Quadcopter Design and Performance Analysis Over Terrain

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

Required Capability Install: This lesson requires an additional capability installation for STK Terrain Integrated Rough Earth Model (TIREM). The TIREM install is included in the STK Pro software download, but requires a separate install process. Read the Readme.htm found in the STK install folder for installation instructions. You can obtain the necessary install by visiting http://support.agi.com/downloads or calling AGI support.

This lesson requires STK 12.9 or newer to complete in its entirety. If you have an earlier version of STK, you can complete a legacy version of this lesson.

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
  • Aviator
  • Aviator Pro
  • Coverage
  • Terrain Integrated Rough Earth Model (TIREM)
  • Communications

Problem statement

Towers, buildings, bridges, and other structures require regular maintenance. Drones enable inspectors to perform a preliminary survey, which is used to determine where and what work is required on the structure and if any hazards are present. In combat, drones can be sent to surveil an area prior to sending in troops.

In this lesson, a remote communication tower sits on top of a large hill. There are no roads to the top of the hill, so inspectors will use a drone to fly to the communication tower, take video of the structure, and fly back to the inspectors. The drone can be pre-programmed to fly its mission. When applicable, inspectors want to have manual control of the drone using a remote controller. Inspectors have a good idea of the location from which they would like to launch the drone but potential problems exist. For example, will the drone's battery last during the entire flight, and can inspectors contact the drone using remote control? Furthermore, inspectors want to determine how well the remote controller will function inside a predetermined geographic area. Due to the size of the communication tower, guyed anchors and wires are a potential hazard, so inspectors want to fly at a safe distance from the communication tower while still obtaining good video inspection using the zoom function on the drone's camera. Based on the drone's configuration, the battery should last 28 minutes.

Solution

Using STK, you will:

  • Simulate the performance of a commercial drone built to specifications.
  • Design the drone's flight. You will launch the drone, ascend up the hill, make two passes to inspect the upper half of the communication tower, and return to the launch site.
  • Determine if the drone's battery will last during the programmed portion of the flight.
  • Build a remote controller.
  • Determine if inspectors can manually control the drone based on their location and local terrain.

    •  

What you will learn

Upon completion of this tutorial, you will understand how to:

  • Use Analytical Terrain.
  • Create a small quadcopter and its flight route.
  • Create a simple link budget using STK's Terrain Integrated Rough Earth Model (TIREM) capability.
  • Determine radio frequency coverage focusing on energy per bit to noise power spectral density ratio using TIREM.

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

Create a new scenario with a run time of one hour.

  1. Launch STK ().
  2. Click Create a Scenario in the Welcome to STK window.
  3. Enter the following in the New Scenario Wizard:
    4. Option Value
    Name AviatorPro_Drone
    Location Default
    Start Default day/month/year 19:00:00.000 UTCG
    Stop + 1 hr
  4. Click OK when you finish.
  5. Click Save () when the scenario loads. A folder with the same name as your scenario is created for you in the location specified above.
  6. Verify the scenario name and location in the Save As window.
  7. Click Save .

Disabling Terrain Server

You're using a local terrain file for analysis and visualization. Turn off Terrain Server.

  1. Right-click on AviatorPro_Drone () in the Object Browser.
  2. Select Properties ().
  3. Select the Basic - Terrain page when the Properties Browser opens.
  4. Clear the Use terrain server for analysis check box in the Terrain Server frame.
  5. Click Apply to accept the changes and keep the Properties Browser open.

Displaying surface lines

Due to disabling Terrain Server, you want to display any object's lines on the surface of the central body when terrain data is available.

  1. Select the 3D Graphics - Global Attributes page.
  2. Select On for On Terrain in the Surface Lines frame.
  3. Click Apply .

Setting TIREM as the Propagation Loss Model

The Terrain Integrated Rough Earth Model (TIREM) extension allows STK's Communication capability to predict radio frequency propagation loss over irregular terrain for ground-based and airborne transmitters and receivers.

  1. Select the RF - Environment page.
  2. Select the Atmospheric Absorption tab.
  3. Select Use.
  4. Click the Atmospheric Absorption Model Component Selector ().
  5. Select the newest TIREM () model installed on your machine in the Atmospheric Absorption Models list.
  6. Click OK.
  7. Click OK to accept the changes and close the Properties Browser.

Enabling a Local Terrain File

Add analytical and visual terrain from a local file. You can use Microsoft Bing Maps for imagery. However, imagery is not required.

  1. Bring the 3D Graphics window to the front.
  2. Click Globe Manager () in the 3D Graphics window toolbar.
  3. Click Add Terrain/Imagery () in the Globe Manager - Hierarchy Window.
  4. Select Add Terrain/Imagery... (Add Terrain/Imagery button).
  5. Click the ellipsis () beside the Path field.
  6. Navigate to <STK install folder>\Data\Resources\stktraining\imagery (e.g., C:\Program Files\AGI\STK 12\Data\Resources\stktraining\imagery).
  7. Click OK.
  8. Select the PtMugu_ChinaLake.pdtt check box.
  9. Click Add .
  10. Click Yes when prompted to Use Terrain for Analysis.

Applying Label Declutter

Use this to separate the labels on objects that are in close proximity, for better identification in small areas and on terrain.

  1. Click Properties () in the 3D Graphics window toolbar.
  2. Select the Details page.
  3. Select Enable for Label Declutter.
  4. Click OK.

Modeling the communication tower

Insert a Place () object to simulate the communication tower.

Inserting a Place object

Insert a Place () object at the tower's location to simulate the communication tower.

  1. Select Place () in the Insert STK Objects tool.
  2. Select the Define Properties () method.
  3. Click Insert....
  4. Select the Basic - Position page.
  5. Set the following parameters:
    6. Option Value
    Latitude 35.393 deg
    Longitude -117.4386 deg
  6. Click Apply .
  7. Right click on Place1 () in the object browser.
  8. Select Rename in the shortcut menu.
  9. Rename the Place1 () to Comm_Tower.

Adding a realistic model

The communication tower model is a generic model file. Change it to be something more realistic.

  1. Select the 3D Graphics - Model page.
  2. Select Show in the Model frame.
  3. Click the Model File: ellipsis ().
  4. Go to <STK install folder>\Data\Resources\stkTraining\samples (e.g., C:\Program Files\AGI\STK 12\Data\Resources\stkTraining\samples).
  5. Select comm_tower.mdl.
  6. Click Open .
  7. Move the All slider all the way to the right in the Detail Thresholds section.
  8. Click OK .

Modeling the technicians

You will insert a Ground Vehicle () object to model the technicians. Then you will create their route.

Inserting a Ground Vehicle object

Insert a Ground Vehicle () object to model the technicians who will drive to a location of the drone launch.

  1. Select Ground Vehicle () in the Insert STK Objects tool.
  2. Select the Define Properties () method.
  3. Click Insert....
  4. Rename Ground Vehicle1 () to Technicians.

Setting the technicians' route

Set the technicians' route. The technicians will drive a ground vehicle to the location of the drone launch. This location is where they are interested in testing the remote controller.

  1. Select the Basic - Route page.
  2. Set the Route Calculation Method field to Specify Time.
  3. Set the Interp Method field to Terrain Height in the Altitude Reference section.
  4. Click Insert Point and set the following parameters:
    5. Option Value
    Latitude 35.4122 deg
    Longitude -117.4634 deg
    Altitude 1 m

    For a vehicle, TIREM requires Terrain as the Altitude Reference, and the waypoint altitude has to be set to at least half a meter above terrain on the Basic Route properties page.

  5. Click Insert Point .
  6. Change the time of the second waypoint to one hour after the first waypoint.
  7. Click OK .

Creating a quadcopter drone

You will build a quadcopter drone using specifications from a popular model used to survey towers. Aviator Pro enables you to model the performance characteristics of rotorcraft as a distinct type of aircraft from a fixed-wing aircraft. You can create a rotorcraft model in the User Rotorcraft Models catalog of the Aviator catalog interface or catalog manager. The buttons on the Initial Aircraft Setup toolbar are used to define the aircraft model that will be used in the mission.

Inserting an Aircraft object

Insert an Aircraft () object, which you will use to create the drone's flight path.

  1. Select Aircraft () in the Insert STK Objects tool.
  2. Select the Insert Default () method.
  3. Click Insert....
  4. Rename Aircraft1 () to Drone.

Using the Aviator Propagator

Set Drone's () Propagator to Aviator, and add a new performance model.

  1. Open Drone's () properties ().
  2. Select the Basic - Route page.
  3. Set the Propagator: to Aviator.

Selecting an aircraft

Use the Aviator catalog interface to select an aircraft.

  1. Click Select Aircraft () on the Initial Aircraft Setup toolbar.
  2. Right-click on User Rotorcraft Models ().
  3. Select New Item.
  4. Right-click on New Rotorcraft ().
  5. Rename New Rotorcraft () to QuadcopterPM (PM stands for performance model).
  6. Click OK .
  7. Click Apply .

Optimizing STK for Aviator

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.

  1. Click Optimize STK for Aviator on the Flight Path Warning window.
  2. Click OK .

Setting the Performance Model properties

You are building a lightweight drone that is carrying a battery and a camera. The battery and camera are added as payload to the drone. You need to build flight characteristics to specifications. You can change them in the Aircraft object's properties.

  1. Return to the Basic - Route page.
  2. Click Aircraft properties ().
  3. Set the following in the Performance Models tab:

    Be mindful of your units when entering these values. Some of the fields have a default unit that is different from the one you are using.

    4. Option Value
    Max Altitude 10000 ft
    Default Cruise Altitude 100 ft
    Descent Rate Factor 50 %
    Max Climb Angle 60 deg
    Max Descent Angle 60 deg
    Min Descent Rate 1000 ft/min
    Max Load Factor G 1.05 G-SeaLevel
    Roll Rate 400 deg/sec
    AOA/Pitch Rate 60 deg/sec
    Sideslip/Yaw Rate 30 deg/sec
    Max Transition Pitch Angle 50 deg
    Max Safe Airspeed 31 nm/hr EAS Equivalent Airspeed: the airspeed at sea level (International Standard Atmosphere) at which the dynamic pressure is equal to the dynamic pressure at the aircraft's current true airspeed and altitude.
    Max Safe Translation Speed 15 nm/hr EAS
  4. Click Save.

Setting the Aerodynamics properties

Now set the Aerodynamics properties of the drone.

  1. Select the Aero/Propulsion tab.
  2. Set the following Aerodynamics properties:

    3. Be mindful of your units when entering these values. Some of the fields have a default unit that is different from the one you are using.

    Option Value
    Rotor Count 4
    Rotor Diameter

    9.4 in
    Blades per Rotor 2
    Blade Chord 1 cm
    Fuselage Flat Plate Area 0.01 m^2
    Blade Profile Drag K .01
    Induced Power Correction Factor 1
  3. Set the following Powerplant section options:
    4. Option Value
    Type Electric
    Max S/L Power 1400 Watt
  4. Click ellipsis () beside the 3D Model File field.
  5. Go to <STK install folder>\Data\Resources\stktraining\samples (e.g., C:\Program Files\AGI\STK 12\Data\Resources\stktraining\samples).
  6. Select the md4-200.mdl file.
  7. Click Open .
  8. Click Save .
  9. Click Close .
  10. Click Apply to ensure the aircraft properties are set.

Setting the aircraft configuration

The drone's empty weight is actually its full weight. In this case, you are saying that the weight of the drone includes the battery, propellers, and the camera.

  1. Return to the Basic - Route page.
  2. Select Configuration ()
  3. Select the Stations tab.
  4. Select Internal Fuel Tank.
  5. Click Delete .
  6. Select the Basic tab.
  7. Set Empty Weight to 1.5 lb.
  8. Set Max Landing Weight to 1.5 lb.
  9. Click OK .
  10. Click Apply to ensure the aircraft configuration is set.

Using the mission wind model

Use the Wind and Atmosphere Model tool to simulate wind and atmospheric conditions for the scenario, a mission, a specific procedure, or a group of selected procedures. With a rotorcraft this small and guy wires around the communication tower, wind conditions are important.

  1. Click Mission Wind Model ().

    2. For the purposes of this scenario, you will use a constant bearing and speed for your wind. If you were mission planning on the current day, you would want to consider using the NOAA ADDS Service model. The NOAA ADDS Service wind model enables you to use forecasts from the Aviation Digital Data Service (ADDS), provided by the National Oceanic and Atmospheric Administration (NOAA), to define the wind effect.

  2. Change the Wind Bearing value to 270 deg.
  3. Change the Wind Speed value to 2 nm/hr.
  4. Click OK .
  5. Click Apply to ensure the wind model is set.

Creating the take-off procedure

Inspectors will launch the drone in a remote desert area at the base of the hill on which the communication tower is located.

  1. Right-click Phase 1 in the Mission List.
  2. Select Insert First Procedure for Phase... () in the Procedures and Sites toolbar.
  3. Select VTOL Point () In the Select Site Type: list.
  4. Set the following parameters:
    5. Option Value
    Name VTOL Drone
    Latitude 35.4121 deg
    Longitude -117.4634 deg
    Altitude 0 ft / AGL (height above ground level )
  5. Click Add To Catalog.
  6. Click OK to close the Add Successful window.

    7. Adding to catalog enables you to use this configuration when landing.

  7. Click Next > .

Modeling a Vertical Takeoff procedure

A Vertical Takeoff () procedure launchers an aircraft directly up into the air.

  1. Select Vertical Takeoff () in the Select Procedure Type: list.
  2. Set the following parameters:
    3. Option Value
    Altitude offset 1.5 ft
    Heading The direction that the aircraft is pointing. into Wind Selected
  3. Click Finish .
  4. Click Apply .

Viewing the takeoff

Zoom to Drone () to see the takeoff.

  1. Bring the 3D Graphics window to the front.
  2. Right-click Drone () in the Object Browser.
  3. Select Zoom To.
  4. Use your mouse to zoom in and out and rotate to get a good view of the Drone's () takeoff.

Drone at VTOL Point

Transitioning to forward flight

A Transition to Forward Flight procedure brings an aircraft from hover mode to forward flight mode.

  1. Return to Drone's () properties ().
  2. Select VTOL Drone in the Mission List.
  3. Click Insert Procedure After () in the Procedures and Sites toolbar.
  4. Select End of Previous Procedure () in the Select Site Type: list.
  5. Click Next > .
  6. Select Transition to Forward Flight () in the Select Procedure Type: list.
  7. Select the Transition into Wind option in the Transition Course field.
  8. Click Finish .
  9. Click Apply .

Inserting a Relative to Stationary STK Object waypoint

A Relative to Stationary STK Object site is a waypoint defined in relation to another stationary object in the current scenario.

  1. Select End of Previous Procedure () in the Mission List.
  2. Click Insert Procedure After () in the Procedures and Sites toolbar.
  3. Select Relative to stationary STK Object () in the Select Site Type: list.
  4. Set the following parameters:
    5. Option Value
    Name Relative to Comm Tower
    Link To Stationary STK Object Comm_Tower
    Bearing 294 deg (True)
    Range 300 ft
  5. Click Next > .

Modeling a Basic Point to Point procedure

A Basic Point to Point procedure is a basic traverse between two waypoints.

  1. Select Basic Point to Point () in the Select Procedure Type list.
  2. Set the following parameters:
    3. Option Value
    Name Arrive at Tower
    Use Aircraft Default Cruise Altitude off
    MSL 4400 ft
    Enroute Cruise Airspeed Max Endurance Airspeed
  3. Click Finish .
  4. Click Apply .

Flying a first pass around the communication tower

An STK Object Waypoint is used to define a waypoint at or relative to the position of another object within the scenario at a specific time. Move closer to the tower and fly a circular pattern around the top of the tower.

  1. Select Relative to Comm Tower () in the Mission List.
  2. Click Insert Procedure After () in the Procedures and Sites toolbar.
  3. Select STK Object Waypoint () in the Select Site Type: list.
  4. Set the following parameters:
    5. Option Value
    Name Comm Tower Pass 1
    Link To Comm_Tower
    Offset Mode Bearing/Range (relative to North)
    Bearing 180 deg (True)
    Range 200 ft
  5. Click Next > .

Modeling a circular holding pattern

You want to move the drone around the tower in a circular fashion. A circular holding procedure is how you can accomplish this.

  1. Select Holding - Circular () in the Select Procedure Type: list.
  2. Set the following parameters in the order shown:
    3. Option Value
    Name Holding - 4400 ft
    Use Aircraft Default Cruise Altitude off
    MSL Altitude 4400 ft
    Hold Cruise Airspeed Minimum Airspeed
    Enroute Cruise Airspeed Minimum Airspeed
    Bearing 305 deg
    Range 150 ft
    Diameter 300 ft
    Number of Full Turns 1
  3. Click Finish .
  4. Click Apply.

Flying a second pass around the communication tower

Reuse the last procedure to fly a circular holding pattern around the communication tower again.

  1. Right-click Comm Tower Pass 1 () in the Mission List.
  2. Select Copy, Paste, Edit.
  3. Select Copy Procedures.
  4. Right-click Comm Tower Pass 1 () again in the Mission List.
  5. Select Copy, Paste, Edit.
  6. Select Paste Procedures After.
  7. Double-click the new Comm Tower Pass 1 to open the STK Object Waypoint Properties window.
  8. Change the Name field to Comm Tower Pass 2.
  9. Click OK .

Updating the altitude of the second pass

Update the altitude of the second circular holding pattern to 4350 ft.

  1. Double-click the new Holding - 4400 ft.
  2. Set the following parameters:
    3. Option Value
    Name Holding - 4350 ft
    MSL Altitude 4350 ft
    Profile Mode Allow climb/descent on station
    Number of Full Turns 2
  3. Click OK .
  4. Click Apply.

Heading away from the tower

Fly away from the tower to avoid guyed wires.

  1. Select Comm Tower Pass 2 in the Mission List.
  2. Click Insert Procedure After () in the Procedures and Sites toolbar.
  3. Select End of Previous Procedure () in the Select Site Type list.
  4. Click Next > .
  5. Select Basic Maneuver () in the Select Procedure Type field.
  6. Set the following parameters:
    7. Option Value
    Name Straight Ahead 300 ft
    Strategy Straight Ahead
  7. Set the following in the Basic Stop Conditions frame:
    8. Option Value
    Fuel State off
    Time of Flight off
    Downrange 300 ft

    You don't burn any fuel because it is an electric battery.

  8. Click Finish three times.
  9. Click Apply.

Returning to the technicians

The drone will turn 180 degrees and return to the VTOL point. Using a positive value of 180 degrees will turn the drone to the right. Using a negative value of 180 degrees will turn the drone to the left. Turn right, which will fly the drone away from the tower.

  1. Select Straight Ahead 300 ft in the Mission List.
  2. Click Insert Procedure After () in the Procedures and Sites toolbar.
  3. Select End of Previous Procedure () in the Select Site Type list.
  4. Click Next > .
  5. Select Basic Maneuver () in the Select Procedure Type field.
  6. Set the following parameters:
    7. Option Value
    Name Turn 180 deg
    Strategy Simple Turn
    Relative Turn Angle 180 deg
  7. Set the following parameters in the Basic Stop Conditions section:
    8. Option Value
    Fuel State off
    Time of Flight off
    Downrange 600 ft
  8. Click Finish three times.
  9. Click Apply.

Transitioning to hover

When the drone returns to the VTOL point, it will transition into a hovering maneuver and then land.

  1. Select Turn 180 deg in the Mission List.
  2. Click Insert Procedure After () in the Procedures and Sites toolbar.
  3. Select VTOL Point from Catalog () in the Select Site Type list.
  4. Select VTOL Drone ().
  5. Click Next > .
  6. Select Transition to Hover () in the Select Procedure Type field.
  7. Set the following parameters in the Altitude frame:
    8. Option Value
    AGL Selected
    Altitude 10 ft
  8. Select Transition into Wind in the Transition Options frame.
  9. Click Finish .
  10. Click Apply.

Landing the drone

The drone lands at the same spot it took off.

  1. Select Transition to Hover in the Mission List.
  2. Click Insert Procedure After () in the Procedures and Sites toolbar.
  3. Select VTOL Point from Catalog () in the Select Site Type list.
  4. Select VTOL Drone.
  5. Click Next > .
  6. Select Vertical Landing () in the Select Procedure Type field.
  7. Set the following parameters:
    8. Option Value
    Altitude above point 10 ft
    Altitude offset 1.5 ft
    Heading - Mode Heading into Wind
  8. Click Finish .
  9. Click Apply .

Viewing the flight path

  1. Bring the 3D Graphics window to the front.
  2. Reset () the scenario.
  3. Right-click Drone () in the Object Browser.
  4. Select Zoom To.
  5. Use your mouse to zoom in and out and rotate to get a good view of the Drone's () takeoff.
  6. Click Start () to animate the scenario. Note the realistic flight characteristics as the drone flies to the communication tower.
  7. Pause () the scenario when the drone is near the communication tower.
  8. Notice the detail of the inspection paths.

    9. Inspection Paths

  9. Click Start () to return and land when you are finished.
  10. Reset () the scenario.

Creating a custom graph

Create a custom graph that depicts selected data providers along Drone's flight profile.

Creating a new graph

  1. Right-click on Drone () in the Object Browser.
  2. Select the Report & Graph Manager... ().
  3. Select the My Styles () folder in the Styles frame in the Report & Graph Manager.
  4. Click Create new graph style () in the Styles toolbar.
  5. Name the new graph to Drone Profile.
  6. Click Enter on your keyboard.

Selecting data providers

Select the data providers you require to graph Drone's () flight profile.

  1. Select the Content page in the Properties Browser.
  2. Expand () the Flight Profile By Time data provider in the data provider list.
  3. Move () the Altitude AGL () element to the Y Axis list.
  4. Move () the Downrange () element to the Y2 Axis list.
  5. Click OK .

Generating the graph

  1. Select Drone Profile () in the My Styles () folder.
  2. Click Generate... .

    3. Based on the drone configuration, you have approximately twenty eight (28) minutes of battery life. You require a buffer of two minutes.

  3. Note the following three important aspects of Drone's () flight that your graph tells you:

    • The ground underneath the quad copter contains some rough terrain.

    • The quad copter travels a distance of approximately four (4) nautical miles.

    • The entire flight takes approximately 12 minutes to complete.

  4. Close the graph and the Report & Graph Manager when finished.

Showing a dynamic display

Place the default Flight Profile by Time data in the 3D Graphics window.

  1. Return to Drone's () properties ().
  2. Select the 3D Graphics - Data Display page.
  3. Click Add... .
  4. Select Flight Profile by Time in the Add a Data Display window.
  5. Click OK .
  6. Make any desired changes to Position and Appearance.
  7. Click OK .

Viewing in 3D

  1. Bring the 3D Graphics window to the front.
  2. Right-click Drone () in the Object Browser.
  3. Select Zoom To.
  4. Adjust the Step Size (,) as required.
  5. Click Start () to animate the scenario.

    6.  

    Dynamic Display

  6. Reset () the scenario when you are finished.

Using the remote controller

There are two requirements that your mission needs to meet. You need to determine if the remote controller has constant contact with the drone during the mission. You also need to know where you would lose control inside the designated communication area if the drone malfunctions. The manufacturer provides a certain amount of remote control specifications, but not a lot. Therefore, you will use simple transmitter and receiver models for the preliminary analysis of the communications.

Modeling the remote controller

Insert a transmitter object

Insert a transmitter to model the remote controller.

  1. Select Transmitter () in the Insert STK Objects tool dialog box.
  2. Select the Define Properties () method.
  3. Click Insert....
  4. Select Technicians () in the Select Object window.
  5. Click OK .
  6. Rename Transmitter1 () to Tech_Tx.

Setting up the simple transmitter

Set the specs of the simple transmitter remote controller.

  1. Set the following on the Basic - Definition page:
    2. Option Value
    Frequency 2.4 GHz
    EIRP 26 dBm
  2. Click Apply .

Updating constraints

Remove the line of sight constraint since you using TIREM.

  1. Select the Constraints - Active page.
  2. Clear Enable - Line of Sight.

    3. Disable Line-of-sight, Terrain Mask, or Az-El Mask constraints to take advantage of the over-the-horizon analysis capabilities of TIREM.

  3. Click OK .

Creating a drone receiver

The manufacturer doesn't provide any specifications for the drone's receiver, so the only thing to do is set it up to use TIREM.

Setting up the simple receiver

Insert a receiver using default properties.

  1. Select Receiver () in the Insert STK Objects tool dialog box.
  2. Select the Define Properties () method.
  3. Click Insert....
  4. Select Drone () in the Select Object window.
  5. Click OK .
  6. Rename Receiver ( to Drone_Rx.

Updating constraints

Remove the line of sight constraint since you using TIREM.

  1. Select the Constraints - Active page.
  2. Clear the Enable - Line of Sight check box.
  3. Click OK .

Generating a link budget report

A simple link budget report generates the values that determine the drone receiver's reception. For the purposes of this scenario, you will focus on Eb/No (energy per bit to noise power spectral density ratio). The minimum Eb/No requirement is 5 dB.

  1. Right-click Drone_Rx in the Object Browser.
  2. Select Access... ().
  3. Expand () Technicians () in the Associated Objects list in the Access Tool.
  4. Select Tech_Tx ().
  5. Click .
  6. Click Link Budget... in the Reports frame.
  7. Browse to the Eb/No (dB) column in the link budget report.

    8. Along the programmed flight route, you have excellent communications between Technician's () and Drone ().

Cleaning up the scenario

Clean up your workspace.

  1. Close () the Link Budget report.
  2. Close () the Access tool.
  3. Open the Analysis menu item.
  4. Select the Remove All Accesses.
  5. Clear the Drone () check box In the Object Browser.

    6. Analytically, Drone () is still in the scenario. Clearing the Drone () check box in the Object Browser turns it off visually in both the 2D and 3D Graphics windows.

Performing coverage analysis

The simple link budget analysis was very good. Basically, the line of sight between the technicians and the drone was never broken, so terrain wasn't much of a factor. However, should the drone's programming malfunction, terrain could become a communication's issue. You want to keep the drone above 100 feet AGL at all times for this analysis.

Inserting a Coverage Definition object

Insert a Coverage Definition object to model the area that you will analyze.

  1. Select Coverage Definition () in the Insert STK Objects tool.
  2. Select the Insert Default () method.
  3. Click Insert....
  4. Rename the CoverageDefinition1 () to Tx_Coverage.

Setting the grid area of interest

Set the coverage grid between latitude and longitude pairs.

  1. Open Tx_Coverage’s () properties ().
  2. Go to the Basic – Grid page.
  3. Select LatLon Region for the Grid Area of Interest - Type.
  4. Set the following parameters:
    5. Option Value
    Min. Latitude 35.3 deg
    Min. Longitude -117.55 deg
    Max. Latitude 35.5 deg
    Max. Longitude -117.35 deg

Setting the point granularity

You are analyzing a smaller area, which requires a smaller point granularity.

  1. Select Distance for Point Granularity.
  2. Set the value to 0.25 km.

Setting the point altitude

Set the height of the grid points to be 100 ft above the terrain.

  1. Select Altitude above Terrain for the Point Altitude.
  2. Set the value to 100 ft.

Setting grid constraints

Assign grid constraints so that the receiver properties are applied to each point in the grid.

  1. Click Grid Constraint Options... .
  2. Set the Reference Constraint Class: to Receiver.
  3. Select Drone/Drone_Rx in the Grid Point Access Options list.
  4. Click OK .
  5. Click Apply .

Selecting assets

Set the remote controller as the asset. Assets properties enable you to specify the STK objects used to provide coverage.

  1. Select the Basic - Assets page.
  2. Expand () Technicians () in the Assets list.
  3. Select Tech_Tx ().
  4. Click Assign .
  5. Click Apply .

Specifying the interval

Use the Basic Interval page to specify the time period over which STK computes the coverage. Change the interval to compute for one second.

  1. Select the Basic - Interval page.
  2. Open the Interval: drop-down menu.
  3. Select Replace With Times.
  4. Change Stop to +1 sec.
  5. Click OK .

Computing coverage

Grid points are laid out every 0.25 kilometer. The grid has been raised 100 feet off the ground based on the terrain at each grid point. When you selected the Receiver object as the grid constraint, you basically placed the receiver at each point in the grid. Selecting the Transmitter object as the asset, you will compute coverage between the transmitter and the receiver at each point in the grid.

  1. Right-click Tx_Coverage () in the Object Browser.
  2. Select CoverageDefinition.
  3. Select Compute Accesses.

Analyzing coverage

You will use a Figure of Merit to evaluate the quality of coverage provided by the transmitter over the coverage area. Use an Access Constraint Figure of Merit object to analyze coverage. Access Constraints measure the value of various constraint parameters used to define visibility within STK.

Inserting a Figure of Merit object

Insert a Figure of Merit object that you will use to analyze the coverage.

  1. Select Figure Of Merit () in the Insert STK Objects tool.
  2. Select the Insert Default () method.
  3. Click Insert....
  4. Select Tx_Coverage () in the Select Object window.
  5. Click OK .
  6. Rename FigureOfMerit1 () to CovAt_100FT.

Setting up the figure of merit

Use an Access Constraint Figure of Merit to analyze coverage. You want to know the Eb/No at each grid point.

  1. Open CovAt_100FT's () properties ().
  2. Select the Basic - Definition page.
  3. Set the following parameters:
    4. Option Value
    Type Access Constraint
    Constraints Eb/No
    Compute Maximum
  4. Click Apply .

Generating a Grid Stats report

Generate a Grid Stats report. It summarizes the minimum, maximum, and average static value for the Figure Of Merit over the entire grid.

  1. Right-click CovAt_100FT () in the Object Browser.
  2. Select Report & Graph Manager... ().
  3. Select Grid Stats () report in the Installed Styles () folder.
  4. Click Generate... .
  5. Scroll to the bottom of the report.
  6. Note the Minimum (dB) and Maximum (dB) values.

    7. You will use the values from the report to create color contours in the 2D and 3D Graphics windows. The contours will show you areas inside the designated communication area in which you will have and not have control of the drone.

Creating contours

You can specify how levels of coverage quality appear in both the 2D and 3D Graphics windows by showing contours. To accurately display contour levels for Figures of Merit in the 2D and 3D Graphics windows, you should know the approximate range of values for the current Figure Of Merit. You obtained these using the Grid Stats report.

  1. Return to CovAt_100FT's () properties ().
  2. Select the 2D Graphics - Static page.
  3. Change Filled Area - % Translucency to 25.
  4. Select Show Contours.
  5. Set the following Level Adding values:
    6. Option Value
    Start 5 dB (this is the lowest acceptable value)
    Stop Round down the maximum value from the Grid Stats report (e.g., 90 dB)
    Step 5 dB
  6. Click Add Levels.
  7. Ensure the Color Method is set to Color Ramp.
  8. Set the following parameters:
    9. Option Value
    Start Color Red
    End Color Blue
  9. Select Natrual Neighbor in the Contour Interpolation (points must be filled) frame.
  10. Click Apply .

Imbedding a 2D and 3D Graphics window legend

A legend provides you with a convenient way to interpret contour data displayed in the 2D and 3D Graphics windows. For in-depth information about the legend layout, see Changing the Layout of a Contours Legend.

  1. Return to the 2D Graphics - Static page.
  2. Click Legend... .
  3. Click Layout... in the Static Legend for CovAt_100FT floating legend.
  4. Select Show at Pixel Location in the 2D Graphics Window frame.
  5. Select Show at Pixel Location in the 3D Graphics Window frame.
  6. Set the following parameters in the Text Options section:
    7. Option Value
    Title Eb/No dB
    Number Of Decimal Digits 0
  7. Set Color Square Width (pixels) to 50 in the Range Color Options field.
  8. Click OK .
  9. Close the floating legend.
  10. Click OK to close the Properties Browser.

Viewing contours in 3D Graphics window

  1. Bring the 3D Graphics window to the front.
  2. Click Orient North () in the 3D Graphics window toolbar.
  3. Click Orient from Top ().
  4. Use your mouse to zoom out until you can see the complete coverage grid.

    5.  

    Coverage

    Areas with color are areas that meet the requirement of an Eb/No of five (5) dB or higher. Areas without color are areas that you'll most likely lose communication to the drone from the controller if it's at an altitude of 100 feet AGL. The lower the drone flies, coverage will most likely decline. Looking at the 3D Graphics window from the back of the hill with the technicians on the other side, you get an excellent example of TIREM in action.

The FAA sets rules on how high a drone can fly. For the purposes of this scenario, we kept the altitude below 400 ft AGL. You can visit the FAA website for more information on Small Unmanned Aircraft Regulations.

Saving your work

  1. When you are finished, close any properties, graphs, reports and tools you still have open.
  2. Save () your work.

Summary

In this lesson, you did the following:

  1. Built an STK scenario that simulates the performance of a commercial drone built to specifications.
  2. Launched the drone, had it ascend up a hill and make two passes to inspect the upper half of a communication tower, and returned it to the launch site.
  3. Created a custom report that determined if the drone's battery lasted during the programmed portion of the flight.
  4. Built a remote controller and a drone receiver to determine if inspectors can manually control the drone based on their location and local terrain.
  5. Generated a simple link budget that determined you had good communications when the drone flew its preprogrammed flight route.
  6. Used STK Coverage to determine where you might lose communications should you have to revert to manual control of the drone.

On your own

Throughout the tutorial, hyperlinks were provided that pointed to in-depth information of various tools and functions. Now is a good time to go back through this tutorial and view that information. Try setting different altitudes in the Coverage Definition () Point Altitude section and recalculate the results. Adjust the quadcopter's flight profile. Be careful that you don't fall into the vortex ring state!