Dynamic Response Test

The Dynamic Response Test option (UCERESPONSED GX) is called from the Instrument Response Test option to perform a dynamic test of the instrument response over known targets.

Dynamic Response Test dialog options

Line To compare	Line name of the database to calibrate Script Parameter: UCERESPONSED.TESTLINE
Reference Line	Line name of the first line in the database Script Parameter: UCERESPONSED.FIRSTLINE
Target Channel	Name of the channel for target measurement Script Parameter: UCERESPONSED.TARGETCHAN
Main direction Channel	Name of the main direction channel. If a perpendicular direction channel is specified (below) then the resultant distance along the survey line will be calculated and used for the instrument position. Script Parameter: UCERESPONSED.MAINDIRCHAN
Orthogonal direction Channel	Name of the perpendicular direction channel (optional). If this entry is left blank then only the main direction channel will be used for the instrument position along the test line. Script Parameter: UCERESPONSED.PERPDIRCHAN
Target Position (Comma-Separated)	List of the positions of the known target along the main direction, separated by comma (,), ex) 402800, 402810, 402820. Script Parameter: UCERESPONSED. TARGETLOCS
Tolerance: Peak level (%)	If the amplitude difference between the peaks at the specified locations exceeds this percentage, the peak is marked with a red marker, otherwise it is marked with a blue marker. Script Parameter: UCERESPONSED.TOLERENCE
Project	Name of the project. This parameter defaults to the project name specified earlier Script Parameter: UCERESPONSED.PROJECT
Instrument	Name of the instrument the data of which is represented. Script Parameter: UCERESPONSED.INST
Grid/Location	Name of the grid Script Parameter: UCERESPONSED.GRID
Operator	Name of the operator Script Parameter: UCERESPONSED.OPERATOR

Application Notes

Dynamic tests along a survey line are necessary in order to measure motional and terrain noise. Emplacement of one or more calibration objects permits evaluation of amplitude response. A repeated dynamic test survey line also measures positional variation. This test should be ideally collected twice a day: at the beginning of the day’s survey and at the end of the day.

Conducting a Dynamic Response Test

1. Establish an area for the static test that offers convenient access, is free of metal (surface and sub-surface), and is sufficiently far from roads and power lines, transmitters, etc. to avoid these sources of noise. This same location should be used throughout the duration of the project for daily static (background) test and response tests and for nulling instruments. On large sites, multiple test points may be necessary.

2. Lay out a survey line with clearly marked start and end locations for daily positional consistency. Place at least one known calibration object with a known amplitude response (e.g. a 2" diameter steel trailer hitch ball) either at an appropriate depth or along this line.

3. Allow the instrument to warm up for at least 5 minutes. During cold weather a longer warm-up time may be required to achieve steady readings. Careful observation of the displayed response should then be made (using the Null/Monitor screen). When the levels of noise are acceptably low, data collection may begin.

4. Place the instrument at its normal operating height and begin data collection.

5. Data collected during static tests should be retained for documentation purposes and can be analyzed daily using the UCERESPONSED GX.

The purpose of the UCERESPONSED GX is to inspect the consistency of the instrument response throughout the course of the project. Dynamic calibration data should be collected daily, imported, and be stored in a calibration database.

Data for the dynamic response test must be imported into one database and that database must be loaded and selected as current prior to running the GX. There must be two or more lines to perform the dynamic response analysis.

Normally the first line in the database is the "Reference Line" to which all other responses will be compared ("Line To Compare"). The user would specify the target position(s) in the same distance units as the collected survey data. The tolerance (%) is also specified by the user to determine what percentage of positional accuracy is required.

The GX produces a figure of profiles of consecutive days for visual inspection. By default, the map will have the same name as the database used to calculate the instrument response.

On the resulting figure, three profiles are drawn:

(1) The top profile graph shows the reference (displayed in red) and comparison profiles (displayed in blue). Grey vertical lines and triangles are the target position(s), as specified by the user. At each target location, the value of the comparison and reference profile are compared and triangles are filled with red if the difference between the two values exceeds the "Tolerance: Peak Level". Triangles are blue if the difference is within the tolerence and green if no value is available for the profiles at that position. Triangles placed at the bottom represents the first half of the profile and triangles placed at the top are for the second half of the profile.

(2) The middle profile graph shows all of the profiles accumulated to date (displayed in grey) and the current profile (displayed in blue).

(3) The bottom graph is a scatter graph which depicts a least square fit of the reference profile against the comparison profile. The scatter plot is best displayed as a logarithmic plot. The minimum of the logarithmic plot must be a positive number. Since the intent of the scatter plot is to represent the relative scatter as opposed to the absolute values, the data is shifted to reside in the positive zone. The amount of this "Shift" is displayed on the map.

Acknowledgments

The following document has been used in the compilation of this Help file, and further information can be obtained directly from it: