18 Parallel Channel?

[gpsindy]

The Cobra website says that two of their units are 18 parallel channel. I didn't believe that 18 satellites are available by line of site at any particular position on the earth. Am I correct or does this indicate that the GPS units can track up to 18 satellites, if available. Perhaps, Cobra is looking into the future because of Europe's GPS system being launched in a couple of years. Also, I believe that the FAA will launch additional WAAS satellites in the future.

[+Renegade Knight]

I think you wil need a ROM upgrade to track the Eurpoean system. I'm not sure if they will use the same frequencies as the US system and so you might need to buy a new GPS to benifit anyway.

[+Tahoe Skier5000]

Yeah, I always thought more than 12 was just for advertising glamour. But you're right though. There are usually no more than 12 satellites at a time above your head.

[peter]

I've had up to 12 satellites being received which didn't include the two WAAS birds. So the total was at least 14. But looking at Cobra's ad copy the claim is only that additional channels could aid in quicker acquisition. Since each channel has to perform a correlation against the assigned code word of a specific satellite and also sweep in frequency to allow for Doppler shifts, there would, in principle, be a slight advantage in being able to assign multiple channels to each satellite during the initial acquisition.

However, user reports about the actual performance of the Cobra units haven't been very positive and it's not at all clear that they actually achieve any faster initial lock-on time. Other technical differences between the various receiver designs may well play much more significant roles than the number of parallel channels.