Relevant Iris Telemetry Fields for Computing PN Range

Field NameSizeDescription
PN Epoch Count4 bytesIndex of PN epoch; increments each time PN chip 0 is received; count begins when the PN ranging correlators are locked; resets to 0 when lock is lost; rolls over to 0 after 65,535
PN Chip Index (q)4 bytesPN component sequence delays; can be used to calculate index of current PN chip (0 to 1,009,469) using the Chinese remainder theorem; valid when PN ranging correlators are locked
PN Chip Accumulator (PCA)8 bytesPN symbol clock phase accumulator from the STL; accumulation begins when the PN ranging correlators are locked; determines a floating-point estimate of the fractional chip phase using Embedded Image
ETT Epoch4 bytesPN epoch count to which the current value of the ETT register belongs
ETT4 bytes32-bit ETT; bit 31 corresponds to the bit encoded in PN chip 0 of the epoch reported in the ETT epoch register