The
Elizabeth
Swann uses an advanced DGPS system to navigate the
Amazon river, as John
Storm and Dan
Hawk travel up the famous river to meet Charley
Temple.
A Differential Global Positioning System (DGPS) is an enhancement to the Global Positioning System (GPS) which provides improved location accuracy, in the range of operations of each system, from the 15-metre (49 ft) nominal GPS accuracy to about 1–3 centimetres (0.39–1.18 in) in case of the best implementations.
Each DGPS uses a network of fixed ground-based reference stations to broadcast the difference between the positions indicated by the GPS satellite system and known fixed positions. These stations broadcast the difference between the measured satellite pseudoranges and actual (internally computed) pseudoranges, and receiver stations may correct their pseudoranges by the same amount. The digital correction signal is typically broadcast locally over ground-based transmitters of shorter range.
The United States Coast Guard (USCG) and the Canadian Coast Guard (CCG) each run DGPSes in the United States and Canada on longwave radio frequencies between 285 kHz and 325 kHz near major waterways and harbors. The USCG's DGPS was named NDGPS (Nationwide DGPS) and was jointly administered by the Coast Guard and the U.S. Department of Defense's Army Corps of Engineers (USACE). It consisted of broadcast sites located throughout the inland and coastal portions of the United States including Alaska, Hawaii and Puerto Rico. Other countries have their own DGPS.
A similar system which transmits corrections from orbiting satellites instead of ground-based transmitters is called a Wide-Area DGPS (WADGPS) Satellite Based Augmentation System.
GEOGRAPHICAL VARIATIONS
DGPS can refer to any type of Ground-Based Augmentation System (GBAS). There are many operational systems in use throughout the world, according to the US Coast Guard, 47 countries operate systems similar to the US NDGPS (Nationwide Differential Global Positioning System). A list can be found at the World DGPS Database for Dxers.
EUROPEAN DGPS NETWORK
European DGPS network has been developed mainly by the Finnish and Swedish maritime administrations in order to improve safety in the archipelago between the two countries.
In the UK and Ireland, the system was implemented as a maritime navigation aid to fill the gap left by the demise of the Decca Navigator System in 2000. With a network of 12 transmitters sited around the coastline and three control stations, it was set up in 1998 by the countries' respective General Lighthouse Authorities (GLA) — Trinity House covering England, Wales and the Channel Islands, the Northern Lighthouse Board covering Scotland and the Isle of Man and the Commissioners of Irish Lights, covering the whole of Ireland. Transmitting on the 300-kHz band, the system underwent testing and two additional transmitters were added before the system was declared operational in 2002.
Effective Solutions provides details and a map of European Differential Beacon Transmitters.
UNITED STATES NDGPS
The United States Department of Transportation, in conjunction with the Federal Highway Administration, the Federal Railroad Administration and the National Geodetic Survey appointed the Coast Guard as the maintaining agency for the U.S. Nationwide DGPS network (NDGPS). The system is an expansion of the previous Maritime Differential GPS (MDGPS), which the Coast Guard began in the late 1980s and completed in March 1999. MDGPS covered only coastal waters, the Great Lakes, and the Mississippi River inland waterways, while NDGPS expands this to include complete coverage of the continental United States. The centralized Command and Control unit is the USCG
Navigation Center, based in
Alexandria, VA. There are currently 85 NDGPS sites in the US network, administered by the U.S. Department of Homeland Security Navigation Center.
In 2015, the USCG and USACE sought comments on a planned phasing-out of the U.S. DGPS. In response to the comments received, a subsequent 2016 Federal Register notice announced that 46 stations would remain in service and "available to users in the maritime and coastal regions". In spite of this decision, USACE decommissioned its remaining 7 sites and, in March 2018, the USCG announced that it would decommission its remaining stations by 2020. As of June 2020, all NDGPS service has been discontinued as it is no longer deemed a necessity owing to the removal of selective availability in 2000 and also the introduction of newer generation of GPS satellites.
CANADIAN DGPS
The Canadian system is similar to the US system and is primarily for maritime usage covering the Atlantic and Pacific coast as well as the Great Lakes and Saint Lawrence Seaway.
AUSTRALIA
Australia runs three DGPSes: one is mainly for marine navigation, broadcasting its signal on the long-wave band; another is used for land surveys and land navigation, and has corrections broadcast on the Commercial FM radio band. The third at Sydney airport is currently undergoing testing for precision landing of aircraft (2011), as a backup to the Instrument Landing System at least until 2015. It is called the Ground Based Augmentation System. Corrections to aircraft position are broadcast via the aviation VHF band.
The marine DGPS service of 16 Ground stations covering the Australian coast was discontinued from 1st July 2020. Improved multichannel GPS capabilities, and signal sources from multiple providers (GPS, GLONASS, Galileo and BeiDou) was cited as providing better navigational accuracy than could be obtained from GPS + DGPS. An Australian Satellite-Based Augmentation System (SBAS) project, led by Geoscience Australia (GA), will offer higher accuracy positioning for GNSS users within the next 2 - 3 years (as of September 2020).
GRAPHIC
BRIEF - SUGGESTED LAYOUTS/ 3 ISSUE FORMAT
PART
I - ISSUE 1.
CHAPTER
1. THE
POISON ASP - Overwhelmed by grief, Cleopatra poisons herself with a
cobra bite in her mausoleum
CHAPTER
2. WRATH OF THE GODS - The destruction of
Thonis and Alexandria
CHAPTER
3. NEW WORLD ORDER - A Neo-Nazi plan to regenerate Aryan supremacy
CHAPTER
4. CYBERCORE
GENETICA - Nano computer technology is purchased at an auction by a
religious sect
CHAPTER
5. INCUBUS - Franco Francisco accepts offer of employment
from Roberta Ferrara
CHAPTER
6. SPLICE
- Klaus von Kolreuter perfects a method of gene manipulation
CHAPTER
7. TREMORS - Cleopatra's
tomb lay lost for centuries, until shift in the tectonic
plates trigger tremor off the coast of Alexandria
PART
II - ISSUE 2.
CHAPTER
8. PANAMANIAN
RUNNING MAN - Marjorie Boyle videos exceptionally fast athlete, Sam Hollis
investigates
CHAPTER
9. AMAZON
QUEEN - Elizabeth Swann navigating river and
docking at Manaus
CHAPTER
10. TOMB
RAIDERS - Safiya
Sabuka and Musa
Bomani dive among sifting sands to discover
precious artifacts and golden treasures
CHAPTER
11. SCOTLAND
YARD - London's secure DNA database is stolen
CHAPTER
12. OPERATION
ALEXANDRIA - Neo-Nazi occultists recover Cleopatra's
sarcophagus from underwater tomb near Palace
CHAPTER
13. KIDNAPPED - Charley is taken prisoner, John, Dan and CIA rescue her
CHAPTER
14. UNESCO -
Catholic Church fear grave desecration heritage
theft, asks agencies for help. Interpol issue Red Notice
PART
III - ISSUE 3.
CHAPTER
15. REPLICANT - The Society reproduce Cleopatra using Francisco's
RepliVator™, uploading synapse sequence, implanted memories
CHAPTER
16. FULL STEAM AHEAD -
To
Thonis, then uses the Swann's AI
sensors and the Ark
database to find tomb has been plundered
CHAPTER
17. RITUAL SACRIFICE - The Baron prepares a drugged Cleopatra for ceremonial
impregnation
CHAPTER
18. SANCTUM
INTERRUPTUS - John finds Nazi hideout near Alexandria,
disturbs ritual - rescues Cleopatra, arresting conspirators
CHAPTER
19. THE CHOSEN ONE - The reincarnated Cleopatra falls for her rescuer. John comes under her
spell, despite her being a replicant
CHAPTER
20. MILITARY
INTERVENTION - Military detain Cleopatra for stakeholders, despite media
& medical protests. Storm distraught
CHAPTER
21. DÉJÀ VU - History repeats itself,
military lock up technology as gross violation of human rights, John left
disillusioned
BOOK CHAPTERS
CHAPTER
1. THE
POISON ASP - Overwhelmed by grief, Cleopatra poisons herself with a
cobra bite in her mausoleum
CHAPTER
2. WRATH OF THE GODS - The destruction of
Thonis and Alexandria
CHAPTER
3. NEW WORLD ORDER - A Neo-Nazi plan to regenerate Aryan supremacy
CHAPTER
4. CYBERCORE
GENETICA - Nano computer technology is purchased at an auction by a
religious sect
CHAPTER
5. INCUBUS - Franco
Francisco accepts offer of employment from Roberta Ferrara
CHAPTER
6. SPLICE
- Klaus von Kolreuter perfects a method of gene manipulation
CHAPTER
7. TREMORS - Cleopatra's
tomb lay lost for centuries, until shift in the tectonic
plates trigger tremor off the coast of Alexandria
CHAPTER
8. PANAMANIAN
RUNNING MAN - Marjorie Boyle videos exceptionally fast athlete, Sam
Hollis investigates
CHAPTER
9. AMAZON
QUEEN - Elizabeth Swann navigating river and
docking at Manaus
CHAPTER
10. TOMB
RAIDERS - Safiya
Sabuka and Musa
Bomani dive among sifting sands to discover
precious artifacts and golden treasures
CHAPTER
11. SCOTLAND
YARD - London's secure DNA database is stolen
CHAPTER
12. OPERATION
ALEXANDRIA - Neo-Nazi occultists recover Cleopatra's
sarcophagus from underwater tomb near Palace
CHAPTER
13. KIDNAP - Charley is taken prisoner,
John, Dan and CIA rescue her
CHAPTER
14. UNESCO -
Catholic Church fear grave desecration heritage
theft, asks agencies for help. Interpol issue Red Notice
CHAPTER
15. REPLICANT - The Society reproduce Cleopatra using Francisco's
RepliVator™, uploading synapse sequence, implanted memories
CHAPTER
16. FULL STEAM AHEAD -
To
Thonis, then uses the Swann's AI
sensors and the Ark
database to find tomb has been plundered
CHAPTER
17. RITUAL SACRIFICE - The Baron prepares a drugged Cleopatra for ceremonial
impregnation
CHAPTER
18. SANCTUM
INTERRUPTUS - John finds Nazi hideout near Alexandria,
disturbs ritual - rescues Cleopatra, arresting conspirators
CHAPTER
19. THE CHOSEN ONE - The reincarnated Cleopatra falls for her rescuer. John comes under her
spell, despite her being a replicant
CHAPTER
20. MILITARY
INTERVENTION - Military detain Cleopatra for stakeholders, despite media
& medical protests. Storm distraught
CHAPTER
21. DÉJÀ VU - History repeats itself,
military lock up technology as gross violation of human rights, John left
disillusioned