pseudorange

Pseudorange

DOP

status
Time

and

, L1

,

 The term “On Change” indicates that the SF-2050 will

output the specified message only when the
information in the message changes. Thus in some
cases, there may be an epoch without a message block
output.

4-32

SF-2050 User Guide - Rev. D

Advanced Configuration Settings

If a third party
your SF-2050
manual/user guide.

Controller

GPS

sensor, please refer to that

Solution was provided with

4-33

SF-2050 User Guide - Rev. D

Chapter 5 Safety Instructions

The SF-2050
navigation and positioning using the

Positioning System

of portable
these safety instructions prior to use of the 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

SF-2050 User Guide - Rev. D

Maintenance

The NavCom equipment can be cleaned using a new
lint free cloth that may be 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 +40C (104F), but greater than 5C (41F) at the
earliest opportunity.

External Power Source

The SF-2050 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

SF-2050 User Guide - Rev. D

Other manufacturer’s equipment must be used in
accordance with the safety instructions issued by that
manufacturer. This includes other manufacturers
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 SF-2050

GPS

sensor. Accessing the inside of the equipment will

void the equipment warranty.

Care should be taken to ensure that the SF-2050 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.

GPS

sensor may be adversely affected

Global Positioning System

The
the United States Air Force. Operation of the
satellites may be changed at any time and without
warning.

is under the control of

GPS

5-36

SF-2050 User Guide - Rev. D

A GPS Sensor Technical Specifications

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:

support.navcomtech.com

SF-2050G and SF-2050M

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

• Global decimeter-level accuracy using StarFire™

corrections

• Fully automatic acquisition of satellite broadcast

corrections

• Rugged and lightweight package for mobile

applications

• Accepts external DGPS input in RTCM v2.2 or CMR

format

• L1 & L2 full wavelength carrier tracking

• C/A, P1 & P2 code tracking

• User programmable output rates:

• Minimal data latency

• 2 separate WAAS/EGNOS channels

• Superior interference suppression

A-37

SF-2050 User Guide - Rev. D

• Patented multipath rejection

• Supports NMEA 0183 v3.1 messages

• Self-survey mode (position averaging)

• CAN bus interface (SF-2050M Only)

• 1PPS Output (SF-2050M Only)

• Event Marker (SF-2050M Only)

Physical and Environmental

• Size (L x W x H): < 8.18” x 5.67” x 3.06”

• Weight: <4 lbs (1.81 kg)

• External Power:
Input Voltage: 10 VDC to 30 VDC
Power Consumption: <10 W

• Connectors:
I/O Ports: 2 x 7 pin Lemo
DC Power: 4 pin Lemo
RF Connector: TNC

(with 5 VDC bias for internal/LNA)

• Temperature (ambient):
Operating: -40º C to +55º C
Storage: -40º C to +85º C

• Humidity: 95% non-condensing

Measurement Performance

• Real-time StarFire™ SBAS Accuracy:
Position (H): <15 cm
Position (V): <30 cm
Velocity: 0.01 m/s

A-38

SF-2050 User Guide - Rev. D

• 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

• User programmable output rates:

PVT: <1Hz, 2Hz, 5Hz Standard

(10Hz, & 25Hz Optional)

Raw data: <1Hz, 2Hz, 5Hz Standard

(10Hz, 25Hz, & 50Hz Optional)

• Data Latency:
PVT: < 20 ms at all nav rates
Raw data: < 20 ms at all rates

• Time-to-first-fix:

Cold Start
Satellite Acquisition: < 60seconds (typical)
Satellite Reacquisition: < 1 second

• Dynamics:

Acceleration: up to 6g
Speed: < 300 m/s*
Altitude: < 60,000 ft*

• 1PPS Accuracy: 12.5ns (Relative; User Configurable)

(SF-2050M Only)

*Restricted by export laws

A-39

SF-2050 User Guide - Rev. D

Connector Assignments

•Data Interfaces:

2 serial ports; from 1200 bps to 115.2 kbps

CAN Bus I/F (SF-2050M Only)

Event Marker I/P (SF-2050M Only)

1PPS (SF-2050M Only)

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

• Code Corrections: RTCM 1 or 9

WAAS/EGNOS

StarFire



LED Display Functions (Default)

• Link

• Base Station N/A in SF-2050

• GPS Position Quality

StarFire

 Signal Strength (Default)

(User Programmable)

(User Programmable)

Satellite Based Augmentation System Signals

• WAAS/EGNOS

StarFire

•



A-40

SF-2050 User Guide - Rev. D

B GPS Antenna Technical Specifications

The standard antenna supplied with the SF-2050
sensor is capable of Tri-Frequency reception.

GPS

L1+L, L2 GPS Antenna

1525-1585 MHz GPS L1 plus Inmarsat L Band

1217-1237 MHz GPS L2

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 -55C to +85C

Altitude 70,000’

 NavCom

mount antenna, also rated to 70,000 feet.

P/N

82-001000-0008 is an optional aircraft

Designed to DO-160D Standard

B-41

SF-2050 User Guide - Rev. D

Figure B1: Tri-Mode Antenna Dimensions

 In order to achieve the greatest level of accuracy, the

absolute phase center values must be incorporated
into your processing. For phase center information for
the Tri-Mode Antenna go to

support.nacvcomtech.com.

B-42

SF-2040G User Guide

C StarFire

Description

The

StarFire

distribution of
ability to measure his
with exceptional reliability and unprecedented accuracy
of better than 10cm (4 inches). Because the
corrections are broadcast via Inmarsat geo-stationary
satellites, the user needs no local

post-processing

Furthermore, the same accuracy is available virtually any
where on the earth's surface on land or sea from 76N
to 76S
geo-stationary satellites.

™ Network is a global system for the

SBAS

corrections giving the user the

position

anywhere in the world

reference stations

to get this exceptional accuracy.

latitude

due to the worldwide coverage of the

SBAS

or

C-43

SF-2050 User Guide - Rev. D

Infrastructure

The system utilizes the
communication satellites, and a worldwide network of

reference stations

positioning.

To provide this unique service, NavCom has built a
global network of
which constantly receive signals from the
as they orbit the earth. Data from these

stations

Torrance, California and Moline, Illinois where they are
processed to generate the differential corrections.

From the two Processing Centers, the correction data is
fed via redundant and independent communication
links to satellite uplink stations at Laurentides in
Canada, Goonhilly in England and Auckland in New
Zealand for uplink to the geo-stationary satellites.

The key to the accuracy and convenience of the

StarFire

satellites transmit navigation data on two
frequencies. The
equipped with geodetic-quality,
receivers. These reference receivers decode
and send precise high quality

pseudorange

the Processing Centers together with the data
messages, which all

is fed to two USA Processing Centers in

 system is the source of

and carrier phase measurements back to

GPS

satellite system,

to deliver real-time high precision

L-Band

dual-frequency reference stations

GPS

satellites

reference

SBAS

corrections.

L-Band

StarFire reference stations

dual-frequency

dual-frequency

GPS

satellites broadcast.

are all

GPS

signals

,

GPS

At the Processing Centers, NavCom's proprietary

differential

time precise orbits and clock correction data for each
satellite in the

Area
dual-frequency
frequency

processing techniques used to generate real

GPS

constellation. This proprietary

DGPS (WADGPS

system such as

ionospheric measurements are available at

) algorithm is optimized for a

StarFire

 in which

Wide

dual-

C-44

SF-2050 User Guide - Rev. D

both the reference receivers and the user receivers. It is
the use of

reference stations

with the advanced processing algorithms, which makes
the exceptional accuracy of the
possible.

Creating the corrections is just the first part. From our
two Processing Centers, the differential corrections are
then sent to the Land Earth Station (

Band

network are equipped with NavCom-built modulation
equipment, which interfaces to the satellite system
transmitter and uplinks the correction data stream to
the satellite that broadcasts it over the coverage area.
Each
earth.

dual-frequency

and the user equipment together

communications satellites. The uplink sites for the

L-Band

satellite covers more than a third of the

receivers at both the

StarFire

 system

LES

) for uplink to

L-

Users equipped with a
actually have two receivers in a single package, a
receiver and an
designed by NavCom for this system. The
tracks all the satellites in view and makes
measurements to the

L-Band

broadcast via the
are applied to the
measurement of unprecedented real time accuracy is
produced.

receiver receives the correction messages

L-Band

StarFire

communications receiver, both

 precision

GPS

GPS

pseudorange

GPS

satellites. Simultaneously, the

L-Band

GPS

satellite. When the corrections

measurements, a

position

receiver

GPS

receiver

Reliability

The entire system meets or exceeds a target availability
of 99.99%. To achieve this, every part of the
infrastructure has a built-in back-up system.

All the
receivers, processors and communication interfaces,

reference stations

are built with duplicate

C-45

SF-2050 User Guide - Rev. D

which switch automatically or in response to a remote
control signal from the Processing Centers. The data
links from the
primary data link and are backed up by dedicated
communications lines, but in fact the network is
sufficiently dense that the
act as back up for each other. If one or several fail, the
net effect on the correction accuracy is not impaired.

There are two continuously running Processing Centers,
each receiving all of the reference site inputs and each
with redundant communications links to the uplink

Land Earth Stations (LES

equipped with two complete and continuously
operating sets of uplink equipment arbitrated by an
automatic fail over switch. Finally, a comprehensive
team of support engineers maintains round the clock
monitoring and control of the system.

The network is a fully automated self-monitoring
system. To ensure overall system integrity, an
independent integrity monitor receiver, similar to a
standard

reference station

these integrity monitors is sent to the two independent
processing hubs in Torrance, California and Moline,
Illinois. Through these integrity monitors the network is
continuously checked for overall
accuracy,
other essential operational parameters.

reference stations

StarFire

L-Band

 user receiver, is installed at every

to monitor service quality. Data from

signal strength, data integrity and

). The

use the Internet as the

reference stations

Land Earth Stations

SBAS

positioning

effectively

are

How to Access the

StarFire

subscription, which licenses the use of the service for a
predetermined period of time.

 is a subscription service. The user pays a

StarFire

 Service

C-46

SF-2050 User Guide - Rev. D

Subscriptions can be purchased for quarterly, biannual
or annual periods and are available via a NavCom
authorized representative, or by logging on to

support.navcomtech.com

An authorized subscription will provide an encrypted
keyword, which is specific to the Serial Number of the
NavCom receiver to be authorized. This is entered into
the receiver using the provided
Typically the initial license is preinstalled at the factory,
and subsequent licenses will be installed by the user.

The only piece of equipment needed to use the

StarFire

a variety of receivers configured for different
applications. Details of all the
available from the NavCom authorized local
representative or the NavCom website at:

 system is a

StarFire

Controller

 receiver. NavCom offers

StarFire

Solution.

 receivers are

www.navcomtech.com

StarFire

receiver and an
unit to provide the exceptional precise positioning
capability of the
anytime.

 receivers include a

L-Band

StarFire

receiver integrated into a single

 Network, anywhere,

dual-frequency GPS

C-47

SF-2040G User Guide

C-48

Figure C1: StarFire Network

SF-2050 User Guide - Rev. D

D Event Input Configuration

Figure D1 details the wiring of the Event/Can cable
assembly NavCom part number P/N 94-310062-3003.
The Event Input is electrically isolated to the internal
circuitry through an opto-isolator, thus a voltage of 3-6
vdc/50Ω (60 - 120mA), and a minimum pulse width of
100nSec must be sensed in order to get through the
opto-isolator. Table D1 details the wiring configuration
required for Event-Hi, and Event-Lo pulse sensing.

Figure D1: 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 indicating
when the event is sensed. The time will be referenced
to the time kept within the NavCom receiver.

Signal
Name

Table D1: Event Wiring Connections

Event Sync Wiring

D-49

SF-2050 User Guide - Rev. D

The Event Input can be triggered on the Falling, or
Rising edge of the input pulse; Figure D2 shows the PPS
& Event Latch window. After configuring the specifics
of the input pulse, the Event Latch message (0xB4)
must be enabled in the NCT 2000 Message Output list.
However the Message Rate for the 0xB4 must be set to
“On Trigger”. The “On Trigger” message rate can be
located by Right- Clicking on the Rate area adjacent to
the B4 Message ID, and following the menus as seen in
Figure D3. T
output when the chosen pulse edge of the incoming
event is sensed by the receiver.

he Event Latch Message 0xB4 will only be

Figure D2: PPS & Event Latch Configuration

Figure D3: Event Latch Output Rate Configuration

D-50

SF-2050 User Guide - Rev. D

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

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

or

geoid

GPS

ellipsoid

.

. It

Glossary-51

SF-2050 User Guide - Rev. D

Autonomous positioning (
in which a
time from satellite data alone, without reference to data
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

GPS

receiver computes

reference station

Autonomous positioning

position

azimu h

.

of a line is its direction as given by

t

reference station

bits per second

baud rate.

baud rate

.

GPS

) a mode of operation

position

or orbital clock

fixes that are precise to 100

meridian

and the line measured

.

) the number of bits sent or

fixes in real

is typically the

GPS

receiver can

baud rate

of 9600

BSW (British Standard Whitworth) a type of coarse
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.

Coarse Acquisition code

channel

of a

GPS

BSW

is the standard

.

receiver consists of the

GPS

Glossary-52

SF-2050 User Guide - Rev. D

civilian code see

Coarse Acquisition code (C/A or
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,

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

GPS

sensor.

DGPS

or any type of data logged from a

Differential GPS

reference s ation

reference station

actual and observed ranges to the satellites being
tracked. The coordinates of the unknown location can
be computed with sub-meter level precision by

Coarse Acquisition code

Civilian code

GPS

selective availability

controller

or data collection device.

corrections used to transmit

reference station

to

rover

GPS

.

GPS (DGPS

t

computes corrections based on the

) a positioning procedure that

rover

at an unknown location and

at a known, fixed location. The

.

)

satellites. It

sensors.

, NMEA,

GPS

receiver.

GPS

Glossary-53

SF-2050 User Guide - Rev. D

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 SF­2050 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.

ellipsoid a mathematical figure approximating the
earth’s surface, generated by rotating an ellipse on its

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-54

SF-2050 User Guide - Rev. D

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

GPS
ellipsoid
geoid

calculating the distance between the

ellipsoid
GPS altitude

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.

GPS

positions are computed relative to the

ellipsoid

GPS altitude

readings, which are measured relative to an

. Conventionally surveyed positions reference a

. More accurate

at each

. An

ellipsoid

measurements can contain a

altitude

mean sea level

GPS

readings can be obtained by

position

measurement.

and subtracting this from the

has a smooth surface,

geoid

, which has an

errors.

over the entire surface of

geoid

is too irregular to use

geoid

and

Global Positioning System (GPS) geometrically, there
can only be one point in space, which is the correct

GPS

distance from each of four known points.
the distance from a point to at least four satellites from
a constellation of 24 NAVSTAR satellites orbiting the

measures

Glossary-55

SF-2050 User Guide - Rev. D

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.

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
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
by
frequency is 1227.6MHz. It is modulated by
Y-code, and a 50 bit/second navigation message.

Global Positioning System

, but does not add periodic ‘leap seconds’ to

.

passing through Greenwich, England.

altitude

GPS

satellites to transmit satellite data. The

GPS

satellites to transmit satellite data. The

altitude

GPS

, and

ellipsoid

L-Band

. These distances are used

position

time is 13 seconds ahead of

range.

.

.

GPS

time is based on

GMT

) the local time of the 0°

.

GPS

carrier

L-Band

carrier used

C/A code

L-Band

carrier used

P-code

or

,

Glossary-56

SF-2050 User Guide - Rev. D

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.

long

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
as

Long

.

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.

) 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-57

SF-2050 User Guide - Rev. D

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

GPS position

position

and time

information.

PDOP see

PDOP mask the highest
computes positions.

Position Dilution of Precision

Glossary-58

.

PDOP

value at which a receiver

SF-2050 User Guide - Rev. D

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

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

height can be calculated by adding the height to

phase center

phase center

reference station

P-code

see

P-code

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-59

SF-2050 User Guide - Rev. D

Proprietary commands those messages sent to and
received from
Technology, Inc. own copyrighted binary language.

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

’s antenna to a satellite, calculated by multiplying

GPS

see

pseudorange

GPS

equipment produced by NavCom

prn

) a sequence of data that

GPS

GPS

receivers use

satellite transmits a unique

PRN

s to identify and

PRN

reference

range

, is not exactly the same

information depicting Position, Velocity, Time

RTCM

.

GPS

range

is approximately equal to

. However, errors can be introduced by

GPS

receiver’s location can be

GPS

satellites. Geometrically, there can only

Glossary-60

SF-2050 User Guide - Rev. D

Ionospheric and Troposphere effects are used for
navigation.

RTK

) a

GPS

Real-Time Kinematic (
very accurate 3D
The

base station
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

as the receiver generates them, and the
use the

dual frequency GPS

positions for this location can be applied to

reference station

accuracy of

RHCP Right Hand Circular Polarization used to
discriminate satellite signals.

position

transmits its

fixes immediately in real-time.

base station

receivers and high speed

reference station

is used to improve the quality and

GPS

data collected by

system that yields

GPS position

to

roving

roving

readings to differentially

RTK

collects

GPS

data

roving receivers

reference station

. A

roving receive s. r

GPS

signals are RHCP.

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

GPS

GPS

receiver and field computer

receiver or by using

SBAS

such as StarFire.

GPS

data. The

RINEX

file

roving receiver’s position

GPS

orbit and clock

Glossary-61

SF-2050 User Guide - Rev. D

roving receiver see

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

rover

.

Differential GPS

base station

real-time kinematic (RTK

.

.

EGNOS

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.

signal by encrypting the

SNR

GPS

signal. There is no compensation for ionospheric

P-code

S/A

, the signal contains

) a measure of a satellite’s

. When the US

Glossary-62

SF-2050 User Guide - Rev. D

SNR see

StarFire a set of real-time global orbit and clock
corrections for
receivers are capable of real-time decimeter positioning
(see Appendix C).

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.

signal-to-noise

GPS

Ratio.

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

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

GPS

satellites, which are valid for a

) a set of

ellipsoid

P-code

.

when the

selective availability

.

Glossary-63