Use Case 16

Time-Ordered Data

(Adam Hincks)

I work a lot on data acquistion for mm/radio observations. Our raw data products consist of time-ordered data (TOD)—e.g., for CMB data, we would record the reading of each bolometer, the position of the telescope, the temperatures of the cryogenics, etc., all as a function of time—everything needed to make a map.

Usually there can be more than one recording rate, so that some TOD's are sampled more frequently than others. The rates can be sychronous (i.e., all data share the same clock and all rates are multiples of a base rate) or asynchronous. Timestamps for the TOD's need to be appropriately recorded.

Simply having tables can make this kind of clunky, because you either need separate tables for each data rate or do some kind of custom packing for the different rates within the same table.