I don’t know if there is such an article to link to. Anyway, here’s a basic explanation of what each graph shows:
Message Rates:
This graph shows an instant count of how many messages your receiver is decoding from all aircraft. The dark blue line is how many messages of all types per second are being received. The green line is the average of this count for the preceding 7 days. The yellow band indicates the maximum and minimum values over the preceding 7 days. The current rate will usually be somewhere near to this band, and if it’s far outside it can indicate a change in receiver performance assuming traffic has been fairly constant. eg damage to the antenna.
The light blue line indicates the number of positions of aircraft being received per second. The red line will appear only if you are using an rtl-sdr dongle and indicates what percentage of the signals received have a very high signal strength. This can be useful for tuning the gain of the receiver - if it’s too high it can become overloaded by close by aircraft leading to messages being missed. If this value is higher than about 5% consider reducing gain slightly.
Aircraft Seen:
This graph indicates the number of actual aircraft your receiver is seeing. The solid green area indicates the total number of aircraft. The blue line is the number of those that are transmitting their position via ADS-B. The black line is the number of aircraft who are not transmitting their position, but for whom a position has been calculated using multilateration.
The red line shows the number of aircraft received that are not transmitting their position, and no position has been calculated for them (perhaps because there are insufficient other receivers in range to do so). This number will also include a few bogus decodes resulting from noise and aren’t actually there. It will also include aircraft that get an mlat position later on.
The yellow line shows the number of messages received via TIS-B, which is those relayed by a ground station and can include aircraft being tracked by ground radar and not ADS-B. It’s only relevant in the US as that system isn’t used elsewhere.
Aircraft tracks:
This graph is probably the least useful - it shows the rate at which new aircraft are being detected by your receiver. The red line shows aircraft tracks where only one message was received - this is highly likely to not have been a real aircraft, but a bad decode from a corrupted message. The less red the better.
Range:
This graph shows a summary of the ranges of the aircraft you are receiving. The dark blue line is probably the most interesting as it indicates the maximum range you are receiving. The higher this is the better, but it will be limited by the terrain surrounding your receiver.
The black line is the median range received, and the green band indicates the upper and lower quartiles. The light blue line is the minimum range received. These are less useful for assessing receiver performance since they are mostly affect by where the aircraft you receive are flying.
Maxima:
This graph shows the absolute maximum values for each line shown. When you change to a graph for a longer time period (a year for example), the resolution of the graph is reduced because of how the data is stored. This means that the other graphs containing those fields will not reflect the peak values as well, but more of an average.
The fields should be fairly self explanatory, but the message rate graph is split into ‘local’ and ‘remote’. Local messages are those received and decoded using dump1090 directly, eg if you have an rtl-sdr dongle connected. Remote messages are those which are fed to dump1090 via a network connection. In my example, you can see I only have ‘remote’ messages as I’m using an airspy, not an rtl dongle.
Messages per aircraft:
This is fairly self-explanatory. The blue line is simply the number of messages received per second, divided by the number of aircraft being received. ADS-B is a ‘non-cooperative’ protocol, in that aircraft do not listen to see if anyone else is transmitting before sending their own messages. This means that when many aircraft are nearby, they transmit over the top of each other and some messages will be lost. The higher this number the better, but it’s of limited use for assessing receiver performance since its affected so much by the amount of traffic and settings used by interrogating radar stations.
The remaining graphs are just standard system monitoring and aren’t specific to ads-b.