This button starts or stops the satellite tracking. The plugin will only calculate satellite positions or adjust for Doppler when started.
<h3>2: Find satellite on map</h3>
Pressing this button centres the Map Feature (if open) on the target satellite.
<h3>3: Automatically select target on AOS</h3>
When checked, the target satellite will be automatically changed on any selected satellite's AOS, if it is a higher priority than the current target or if the current target satellite is not visible.
Priority is determined by the order the satellites appear in the Satellite Selection dialog.
When clicked, the TLE (two line element) files selected in the Settings dialog are downloaded, as well as the latest SatNogs satellite database, containing details of satellites' transmitter and receiver frequencies. While downloading, this button will appear green.
Satellite positions can only be predicted with limited accuracy, so the TLEs need to be updated frequently for accurate positioning. This could be daily, weekly or monthly depending upon the individual satellite. This downloads around 1MB of data.
This dialog determines the actions the Satellite Tracker will take when AOS or LOS occurs for a satellite. First, select a satellite from the dropdown box. Information about the satellite's transmit and receive modes should appear in the field at the bottom of the dialog, if available in the SatNogs database.
* The device set that will be controlled. This will list all currently open device sets. You can also type the name of a new device set.
* The preset to load on AOS. This allows preset device settings (E.g. centre frequency) and demodulators to be opened when the satellite becomes visible.
* Which channels Doppler correction should be applied to. The list of channels is taken from the selected preset. Check a channel to enable Doppler correction for that channel. The Doppler correction is applied to the channel's input frequency offset.
* Whether to start acquisition (i.e. start the SDR device) on AOS.
* Whether to stop acquisition on LOS.
* Whether any file sinks in the preset should be started on AOS and stopped on LOS. This allows the baseband signal received from the satellite to be recorded to a file.
Multiple tabs can be added, to allow independent control of multiple device sets. To remove a tab, click the cross next to the device set name in the tab list.
On the left hand side are a list of all available satellites, as determined by the TLE files that have been downloaded. (If none are visible, ensure the TLEs tab of the Satellite Settings dialog (8) contains at least https://db.satnogs.org/api/tle/ and then press the Update satellite data (4) button)
The list of satellites that the Satellite Tracker will track is on the right hand side.
To move satellites from side to side, either double click them, or select them and press the left or right arrows in the middle.
The Satellites to track list is ordered in priority for the auto target feature (3). The change the order, select a satellite in the list and press the up or down arrows to the right.
Satellite information at the bottom of the dialog comes from the SatNogs database: https://db.satnogs.org/
<h3>7: Set latitude and longitude from My Position</h3>
When clicked, it sets the latitude, longitude and height fields to the values from SDRangel's My Position preferences.
<h3>8: Show Settings dialog</h3>
Pressing this button displays the Settings dialog.
* The minimum elevation in degrees from the antenna location, which a satellite much reach in order for a pass to be indicated.
* A time window for which passes must start and end between, to be displayed or acted upon. For example, for day time passes, you could set "must start after" to 8:00 and "must end before" to 18:00. For night time passes, set "must start after" to 20:00 and "must end before" to 6:00.
* The maximum azimuth angle in degrees supported by your rotator. 450 degree support is beneficial for passes that pass through 360/0 degrees, to avoid the rotator having to do a complete rotation mid pass.
* The maximum elevation angle in degrees supported by your rotator. 180 degree support is beneficial for passes that pass through 360/0 degrees, to avoid the rotator having to do a complete rotation mid pass.
* A command/script to be executed on AOS. This applies to all satellites. It is also possible to set a per-satellite command in the SDRangel Control dialog. See below for a list of variable substitutions.
* A command/script to be executed on LOS. This applies to all satellites. It is also possible to set a per-satellite command in the SDRangel Control dialog.
* The Doppler correction period in seconds, which controls how frequently Doppler correction is applied. Which channels have Doppler correction applied is set on a per-channel basis in the SDRangel Control dialog.
For commands, scripts and speech, the following variables can be substituted: `${name}`, `${duration}`, `${aos}`, `${los}`, `${elevation}`, `${aosAzimuth}`, `${losAzimuth}`, `${northToSouth}`, `${latitude}`, `${longitude}`, `${altitude}`, `${azimuth}`, `${elevation}`, `${range}`, `${rangeRate}`, `${speed}` and `${period}`.
Select the target satellite. The target satellite is the source of data for the Time to AOS, Azimuth and Elevation fields. The azimuth and elevation of the target satellite is sent to the Rotator Controller features.
<h3>13: Time to AOS</h3>
This field displays the time to AOS (Acquisition of Signal) for the target satellite. It is displayed in hours, minutes and seconds, unless the satellite is currently visible, in which case it will display "Now".
<h3>14: Azimuth</h3>
Displays the calculated azimuth (angle in degrees, clockwise from North) to the target satellite.
<h3>15: Elevation</h3>
Displays the calculated elevation (angle in degrees - 0 to horizon and 90 to zenith) to the target satellite.
<h2>Pass Charts</h2>
Pass charts can be plotted showing the azimuth and elevation of the target satellite from AOS to LOS. This can be in polar of Cartesian form:
The arrows next to the chart combobox, allow the pass number to be selected. Pass 0 is the next pass, with higher numbered passes occurring later in time.
* The Doppler shift due to the satellite's motion that would be observed on a signal at the default frequency (which can be set in the Settings dialog).
* The free space path loss to the satellite, at the default frequency.
* The one-way propagation delay to the satellite from the antenna location in milliseconds.
