About BLAST, VORF, MSS and LAT. Dr Ole B. Andersen, … BLAST, VORF, MSS and LAT. Dr Ole B. Andersen, DTU Space, Copenhagen, Denmark,

About BLAST, VORF, MSS and LAT.

Dr Ole B. Andersen,

DTU Space,

Copenhagen, Denmark,

2 DTU Space, Technical University of Denmark

VORF and BLAST

•VORF = Vertical Offshore Reference Frame

•A set of mathematical models of the major surfaces used in the current and “future charting”

•A suite of software utilities allowing the transformation of mapping and positioning data between the VORF surfaces

•UKHO established first demonstrator UK-VORF for Britain in 2007

•UK-HO is currently extending VORF ???

•BLAST established North Sea VORF in 2011


BLAST (EU 7th Interreg FW project)

"Bringing Land and Sea Together“ (BLAST),

–by harmonizing and

integrating on+offshore

data.

Creating a VORF

With matematical

Transformations.


Blast/VORF computation method



Tide gauge



Tide gauge

MSS



Tide gauge

MSS MSS (altimetry)



Tide gauge

geoid

MSS MSS (altimetry)



Tide gauge

geoid

MSS MSS (altimetry)5km interpolate



Tide gauge

Altimetric LAT= VORF


How to derive the MSS Satellite Altimetry

Ground Tracks

ENVISAT

TOPEX

JASON

GFO

ERS1/2


GPS vs MSS

DTU10MSS-Special NoIB version

Derived.

320 GPS measured Tide Gauges

Around Britain.

TG – MSS (extrapolated)

Mean = 1.24 cm (DNSC08)

Std = 6.8 cm

Upgrading MSS to DTU10

Comparison curtesy by

Marek Ziebart, UCL London,


GPS vs MSS

DTU10MSS-Special NoIB version

Derived.

320 GPS measured Tide Gauges

Around Britain.

TG – MSS (extrapolated)

Mean = 1.24 cm (DNSC08)

Std = 6.8 cm

Upgrading MSS to DTU10

Mean = 0.11 cm (DTU10)

Comparison curtesy by

Marek Ziebart, UCL London,


Run the tide model for 19 years to find minimum


Run the tide model for 19 years to find minimum


country LAT CD

B Grid No

D Grid (part of NS territorial

region)

No

F Available but Outside Available

but outside

DK Defined by 8 points

Recommend GOT4.7 LAT

No

N Defined by 3 points

Uses GOT4.7 LAT

No

NL Grid No

UK Grid Grid

MARINE:

VRF program includes the following

National LAT / CD datums

All implemented on to common highresBLAST grid

Associated coverage file associated with each grid

Informs on ”reliable coverage”


country LAT CD

B Grid No

D Grid (part of NS territorial

region)

No

F Available but Outside Available

but outside

DK Defined by 8 points

Recommend GOT4.7 LAT

No

N Defined by 3 points

Uses GOT4.7 LAT

No

NL Grid No

UK Grid Grid

MARINE:

VRF program includes the following

National LAT / CD datums

All implemented on to common highresBLAST grid

Associated coverage file associated with each grid

Informs on ”reliable coverage”


Backup slides -


Blast transformation program

Created a ”command line”

Interface program.

Development of User

interface baced

On response from users


Outlook

Satellite derived MSS and Ocean Tide LAT applicable.

Could be established and quality controlled for the Arctic.

UKHO – UK Navy currently extending VORF with global DTU10MSS

UK VORF + BLAST paved the road

Must be integrated with local data to enhance local modelleing.

Implementing ”error handling”


Arctic Ocean TPX 7.2 vs GOT 4.7 DTU10 vs GOT 4.7


BLAST Reference

surface

EGG02008 Geoid (N)

Numbers are

GPS levelling height

Hellip-Hlevel-N

Clear tilt in the UK

Levelling data.


EVRF-EGG Transformation

The EVRF2007 based surfaces (land) will be

Tranformed via the the EGG08 geoid.

The surface “EVRF-DIF” has been modelled to handle this.

And this is implemented in the BLAST program.


BLAST LAT surface

Based on DTU10

Ocean tide model

Identical to within 5 cm of

GOT4.7 ocean tide model


Blast transformation programInput / Output

• Input specify which country and ”system” you are in

#The data is as follows:

#ID lat lon h country system

pt1 55.1 8.4 2 1 1

2 56.3 9.8 3.7 2 1

33 57.8 10.34 4 2 1

hgt 57.8 10.321 43.5 8 5


MSS from Satellite Altimetry


The DNSC08 Mean Sea Surface

– First purely Geometrical MSS – Mean 1993-2004 period

– Derived from T/P, T/P TDM, ERS1 ERM+GM, ERS2 ERM, ENVISAT, Geosat GM, GFO

– Total 12 years of data using T/P + Jason-1 as reference

– The MSS has been derived in the Mean Tide System

– NEW!!!! DTU10 Available – Mean 1993-2009

– Vertical Accuracy 4-6 cm deep ocean best - less accurate close to coast

Want complete coverage in space and time”

”Get the best out of ERM (Variability averaged out) and GM (high spatial resolution)”

MSS = MDT + Geoid

Model(Name)

T/P data

Years

Res

KMS04

CLS01

GSFC00/00.1.

KMS01

NCU01

GSFC98

CLS-SHOM 98,

KMS98

CSR95

OSU95

9 (93-01)

7 (93-99

7 (93-99)

7 (93-00)

6 (93-98)

3 (93-95)

3 (93-95)

3 (93-95)

2 (93-94)

1 (93-93)

2

2

2

2

2

2

2

3.75

3.75

5


MDT (DNSC08MSS-EGM2008 = DNSC08MDT)


Hantenna(t) = HLaser (t) + Hoffset

Hlaser(t)=Hpitch+Hspeed+Hpoint+Hweight+Hbow-wave

GPS PPP processing

TIDE SYSTEMS

GPS TIDE FREE!!!!!!!


Latitude (degrees)

Sea S

urf

ace H

eig

ht

(mete

rs)

28,5 30 31,5 33 34,5 36 37,5 39 40,5 42-1,2

-0,8

-0,4

0

0,4

0,8

1,2

1,6

2SSH - Tides not removedSSH - Tides RemovedDNSC08 MDT - no IB

Hantenna(t) = HLaser (t) + Hoffset

Hlaser(t)=Hpitch+Hspeed+Hpoint+Hweight+Hbow-wave

GPS PPP processing

TIDE SYSTEMS

GPS TIDE FREE!!!!!!!


A good MSS and Geoid -> Good MDT

MDT = DNSC08MSS – NAT04G


DNSC08MSS-LAT47 (Ref to GRS80)

About BLAST, VORF, MSS and LAT. Dr Ole B. Andersen, … BLAST, VORF, MSS and LAT. Dr Ole B. Andersen, DTU Space, Copenhagen, Denmark,

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