Glossary



'When I use a word,' Humpty Dumpty said in rather a scornful tone, 'it means just what I choose it to mean - neither more nor less.'

 

Auto Mlat

Assuming that you are a Master User, then checking the Auto Mlat option in Options, I/O settings means that whenever Plane Plotter is idle (no user interaction for some time), every minute or so it will attempt to Mlat any position-less aircraft in the list that have sufficient Ground Stations in the sharer list.  Unlike manual Mlats, the progress is shown in the status bar and not in a pop up progress window.

 

Condex

Short for "conditional expression", which refers to the feature in PlanePlotter by which you can control which aircraft are displayed, logged or can trigger alerts.

 

CRC

Cyclic Redundancy Check - error detection.


Delete after

The "Delete after" time removes all trace of the aircraft from Plane Plotter's internal database.  Such aircraft will not reappear, even if the times are subsequently increased and they do not appear on the OLE/COM interface.

 

Downloader

A Plane Plotter sharer who downloads data from the Sharing Server but does not upload data to the Server - usually because they have no receiver of their own.

 

GPSD

Software reading serial data from a GPS receiver, can be used in a stratum-1 NTP server and other applications.  More

 

Ground Station (GS)

A Plane Plotter user who is able to transmit Raw Data to other users to allow them to perform Mlats.  Because of the sensitivity of the Mlat method to errors in the Ground StationĀ“s setup, they must be validated before they are enabled, and they must have configured port-forwarding on their router.  Many receiver types can now provide raw data for Mlat purpose, including The Mode-S Beast, microADSB and SBS1 .  The supply of data is entirely automatic and requires no user intervention.  Ground Stations (subject to some availability conditions) are also Master Users by right. We always welcome more Ground Stations.  There are many parts of the world where just one or two more Ground Stations would make a dramatic difference to the availability of Mlats.

 

Hypersharing

Hypersharing is a new feature from version 5.4.9.1.  Up to now, aircraft that were received by sharing (ie. aircraft that you are not receiving directly yourself) were downloaded from the sharing server once per minute.  The new feature allows some aircraft, under some circumstances, to be refreshed as often as once per second.  The feature is only available to Master Users and initially, you will see it refresh only the currently designated aircraft, if any.  The method requires there to be one or more operational Ground Stations within range of the chosen aircraft.  In due course, other aircraft will be added to the hypersharing process.  The new option is enabled in the Options..Sharing, Setup dialogue.


To expand on that.: a designated aircraft is one that you double click on and which acquires a blue ring around it.  If you are a Master User, and if you designate an aircraft, after the next sharing cycle, Plane Plotter will poll the Ground Stations in the share string for that chosen aircraft and ask for all their current aircraft (not just the designated aircraft as stated in the release announcement).  It polls one Ground Station per second so depending on the coverage of the Ground Stations in the sharer list for the designated aircraft, you should see shared aircraft moving every second, rather than once per minute.
This is not to be confused with prediction, which simply estimates where the aircraft has moved.  Hypersharing gets live data more quickly.

Master User (MU)

Master User - a Plane Plotter user who can initiate Mlat requests.  There are two types of Master User.  Those who are validated Ground Stations and provide Raw Data on a regular basis, are Master Users by right.  Other users, who are not validated Ground Stations, can be Master Users on payment of a small annual subscription.  The Master User's PC will typically have to add port forwarding to their router so that the responses from the Ground Stations will be passed to the PC running Plane Plotter.  A Master User can see the results of other user's Mlats and can perform their own manual Mlat requests.  A Master User can also optionally enable Auto Mlats, which will put their system at the disposal of the network to perform Mlat requests automatically, when unattended.  The results of any MU's Mlat requests will become available to all other MUs via the sharing system.

 

Mlat

The process of determining the position of a Positionless aircraft using Multilateration (Mlat), or the result of such a process.  Multilateration uses Raw Data from multiple users to determine the position of the otherwise Positionless aircraft by solving intersecting hyperboloids based on relative time delays.  Mlats are organised through the Sharing Server but the Raw Data is sent directly between users.

 

MRTG

Multi Router Traffic Grapher - for graphing performance data.  More

 

NTP

Network Time Protocol - keeps your PC's clock accurate.  How to install on Windows.

 

Omit after

The "Omit after" time applies only to the chart/outline displays.  Such aircraft are still shown on the View..Aircraft screens and can be made to reappear by increasing the "Omit after" time.  The OLE/COM interface provides two means of accessing the internal database.  One family of methods yields only those aircraft that are currently displayed on the chart (within the "Omit after" time) and the other family of methods yields all aircraft that are in the system.

 

Positionless aircraft

An aircraft transmitting Mode-S information but not ADS-B messages containing the position.  Such reports appear in the View..Aircraft screen (if enabled) but not on the View..Chart display.

 

PuTTY

Terminal emulation program for the PC and other platforms - used to talk over the SSH protocol.  More

 

RHCP

Right-hand circular polarisation - see the Wikipedia.

 

Raw Data

Raw Mode-S format data from an SBS1 receiver before processing by the BaseStation software.  Raw Data contains timing information that is used in the Mlat process.  It requires a DLL to be substituted to give Plane Plotter access to this Raw Data.  When a user is performing an Mlat, the Raw Data is sent directly to that user from each contributing Ground Station, without passing through the Sharing Server.

 

Remote Mlat

An Mlat that is initiated by the Sharing Server, rather than by the user.  Such requests are only made to Ground Stations who have signalled their willingness to participate (by enabling Allow Remote Mlats in Options..I/O settings) and who are not otherwise engaged.


SAMBA

No, not the dance, but software allowing Windows PCs to see into UNIX servers.  More.

 

Sector Master User (SMU)

A Sector Master User (SMU) is a new component in the network.  An installation of Plane Plotter that is activated as a Sector Master User will automatically perform a large number of simultaneous Mlat solutions once every minute or so.  The results will, of course, appear on the display of the SMU and they will also appear on the screens of any other MU (Master User) looking at the same area.
Apart from the undoubted prestige, there is no extra benefit to the individual in being the Sector MU for that area.  All Master Users get to see the same results of the operation and for the Sector MU concerned, the operation is largely invisible.  In fact, ideally, the Sector MU should resist the temptation to perform manual Mlats on top of the automated ones.  There is therefore some small sacrifice in fulfilling that role in an ideal way.  The way the new system works means that pretty much all 24/7 Ground Stations are likely to be participating by providing their data to the local Sector MU analysis.  There is nothing extra that needs to be enabled for that to happen.

Because the process is done on an area basis, only a small percentage of users are needed to be SMUs.  John Locker is still experimenting to find the best configuration but the current thinking is that eventually, to eliminate any conflict with local data, the SMU role may be best performed by MUs who do not actually have their own receiver.  Such MUs will currently be paying the small subscription to maintain their MU status, so the plan is that as compensation for allowing their system to be an SMU round the clock, the subscription fee will be waived, subject to some availability criteria.

 

Share Code

A two letter code uniquely identifying an Uploader.  The Share Code is used in the Circles/MyCircles methods.  Downloaders may have a Share Code but such use is not managed and may not be unique.

 

Sharer

A Plane Plotter user who configures the program to interact with the Sharing Server.  Sharers may be "Uploaders" or "Downloaders".

 

Sharing Server

The central computer that collates the reports from many Plane Plotter Sharers and distributes the information to all other Sharers.

 

SNMP

Simple network Management Protocol - allows network-wide performance monitoring with MRTG.  More.

 

SPI

Squawk Packet Ident - the "squawk ident" triggers a highlight on the screen, and is noted as "SPI" on the status bar.  The rings are the same colour as you have chosen for waypoints.  See this message.

 

SSH

Protocol allowing you to have a more secure terminal session with a remote PC.  More.

 

Static IP address

A network address for your PC which does not change, making it easy to forward packets for Mlat from the router to your PC.  See: http://www.makeuseof.com/tag/static-ip-address-advantages-disadvantages/

 

Uploader

A Plane Plotter sharer who contributes data from a local receiver (Mode-S/ADS-B, ACARS or HFDL) to the Sharing Server.  Shared data is not the same as Raw Data qv.