Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
-
Upload
conselho-nacional-de-praticagem -
Category
Documents
-
view
221 -
download
0
Transcript of Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
1/27
Photoc
ourtesyofFlindersPorts
GPS Technologies in PPUs
Clarifying some misunderstandings
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
2/27
Our staff:
Experienced mariners
Marine electronics experts
PPU experts
Our customers:
Government Marine Departments
Port Authorities
Terminal operators
Pilotage companies
Independent pilots
Large oil & gas corporations
Coast Guards
In over 25 countries
Our Company
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
3/27
Producing PPUs since 2003
Supported by world-leading software, electronics and GPS experts
Presented and published a wide variety of industry papers
Industry members of bodies such as IHMA
Experience
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
4/27
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
5/27
What is a PPU (Portable Pilot Unit)?
Is it the display? (Laptop, Tablet, iPad, etc)
Is it the Software? (Basic, Advanced)
Is it the sensor equipment?
Ship-based (normally via AIS interface)
Wired (AIS Cable)
Wireless (AISPilot)
Independent GPS
Single GPS antenna
Without gyro assistance (LightPilot)
With gyro assistance(ChannelPilot)
Semi independent heading/ROT
Dual GPS antenna (HarbourPilot)
Fully independent heading/ROT
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
6/27
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
7/27
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
8/27
Wired and Wireless AIS
connectors
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
9/27
Single antenna GPS with and
without gyro assistance
LightPilot
(no gyro)
ChannelPilot
(with gyro assistance)
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
10/27
Dual antenna
(fully independent system)
HarbourPilot
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
11/27
Only as good as the data from the sensors
Only as good as the software being used
Only as good as the chart on which its displayed
Only as good as the level of training of the user touse it
This presentation will concentrate on the datageneration aspects
A lot of confusion over accuracy and terminology
The PPU is the combination of all the above
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
12/27
Basic GPS (iPhone/Android/handheld GPS)
15-30m
Basic GPS with DGPS corrections
10-15m
High quality GPS
2-3m
High quality GPS with DGPS corrections
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
13/27
Any GPS will give you a position
But knowing the position only tells you where the
antenna is
It doesnt tell you where the bow or the stern are
The most important factor is:
HEADING
(Proa)
But - whats the most important factor?
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
14/27
Ship points in wrong direction on screen
Position showing with 15m error circle
What happens if we dont know heading?
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
15/27
Position with 2m error
What happens if we dont know heading?
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
16/27
If ship is moving, the heading will follow COG, not true
heading
What happens if we dont know heading?
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
17/27
If we add the true heading, with ROT as well, we get a
much better image of what is happening
What happens if we dont know heading?
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
18/27
Ships gyro via AIS Pilot Plug
Gyro error
Whole-degree rounding
Gyro-assisted PPU
Single-antenna system with gyro assistance
Eg ChannelPilot
Fully independent PPU
Dual antenna system
Eg HarbourPilot
Where does heading come from?
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
19/27
Antennas 1.6m apart = 0.1 deg error (95%)
Error at bow (250m distance) =
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
20/27
GNSS (Global Navigation Satellite System) GPS American System
GLONASS Russian System
Beidou (Compass) Chinese System
Dual Frequency
L1/L2
Making Position more accurate
DGPS (Ground-based)
SBAS (Space-Based Augmentation Systems)
(WAAS/EGNOS/MSAS/GAGAN)
RTK (Real Time Kinematic)
A little about terminology?
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
21/27
For position accuracy absolutely NO! Glonass by itself is less accurate than GPS
GPS + GLONASS is not possible (clock systems areincompatible)
Only advantage is it gives an alternative system whenGPS reception is poor
For heading accuracy Yes.
More data for heading computer to use
Heading is calculated quicker and more reliably
Allows for greater antenna separation (dual antennasystems)
Single antenna systems
Glonass does very little except provide redundancy
Do I need GLONASS as well as GPS?
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
22/27
For position accuracy a qualified yes, but notmuch
Civilian users cannot use the all the data from the L2 freq
Addition of L2 data helps to reduce Ionospheric errors
For heading accuracy Yes.
More data for heading computer to use
Heading is calculated quicker and more reliably
Allows for greater antenna separation in dual antennasystems
Single antenna systems for pilotage
Dual frequency is not so important
Do I need Dual Freq (L1/L2)?
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
23/27
Yes but not so much for the absolute positionalinformation itself
How accurately do you measure your antenna offsets?
How accurate is the chart?
Pilots use their eyes
Velocity data is improved if position is moreaccuracy
Do I need better posit ion accuracy?
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
24/27
Dont rely on AIS (notoriously poor data) Single antenna PPU
Make sure its gyro integrated (eg ChannelPilot)
Dual antenna systems
By putting the antennas further apart
Add GLONASS for more data
Add L2 frequency for more data
How do I make heading more accurate?
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
25/27
Dual antenna systems
For Position accuracy
DGPS is fine.
RTK adds a little but really only to velocity
For Heading accuracy
Glonass and dual freq allow greater antenna separation hence moreaccurate
Single antenna systems
Get the best you can
Be gyro-integrated
In summary 1
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
26/27
Most important of all..
Dont forget to look out the window
This is not a video game!!!
Its just an aid no different from any other aid
In summary 2
-
7/27/2019 Peter Selwyn Gps Technologies in Ppus Claryfing Some Misunderstandings
27/27
MUCHAS GRACIAS
MUITO OBRIGADO
THANK YOU