Abstract
Modern passive emitter-location systems are often based on joint estimation of the time-difference of arrival (TDOA) and frequency-difference of arrival (FDOA) of an unknown signal at two (or more) sensors. Classical derivation of the associated Cramér-Rao bound (CRB) relies on a stochastic, stationary Gaussian signal-model, leading to a diagonal Fisher information matrix with respect to the TDOA and FDOA. This diagonality implies that (under asymptotic conditions) the respective estimation errors are uncorrelated. However, for some specific (nonstationary, non-Gaussian) signals, especially chirp-like signals, these errors can be strongly correlated. In this work we derive a conditional (or a signal-specific) CRB, modeling the signal as a deterministic unknown. Given any particular signal, our CRB reflects the possible signal-induced correlation between the TDOA and FDOA estimates. In addition to its theoretical value, we show that the resulting CRB can be used for optimal weighting of TDOA-FDOA pairs estimated over different signal-intervals, when combined for estimating the target location. Substantial improvement in the resulting localization accuracy is shown to be attainable by such weighting in a simulated operational scenario with some chirp-like target signals.
Original language | English |
---|---|
Article number | 5678660 |
Pages (from-to) | 1612-1623 |
Number of pages | 12 |
Journal | IEEE Transactions on Signal Processing |
Volume | 59 |
Issue number | 4 |
DOIs | |
State | Published - Apr 2011 |
Keywords
- Chirp
- conditional bound
- confidence ellipse
- frequency-difference of arrival (FDOA)
- passive emitter location
- time-difference of arrival (TDOA)
All Science Journal Classification (ASJC) codes
- Signal Processing
- Electrical and Electronic Engineering