6 - 3

CHAPTER 6

LONG RANGE NAVIGATIONAL AIDS

PART I LORAN-C

600A. General

LORAN is a long range system which operates on the

principle that the difference in time of arrival of signals

from two precisely synchronized transmitting stations

describes a hyperbolic line of position (LOP). This time

difference is measured with a LORAN receiver, and is

either converted into geographic LOPs for use with

nautical charts overprinted with LORAN lines or directly

into latitude and longitude readouts. Since at least two

LOPs must be determined to establish a position, the user

must be within the range of two pairs of transmitting

stations or, as is normally the case, a LORAN chain where

a centrally located station serves as a timing reference for

the other stations in the chain. This station is called the

master station (designated M) and the secondaries are

usually designated by the letters V, W, X, Y, or Z. In the

United States, LORAN-C is operated by the U.S. Coast

Guard. Developed in the late 1950’s, LORAN-C operates

on a frequency of 100 kHz. Each LORAN-C chain

operates on a different pulse group repetition interval

(GRI). This allows the operator to make at least two time

difference (TD) measurements without changing channels

on the receiver. The low frequency of LORAN-C permits

usable groundwave signals over several hundred miles.

600B. Operation

The LORAN-C GRI rate structure is such that a GRI

between 40,000 and 99,990 microseconds is chosen for

each chain. The chain designations are four digit numbers

which indicate the GRI in tens of microseconds. For

example, the northeast U.S. LORAN-C chain is designated

9960 and has a GRI of 99,600 microseconds.

The accuracy of a LORAN-C fix is determined by the

accuracy of the individual lines of position used to

establish the fix, as well as by their crossing angle of

intersection. The accuracy of the individual lines of

position depends on the following factors:

– Synchronization of the transmitting stations.

– Operator skill.

– Type of receiver and its condition.

– Skill in plotting the line of position.

– Position of user relative to the transmitting stations.

– Accuracy of charts.

– Accuracy of corrections to compensate for the overland

path.

Some LORAN-C receivers employ a coordinate

converter function, which is designed to internally

compute the latitude and longitude and directly display

these values. This eliminates the need for charts

overprinted with LORAN-C time difference 

(CAUTIONARY NOTE: The conversion computati

some models is based upon an all sea water propa

path. This leads to errors if the LORAN-C signals fro

various stations involve appreciable overland paths

recommended that operators using coordinate conv

check the manufacturer’s operating manual to determ

and how corrections are to be applied to compensa

overland paths.)

Each LORAN-C rate is continuously monitor

determine that proper synchronization is being maint

When the synchronization error exceeds the adve

tolerance, the user is advised by the blinking of pul

the affected secondary and is warned not to use the 

for navigational purposes. The blink signal will cause 

receivers to indicate by an alarm that the navigationa

displayed is in error. Mariners should check equi

manuals to determine if their receivers are equipped 

Blink Alarm and, if not, should exercise caution whe

known hazards or when in restricted waters.

LORAN-C position determinations on or nea

baseline extensions are subject to significant error

should be avoided wherever possible. A great circl

between two LORAN stations is a baseline; the ba

extension is the extension of that line beyond either s

LORAN-C coverage presently exists along the w

coast of North America from the Bering Sea sout

along the Gulf of Alaska, western Canada, and the 

west coast to the Mexican border. Along the eastern 

of North America, LORAN-C coverage exists 

Newfoundland to the southern tip of Florida. Gulf 

coverage exists from the southern tip of Florida 

Texas-Mexico border. Coverage of Lakes Sup

Michigan, and Huron is provided by the Great Lakes 

rate 8970. Coverage of Lakes Huron, Erie, and Ont

provided by the Northeast U.S. chain, rate 9960. Cov

over the central region of the U.S. is provided by the 

and South Central chains, rates 8290 and 

respectively. For foreign LORAN-C coverage (incl

that described above) refer to the LORAN-C Pl

Charts diagram in the latest edition of NGA Catal

Maps, Charts, and Related Products Part 2-Volu

Hydrographic Products (CATP2V01U).

Detailed LORAN-C information is contained in th

Coast Guard’s LORAN-C User Handbook (COMDT

P16562.6).

NOTE: While the United States continues to evalua

long-term need for continuation of the Lo

radionavigation system, the Government will opera

Loran-C system in the short term. The U.S. Gover

will give users reasonable notice if it conclude
LONG RANGE NAVIGATIONAL AIDS

6 - 4

Loran-C is not needed or is not cost effective, so that users

will have the opportunity to transition to alternative

navigation aids. With this continued sustainment of the

Loran-C service, users will be able to realize additional

benefits. Improvement of GPS time synchronization of the

Loran-C chains and the use of digital receivers may

support improved accuracy and coverage of the service.

Loran-C will continue to provide a supplemental means of

navigation.

For further information and/or operational questions

regarding LORAN-C in the United States, contact:

COMMANDING OFFICER

U.S. COAST GUARD NAVIGATION CENTER

7323 TELEGRAPH ROAD

ALEXANDRIA VA 22315-3998

Telephone: (1) 703-313-5900.

Fax: (1) 703-313-5920.

The Navigation Information Service (NIS) is internet

accessible through the U.S. Coast Guard Navigation

Center Website at:

http://www.navcen.uscg.gov/

http://www.navcenter.org (Mirror site)

FOREIGN LORAN-C COVERAGE: In 1992, the U.S.

Coast Guard, which operated LORAN-C overseas for the

Department of Defense, initiated plans to accomplish

transfer or closure of U.S. Coast Guard LORAN-C stations

located on foreign soil. As a result of these efforts, new

LORAN-C systems have developed in areas of the world

previously covered by the U.S. chains.

The countries of Norway, Denmark, Germany, Ireland,

the Netherlands and France have established a common

LORAN-C system known as the Northwest European

Loran-C System (NELS). The developing system will be

comprised of nine stations forming four chains. Since

1995, two chains, Bo and Ejde, have been in experimental

(continuous) operation. The Sylt chain became operational

in late 1995, but users are warned of its unstable condition.

The Lessay chain became operational in September 1997.

For further information regarding NELS, contact:

NELS COORDINATING AGENCY OFFICE

LANGKAIA 1

N-0150 OSLO NORWAY

Telephone: 47 2309 2476.

Fax: 47 2309 2391.

Internet: http://www.nels.org

The countries of Japan, the People’s Republic of China,

the Republic of Korea and the Russian Federation have

established an organization known as the Far East

Radionavigation Service (FERNS). Japan took over

operation of the former U.S. Coast Guard stations in its

territory and they are currently operated by the Japanese

Maritime Safety Agency (JMSA). In 1996, five chains

(Korea, North China Sea, East China Sea, South 

Sea, and Russian) became operational.

600C. Receivers

There are many types of LORAN-C receivers av

Each type employs various techniques for acquir

tracking LORAN-C signals, and for indicating t

difference or position information to the u

LORAN-C receiver which will be useful within th

of the Coast Guard’s coverage for the U.S., and w

capable of measuring positions with the accuracy w

advertised for LORAN-C, has the fo

characteristics:

– It acquires the LORAN-C signals automatically, 

the use of an oscilloscope.

– It identifies master and secondary groundwave 

automatically.

– It tracks the signals automatically once they ha

acquired.

– It displays two time difference readings, to a prec

at least one tenth of a microsecond, and/or latit

longitude.

– It has notch filters to minimize the effects o

frequency interference in the area of its operation

– It automatically detects blink and alerts the opera

Proper LORAN-C receiver installation is nece

ensure optimum results. Some of the essential elem

good LORAN-C receiver installations are:

– Use of the correct antenna and antenna coupler

the antenna as high as possible and away from a

objects, stays, and other antennas. Do not conn

other equipment to a LORAN-C antenna.

– Connect both the antenna coupler and the recei

good ground. LORAN-C, operating at low fre

requires proper grounding.

– Electrical and electronic interference, or noise, ca

from many sources, both aboard the vessel as 

from the surrounding environment. Onboard 

comes from anything that generates or uses elect

is a more severe problem at 100 kHz than at 

frequencies, and it must be suppressed in order 

good results from LORAN-C. Alternators, gen

ignition systems, electrical motors, fluorescent 

radars, and television sets are examples of int

sources. Interference suppression may 

installation of filters, shields, grounds, and cap

Interference suppression should be accomplish

the vessel engine running.

– Protection of the LORAN-C receiver from ex

heat, dampness, salt spray, and vibration m

ensured. Do not mount the receiver in direct sun

within one meter of your magnetic compass. 

adequate ventilation.

600D. Station List

LORAN-C stations, grouped geographically by 

are contained in the following list.
LONG RANGE NAVIGATIONAL AIDS

6 - 5

(1)

No.

(2)

Name

(3)

Type

(4)

Component

(5) Position(6)

Freq.

(7) Remarks

NORTH PACIFIC CHAIN

6100 St. Paul, AK 9990 (SS1). LORAN-C Master 57 09 12N 170 15 06W

Attu Is., AK 9990-X. Secondary 52 49 44N 173 10 50E

Port Clarence, AK 9990-Y. Secondary 65 14 40N 166 53 12W

Kodiak, AK 9990-Z. Secondary 57 26 20N 152 22 11W

RUSSIAN (CHAYKA)-AMERICAN CHAIN

6105 Petropavlovsk, Russia 5980. LORAN-C Master 53 07 48N 157 41 43E

Attu Is., AK 5980-X. Secondary 52 49 44N 173 10 50E

Alexandrovsk, Russia

5980-Y.

Secondary 51 04 43N 142 42 05E

RUSSIAN CHAIN

6110 Alexandrovsk, Russia 7950. LORAN-C Master 51 04 43N 142 42 05E

Petropavlovsk, Russia

7950-W.

Secondary 53 07 48N 157 41 43E

Ussuriysk, Russia 7950-X. Secondary 44 32 00N 131 38 23E

Tokachibuto, Hokkaido,

Japan 7950-Y.

Secondary 42 44 37N 143 43 10E

Okhotsk, Russia 7950-Z. Secondary 59 25 02N 143 05 23E

NORTHWEST PACIFIC CHAIN

6120 Nii Jima, Japan 8930 (SS3). LORAN-C Master 34 24 12N 139 16 19E

Gesashi, Okinawa, Japan

8930-W.

Secondary 26 36 25N 128 08 57E

Minami-tori Shima (Marcus

Island), Japan 8930-X.

Secondary 24 17 08N 153 58 54E

Tokachibuto, Hokkaido,

Japan 8930-Y.

Secondary 42 44 37N 143 43 10E

Pohang, South Korea 8930-Z. Secondary 36 11 05N 129 20 27E
LONG RANGE NAVIGATIONAL AIDS

6 - 6

KOREA CHAIN

6122 Pohang, South Korea 9930. LORAN-C Master 36 11 05N 129 20 27E

Kwangju, South Korea

9930-W.

Secondary 35 02 24N 126 32 27E

Gesashi, Okinawa, Japan

9930-X.

Secondary 26 36 25N 128 08 57E

Nii Jima, Japan 9930-Y. Secondary 34 24 12N 139 16 19E

Ussuriysk, Russia 9930-Z. Secondary 44 32 00N 131 38 23E

NORTH CHINA SEA CHAIN

6124 Rongcheng, China 7430. LORAN-C Master 37 03 52N 122 19 26E

Xuancheng, China 7430-X. Secondary 31 04 08N 118 53 10E

Helong, China 7430-Y. Secondary 42 43 12N 129 06 27E

EAST CHINA SEA CHAIN

6126 Xuancheng, China 8390. LORAN-C Master 31 04 08N 118 53 10E

Raoping, China 8390-X. Secondary 23 43 26N 116 53 45E

Rongcheng, China 8390-Y. Secondary 37 03 52N 122 19 26E

SOUTH CHINA SEA CHAIN

6128 Hexian, China 6780. LORAN-C Master 23 58 04N 111 43 10E

Raoping, China 6780-X. Secondary 23 43 26N 116 53 45E

Chongzuo, China 6780-Y. Secondary 22 32 35N 107 13 22E

GULF OF ALASKA CHAIN

6130 Tok, AK 7960 (SL4). LORAN-C Master 63 19 43N 142 48 31W

Kodiak, AK 7960-X. Secondary 57 26 20N 152 22 11W

Shoal Cove, AK 7960-Y. Secondary 55 26 21N 131 15 19W

Port Clarence, AK 7960-Z. Secondary 65 14 40N 166 53 12W

(1)

No.

(2)

Name

(3)

Type

(4)

Component

(5) Position(6)

Freq.

(7) Remarks
LONG RANGE NAVIGATIONAL AIDS

6 - 7

WEST COAST CANADA CHAIN

6140 Williams Lake, B.C., Canada

5990 (SH1).

LORAN-C Master 51 57 59N 122 22 02W

Shoal Cove, AK 5990-X. Secondary 55 26 21N 131 15 19W

George, WA 5990-Y. Secondary 47 03 48N 119 44 39W

Port Hardy, B.C., Canada

5990-Z.

Secondary 50 36 30N 127 21 28W

WEST COAST U.S. CHAIN

6150 Fallon, NV 9940 (SS6). LORAN-C Master 39 33 07N 118 49 56W

George, WA 9940-W. Secondary 47 03 48N 119 44 39W

Middletown, CA 9940-X. Secondary 38 46 57N 122 29 44W

Searchlight, NV 9940-Y. Secondary 35 19 18N 114 48 17W

EAST COAST CANADA CHAIN

6160 Caribou, ME 5930 (SH7). LORAN-C Master 46 48 27N 67 55 37W

Nantucket, MA 5930-X. Secondary 41 15 12N 69 58 39W

Cape Race, Nfld., Canada

5930-Y.

Secondary 46 46 32N 53 10 28W

Fox Harbor, Nfld., Canada

5930-Z.

Secondary 52 22 35N 55 42 28W

NEWFOUNDLAND EAST COAST CHAIN

6165 Comfort Cove, Nfld., Canada

7270.

LORAN-C Master 49 19 54N 54 51 43W

Cape Race, Nfld., Canada

7270-W.

Secondary 46 46 32N 53 10 28W

Fox Harbor, Nfld., Canada

7270-X.

Secondary 52 22 35N 55 42 28W

GREAT LAKES CHAIN

6170 Dana, IN 8970. LORAN-C Master 39 51 08N 87 29 12W

Malone, FL 8970-W. Secondary 30 59 39N 85 10 09W

Seneca, NY 8970-X. Secondary 42 42 51N 76 49 33W

Baudette, MN 8970-Y. Secondary 48 36 50N 94 33 18W

Boise City, OK 8970-Z. Secondary 36 30 21N 102 53 59W

(1)

No.

(2)

Name

(3)

Type

(4)

Component

(5) Position(6)

Freq.

(7) Remarks
LONG RANGE NAVIGATIONAL AIDS

6 - 8

NORTHEAST U.S. CHAIN

6180 Seneca, NY 9960 (SS4). LORAN-C Master 42 42 51N 76 49 33W

Caribou, ME 9960-W. Secondary 46 48 27N 67 55 37W

Nantucket, MA 9960-X. Secondary 41 15 12N 69 58 39W

Carolina Beach, NC 9960-Y. Secondary 34 03 46N 77 54 46W

Dana, IN 9960-Z. Secondary 39 51 08N 87 29 12W

SOUTHEAST U.S. CHAIN

6190 Malone, FL 7980 (SL2). LORAN-C Master 30 59 39N 85 10 09W

Grangeville, LA 7980-W. Secondary 30 43 33N 90 49 43W

Raymondville, TX 7980-X. Secondary 26 31 55N 97 50 00W

Jupiter, FL 7980-Y. Secondary 27 01 59N 80 06 53W

Carolina Beach, NC 7980-Z. Secondary 34 03 46N 77 54 46W

EJDE CHAIN

6205 Ejde, Faroe Is., Denmark

9007.

LORAN-C Master 62 17 59N 7 04 26W

Jan Mayen Is., Norway

9007-W.

Secondary 70 54 51N 8 43 56W

Bo, Norway 9007-X. Secondary 68 38 06N 14 27 47E

Vaerlandet, Norway 9007-Y. Secondary 61 17 49N 4 41 46E

BO CHAIN

6215 Bo, Norway 7001. LORAN-C Master 68 38 06N 14 27 47E

Jan Mayen Is., Norway

7001-X.

Secondary 70 54 51N 8 43 56W

Berlevag, Norway 7001-Y. Secondary 70 50 43N 29 12 15E

SYLT CHAIN

6220 Sylt, Germany 7499. LORAN-C Master 54 48 29N 8 17 36E

Lessay, France 7499-X. Secondary 49 08 55N 1 30 17W

Vaerlandet, Norway 7499-Y. Secondary 61 17 49N 4 41 46E

(1)

No.

(2)

Name

(3)

Type

(4)

Component

(5) Position(6)

Freq.

(7) Remarks
LONG RANGE NAVIGATIONAL AIDS

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LESSAY CHAIN

6225 Lessay, France 6731. LORAN-C Master 49 08 55N 1 30 17W

Soustons, France 6731-X. Secondary 43 44 23N 1 22 49W

Sylt, Germany 6731-Z. Secondary 54 48 29N 8 17 36E

NORTH SAUDI ARABIAN CHAIN

6240 Afif, Saudi Arabia 8830. LORAN-C Master 23 48 37N 42 51 18E

Salwa, Saudi Arabia 8830-W. Secondary 24 50 02N 50 34 13E

Al Khamasin, Saudi Arabia

8830-X.

Secondary 20 28 02N 44 34 53E

Ash Shaykh Humayd, Saudi

Arabia 8830-Y.

Secondary 28 09 16N 34 45 41E

Al Muwassam, Saudi Arabia

8830-Z.

Secondary 16 25 56N 42 48 05E

INDIA (BOMBAY) CHAIN

6260 Dhrangadhara 6042. LORAN-C Master 23 00 14N 71 31 39E

Veraval 6042-W. Secondary 20 57 07N 70 20 13E

Billimora 6042-X. Secondary 20 45 40N 73 02 17E

INDIA (CALCUTTA) CHAIN

6270 Balasore 5543. LORAN-C Master 21 29 08N 86 55 18E

Patpur 5543-W. Secondary 20 26 48N 85 49 47E

Diamond Harbor 5543-X. Secondary 22 10 18N 88 12 25E

(1)

No.

(2)

Name

(3)

Type

(4)

Component

(5) Position(6)

Freq.

(7) Remarks
LONG RANGE NAVIGATIONAL AIDS

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PART II SATELLITE NAVIGATION

610A. General

Satellite navigation presently consists of two global

systems. Each may be considered a refinement of celestial

navigation, using artificial earth-orbiting satellites to form

an electronic “constellation”, serviced by land-based

control and tracking stations, and passively “sighted” by

mobile receivers. Both systems provide precise, global,

and continuous position-fixing capabilities, in all weather,

to a properly equipped user.

The U.S. Air Force system is the NAVSTAR Global

Positioning System (GPS). GPS development began in

1973 and reached full operational capability in 1995. (The

U.S. Navy system, the Navy Navigation Satellite System

(NAVSAT, also known as Transit) became operational in

1964 and ceased operation as a positioning and timing

system on December 31, 1996. Users should recognize that

navigational equipment using the NAVSAT system should

no longer be used since any signals received will no longer

provide valid position or timing references.)

The Russian system is the Global Navigation Satellite

System (GLONASS). GLONASS became fully operational

in January 1996.

610B. GPS

GPS is a highly precise satellite-based radionavigation

system providing three-dimensional positioning, velocity,

and time information. GPS is an all-weather system with

continuous and worldwide coverage. GPS consists of three

segments: space, control, and user.

The Space Segment is composed of 24 operational

satellites in six orbital planes. The satellites operate in

circular 20,200 km (10,900 nm) orbits at an inclination

angle, relative to the equator, of 55 ̊ and with a 12-hour

period. The satellites are spaced in orbit so that at any time,

a minimum of six satellites are observable from any

position on earth, providing instantaneous position and

time information.

Each satellite transmits on two L band frequencies:

1575.42 MHz (L1) and 1227.6 MHz (L2). Three

pseudo-random noise (PRN) ranging codes are in use:

– The coarse/acquisition (C/A) code has a 1.023 MHz chip

rate, a period of one millisecond, and is used primarily to

acquire the P-code.

– The precise (P) code has a 10.23 MHz rate, a period of

seven days, and is the principal navigation ranging code.

– The Y-code is used in place of the P-code whenever the

anti-spoofing (A-S) mode of operation is activated.

L1 carries a P-code and a C/A-code. L2 carries the

P-code. A navigation data message is superimposed on the

codes. The same navigation data message is carried on

both frequencies. This message contains satellite

ephemeris data, atmospheric propagation correction data,

and satellite clock bias.

Selective Availability (SA), the denial of full accu

accomplished by manipulating the navigation m

orbit data (epsilon) and/or the satellite clock fre

(dither). Anti-spoofing (A-S) guards agains

transmissions of satellite data by encrypting the P-

form the Y-code.

The Control Segment consists of five monitor s

three of which have uplink capabilities, loc

Colorado, Hawaii, Kwajalein, Diego Garci

Ascension Island. The monitor stations use a GPS 

to passively track all satellites in view, accum

ranging data from the satellites’ signals. The info

from the monitor stations is processed at the 

Control Station (MCS), located in Colorado S

Colorado, to determine satellite orbits and to upd

navigation message of each satellite. The 

information is transmitted to the satellites via 

antennas. The ground antennas, located at Kw

Diego Garcia, and Ascension Island, are also u

transmitting and receiving satellite control informa

The User Segment consists of antenna

receiver-processors that provide positioning, veloc

precise timing to the user. The GPS receiver 

time-of-arrival measurements of the satellite sig

obtain the distance between the user and the satelli

distance calculations, known as pseudoranges, t

with range rate information, are converted to yield 

time and the user’s three-dimensional position and 

with respect to the satellite system. A time coord

factor then relates the satellite system to earth coor

A minimum of four pseudoranges are needed to pr

three-dimensional fix (latitude, longitude, and a

GPS receivers compute fix information in terms 

World Geodetic System (1984), which may need 

shift correction before it can be accurately plotte

chart.

There are three different types of receivers. Se

receivers track only one satellite at a time, computi

after a series of pseudoranges have been sequ

measured; these receivers are inexpensive bu

Continuous receivers have at least four channels to 

information from several satellites simultaneously

process fix information the fastest. Multiplex r

switch at a fast rate from satellite to satellite, receiv

processing data from several satellites simultan

producing a fix by a sort of “round-robin” process.

GPS provides two levels of service for 

determination:

– The Standard Positioning Service (SPS) for 

public use. (Until 1 May 2000, the SPS signal a

was intentionally degraded to protect U.S. 

security interests through the process of S

Availability.)

– The encoded Precise Positioning Service (PPS) p

intended for use by the Department of Defense.
LONG RANGE NAVIGATIONAL AIDS

6 - 11

Accuracy of a GPS fix varies with the capability of the

user equipment. SPS is the standard level of positioning

and timing accuracy that is available, without restrictions,

to any user on a continuous worldwide basis. SPS provides

positions with a horizontal accuracy of approximately 100

meters. (This accuracy specification includes the effects of

SA.) PPS provides full system accuracy to designated

users. Selective Availability was set to zero (ceased) as of

midnight (EDT) 1 May 2000. Users should experience a

GPS horizontal accuracy of 10-20 meters or better.

NOTE: The following information is provided for

informational purposes only and does not relieve any

existing domestic or international safety, operational, or

material requirement:

It has come to the attention of the U.S. Coast Guard and

Federal Communications Commission that certain

consumer electronics-grade active VHF/UHF marine

television antennas are causing operational degradation in

the performance of GPS receivers. This interference may

be realized as a display of inaccurate position information

or a complete loss of GPS receiver acquisition and

tracking ability.

The interference is not limited to the GPS equipment

onboard the vessel with the installed active marine

television antennae. There have been reports of

interference occurring on other vessels and installations

operating up to 2000 feet away from vessels using such

antennas.

In one particular case, the interference caused the

position of the vessel as displayed on the electronic chart to

move erratically and dramatically, often across large

expanses of land. Various data displays indicated

erroneous information such as excessive speeds. In these

instances the problem would occasionally correct itself

while at other times required resetting the system.

If you are experiencing recurring outages or degradation

of your GPS receiver you should perform an on-off test of

your TV antenna. If turning off the power to the antenna

results in improvement in the GPS receiver performance,

the antenna may be the source of interference in the GPS

band. In that case, you should contact the manufacturer of

the antenna and identify the symptoms. If the test is not

positive and the GPS interference persists, contact the

watchstander at the Coast Guard Navigation Information

Service at:

Telephone: (1) 703-313-5900.

E-mail: nisws@navcen.uscg.mil.

The following antennae models were indentified during

investigations of GPS interference:

– TDP (Tandy Distribution Products) Electronics - MINI

STATE Electronic Amplified UHF/VHF TV Antenna -

Models 5MS740, 5MS750, 5MS921

– Radio Shack Corporation - Long Range Amplified Omni

Directional TV Antenna - Model 15-1624

(For further information see:

http://support.radioshack.com/SUPPORT_VIDEO/DOC

68/68779.HTM)

– Shakespeare Corporation - SeaWatch - M

2040/Code Date 02A00, 2050/Code Date 03A00 

Dates are found on the antenna power supply.)

(For further information see:

http://www.shakespeare-marine.com/ANTENNAS

AFETYALERT-TVANTENNAS.HTM

610C. DGPS

The U.S. Coast Guard Navigation Center operat

Maritime Differential GPS (DGPS) Service an

developing Nationwide DGPS (NDGPS) Se

consisting of two control centers and over 60 r

broadcast sites. The service broadcasts correction s

on marine radiobeacon frequencies to improv

accuracy of and integrity to GPS-derived positions

system is operated to International Telecommunic

Union (ITU) and Radio Technical Commissio

Maritime Services (RTCM) standards. More than 

foreign maritime nations have implemented sta

DGPS services modeled after the U.S. Coast G

system to significantly enhance maritime safety in 

critical waterways.

The U.S. Coast Guard’s Maritime DGPS S

provides 10-meter (2 dRMS) navigation accuracy 

established coverage areas, integrity alarms for GP

DGPS out-of-tolerance conditions within 10 secon

detection, and an availability of 99.7% per m

Typically the positional error of a DGPS position is 

meters, greatly enhancing harbor entrance and app

navigation. The system provides service for c

coverage (to a minimum range of 20 nm from shore) 

continental U.S., the Great Lakes, Puerto Rico/U.S. 

Islands, portions of Alaska and Hawaii, and a greate

of the Mississippi River Basin.

DGPS reference stations determine range error

generate corrections for all GPS satellites in view

DGPS signals are broadcast, using existing Coast 

radiobeacons, on frequencies in the 285-325 kHz 

Monitor stations independently verify the quality 

DGPS broadcast.

The Maritime DGPS service achieved Full Opera

Capability (FOC) on 15 March 1999. The Coast 

advises that Coast Guard DGPS broadcasts should n

used under any circumstances where a sudden s

failure or inaccuracy could constitute a safety h

Users are further cautioned to use all available naviga

tools to ensure proper evaluation of positioning solut

The U.S. Department of Transportation is coordi

the implementation of the Nationwide DGPS (ND

Service. NDGPS is an expansion of the Maritime D

network and, when complete, this service will pr

uniform differential GPS coverage of the continenta

and selected portions of Hawaii and Alaska regardl

terrain, man made, and other surface obstructions

predictable accuracy of the NDGPS service with

established coverage areas is specified 10 meters (2d

or better. Typical system performance is better than 1 

in the vicinity of the broadcast site. Achievable acc

degrades at an approximate rate of 1 meter for each 1
LONG RANGE NAVIGATIONAL AIDS

6 - 12

distance from the broadcast site. The service also provides

a GPS integrity monitoring capability; it gives an alarm to

users within 6 seconds of detecting a fault with the signal

from any GPS satellite in view. Availability, on a per site

per month basis, will be 99.9% for dual coverage areas and

99.7% for single coverage areas. The NDGPS Service will

achieve FOC when it provides dual coverage of the

continental U.S. and selected portions of Hawaii and

Alaska with single coverage elsewhere.

A complete list of all U.S. Coast Guard DGPS broadcast

sites is available from the Navigation Center. For further

information and/or operational questions regarding GPS or

DGPS, or to report GPS/DGPS service degradations,

outages, and other incidents or anomalies, contact:

COMMANDING OFFICER

U.S. COAST GUARD NAVIGATION CENTER

7323 TELEGRAPH ROAD

ALEXANDRIA VA 22315-3998

Telephone: (1) 703-313-5900.

Fax: (1) 703-313-5920.

The Navigation Information Service (NIS) is internet

accessible through the U.S. Coast Guard Navigation

Center Website at:

http://www.navcen.uscg.gov/

http://www.navcenter.org (Mirror site)

610D. GLONASS

The Russian Global Navigation Satellite System

(GLONASS), similar to GPS, is a space-based navigation

system that provides continuous, global, all-weather,

precise position, velocity and time information. The space

segment consists of 24 satellites in three orbital planes at

an altitude of 19,100 km. The satellites operate in 

orbits with an inclination of 64.8 ̊ and a period of 1

All satellites transmit simultaneously, using two 

frequencies in the L band, to allow users to cor

ionospheric delays of the transmitted signals. H

each satellite is allocated a particular frequency wi

band, determined by the frequency channel numbe

satellite. These different frequencies allow the 

receiver to identify the satellite. The L1 band rang

1602.5625 MHz to 1615.5 MHz in increments of 

MHz, while the L2 band ranges from 1246.4375 

1256.5 MHz in increments of 0.4375 MHz. Superi

to the carrier frequency, the GLONASS satellites m

their navigation message by using either or both 

MHz precision (P) code and/or and a 0.51

coarse/acquisition (C/A) code. The satellites also t

ephemeris data, an almanac of the entire constellat

correction parameters to the time scale. The coo

system of the GLONASS satellite orbits is defined 

PZ-90 system, formerly the soviet Geodetic 

1985/1990.

The Coordinational Scientific Informational 

(CSIC) of the Russian Space Forces provides 

information on GLONASS status and plans, info

and scientific method services to increase the effici

GLONASS applications. For further information co

CSIC OF RUSSIAN SPACE FORCES

PO BOX 14

MOSCOW 117279

RUSSIA

Telephone: 7 095 333 72 00.

Fax: 7 095 333 81 33.

E-mail: sfcsic@space.ru.

Internet: http://www.glonass-center.ru/frame_e.h