New Job (or Project-New)

Setting the Projection & Dimension switch (Automatically appears)

Options | General | Geometry

In the Geometry tab sheet the dimension of the solution can be changed. If you are working only in 2D make sure the dimension switch is correctly set.

Setting the Projection

One of the first things to be done is Set the Projection this is important to work in your

Local XY coordinates.

OPTIONS – GEOMETRY – MORE

Select which MGA94 zone you are in.

(Note: If you want to work with ellipsoidal coordinates you can use the Projection: None. If

you want to work Easting Northing (XY) set the appropriate MGA 94 zone projection.

OPTIONS – GEOMETRY – MORE Australia

Set the correct unit settings

OPTIONS – GENERAL – UNITS

Setting the Parameters for Standard deviations for observations and for stations

OPTIONS – STANDARD DEVIATIONS

OPTIONS-LOAD

Use this command to LOAD options from another project file (*.PRJ) or a previous saved options file (*.OPT). This way your options, parameter settings are set for another project and can be used instead of setting the same options all over again using the options tab sheets. The Options LOAD command opens a File Open dialog box where an option or project file can be selected.

OPTIONS – ADITIONAL PARAMETERS – GPS

IMPORT/EXPORT – GPS BASELINES

Check OPTIONS – GENERAL – PROJECT the terrestrial Observations and Coordinates and

GPS Observations & Coordinates. If applicable set the Geoid model SGEOID09

Set the Phase to Free Network OPTIONS – GENERAL – ADJUSTMENT and check the box

Inner Constraint. With the Inner Constraint option it is not necessary to provide any known

points for a Free network adjustment. With the Inner Constraint checked MOVE3 will solve

the rank deficiency by adding additional constraints (Centre of Gravity, orientation and

scale). If the item is not checked adding the minimum number of known stations or the

selected base stations will solve the rank deficiency.

Adjust the free network using COMPUTE – MOVE3 and have a look at the results. Try to find

out what’s the reason to the largest rejections in the network.

Results - Report

MOVE3 has a number of tools to analyse the rejections. The output file contains a summary

of the largest rejections.

Largest W-tests: 1D-test (test for an error in a single baseline component);

Largest T-tests: 3D-test (test for an error in a complete baseline);

Largest tests for antenna height errors: 1D- test in the direction of the height system.

This test value will only be shown if only the height component of the baseline is

rejected.

The test value with the largest factor is the most suspect observation. This specific

observation can be deselected (Do not remove!) and then do a re-adjustment.

Rejections after the re-adjustment are also analysed.

In case a lot of rejections appear, it’s time to find out what’s wrong with the network.

Have a close look at the adjustment resulted and also make use of:

PRERUN3 to do a pre-analyses of the observations;

LOOPS3: to detect loops in the network and to compute closing errors in the loops.

Results – Test Summary

After running a MOVE3 adjustment computation, rejected items (observations and coordinates) can be viewed and edited with this command. In the Test Summary dialog box the type of the rejected item, the type of test, the factor and the station(s) are shown.

To edit a rejected item select one of the listed items and use View to jump to the Edit observation dialog box (for observations) or the Edit station dialog box (for coordinates). This specific observation can be deselected (Do not remove!)

Possible Problem

If you have a lot of rejected GPS baselines this may be caused by a too optimistic estimate

for the covariance matrix:

Usually the covariance matrix of the computed GPS baselines has overoptimistic values for

the standard deviations of the baseline components. When using the correlation matrix for

the precision of the GPS baselines this will result in rejections for almost all baselines, as in

this particular network. Standard deviations are about 1mm, which is rather optimistic. The

variance component analysis can be used to estimate the scaling factor for the stochastic

model. The variance component (from the F-test) is 122.606. Rescale the correlation matrix

with the factor SQRT (122.606) = 11.

Use VIEW – OBSERVATIONS – TOOLS change St. deviations and rescale the correlation for

the GPS baselines with a factor 11. Most of the rejections have disappeared. The remaining

rejections need to be solved. Record 23, baseline 1009-1005 is the largest rejection. From

the factors one can conclude that it is most likely an antenna height error. Deselect the

baseline record 23. The network is now accepted.

Import known coordinates

After the scaling of the correlation matrices of the baselines and a new adjustment the

network will be connected to known stations in the local MGA94 Zone.

Set the Check under OPTIONS – GENERAL – PROJECT for the terrestrial coordinates.

Import the known coordinates from the project with “KNOWN COORDINATES”

Via IMPORT/EXPORT – MOVE3 and adjust the network with COMPUTE – MOVE3

Combine adjustment of terrestrial and GPS observations

Terrestrial observations will be added to the GPS observations for a combined adjustment

Set the Check under OPTIONS – GENERAL – PROJECT for the terrestrial observations

Import the terrestrial observations using IMPORT/EXPORT

Compute all approximate coordinates from the network one by one until the F-test is

accepted.

Connection to the local system

After removing the rejections in the observations, the network can be connected to the

local system. Rejections that appear in this step will be caused by errors in the known

coordinates.

Phase

This determines the type of adjustment that will be performed:

free network for a free network adjustment with minimum constraint;

Pseudo constrained a pseudo least squares adjustment with pseudo least

squares precision (coordinates and standard deviations of

the known stations do not change in the adjustment);

weighted constrained for a weighted constrained adjustment (coordinates and

standard deviations of the known stations get a

correction);

absolute constrained for an absolute constrained adjustment (coordinates of

the known stations do not change, standard deviations of

these stations are fixed at zero).

Set the Phase to e.g. Pseudo Constrained to test the connection to the known

coordinates and compute the final adjusted coordinates.

Try and get an accepted F-test.

Setting the Phase Options – General – adjustment

Or via the Compute - Adjustment

Other options to viewing Base Lines

Click on Base Line to view and edit.

Wayne Pappas September 2012

MOVE3 ICT Helpdesk GIS ICT Australia

wtpappas@xs4all.nl