strong signals are acquired first using a high threshold a threshold for acquisition of any remaining needed signals will then be set in the case of gps 20 db below the strongest signal acquired while the fig2 contains information pertinent to gps system its general application would be equally applicable to any other sps system referring to fig2 the device starts with the first request response exchange in attempt to acquire the sps receiver 39 s 1 approximate location from the aiding source 2 if the exchange is successful and the approximate location aiding data is received the device sets its initial search parameters in step 11 with the goal of acquiring the strong signals the parameters for the search are initially set to a high threshold and with a short integration period adequate for acquisition at the selected threshold there is no prior knowledge of the code phases of the satellites and therefore the search is unrestricted the reference frequency offset is assumed to be a prior value that was measured when the receiver was previously active i e u201c old u201d in subsequent step 12 with these parameters the sps receiver 1 uses a multi channel device to perform a concurrent search for the strong signals of all visible satellites in the gps example conducting such an unrestricted code search with 1 channel per satellite at 1 chip per integration period using 2 arms per channel with 0 5 chip spacing would take 1023 4 256 integration periods or approximately 1 second in most cases this would be adequate to acquire any strong signals present however in some instances the assumed frequency offset of the receiver 39 s reference oscillator may have changed by a larger amount than can be accommodated for by the sampling rate of.