questionable "Number of Tracking Channel" of a receiver

In the earlier years it was easy to learn from GPS chipset datasheets
how many tracking channels a GPS receiver supports:

Zarlink GP2021, 12channel

SiRFstarII, 12 channel

EverMore BBP1202, 12 channel

Nemerix NJ1030, 16 channel

Sony CXD2951, 12 channel

Atmel Antaris 4, 16 channel

With the earlier SiRFstarIII product brief, on the front-page it claims
20 Channel GPS. On the backside, it lists 12-channel receiver. Thus it
looks like an 8 search channel + 12 tracking channel design (making it
20 channels total). Yet nearly all SiRFstarIII-based GPS products now
claim 20-channel parallel tracking.

As the seemingly "20 channel" receiver becoming the performance
standard in the industry, GPS receiver products based on the newer GPS
chipset nowadays all begin to list their products having 20 tracking
channels or more:

Prolific 20 channel GPS receiver (actually 12 tracking channel)
http://www.globalsources.com/gsol/I/Portable-GPS/p/sm/1002780202.htm

Mediatek MTK 32 channel GPS receiver (NavStream 4000-based, 14 tracking
channel)
http://www.qstarz.com/products/bt-q810.aspx
http://www.transystem.com.tw/p-gps-iblue737.htm

Actually the number of tracking channels is becoming irrelevant to GPS
performance nowadays when there is usually a separate search engine
available for fast and high-sensitivity acquisition of weak GPS signal.


As the competitions among GPS receiver manufacturers continue on, I
guess we'll soon see products claiming having 50 tracking channel in
2007 !


Mike

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