CORS

NGS No Longer Updates Published CORS Coordinates in the Following Reference Frames


Table Composite coordinate files and transformation parameters for frames no longer supported at CORS sites.

Composite Coordinate Tables Explain Transformation Parameters Explain

Ended support 6 Sep 2011

ITRF00    epoch 1997.00
x, y, z; Vx, Vy, Vz

ITRF00    epoch 1997.00
lat, lon, height; Vn, Ve, Vu

 Not applicable


Ended support 6 Sep 2011

NAD 83(CORS96,MARP00,PACP00)
epoch 2002.00
x, y, z; Vx, Vy, Vz

NAD 83(CORS96,MARP00,PACP00)
epoch 2002.00
lat, lon, height; Vn, Ve, Vu

 ITRF00 --> NAD83 (CORS96)
[12 common points at the ARP]
t0 = 1997.0
x(t0) = 0.9956 m; y(t0) = -1.9013 m; z(t0) = -0.5215 m
x(t0) = 25.915 mas; y(t0) = 9.426 mas; z(t0) = 11.599 mas
s(t0) = 0.62 · 10-9 (unitless)
x = 0.0007 m · year-1; y = -0.0007 m · year-1; z = 0.0005 m · year-1
x = 0.067 mas · year-1; y = -0.757 mas · year-1; z = -0.051 mas · year-1
= -0.18 · 10-9 year-1
Ended support 2002
Not Available
ITRF97 --> NAD83 (CORS96)
[12 common points at the ARP]
t0 = 1997.0
x(t0) = 0.9889 m; y(t0)= -1.9074 m; z(t0) = -0.5030 m
x(t0) = 25.915 mas; y(t0) = 9.426 mas; z(t0) = 11.599 mas
s(t0) = -0.93 · 10-9 (unitless)
x = 0.0007 m · year-1; y = -0.0001 m · year-1; z = 0.0019 m · year-1
x = 0.067 mas · year-1; y = -0.757 mas · year-1; z = -0.031 mas · year-1
= -0.19 · 10-9 year-1
 
Ended support in 2000
No Tables Available
ITRF96 --> NAD83 (CORS96)
[12 common points at the ARP ]
t0 = 1997.0
x(t0) = 0.9910 m; y(t0) = -1.9072 m; z(t0) = -0.5129 m
x(t0) = 25.79 mas; y(t0) = 9.65 mas; z(t0) = 11.66 mas
s(t0) = 0.0 (unitless)
x = y = z = 0.0
x = 0.0532 mas · year-1;y = -0.7423 mas · year-1;z = -0.0316 mas · year-1
= 0.0
 
Ended Support 1998
No Tables Available
ITRF94 --> NAD83 (CORS94)
[8 common points at the L1 phase center]
t0 = 1996.0
x(t0) = 0.9738 m; y(t0) = -1.9353 m; z(t0) = -0.5486 m
x(t0) = 27.55 mas; y(t0) = 10.05 mas; z(t0) = 11.36 mas
s(t0) = 0.0 (unitless)
x = y = z = 0.0
x = 0.09 mas · year-1; y = -0.77 mas · year-1; z = 0.02 mas · year-1
= 0.0
 
Ended Support 1996
No Tables Available
ITRF93 --> NAD83 (CORS93)
[9 common points at the L1 Phase Center]
t0 = 1995.0
x(t0) = 0.9769 m; y(t0) = -1.9392 m; z(t0) = -0.5461 m
x(t0) = 26.40 mas; y(t0) = 10.10 mas; z(t0) = 10.30 mas
s(t0) = 0.0 (unitless)
x = y = z = x = y = z = = 0.0
 

Explanation of the Table

The available composite tables contain sites that have both computed and modeled velocities.
Transformation Coefficients are applied to the equations shown below to transform from the specificed global frame e.g. ITRF00 to NAD 83 by NGS.

xNAD83 = x(t) + [1+s(t)] · xITRF + z(t) · yITRF - y(t) · zITRF
yNAD83 = y(t) - z(t) · xITRF + [1+s(t)] · yITRF + x(t) · zITRF
zNAD83 = z(t) + y(t) · xITRF - x(t) · yITRF + [1+s(t)] · zITRF
x(t) = x(t0) + x · (t-t0)
y(t) = y(t0) + y · (t-t0)
z(t) = z(t0) + z · (t-t0)
x(t) = [x(t0) + x · (t-t0)] · mr
y(t) = [y(t0) + y · (t-t0)] · mr
z(t) = [z (t0) + z · (t-t0)] · mr
s(t) = s(t0) + · (t-t0)
mr = 4.84813681×10-9 , conversion factor from milli-arcseconds (mas) to radians
x(t0),y(t0), and z(t0) are differential rotations about the xITRF, yITRF, and zITRF axes respectively.
The sense of the rotations is counterclockwise (anticlockwise) positive.
Note.- The equations given above serve to transform ITRF positional coordinates (xITRF, yITRF, zITRF) whose epoch date is at time t to NAD 83 positional coordinates (xNAD83, yNAD83, zNAD83) for this same epoch date.
Positional coordinates for a different epoch date (and for a particular reference frame) can only be obtained by knowing the velocity of the point in this reference frame.
For more information consult the following paper

CORS Data