W3SZ Aircraft Scatter SqLite Page

Aircraft Scatter Database

The Aircraft Scatter Visual Basic program I wrote will save all received aircraft data either to a CSV file or an sqlite file. It has a built-in sqlite engine, so you don't need to install an sql program to make use of this feature. However, if you want a nice, free sqlite program I recommend SQLite Expert Personal edition.

The purpose of the SQL database is so that you can determine when there are likely to be aircraft where you want them, so that you can set up scheduled contacts. The simple form I created allows you to query the database and receive information on aircraft that meet position criteria that you can determine in one of several ways. You can:

1. View the entire database

2. Manually enter the maximum and minimum latitude and longitude you want to include in your search.

3. Center the mouse on your area of interest on the PlanePlotter Aircraft View window and see all aircraft that passed thru a square with half-side lengths of either 5,25, 50, or 100 km.

4. Use a mouse to mark the edges of the region you want to include [North, South, East, West].

5. View all aircraft that traveled within the domain of the current PlanePlotter Aircraft View window.

6. View all aircraft that traveled within 5, 25, 50, or 100 km of the great circle path between any two points.

7. Limit the search to specific times or dates (or both).

8. Order the search by multiple parameters (up to 9).

9. Set the first search parameter to be either ascending or descending.

The mouse functions are activated by clicking on the "Start Keycapture" button on the scheduler form's window. Then, you need to give PlanePlotter focus by clicking on it somewhere. Just hover the mouse over the point of interest [you don't have to click it] and press on the "Home" key to center the region of interest on that point. This function is also used by the Path Loss Calculator form in order to calculate the aircraft scatter path loss for an arbitrary location on the PlanePlotter Aircraft View display. Or, if you want to define a box on the PlanePlotter Aircraft View display and view all of the aircraft that at some point fly within that box, press the UpArrow to set the northern border of the box, press the DownArrow to set the southern border of the box, press the RightArrow to set the eastern border of the box, and press the LeftArrow to set the western border of the box. Its easy to remember: top-bottom-right-left == NSEW [NorthSouthEastWest]. To select all aircraft within 5, 25, 50, or 100 km of a great circle path between any two points, hover the mouse over the first point and press on the "Insert" key, and then hover the mouse over the second point and press on the "Delete" key. A closeup of the scheduler window is below:

To use this database query agent, just click the radio button on the left to pick which method of localization you want to use. Then, if you want to see the entire database, just click "query database", or if you have the KeyCapture button activated, just press the EndKey. If you want to manually enter the limits of latitude and longitude, click that choice and do so, and then click "query database". If you want to review an area of 5, 25, 50, or 100 km around a given point, chose the third option, select the size of the area you want to include, click on "start keycapture", and then click on PlanePlotter to give it focus and put the mouse over the point of interest, and press the HomeKey [its in the 6 key array above the ArrowKeys]. You will see the latitude and longitude appear in the text boxes, and you can click "query database" to see the planes that fit your criteria. To mark the N-S-E-W borders of a region just hover the mouse over each boundary and UpArrow-DownArrow-RightArrow-LeftArrow for North-South-East-West. The positions will appear in the appropriate text boxes, and you can then click on "query database" to see the results. To select all aircraft that come within 5, 25, 50, or 100 km of a great circle path between any two points, click that choice and use the mouse and the "Insert" and "Delete" keys to select the two ends of the path. If you are going to be working with other programs, you may want to turn off the key capture by clicking the "Start KeyCapture" button again, although I tried to choose keys that wouldn't '"get in the way" if KeyCapture is left activated. The button is red when active, and beige when not active. I tested this using ControlKey combinations, but that just added a level of difficulty to the keystrokes. The preview query button is there primarily for testing, as is the window that shows the query that the software generated.

As noted above, you can also limit the search by date (format yyyymmdd) and time (format hhmm), and you can order (sort) the search by multiple parameters. The first parameter you enter will be the primary sort variable, and the others will be used sequentially. The screen shown is sorting first by date (selected to be in descending order), then time, latitude, and longitude, all also in descending order. The records selected include all aircraft that passed within 5 km of the portion of the great circle path between W3SZ and W4DEX that is above the horizon for both locations for all aircraft flying at an altitude of 30000 feet or higher. This portion of the path was first found by using the Path Calculator Form and the mouse to find the portion of the path for which the elevation was greater than zero for both stations (this form and this process will be discussed further below). Then, the "Insert" and "Delete" keys were used to mark the two ends of this portion of the path, and the "Query Database" command button on the Scheduler page was clicked. Doing this, 152 aircraft records were located in the database and displayed on the Scheduler form, sorted by Date-Time-latitude-longitude. The Scheduler form shows you the order of the sort right next to the "Order By" check boxes, and the listed order of the sort criteria is updated any time a checkbox is selected or deselected (but you need to click the "Query Database" command button to do another query or actually re-sort the data).

The program also includes a path loss calculator that automatically calculates path loss for the aircraft scatter path using for the scattering object either [1] the designated aircraft flying between you and the DX station or [2] an arbitrary location defined by hovering the mouse over that location on the PlanePlotter Aircraft View display and hitting the "Home" key on the keypad, as described above in the discussion of the Scheduler form, when the PlanePlotter display has the focus. The Path Loss Calculator form looks like this:

The Home Station and DX Station location information are automatically pulled from where they were entered on the main form when you entered the appropriate grid square information. The aircraft that you selected as the "designated aircraft" by double-left-clicking on it in the PlanePlotter window is used as the reflector, unless you elect to use an arbitrary mouse-defined point, as described above. Using this data, total path loss is calculated using the bistatic radar equation, and displayed in dB. You can choose from among 4 aircraft sizes to determine the radar cross section used by the formula. You can select amateur bands from among the 8 bands shown; essentially, all bands from 2M thru 3 cm except for 222 MHz.

Then, you can put in the actual transmit powers, antenna gains, and receiver Noise Figures for both stations, and the program will calculate the signal margin for a 100 Hz CW bandwidth. If the number is negative, you are below the noise level and need more power, more antenna gain, a better noise figure, a larger reflector, or shorter path.

This calculator uses the classical bistatic radar equation. It does not include the effects of forward scatter enhancement that may give additional enhancement of 20-30 dB under certain conditions where the aircraft is on or very close to the direct path line between the two stations, as described by Rex Moncur in this paper, but it does indicate when favorable geometry for forward scatter enhancement is present by coloring the Path Loss and Received Signal Text Boxes red under these conditions, when the plane azimuth is within 3 degrees of the direct path for both stations, as shown in the illustrations on the left side of this page.

This is a work in progress, so let me know if you have problems or suggestions.

A 12 MB zip file with an installer for the Visual Basic program, plus the source code, plus a starter sqlite database file plus some dlls that are needed for the sql engine is available here.

Brought to you by the folks at W3SZ