PDA	Probabilistic data association.
MD-JPDA	Multiple detection joint probabilistic data association.
MHT	Multiple hypothesis tracker.
LM-IPDA	Linear multitarget integrated probabilistic data association.
PTE	Probability of target existence.
OTHR	Over-the-horizon-radar.
MP-JIPDA	Multi-path joint integrated probabilistic data association.
MP-LM-IPDA	Multi-path LM-IPDA.
NCV	Nearly constant velocity.
CFT	Confirmed false track.
CTTs	Number of the confirmed true tracks.
RMSE	Root mean square error.
Nomenclature
$\tau$	A track as well as the potential target being tracked by this track.
$m_k$	The number of selected measurements at scan k.
L	The number of signal propagation paths in the OTHR system.
${\phi }_{\tau ,max}$	The maximum number of target-originated measurements, which satisfies ${\phi }_{\tau ,max}=min(L,m_k)$.
${\phi }_{\tau }$	The number of target originated measurements ${\phi }_{\tau }\in \left\{1,2,\dots ,{\phi }_{\tau ,max}\right\}$.
$n_{{\phi }_{\tau }}$	A variable that enumerates the measurement cells under the condition that there are ${\phi }_{\tau }$ measurements generated by target $\tau$, $n_{{\phi }_{\tau }}\in \left\{1,2,\dots ,c_{{\phi }_{\tau }}\right\}$ and $c_{{\phi }_{\tau }}=C_{{\phi }_{\tau }}^{m_k}=\frac{m_k!}{{\phi }_{\tau }!\left(m_k-{\phi }_{\tau }\right)!}$.
$z_{{\phi }_{\tau },n_{{\phi }_{\tau }}}\left(k\right)$	A measurement cell specified by ${\phi }_{\tau }$ and $n_{{\phi }_{\tau }}$ at scan k.
${\chi }_k^{\tau }$	The event that target $\tau$ exists at scan k.