The Jetvision Multilateration Network has now started to provide precison results for flights in New York.
(MLAT track in color, ADS-B track in dashed black)
After setting up a 3rd Radarcape/Air!Squitter there we now can provide MLAT results in some parts around the city.
This map shows actually observed aircraft locations:
Blue is altitude above 7000ft, orange, red and brown towards low altitude