cadrcs usersmanual51

cadRCS

User’s Guide

The solution for RCS simulations

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Co-operation partners

Dr. H. Essen, FGAN, Germany Dr. Werner Kellner, WTD71, Germany

Marcus Güenter, Blohm & Voss GmbH, Germany Gregor Biegel, FGAN, Germany

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Table of Contents

User’s Guide............................................................................................................. 1 The solution for RCS simulations ............................................................................. 1 Co-operation partners............................................................................................... 2 Getting Started ......................................................................................................... 5

Installation............................................................................................................. 5 What you need to run cadRCS ............................................................................. 5 Hardware .............................................................................................................. 5 Software................................................................................................................ 5 CAD Changing file-format.............................................................................................. 5

Running cadRCS:..................................................................................................... 6 1. Starting cadRCS .............................................................................................. 6

1.1. File ............................................................................................................. 6 1.2. Settings...................................................................................................... 6

1.2.1. Export settings ........................................................................................ 6 1.2.2. Import settings ........................................................................................ 7 1.2.3. RCS settings........................................................................................... 7 1.2.4. Silhouette colour ..................................................................................... 8 1.2.5. Editing material numbers and reflection coefficient................................. 9

1.3. Actions ..................................................................................................... 10 1.3.1. Distance images ................................................................................... 10 1.3.2. RCS calculation .................................................................................... 10 1.3.3. Creating RCS images ........................................................................... 10 1.3.4. Creating error images ........................................................................... 10

1.4. Stop ......................................................................................................... 11 1.5. Exit........................................................................................................... 11

2. Geometrical set-up......................................................................................... 12 2.1 Aiming point (x,y,z) .................................................................................. 13 2.2 Rotation axis (x,y,z) ................................................................................. 13 2.3 First viewing point .................................................................................... 14 2.4 Number of viewing points......................................................................... 14 2.5 Inspection angle....................................................................................... 14 2.6 Frame size width/height ........................................................................... 14 2.7 Number of columns/rows ......................................................................... 14 2.8 Frame angle............................................................................................. 14 2.9 Near field calculation ............................................................................... 15 2.10 Default Aiming point................................................................................. 15 2.11 Default Frame size................................................................................... 16 2.13 Distance................................................................................................... 16 2.14 Angle to x-axis ......................................................................................... 16 2.15 Elevation angle ........................................................................................ 16 2.16 Use extended ray trace............................................................................ 16 2.17 Only process a partition of the Viewing points Process ........................... 16 2.18 Add water surface.................................................................................... 16 2.19 Process.................................................................................................... 16

3. Running cadRCS in the background .............................................................. 17

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4. Example of the cadRCS.ini file....................................................................... 17 5. Description of the ASCII output files............................................................... 19 6. Colours used in the cadRCS Hot Spot images............................................... 22 7. cadRCS theory............................................................................................... 22 8. Comparisons with measurements .................................................................. 23 9. Description of the micro (*.mic) files made by cadRCS.................................. 23 10. License agreement ...................................................................................... 25 11. Movie.exe – visualise the RCS results......................................................... 29 12. Object – background CAD program............................................................. 31 13. Example of running object and cadRCS in the background......................... 32

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Getting Started

Installation Insert the CD in your computer CD-ROM drive and follow the instructions. Attach the USB hasp to your computer. Run cadRCS and start with the demo.ini file.

What you need to run cadRCS

Hardware You need a PC with 2Gbytes of RAM, the extensive use of RAM is used by cadRCS to minimise the calculation time.

Software Windows XP/2000/NT is recommended, but any Windows system will work.

CAD You need a three dimensional Computer Aided Design (CAD) description of the ob-ject you want to RCS calculate. The CAD model has to be translated into a cadRCS readable file format; witch can be ASCII or binary STL files, Rhino1 RAW files or ASCII or binary NATO format files. Almost all CAD programs can save the CAD file in the STL file format. If you do not have a CAD program and just want to calculate the RCS of different objects, you can download different CAD files from the homepage: http://www.3dcadbrowser.com

Changing file-format

When you change the file-format of your CAD-model, make sure to use the metric system, all measurements has to be in meters. !!

1 Rhino is obtainable at www.rhino3d.com.

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Running cadRCS: 1. Starting cadRCS There are two ways of starting cadRCS; if you are starting a new project, you can choose to start cadRCS without a CAD file. Then you should add your project name at the menu file->Project name and working directory. Find or create a folder for your project. Then open your CAD file using file->open CAD file. It is then recom-mend to choose the default Aiming point and to use quadratic pixels. Then choose the first Viewing point for your calculation or set the viewing distance and angles. Use default frame size and go to the menu item Settings and chose RCS settings. Set the polarization and frequencies(s) of your calculation. Shut down cadRCS and save your initialising file under this process in your project folder. cadRCS has then made your project ready for RCS calculation of your CAD object; your CAD file is stored in your project folder in a binary NATO file format, which is necessary in order to add material properties. Then restart cadRCS, start with the *.INI file, and choose the file, that you just saved. Opening the *.INI file will load the binary NATO CAD model and the previously saved settings. The binary NATO file format is chosen in order to make quick ac-cess. General: !!

Illegal settings will create a red background in the box

1.1. File In the File menu new CAD models can be imported or added. The CAD model is now ready for RCS prediction. When you use cadRCS for the first time, it is recommended to use the default val-ues. You should always start a new project by selecting: file-> Project name and working directory giving the folder name and project name.

1.2. Settings In the Settings menu you can customize the RCS settings; polarization, frequency, High Resolution Range gate size etc. 1.2.1. Export settings

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Current settings can be saved in an *.INI file. 1.2.2. Import settings Settings used previously can be imported and edited. 1.2.3. RCS settings

Use RCS settings to set the polarization of the transmitter and the receiver(s). The main frequency is used in order to mark the RCS images with “HOT SPOTS”. The additional frequencies are for RCS-calculation only. The results of these calcu-lations are saved in text files. It is possible to operate with two receivers, which is normal when using circular po-larization. The High Resolution Range gate size must be set in metric units. The minimum RCS must be set in square meters. Minimum and maximum numbers of reflections are used to visualize the character of the “HOT SPOTS”. With a setting of three reflections or more, “HOT SPOTS” visible from a large spatial angle will be shown. If maximum number of reflections is set to one, only direct reflections will be calcu-lated. Only the maximum number of reflections affects the RCS calculations, which are saved in text files. Changing the minimum RCS will change the colour code of the “HOT SPOTS”. Recommended value is –30 dB.

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If the value is increased to e.g. –10dB, only “HOT SPOTS” of large intensity will be shown. It is only recommenced to use antenna gain factors when comparing calculations to real measurements. 1.2.4. Silhouette colour

Examples of the two different settings: The default setting (grey on blue):

and the other possibility (blue on white):

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1.2.5. Editing material numbers and reflection coefficient

If the CAD model contains any information about the materials (NATO and Polygon files) the material numbers are imported and set as default. If you wish to add a new material number, it is saved by subsequently adding it to your file under the file panel. The STL and Rhino files do not contain material numbers. After setting the first ma-terial number, save your file as NATO or Polygon file and add to your file for any further material numbers. Material number 9999 is reserved for sea surface. Import-ing CAD models for the first time, the description will be set to the file name without path and extension. The reflection coefficient and roughness must be set according to the material in question.

Incoming ray Random direction added to the reflected ray. The size is given by the roughness factor

Surface

Figure 1.1 The roughness factor affects only the direction of the reflected ray. Figure 1.1 shows the effect of changing the value. A large value (>0.0001) will result in differ-ent calculation results for the same settings.

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1.3. Actions

1.3.1. Distance images If you use the model for the first time, you could start by creating only a distance image of your object. In this way you can make sure that your CAD model has been translated into the correct format, and you will get a quick first picture. 1.3.2. RCS calculation In this menu you switch on RCS calculation. When switching on the RCS calculation you will be prompted to save your results in a text file. This is necessary for RCS calculations to start. 1.3.3. Creating RCS images If you want to create RCS images you will be prompted to save your results in a micro or bitmap file. The micro file format is a compact file format used by cadRCS, it contains all the results of the calculation and the file format can be used by the program movie.exe. If you want the format of this file for your own use, the format can be sent to you. Please contact: [email protected]. !! .

If RCS-calculation is not switched on, you will also be prompted to save the calculation result in a text-file. If you cancel, the calculations will be cancelled.

If you want to watch the RCS images without saving the images in a file, switch only RCS calculation on. 1.3.4. Creating error images The error images will show when the object is too complicated for RCS calculations to be reliable. If you choose error images you will be prompted to save your results in a bitmap file.

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!! If RCS calculation is not switched on, you will also be prompted to save the calculation result in a text file. If you cancel, the calculations will be cancelled.

1.4. Stop If the stop key is activated, RCS calculation is stopped, but the settings are main-tained.

1.5. Exit If the exit key is activated, you will be prompted to save your settings in an *.INI file for later use.

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2. Geometrical set-up

Figure 2.1

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Rotation axis

Aiming point

First Viewing point

Inspection angle

Number of viewing points

Figure 2.2

2.1 Aiming point (x,y,z) The Aiming point is a point in or very near the object and is the centre of the pic-tures calculated by the program. If you want to implement e.g. the sea surface in connection with near field calcula-tions it is recommended to set the z-co-ordinate of the aiming point to zero (default).

!! It is strongly recommended always to use the default co-ordinates for the Aiming point.

2.2 Rotation axis (x,y,z) The Rotation axis is illustrated in Figure 2.2. The co-ordinates in the rotations axis determine the vector for calculation of the Viewing point position.

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2.3 First viewing point First Viewing point is the observer co-ordinates for image no. 1 and the phase cen-tre of the radar antenna. First Viewing point must be different from Aiming point.

2.4 Number of viewing points In Number of Viewing points the number of calculation runs is determined.

2.5 Inspection angle First Viewing point determines the start angle, and the Inspection angle (0 – 360°) is the difference between the start angle and the stop angle.

2.6 Frame size width/height The Frame size describes the spatial section, in which calculations are performed. !! . If the Frame size is set to be smaller than your object, the calculations

will be incomplete, because rays outside the calculated section are not included. If the Frame size is set too large the calculations will be less accurate due to a smaller resolution. It is always recommended to use the defaults.

If your object is very complicated, it is recommended to obtain a high resolution in the calculations.

2.7 Number of columns/rows The resolution of the images is set in Number of columns and rows. The number of rays is equal to the number of pixels, unless you have chosen the extended ray trace option.

2.8 Frame angle Changing the Frame angle will rotate your object clockwise around the axis of View-ing and Aiming point.

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Without near field calculation

With near field calculation

Figure 2.3

2.9 Near field calculation If the distance to the object is short or if there are surfaces close to the radar (e.g. the sea surface); it necessary to use near field calculations (Figure 2.3).

!! Real near field calculation time is substantially longer than far field cal-culation time.

2.10 Default Aiming point Default aiming point is the centre of the object and is calculated by cadRCS, when the CAD model is imported. If near field calculation is activated and a sea surface is detected, the z-co-ordinate for Aiming point is set to zero.

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2.11 Default Frame size The Default Frame size is defined by the size of the object and is calculated by the program when Aiming point and Viewing point are set. In the case of near field calculations it is recommended to check whether the RCS image is cut off due to near field properties, e.g. when Viewing point is very close to the object.

2.13 Distance The distance between the observer and the object can be set in meters.

2.14 Angle to x-axis The azimuth angle or the angle to the x-axis can be set in degrees.

2.15 Elevation angle The elevation angle in degrees can be set.

2.16 Use extended ray trace If you want extra rays in the calculation and do have used the maximum possible number of columns/rows select this option; this will add four times the number of rays in the calculation – note this will extend the calculation time by four.

2.17 Only process a partition of the Viewing points Process It is possible to calculate any section of the Inspection angle separately, if e.g. the calculations have been interrupted.

2.18 Add water surface This will add a surface to your calculation, which is centred at the Origin of your co-ordinate system. It is 10.000 meters in radius and has the material number 9999 – known to cadRCS as the water surface; the recommended sea surface roughness is about 1.0E-6.

2.19 Process This activates the calculation.

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3. Running cadRCS in the background 3.1 Background parameters cadRCS can be activated in the background in a batch file, the run string parame-ters follows the syntax: cadRCS <cadrcs.ini file> <run number> <azimuth angle> <elevation angle> <roll angle> <pitch angle> <distance> The angles are in degrees and the distance is in meters and is optional, whereas the other parameters are required. The other settings are from the “cadRCS.ini” file. 4. Example of the cadRCS.ini file All input parameters are given in the cadRCS.ini file. An example of an initialise file (*.ini):

• Lines starting with * are only comments in this file. • CAD file : Wolf1.nat

• Project : Wolf1

• Start Working directory : G:\Demo2\Wolf\ini12

• Aiming point : 0.00000 0.00000 0.00000

• Rotation axis : 0.00000 0.00000 1.00000

• First Viewing point : 1.00000E+4 0.00000 8.73000E+1

• Number of Viewing points: 360

• Image Width and Height: 1.00000E+1 1.00000E+1

• Inspection Angle: 0.00000

• Frame Angle: 0.00000

• Number of Columns and Rows: 512 512

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• Nearfield calculation on: No

• Add water surface: No

• Use micro file type: No

• Only process a part on: Yes

• IF only a part then from and to number: 1 1

• Use extended ray trace: No *Number of wavelengths :

4 *Polarization of transmitter:(X ~ horizontal,Y ~ vertical,X + iY ~ circular) *and other combinations of X and Y

1.00000+ 0.00000iX+ 0.00000+ 0.00000iY • Two receivers Yes/No

Yes *Polarization of first receiver (notation as transmitter): *results in file with extension R1.txt

1.00000+ 0.00000iX+ 0.00000+ 0.00000iY *Polarization of second receiver( notation as transmitter ): *results in file with extension R2.txt

0.00000+ 1.00000iX+ 0.00000+ 0.00000iY *Wavelength(s) in meters:

9.99000E-2 .. 9.9932000E-3

• Min display RCS in images 1.00000E-3

• Range gate size 5.00000E-1

• Min RCS in HRR 1.00000E-1

• Output phase results: Yes

• Use antennagain parameters: No

• Antenna width : 6.00000E-1

• Antenna height :

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6.00000E-1

• Use theoretical far field: No

• Minimum number of reflections in images: 1

• Maximum number of reflections in images: 10

*Material numbers for the object: *Material number: New number: Reflection coef: Number of facets: Roughness Descriptions: 1 1 1.000 4374 0.000 Wolf1 9999 9999 1.000 841 1.000E-6 Watersurface

5. Description of the ASCII output files There are different ways of getting results from cadRCS. Following a description with “HRR data in phase” unselected and with “Discrete frequencies” selected. Ex-ample of the results of total RCS result files. First the <project name> Q file: Computer prediction of RCS. Radar Cross Section calculation made by cadRCS, project: C:\Powerplant\example\Triple CAD file: C:\Powerplant\example\Triple.bna Transm. pol.: ( 1.00 0.00i )X + ( 0.00 0.00i )Y Receiver pol.: ( 1.00 0.00i )X + ( 0.00 0.00i )Y Frame angle: 0.0 Wave length = 1.00000000E-1 2.99796000E-2 Angle to X-axis: Total: 2 bounce: 3 bounce: Rest: Direct: Total: 2 bounce: 3 bounce: Rest: Direct: 6.0020078 5.96E+4 3.95E+3 1.08E+2 3.91 8.20E+4 5.75E+4 7.57E+3 1.50E+2 8.71 3.97E+4 7.0020078 3.28E+4 9.85E+2 2.83E+2 3.82 2.25E+4 6.45E+4 6.73E+3 6.87 6.44 3.55E+4 8.0020078 4.51E+4 1.68E+4 1.00E+3 8.81E-2 4.99E+4 1.61E+6 3.66E+3 5.01E+1 1.26E-1 1.77E+6 9.0020078 2.31E+3 4.35E+3 5.54E-1 7.74E-2 5.60E+3 3.06E+4 1.90E+4 6.56E-1 2.39E-1 9.60E+3

and the other polarization – if selected - the <project name> R file: Computer prediction of RCS. Radar Cross Section of the object: Polygon file: Wolf1.nat Transm. pol.: ( 1.00 0.00i )X + ( 0.00 0.00i )Y Receiver pol.: ( 0.00 0.00i )X + ( 1.00 0.00i )Y Frame angle: 0.0 Wave length = 9.99000000E-2 6.99310667E-2 3.99621333E-2 9.99320000E-3 Angle to X-axis: Amplitude: Phase: Amplitude: Phase: Amplitude: Phase: Amplitude: Phase: 0.0000000 5.05E-2 7.19E+1 1.02E-1 -8.77E+1 1.37E-1 -1.09E+1 1.69E-1 -4.27E+1

The “Total” is the result of adding all reflections in phase, the “Multi” is only the mul-tiple reflections and the “Direct” is the first reflection. Please note, it is possible, that the total RCS can be smaller than the other two, due to the fact, that the results is added in phase. Example of the <project name> fq<frequency number> files: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

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0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5.12E+3 3.62 3.53E-3 3.14E-3 0 0 0 0 0 1.79E-4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

This is a listing of the RCS in the different range gates, centered about the “Aiming point”. Similar file(s) is created for the second receiver. The four files <project name> HRRQ/R and HHHQ/R all follow the same syntax. The HRR is the High Resolution range gate files and the HHH is the height informa-tion files all given in the “Range gate size”; the RCS is always in square meters. Example of a HRRQ file: 1 10000 5.0E-1 0.0000000 5.0017945E-1 HH 99999 3.00 5.12E+3 5.34E+3 255 5.12E+3 256 3.62 99999 4.29 3.53E+3 3.66E+3 255 3.52E+3 256 2.64 99999 7.50 3.15E+3 3.15E+3 255 3.15E+3 99999 30.00 2.40E+2 2.39E+2 255 2.40E+2

The first number is the run number (1 ), the distance (10000) in meters, range gate size in meters (5.0E-1), azimuth angle or angle to x-axis in degrees (0.0000000), elevation angle in degrees (5.0017945E-1), the polarization of transmitter/receiver (HH), followed by a indicator of start of frequency dependent numbers (99999), ), the frequency in GHz (3.00), sum of RCS of the range gates in square meters (5.12E+3), total RCS added in phase(5.34E+3), the rest of the numbers is only dis-played, if the RCS is greater than the “Minimum RCS in HRR profile in sqm”, see section 1.2.3; then the range gate number and the RCS in this rang gate, etc. If the “Discrete frequencies” is unselected, then you will get amplitude and phase results in the <project name> Q/R files. Example of the Q file:

Computer prediction of RCS. Radar Cross Section of the object: Polygon file: Wolf1.nat Transm. pol.: ( 1.00 0.00i )X + ( 0.00 0.00i )Y Receiver pol.: ( 1.00 0.00i )X + ( 0.00 0.00i )Y Frame angle: 0.0 Wave length = 9.99000000E-2 6.99310667E-2 3.99621333E-2 9.99320000E-3 Angle to X-axis: Amplitude: Phase: Amplitude: Phase: Amplitude: Phase: Amplitude: Phase: 0.0000000 7.31E+1 8.61 8.64E+1 3.37E+1 1.40E+2 -3.68E+1 1.55E+2 -2.52E+1

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If you select the option “HRR data in phase” (section 1.2.3), you will get phase in-formation in the HRR files in two different ways. Example of the <project name> fq<frequency number> files: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7.09E+1 9.59 1.33 1.36 -8.98E-3 5.88E-2 -1.09E-2 -5.50E-2 0 0 0 0 0 0 0 0 0 0 7.86E-3 -1.08E-2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

The results will be listed in (I,Q) for all range gates. In the four files <project name> HRRQ/R and HHHQ/R you will get amplitude and phase. An example: 1 10000 5.0E-1 0.0000000 5.0017945E-1 HH 99999 3.00 5.12E+3 5.34E+3 255 7.09E+1 9.59 256 1.33 1.36 99999 4.29 3.53E+3 3.66E+3 255 4.88E+1 3.39E+1 256 1.58 -3.84E-1 99999 7.50 3.15E+3 3.15E+3 255 4.51E+1 -3.34E+1 99999 30.00 2.40E+2 2.39E+2 255 -1.40E+1 6.63

All these results can be designed for your own purpose if requested!

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6. Colours used in the cadRCS Hot Spot images Colours used to show the intensity of the radar reflection:

The red colour is the highest reflection and the green colour is the lowest, the scale is linear. The default silhouette colours:

The brightest colour is used for parts of the objects close to the observer and the darkest is the parts most distant from the observer. The colour of free air, no reflection:

The watercolour, material number 9999:

The colour of Radar Absorbing Material (RAM), identified as material with a reflec-tion coefficient below 0.1:

7. cadRCS theory The theory used in cadRCS is unique and have never been published – due to the fact that terrorists can read, the theory will remain a Css property.

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8. Comparisons with measurements During the years a lot of comparisons with results from cadRCS and measurements have been performed. After evaluation of the results it always had end up with agreement within the measurement noise. If you have disagreements, try to do some of the following tasks:

1. Reconsider you CAD model – it may not agree with your real model used for the measurement.

2. Make sure, that your calibration of your measurement system is OK. Spheres is always a good way to do calibration with – remember place it in free space using a balloon or something else.

3. Enlarge the number of rays in the calculation and use the “Nearfield” option – even if you think, that your measurement takes place in the “far field”.

4. Remember that targets placed in the real world isn’t stiff – especially ships will bend on the sea surface.

5. If you are using low reflecting foam in your measurement, then find the re-flection coefficient of the foam by making a dihedral with a metal plate. Then set in the foam in your calculation.

If – by any chance you have done a good, reliable measurement and still have dis-agreements with the calculation results from cadRCS – please contact us and we will be very interested in getting an improvement – if needed. In the last five years there has been no such disagreement!

9. Description of the micro (*.mic) files made by cadRCS Following definitions is used: Byte – size one byte Integer – size four bytes Real – size eight bytes String definition: First four bytes: integer number = number of characters in the string Followed by the characters in ASCII format. The micro file: String: CAD file name String: Working directory Three real: Aiming point coordinates x,y,z Three real: Rotation axis x,y,z Three real: Viewing point coordinates x,y,z Real: Image width Real: Image height Real: Frame angle Integer: Number of columns Integer: Number of rows String: Nearfield is defined, if first character = Y

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String: Water surface is added, if first character = Y String: Left for future use Integer: Number of wave lengths Four real: Transmitter polarization Four real: Receiver 1 polarization Four real: Receiver 2 polarization Number of wave length real: wave length 1, wave length 2 …. Real: Minimum display RCS in images Real: Range gate size Real: Minimum RCS in HRR and HHH profiles String: Antenna gain is used, if first character = Y Real: Antenna width Real: Antenna height Real: Future use Real: Future use Block start: repeated number of wavelengths

Real: Total RCS added in phase Real: All double reflections added in phase Real: All triple reflections added in phase Real: Rest of multiple reflections added in phase Real: Only direct RCS added in phase

Block end: repeated number of wavelengths Block start: repeated number of wavelengths

Real: RMS sum of range gate RCS for HRR Real: Future use Integer: Number of range gate data - HRR Block start: repeated number of range gate data Integer: Range gate number – HRR data Real: RCS of the range gate – HRR data Block end: repeated number of range gate data Real: RMS sum of range gate RCS for HHH Real: Future use Integer: Number of range gate data - HHH Block start: repeated number of range gate data Integer: Range gate number – HHH data Real: RCS of the range gate – HHH data Block end: repeated number of range gate data

Block end: repeated number of wavelengths Integer: Future use ROW = 1, COL = 1 Repeated until ROW exceeds Number of rows:

Byte: 0 or number of items If last byte = 0 then Integer: number of items Byte: Image lookup number COL = COL + number of items If COL exceeds Number of columns then ROW = ROW + 1 and COL = COL – Number of columns

End of data

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10. License agreement END-USER LICENSE AGREEMENT—cadRCS® IMPORTANT-READ CAREFULLY: This End-User License Agreement (Agreement) is a legal contract between you (either (a) an individual user or (b) a business or-ganization (you) and Licensor (as designated below) for the cadRCS software, in-cluding any associated media, printed materials and electronic documentation (the Software). By clicking on one of the “I accept” buttons, by opening the package that contains the Software, or by copying, downloading, accessing or otherwise using the Soft-ware, you agree to be bound by the terms of this Agreement and you represent that you are authorized to enter into this Agreement on behalf of your corporate entity (if applicable). If you do not wish to be bound by the terms of this Agreement, click the “I do not accept” button, and do not install, access or use the Software. An original purchaser who has not accepted the terms of this Agreement may return the Software to the place of purchase, within 30 days of the date of purchase, for a full refund. As used herein, Licensor means Css, Omoegade 8, st. th. DK-2100 Copenhagen Denmark.

SOFTWARE LICENSE 1. Grant of License. Upon your payment of the fees shown on the invoice and ac-

ceptance of this Agreement, Licensor grants you a limited, personal, non-exclusive license to install and use the Software on the terms and conditions set forth herein.

You may install and use the number of seats settled in the invoice. You may make back up and/or archival copy of the Software.

2. Restrictions on Use of Software. You may not (a) make the Software available for use by others in any service bureau or similar arrangement; (b) distribute, sublicense, transfer, or lend the Software to any third party; or (d) disassemble or reverse engineer the Software. You may copy the Software solely for backup/archival purposes, provided that you include all copyright and similar rights notices. Licensor (or its licensor) re-tains all right, title, and interest in the Software (and in all copies). Unauthorized copying and modification of the Software is not permitted.

3. Subject to the exceptions set forth herein, a copy of the Software installed on a single common machine may be shared for internal use by your employees, pro-vided that a license has been purchased for each individual user.

4. Redistributable Files. The Software component parts may not be separated for use on more than one computer, except as set forth in this Agreement. You may copy the files specifically identified in the documentation as redistributables and

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redistribute such files to your end users of your products, provided that: (a) such products add primary and substantial functionality to the redistributables, (b) all copies of the redistributables must be exact and unmodified; and (c) you grant your end users a limited, personal, non-exclusive and non-transferable license to use the redistributables only to the extent required for the permitted operation of your products and not to distribute them further. You will reproduce with the redistributables all applicable trademarks and copy-right notices that accompany the Software.

5. Limited Warranty and Disclaimer of Warranty. Licensor warrants that:

A. it has the right and authority to grant the rights described in this Agreement, and;

B. the Software, as provided, will substantially perform the functions described in the documentation when operated in the intended environment for a period of ninety (90) days from the date of delivery (the Warranty Period).

THE WARRANTIES ABOVE ARE EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED. LICENSOR EXPRESSLY DISCLAIMS ANY WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FIT-NESS FOR A PARTICULAR PURPOSE. Licensor does not warrant that the Soft-ware will (a) achieve specific results, (b) operate without interruption, or (c) be error free. 6. Ownership. This Agreement does not convey to you any rights of ownership in

the Software. All right, title, and interest in the Software and in any ideas, know-how, and programs which are developed by Licensor in the course of providing any technical services, including any enhancements or modifications made to the Software, shall at all times remain the property of Licensor or its licensor. You acknowledge and agree that the Software is licensed, not sold. You shall not permit the Software to be accessed or used by anyone other than your em-ployees whose duties require such access or use. You will not remove, modify or alter any of Licensor’s copyright, trademark or pro-prietary rights notices from any part of the Software, including but not limited to any such notices contained in the physical and/or electronic media or documen-tation, in any of the runtime resources and/or in any web-presence or web-enabled notices, code or other embodiments originally contained in or otherwise created by the Software, or in any archival or back-up copies, if applicable.

7. Transfer of Software. You may not, by operation of law or otherwise, transfer any license rights or other interests in the Software. You may not transfer any license rights or other interests in any other Software.

8. Limitation of Remedy and Liability. During the Warranty Period, in the event of any breach of the warranty outlined in Section 5b above, Licensor’s ( and its sup-pliers), entire liability and your exclusive remedy will be, at Licensor’s option, to either, repair or replace the defective Software.

NEITHER LICENSOR NOR ITS LICENSOR, IF ANY, SHALL BE LIABLE FOR INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, OR

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FOR DAMAGE TO SYSTEMS OR DATA, EVEN IF LICENSOR HAS BEEN AD-VISED OF THE POSSIBILITY OF SUCH DAMAGES. LICENSOR’S LIABILITY FOR DAMAGES HEREUNDER SHALL IN NO EVENT EXCEED THE AMOUNT OF LICENSE FEES THAT YOU HAVE PAID.

9. Maintenance Services. If ordered by you and upon payment of the applicable fee, you are entitled to receive technical support services, including corrections, fixes and enhancements to the Software as such are made generally available (the maintenance services) from Licensor in accordance with Licensor’s then-current maintenance terms for the applicable maintenance level purchased by you. Maintenance services will not include any releases of the Software which Licen-sor determines to be a separate product or for which Licensor charges its cus-tomers extra or separately.

10. Upgrades and Subscription. If you purchased a license for the Soft-ware which is identified as an upgrade or subscription, you must have a valid li-cense for the version of the Software which the upgrade or subscription supple-ments.

11. Dual-Media Software. You may receive the Software in more than one medium (electronic and on a CD, for example). Receipt of the Software in more than a single manner (electronic or on a CD, for example) does not expand the li-cense rights granted to you hereunder. Your use of the Software is limited to the number of licenses that you have acquired overall, regardless of number or type of medium on which it has been provided.

12. You will not, directly or indirectly, export, re-export, divert, or transfer the Software, any portion thereof or any materials, items or technology relating to Licensor’s business or related technical data or any direct product thereof to any Restricted Person.

13. Termination. Your license may be terminated by Licensor if (a) you fail to make payment and/or (b) you fail to comply with the terms of this Agreement within ten (10) days after receipt of written notice of such failure. In the event of termination, you must cease using the Software, destroy all copies of the Soft-ware (including copies in storage media) and certify such destruction to Licensor. This requirement applies to all copies in any form, partial or complete. Upon the effective date of any termination, you relinquish all rights granted under this Agreement.

14. Relationship of Parties. You and Licensor are independent parties. Nothing in this Agreement shall be construed as making you an employee, agent or legal representative of Licensor.

15. No Third-Party Beneficiaries. There are no third-party beneficiaries of this Agreement.

16. Company Name. Licensor may include your company name in a list of Licensor customers.

17. Payment Terms/Shipments. All fees are non-refundable. Fees are due within 30-days of the date of the invoice. Maintenance services purchased may be renewed for the next two annual periods for the amount specified on the origi-nal invoice for the Software.

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18. Taxes. All fees do not include taxes. If Licensor is required to pay any sales, use, GST, VAT, or other taxes in connection with your order, other than taxes based on Licensor’s income, such taxes will be billed to and paid by you.

19. Entire Agreement. This Agreement constitutes the complete and entire understanding and agreement of all terms, conditions and representations be-tween you and Licensor with respect to the Software and may be modified only in writing by both parties. No term or condition contained in your purchase order will apply unless expressly accepted by Licensor in writing. Failure to prosecute a party’s rights will not constitute a waiver of any other breach. If any provision of this Agreement is found to be invalid, it will be enforced to the extent permissible and the remainder of this Agreement will remain in full effect. This Agreement has been written in the English language and you waive any rights you may have under the law of your country or province to have this Agreement written in any other language.

Css

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11. Movie.exe – visualise the RCS results With movie.exe you can visualise the results from the RCS calculations done by cadRCS.

The most information about the RCS properties of your object is done by using the micro files (*.mic). If you choose to save the results in bitmap files (*.bmp), not all the information is included. As seen from the high resolution range profile in the above example, there are re-flections “behind” the object. This is also shown by real measurements and is due to multiple reflections. The two different polar plots in this example is the HH (horizontal – horizontal) po-larization and the HV (horizontal - vertical) reflection. As seen the HH often is more than 30dB larger than the HV, and in that case it is impossible to measure due to the fact, that isolation on more than 30 dB is very tough to get. Please also see the next example.

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12. Object – background CAD program Object is a CAD program, which can be activated in the background. The back-ground syntax: Object * <commands> Short description of commands for CAD code object.exe:

Command Parameters Description OBJECT Start of data * Comment in file, or data in runstring COPY file1,file2,… Copies CAD files:file1,file2,.. COPYPURGE file1,file2,… Copies CAD files:file1,file2,.. and delete the

sources CONTOUR Z-coordinate or

floating z-coordinate The next lines describe a poly-gon: x-coor y-coor matnr1 matnr2 or floating: x-coor y-coor z-coor matnr1 matnr2

TRANS X Y Z Move all CAD points (X,Y,Z) MULT MX MY MZ Multiply all CAD points with vector:

(MX,MY,MZ) ROTX degree Rotation about X-axis ROTY degree Rotation about Y-axis ROTZ degree Rotation about Z-axis STORE filename Stores CAD data in a polygon file RAWSTORE filename Stores CAD data in a Rhino raw file format END End of data Extensions: STLSTORE filename Stores CAD data in a ASCII STL file BINSTORE filename Stores CAD data in a binary STL file NATOSTORE filename Stores CAD data in a ASCII NATO file NATOBINSTORE filename Stores CAD data in a binary NATO file Object.exe is a MS-DOS code and can either run on an input file in normal ASCII format (*.txt) using a new line for a new command. It can also use the run string, where commands are delimited by a “;”( semicolon).

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13. Example of running object and cadRCS in the background In the following example, the wing of a power plant gets turning. OBJECT * OBJECT; COPY WINGS.RAW;TRANS 0,0,-102.9735;ROTY 54;TRANS 0,0,102.9735;STORE WING2.POL;COPY WING2.POL,PP.POL;STORE POWERPLANT1.POL;END cadrcs powerplant1.ini 55 0 0.4 0 0 OBJECT * OBJECT; COPY WINGS.RAW;TRANS 0,0,-102.9735;ROTY 55;TRANS 0,0,102.9735;STORE WING2.POL;COPY WING2.POL,PP.POL;STORE POWERPLANT1.POL;END cadrcs powerplant1.ini 56 0 0.4 0 0 OBJECT * OBJECT; COPY WINGS.RAW;TRANS 0,0,-102.9735;ROTY 56;TRANS 0,0,102.9735;STORE WING2.POL;COPY WING2.POL,PP.POL;STORE POWERPLANT1.POL;END cadrcs powerplant1.ini 57 0 0.4 0 0

etc. Such a batch file is easily made with Microsoft Excel.