BaseOps User's Guide, Chapter 10: Setting Core Case Properties

After creating a new BaseOps case, your first task should be setting the core case properties. Core case properties can affect how the rest of a case's data is entered.

In the list pane, choose Case from the object type selector dropdown list. Then set the properties in the text pane.

Tip:

Case Information

The Case Name is a short (60 characters maximum) description of a BaseOps case, such as "Wright-Patterson Air Force Base 1990 Noise Study". It should unambiguously identify the case.

The Case Abstract is a narrative summary of a BaseOps case. It describes the "what" aspects of the case. There is no restriction on the length of the abstract. Press the Enter key to insert additional lines.

The Case Purpose is a brief description of the reason that a BaseOps case was created. It describes the "why" aspects of the case. There is no restriction on the length of the description. Press the Enter key to insert additional lines.

Use the Case Notes to store miscellaneous information about a case. There is no restriction on the length of notes. Press the Enter key to insert additional lines.

Site Information

The Site Name is a short (60 characters maximum) description of the location being modeled by a BaseOps case. Typically, this will be an airfield name, such as "Wright-Patterson Air Force Base". However, it may also be the name of a region, such as "Boston Metropolitan Area" or "NAS Oceana and Associated Outlying Airfields".

Use the Site Notes to store miscellaneous information about a site. There is no restriction on the length of notes. Press the Enter key to insert additional lines.

Noise Models

BaseOps supports the following noise models:

• NMap, the US Department of Defense's model of aircraft flight and run-up noise near air bases

• AAM, the Advanced Acoustical Model, the next-generation model of aircraft flight noise developed jointly by the US Department of Defense and NASA.

• MRNMap, the US Department of Defense's model of subsonic aircraft noise from Military Operations Area (MOA) and Military Training Route (MTR) operations.

• RNM, the Rotorcraft Noise Model, NASA Langley's model of helicopter and tilt-wing aircraft noise

Check the box next to each noise model that you wish to use as part of this BaseOps case. At least one model must be selected.

When you run the case, BaseOps runs each of the selected noise models. If more than one model is selected, BaseOps creates a combined noise grid containing the summed noise from all of the selected models.

Note:

Reference Point

The reference point is a well-defined location associated with a BaseOps case. The latitude, longitude, and elevation of the reference point must be known, and the point should be easily identifiable on maps.

The reference point serves as the origin of the local X-Y coordinate system used by the noise models. As such, it should be located near the center of the case's area of interest.

Tip:

The reference point has the following properties.

• Reference Point Name - Type a short (60 characters maximum) description of the reference point: for example, "Centerline, Beginning of Runway 32".

• Reference Point Lat/Long - Specify the horizontal coordinates of the reference point, in degrees of latitude and longitude, using the WGS-84 datum.

  Note:

  The reference point location must be specified using latitude and longitude, regardless of the current case coordinate system. This is because the case coordinate system can be defined in terms of the reference point (for example, feet east and north of the reference point). Thus, allowing the reference point to be specified in the case coordinate system could cause a circular reference.

• Reference Point Elevation - Type the elevation (above mean sea level) of the ground at the site reference point. See Setting the Case's Physical Units for information on selecting the units used to specify elevations.

  The reference point elevation is used to convert between AGL (above ground level) and MSL (mean sea level) heights in a BaseOps case. It is also used as the default ground elevation when NMap, AAM, and RNM are run without elevation data.

Operations

The Flying Days per Month and Annual Operating Days are the average number of days per month and year, respectively, on which aircraft typically operate at the principal airfield being modeled by the BaseOps case. For airfields that operate continuously, 30 days per month and 365 days per year are typically used. The monthly average is used by the MRNMap noise model. The yearly average is used by NMap, AAM, and RNM. These data entry fields may be hidden, depending on which noise models you selected: see Noise Models.

The Number of Daily Periods specifies the number of periods into which a 24-hour day is partitioned for the purpose of noise modeling. This allows the noise models to give some consideration to the time at which noise events occur (events that occur at night are considered more significant, due to their greater potential to annoy).

The number of daily periods is determined by the noise metric (DNL or CNEL) being used, which in turn is generally determined by the applicable laws governing the site being modeled.

You have two choices for the number of daily periods.

• 2 (day, night) - Two periods are used: day (for aircraft operations between 0700 and 2200 hours local time) and night (for operations before 0700 or after 2200 hours).

• 3 (day, evening, night) - Three periods are used: day (for aircraft operations between 0700 and 1900 hours local time), evening (for operations between 1900 and 2200 hours) and night (for operations before 0700 or after 2200 hours).

Magnetic Declination

The Magnetic Declination is the difference between true and magnetic north at the location being modeled by a BaseOps case. It is specified in decimal degrees.

The current magnetic declination is indicated by BaseOps' north arrow: see North Arrow.

Contact Information

The requested contact information identifies the person or organization that is responsible for a BaseOps case. All of the information is typed as freeform text; there are no restrictions on what can be typed into each of the text boxes.

AAM Advanced Options

The AAM Advanced Options section pertains only to the AAM noise model. This section is hidden unless that noise model is selected: see Noise Models.

For non-helicopter AAM aircraft (such as the fixed-wing vectored thrust F-35 and the tilt-rotor V-22 Osprey), accurate values for the angle of attack and the yaw angle are difficult to obtain. Under realistic flying conditions, these values rarely depart significantly from zero, so by default, BaseOps assumes zero for these parameters, and hides the portions of the BaseOps user interface where these parameters are edited and/or displayed. Most uses should leave these parameters locked at zero.

If you have specialized needs, you can check the box labeled Allow editing of attack and yaw angles for non-helicopter AAM aircraft. This will display the sections of the BaseOps user interface where these parameters can be edited.