Database
[{SensorName:"Sensor 1",TimeSequence:1,Val1:0.1,Val2:0.2,Val3:0.3,},{SensorName:"Sensor 1",TimeSequence:2,Val1:0.4,Val2:0.5,Val3:0.6,},{SensorName:"Sensor 1",TimeSequence:3,Val1:0.7,Val2:0.8,Val3:0.9,},{SensorName:"Sensor 2",TimeSequence:1,Val1:0.1,Val2:0.2,Val3:0.3,},{SensorName:"Sensor 2",TimeSequence:2,Val1:0.1,Val2:0.2,Val3:0.3,},{SensorName:"Sensor 2",TimeSequence:3,Val1:0.1,Val2:0.2,Val3:0.3,},]
Query
db.collection.aggregate([{$sort:{SensorName:1,TimeSequence:1}},{$group:{_id:"$SensorName",lastData:{$lastN:{input:"$$ROOT",n:2}}}},{$unwind:"$lastData"},{$replaceRoot:{newRoot:"$lastData"}}])