A grid of 10 miles mesh length will allow MLAT almost down to ground level. For higher altitudes the distance between the stations can be higher as the range of each station will increase with the altitude.
Example: At FL10 my range is about 25nm.
To have at least three overlapping stations in each grid-cell, the distance between the three closest neighbours of each station shall at least be equal to or lower than 18,5nm.
At FL200 and about 75nm of range the distance could be as high as about 55,5nm to achieve the at least three station rule.
A more dense grid will increase the accuracy as more stations can be used for the position calculating.
The calculation is based on best guess / long shot of my average ranges so don't "nail me" to the values.
Ingo
