Radar Tracking and Jamming

STK Premium (Air) or STK Enterprise
You can obtain the necessary licenses for this training by contacting AGI Support at support@agi.com or 1-800-924-7244.

The results of the tutorial may vary depending on the user settings and data enabled (online operations, terrain server, dynamic Earth data, etc.). It is acceptable to have different results.

Capabilities covered

This lesson covers the following STK capabilities:

  • STK Pro
  • Radar
  • Aviator
  • Terrain Integrated Rough Earth Model (TIREM)

Problem statement

You heard about an exercise that tested a Search/Track radar system against a small single-engine aircraft flying in rugged mountainous terrain. You want to replicate the test to determine if new radar settings will work better than the original.

Then, the second phase of the exercise tests whether an experimental aerostat with a radar jamming package could jam the tracking radar. You know in the original exercise the aerostat with a radar jamming package was tethered in a remote mountainous area 10,000 feet above ground level (AGL).

You want a scenario that simulates both phases of the test. With the simulation, you or others can further adjust parameters to study the effects against the radar.

Solution

In this lesson, you will simulate both phases of the exercise: tracking the aircraft with radar and seeing the effects of radar jamming. You will use STK's Aviator capability to create a flight path using the STK Basic General Aviation model which simulates the small aircraft. You will build a monostatic tracking radar and create a custom graph that shows the effectiveness of the Search/Track radar. Then, you will build a simulated aerostat with its attached radar jamming system. Using a custom graph, you will demonstrate how well the aerostat jammed the search track radar.

What you will learn

In this lesson, you will learn how to:

  • Insert an STK Terrain File (pdtt) for analysis and visualization using Globe Manager.
  • Build a Search/Track radar that is monostatic.
  • Specify an aircraft's radar cross section.
  • Produce a simple out and back flight route for a single engine aircraft.
  • Employ STK's TIREM capability in order to take into account how terrain affects a radar signal.
  • Create a radar which jams the Search/Track radar.
  • Design custom graphs.
  • Use constraints that customize reports and graphs.

Video guidance

Watch the following video. Then follow the steps below, which incorporate the systems and missions you work on (sample inputs provided).

Creating a new scenario

First, you need to create a new scenario.

  1. Click the Create a Scenario button.
  2. Enter the following in the New Scenario Wizard:
    3. Option Value
    Name Radar_Jamming
    Location C:\Users\<username>\Documents\STK 12\
    Start 1 Jul 2019 16:00:00.000 UTCG
    Stop 1 Jul 2019 18:00:00.000 UTCG
  3. Click OK to let the scenario load.
  4. Click Save () once the scenario loads. STK creates a folder with the same name as your scenario in your file directory, specified in the above table.
  5. Verify the scenario name and directory.
  6. Click Save .

Save () often!

Set scenario properties

Before you can simulate the aircraft, radar, and aerostat, you need to set other general properties to the entire scenario with the Scenario object.

Disable the streaming terrain

The AGI SEDS/Geospatial Content Server distributes Earth terrain data for analysis and visualization. In this instance, you will use a local terrain file. Therefore, you will disable the streaming terrain because you do not need it for this scenario.

To use STK's Terrain Integrate Rough Earth Model (TIREM) capability, the scenario must have terrain from a local terrain file (not from a terrain server).

  1. Open Radar_Jamming's () properties ().
  2. Browse to the Basic - Terrain page.
  3. Clear the Use terrain server for analysis check box. Since you want to use a terrain file for this lesson, you don't need to stream from the terrain server.
  4. Click Apply .

Scenario RF environment

You will track the aircraft in mountainous terrain. Therefore, you will enable TIREM to account for the mountainous terrain in the scenario.

  1. Browse to the RF - Environment page.
  2. Open the Atmospheric Absorption tab.
  3. Select the Use check box.
  4. Click the ... button.
  5. Select the TIREM model.
  6. Click Apply .

Radar Cross Sections (RCS) in STK

Prior to setting up and constraining a radar system, STK Radar enables you to specify an important property of a potential radar target: the Radar Cross Section (RCS).

Since you will have one object that uses an RCS, you can set the properties at the scenario level. If multiple objects required an various Radar Cross Sections, you would insert the RCS at the individual object level.

You will use the Swerling Case II model fluctuations, which are more rapid and are assumed to be uncorrelated from pulse to pulse.

You can express RCS Values in decibels referenced to a square meter (dBsm). STK can use External Radar Files. Since you don't have an external RCS file, you will use a constant value. The small aircraft in this scenario would have a small dBsm.

Adding a RCS to the scenario

  1. Browse to the RF - Radar Cross Section page.
  2. Make the following changes in the Band Properties section:
    3. Option Value
    Swerling Case II
    Constant RCS Value: 4 dBsm
  3. Click OK .

Add a Custom Analysis Terrain Source

You will use the Custom Analysis Terrain Sources table to specify locally available terrain data files for analysis and visualization in the scenario. Although you could use the Custom Analysis Terrain Sources table while streaming terrain data from a terrain server, you don't need to do that for this lesson.

  1. Bring the 3D Graphics window to the front.
  2. Launch the Globe Manager ().
  3. Extend the Add Terrain/Imagery () menu on the Globe Manager toolbar.
  4. Select Add Terrain/Imagery (Add Terrain/Imagery button).
  5. Browse to <STK install folder>\Data\Resources\stktraining\imagery.
  6. Click OK .
  7. Return to the Globe Manager.
  8. Check StHelens_Training.pdtt.
  9. Click Add .
  10. Click Yes . on the Use Terrain for Analysis prompt.

This adds visual terrain to the 3D Graphics window and enables the StHelens_Training.pdtt for analysis at the scenario level.

Waypoints

There are multiple ways to design waypoints in STK. For this scenario, the aircraft will fly direct to waypoints that can easily be inserted into your scenario using the Place () object.

  1. Insert a Place () object using the From City Database () method:
    • Eatonville (Washington)
  2. Insert a Place () object using the Define Properties () method.
  3. Make the following changes:
    4. Option Value
    Latitude: 46.1155 deg
    Longitude: -122.1957 deg
  4. Click OK .
  5. Rename the Place object StHelens.

Visualize in the 3D Graphics window

When using the default settings, Label Declutter declutters labels away from the central body and towards the viewer, keeping the labels from being obscured by the terrain .

  1. Bring the 3D Graphics window to the front.
  2. Open the 3D Graphics window's properties.
  3. Select the Enable check box in the Label Declutter section.
  4. Click OK .
  5. Right-click StHelens_Training.pdtt and select Zoom To in Globe Manager.
  6. Use your mouse to get a good view of the terrain and the Place objects.

Terrain and Waypoints

STK's Aviator capability

You will insert an Aircraft () object that simulates a small single-engine aircraft, using Aviator.

  1. Insert an Aircraft object () using the Insert Default method.
  2. Rename the Aircraft object "TestFlight."
  3. Open TestFlight's () properties ().
  4. Change the Propagator field to Aviator on the Basic - Route page.
  5. Click Apply .
  6. Click Optimize STK for Aviator when the Flight Path Warning window opens
  7. Click OK .

Using Aviator and Mean Sea Level

Aviator performs best in the 3D Graphics window when the surface reference of the globe is set to Mean Sea Level. You will receive a warning message when you apply changes or click OK to close the properties window of an Aviator object with the surface reference set to WGS84. It is highly recommended that you set the surface reference as indicated before working with Aviator.

Mission window

The Mission Window is used to define the aircraft's route when Aviator has been selected as the propagator.

Mission Window

Initial Aircraft Setup toolbar

The buttons on the Initial Aircraft Setup toolbar are used to define the aircraft model that will be used in the mission.

The User Aircraft Models represent of different types of aircraft. They don't contain actual specifications for any one type of aircraft but their properties are close to the type of aircraft selected. If you desire to build an aircraft to your specifications, you would duplicate the desired type and then edit that type to match your aircraft.

Select Aircraft

Select the aircraft to be used for the Mission.

  1. Click the Select Aircraft () button on the Initial Aircraft Setup toolbar.
  2. Select Basic General Aviation on the Select Aircraft window.
  3. Click OK .
  4. Click Apply .

Add STK Static Object Waypoints

The test flight aircraft will fly from Eatonville to StHelens, turn left, and fly back to Eatonville. STK Static Object Waypoints are used to define a waypoint at the position of another, stationary, object within the scenario over time. Although Aviator allows you to design the complete flight route (takeoff through landing), this test only models the time when the aircraft flew from Eatonville to StHelens and back.

Start at Eatonville

  1. Right-click on Phase 1 in the Mission List.
  2. Click Insert First Procedure for Phase ().
  3. Select STK Static Object in the Select Site field.
  4. Change the Name: to Eatonville.
  5. Select Eatonville in the Link To: field.
  6. Click Next > .
  7. Select Basic Point to Point () in the Select Procedure Type: field.
  8. Click Finish .
  9. Click Apply .

Proceed to StHelens

  1. Right-click on Eatonville in the Mission List.
  2. Click Insert Procedure After ().
  3. Select STK Static Object in the Select Site field.
  4. Change the Name: to StHelens.
  5. Select StHelens in the Link To: field.
  6. Click Next > .

Define the Procedure Type

  1. Select Basic Point to Point () in the Select Procedure Type: field.
  2. Clear the Use Aircraft Default Cruise Altitude check box.
  3. Set Altitude to 9000 ft.
  4. Change Nav Mode: to Arrive on Course in the Navigation Options section.
  5. Set the course value to 90 deg True.
  6. Click Finish .
  7. Click Apply .

When the aircraft gets to the waypoint StHelens, setting the Nav Mode to Arrive on Course and setting the course to 90 degrees true places the aircraft on a heading The direction that the aircraft is pointing. of 90 degrees at StHelens.

Return to Eatonville

  1. Right-click on StHelens in the Mission List.
  2. Select Insert Procedure After ().
  3. Select STK Static Object in the Select Site field.
  4. Change the Name: to Return to Eatonville.
  5. Select Eatonville in the Link To: field.
  6. Click Next > .
  7. Select Basic Point to Point () in the Select Procedure Type: field.
  8. Click Finish .
  9. Click Apply .

Disable the line of sight constraint

Since you are using TIREM, you should turn off line of sight in the Aircraft object's properties.

  1. Open the Constraints - Basic page.
  2. Clear the Line of Sight check box.
  3. Click OK .

To make the most efficient use of the TIREM analysis, you should disable Line-of-sight, Terrain Mask, or Az-El Mask constraints to take advantage of the over-the-horizon analysis capabilities of TIREM.

View the flight route

With the aircraft modeled, view the flight path you made.

  1. Bring the 3D Graphics window to the front.
  2. Use your mouse to get a good view of TestFlight () and both waypoints.

TestFlight and Waypoints

Tracking Radar

The tracking radar is located at a small regional airport.

  1. Insert a Place () object using the Define Properties () method.
  2. Make the following changes:
    3. Option Value
    Latitude: 46.6774 deg
    Longitude: -122.9858 deg
  3. Click OK .
  4. Rename the Place object RadarSite.
  5. Zoom to RadarSite.

The radar will be built using selected specifications from an airport tracking radar. However, instead of creating a spinning antenna, you will lock the antenna onto the aircraft.

Servomotor

The Radar object's antenna can be bore-sited. However, in STK, if you have an antenna that can track another object, use a Sensor object as the servomotor.

  1. Insert a Sensor () object using the Insert Default method
  2. Attach it to RadarSite.
  3. Rename the Sensor () object Servo.
  4. Open the Servo's () properties ().
  5. Change the Cone Half Angle to 1 deg in the Simple Conic field on the Basic - Definition page. You will use the Sensor () object's projection for situational awareness (where the antenna is pointing).

Repositioning the Sensor object

The Sensor object is attached to the center point of the Place object (its parent). In this analysis, the antenna needs to be 50 feet in altitude.

Facility, place and target objects have body-fixed coordinate axes, which align the x-axis along local horizontal North direction, the y-axis along local horizontal East direction, and the z-axis along local Nadir direction. Therefore, if you desire to leave the parent object (in this case the Place () object) on the ground, but you want to move the child object (in this case the Sensor () object) up, you move the child along the parent's axis, not the child's. In this instance, if you want to move the Sensor object up in altitude, you will use the parent's Z body. Since the positive Z points to Nadir (down), you will use a negative value to move the sensor object up along the parent's Z body.

Moving the Sensor up 50 ft.

  1. Browse to the Basic - Location page.
  2. Change the Location Type to Fixed.
  3. Enter -50 ft in the Z: field.
  4. Click Apply .
  5. After applying your change, return to the 3D Graphics window. You will see that the Sensor object is elevated in altitude (50 feet).

Sensor Object and Place Object Locations

Target the Aircraft

As stated earlier, the radar will lock on to the Aircraft. The Sensor () object is acting as a servomotor. Target the sensor which in turn will target the antenna later in the lesson.

  1. Return to Servo's () properties ().
  2. Browse to the Basic - Pointing page.
  3. Change the Pointing Type to Targeted.
  4. Move () TestFlight to the Assigned Targets list.
  5. Browse to the Constraints - Basic page and clear the Line of Sight check box.
  6. Click OK .

If you return to the 3D Graphics window, click the Start button in the Animation toolbar. As you watch the Sensor object track the aircraft , you will see that, at times, you have unobstructed line of sight. At other times, the aircraft dips behind terrain. Both the terrain and distance from the radar site will affect how well your radar can track the aircraft.

Sensor Tracking Aircraft

Model the Tracking Radar

For this analysis, you will use a single beam. The Radar object will be a child of the Sensor object. Since the Sensor object is bore sighted towards the aircraft, the Radar object, which is pointing along the parent's Z body, will also point at the aircraft. (Orientation Methods)

  1. Insert a Radar () object using the Insert Default method
  2. Attach the Radar object to Servo.
  3. Rename the Radar object "Tracking_Radar".
  4. Open Tracking_Radar's () properties ().
  5. Verify the Type: is Monostatic on the Basic - Definition page.

Waveform tab

Begin with the Waveform tab, which is within the Mode tab on the Basic - Definition page, to further define the radar. The Waveform tab is further split into five more tabs: Pulse Definition, Modulator, Probability of Detection, Pulse Integration, and Specs.

  1. Set the PRF to 0.002 MHz on the Waveform tab.
  2. Change the Pulse Width to 1e-005 sec.
  3. Select the Probability of Detection tab.
  4. Change the Probability of False Alarm to 0.000001.
  5. Select the Pulse Integration tab.
  6. Open the pull down menu and select Fixed Pulse Number.
  7. Change Pulse Number to 5 (five).
  8. Click Apply .

Doppler Filters tab

Use the Doppler Filters tab, which is within the Mode tab on the Basic - Definition page, to enable Main Lobe Clutter definitions.

  1. Select the Doppler Filters tab.
  2. Select the Main Lobe Clutter (MLC) check box.
  3. Set the Bandwidth to 20 m/s.
  4. Click Apply .

Set Antenna specifications

Select the radar's antenna pattern and change its design to particular specifications.

  1. Click the Antenna tab.

    2. The Antenna tab is next to the Mode tab and consists of two tabs:

    • Model Specs
    • Orientation
  2. Use the ... button to change the Type to Pencil Beam on the Model Specs tab. (Pencil Beam Antenna)
  3. Change the Design Frequency value to 3 GHz.

Build the transmitter

  1. Click the Transmitter tab.

    2. The Transmitter tab is next to the Antenna tab and consists of four tabs:

    • Specs
    • RF Filter
    • Polarization
    • Additional Gains and Losses
  2. Select the Frequency option on the Specs tab.
  3. Change the frequency value to 3 GHz.
  4. Change Power to 25 kW.

Build the receiver

The radar's receiver has a pre-receive gain of five (5) dB. The Receiver tab is next to the Transmitter tab and consists of six tabs: Specs, RF Filter, Polarization, System Noise Temperature, STC, and Additional Gains and Losses.

  1. Select the Receiver tab.
  2. Select the Additional Gains and Losses tab.
  3. Click Add .
  4. Enter 5 dB in the Gain cell.
  5. Click Apply .

Enable TIREM

The last step is to ensure that TIREM is used in the analysis.

  1. Browse to the Constraints -  Basic page.
  2. Clear the Line of Sight check box.
  3. Click OK .

Analyze the Radar

You are ready to determine the radar's tracking ability. The first step is to determine how well your radar can track the aircraft.

  1. Right-click on Tracking_Radar () in the Object Browser.
  2. Open the Access () tool.
  3. Select TestFlight and click in the list.
  4. Click Report & Graph Manager... .

Create a custom graph

For your analysis, you are interested in two report contents, S/T Integrated PDet (Search/Track Integrated Probability of detection) and Range. The radar uses five pulses for integration. The process of summing all the radar pulses to improve detection is known as “Pulse integration." By creating a custom graph that contains these contents, you can quickly determine the effectiveness of your radar.

Navigating to the custom graph

  1. Select the My Styles folder.
  2. Click the Create new graph style () button.
  3. Give the graph a name such as "PDet and Range."
  4. Press Enter. This will take you to the custom graph's properties.

Move the data providers

  1. Expand Radar SearchTrack in the Data Provider.
  2. Move () the S/T Integrated PDet element to the Y Axis window.
  3. Return to the Data Provider.
  4. Expand the AER Data data provider.
  5. Expand the Default group.
  6. Move () the Range element to the Y2 Axis.
  7. Click OK .
  8. Click Generate... .

    9. S/T Integrated PDet Range Graph

    You are looking for a PDet of 0.8 or greater. It's a given that as distance increases, your PDet will decrease. There are instances where your tracking drops well below a PDet of 0.8. Using the Toggle animation time line button, right-clicking on the graph, and selecting Set Animation Time, you can jump back to the 3D Graphics window to visualize what is occurring.

    Overall, the radar system is able to track the aircraft when it's within range and unobstructed by terrain. What effect did the jammer have against the tracking radar?

  9. Close the graph, the Report & Graph Manager, and the Access Tool.

Radar jamming

You will simulate an aerostat flying near Mount St. Helens. The aerostat is tethered at 10,000 ft above ground level (AGL). An easy way to do this in STK, if you're not taking drift into your analysis, is by using a Place object.

  1. Insert a Place () object using the Define Properties () method.
  2. Make the following changes on the Basic - Position page:
    3. Option Value
    Latitude 46.1173 deg
    Longitude -122.315 deg
    Height Above Ground 10000 ft
  3. Click OK .
  4. Rename the Place () object Aerostat.

Adding the Aerostat radar jammer

You can model the radar jammer by simply reusing the previously built tracking radar and making a couple of changes.

  1. Copy Servo in the Object Browser.
  2. Paste Servo into Aerostat.
  3. Expand Aerostat ().
  4. Expand Servo1 ().
  5. Rename Servo1 () "Jam_Servo".
  6. Rename Aerostat's () Radar () object "Jammer".

Targeting the Aerostat radar jammer

  1. Open Jam_Servo's () properties ().
  2. Browse to the Basic - Location page.
  3. Change the Location Type to Center.
  4. Browse to the Basic - Pointing page.
  5. Remove TestFlight from the Assigned Targets list and replace it with RadarSite..
  6. Click OK .
  7. Return to the 3D Graphics window and Zoom To Aerostat.

Aerostat

Define the jammer

Aerostat is "floating" at 10,000 ft AGL. The Jam_Servo () is attached to Aerostat's center point and is targeting RadarSite. Make the required specification changes to the jammer.

  1. Open Jammer's () properties ().
  2. Click the Antenna tab on the Basic - Definition page.
  3. Click the ... button to change the Type: to Square Horn on the Model Specs tab.
  4. Change the Diameter to one foot (1ft).
  5. Set the Design Frequency: to 3 GHz.
  6. Select the Transmitter tab.
  7. Change the Power to 1 W on the Specs tab.
  8. Click OK .

Jam the radar

The next step is to tell the tracking radar that it's being jammed.

  1. Open Tracking_Radar's () properties ().
  2. Select the Jamming tab on the Basic - Definition page.
  3. Select the Use check box.
  4. Move () Jammer to the Assigned Jammers field.
  5. Click OK .

Jam effectiveness

You are now ready to analyze the radar jammer's effectiveness against the tracking radar. Create a custom graph that shows only those contents you are interested in for your analysis. You are interested in S/T Integrated PDet and S/T Integrated PDet w/ Jamming (Search/Track Integrated Probability of detection with jamming).

  1. Right-click on Tracking_Radar () and open the Access () tool in the Object Browser.
  2. Select TestFlight in the list.
  3. Click Report & Graph Manager... .
  4. Select the My Styles folder.
  5. Click the Create new graph style () button.
  6. Give the graph a name such as PDet Jamming then press the Enter key.

Generating the report

  1. Expand the Radar SearchTrack data provider in the Data Provider.
  2. Move () the S/T Integrated PDet to the Y Axis window.
  3. Move () the S/T Integrated PDet w/ Jamming to the Y Axis window.
  4. Click OK .
  5. Click Generate... .

    6. By placing the S/T Integrated PDetand S/T Integrated PDetwith jamming on the same axis, it's easier to read the graph. As you can see by looking at the graph, the jammer attached to the aerostat is effectively jamming the tracking radar.

    S/T Integrated PDet With Jamming

    You can see from the graph that the radar jammer effects the return signal back to the radar's receiver.

  6. Close the graph.

Radar jamming report

Run a report that will show the jammer's affect against the tracking radar. This report will provide a comparison of the probability of detection with or without jamming.

  1. Select the Radar SearchTrack with Jamming report from the Installed Styles list.
  2. Click Generate.

Four columns of data might be of interest in this report. Start by looking at S/T PDet1 and S/T PDet1 w/Jamming (single pulse) and compare it to S/T Integrated PDet and S/T Integrated PDet w/Jamming. This gives a good example of how integration provides better tracking than single pulse.

Add a Search/Track Constraint

In the report, you are looking for instances greater than or equal to 0.5 in the S/T Integrated PDet column. Any instance greater than or equal to 0.5 is when the Tracking_Radar can see TestFlight. Add a constraint to Tracking_Radar.

  1. Open Tracking_Radar's () properties.
  2. Select the Constraints - Search/Track page.
  3. Turn on the Min field under Integrated PDet.
  4. Set the Min value to 0.5.
  5. Click OK .
  6. Refresh () the Radar SearchTrack with Jamming report.

What the report shows

Notice that access duration has been reduced, and all S/T Integrated PDet values are equal to or greater than 0.5. The report is only showing those times when Tracking_Radar () is able to track TestFlight (). This makes it easier to compare those times against the effects of the jamming radar. You can further modify the report by selecting the Constraints - S/T w/Jamming page and enabling the Max: field in Integradted PDet w/Jamming with a value of 0.5. This would show when Jammer is effective.

Determine when the radar jammer is ineffective

  1. Return to Tracking_Radar's () properties.
  2. Select the Constraints - S/T w/Jamming page.
  3. Enable Max: in the Integrated Pdet w/Jamming field.
  4. Set the value to 0.5.
  5. Refresh () the Radar SearchTrack with Jamming report.

Conclusion

This scenario determined that a ground based tracking radar successfully tracked a small aircraft in mountainous terrain. For the most part, tracking was successful except in those instances when the plane was behind the mountains. The second half of the scenario determined that an aerostat radar jamming system effectively jammed the ground based radar. Based on the radar jammer's specifications, you know that the jammer worked well against the tracking radar.

Save your work

  1. Close all reports and graphs.
  2. Save () the scenario.

On your own

Try adjusting the tracking radar's pulse count, frequency or PRF. Different combinations will effect the tracking radar's efficiency. Incrementally increase the jammer transmitter's power by 1 watt at a time to find the power needed to completely jam the tracking radar.