 cell as being incor- rect (see Figure 1.65). The basic philosophy behind the above strategy is to assign a small dwell time Td1 to the first search state SO as to search the code phases quickly and a larger dwell time Td2 to the second search state to provide a better estimate (higher probability of detection and lower false alarm probability) of whether the correct cell has been found. In this way, some of the false alarm protection is apportioned in the first integration and the remaining (usually greater) protection is placed in the second inte- gration. Finally, the lock mode portion of the SLS uses a third integration time Td3 (in practice it could be the same as Td2) with the same algorithm as in Figure 1.59, i.e., a reinitiation of the search requires three consecu- tive misses. Before proceeding with the performance analysis of the SLS in Figure 1.65, we point out its similarity with the multiple (here double) dwell time acquisition system alluded to above. In particular, the double dwell time sys- tem which incorporates the search mode of the SLS in Figure 1.65 employs independent (non-overlapping) integration intervals for its two dwells, whereas a two-dwell version of the multiple dwell time procedure discussed in Section 1.3 uses overlapping integration intervals. Since the SLS of Figure 1.65 can also be modelled by a Markov chain, the mean and variance of the acquisition time are still given by (1.288) and (1.289), however, with different relationships for PL and Td. Clearly, since Search / Lock Strategies REJECT CELL, SEARCH ADJUST PHASE (rdl) SEARCH (Td2) ENTER LOCK MODE, SET LOCK MODE PARAMETERS ENTER SEARCH MODE, SET (rd3) SEARCH MODE PARAMETERS (Td3) Figure 1.65. Another search/lock strategy. the only event which causes an entering of the lock mode starting in search state 1 is hit-hit, the probability of lock is now given by PL = PD1PD2 (1.304) where PD1 and P D2 are, respectively, the detection probabilities for search states 1 and 2. To compute the mean dwell time we again separate the event