GPS Chips
As far as I know there are three GPS chipset manufacturers for products used for PPCs:
 |
SiRF - the most popular one
with OEMs by far, with virtually current dedicated PPC GPS solutions being
based on these chipsets.
Almost all GPS receivers based on this chipset can
be switched between NMEA
or SiRFoutput except the Pharos i180 mouse GPS. The utilities to
switch your GPS can be found here. |
|
Evermore - Used only in one serial and usb mouse that I know of |
|
Trimble - Apparently the Pretec CF GPS-LP released in September 2002 uses a Trimble chipset |
|
Other GPS Chipset Manufacturers are listed
here but their chips aren't used
in Pocket PC solutions |
| Maker | Name | Launched | CPU |
Fab Process |
TTFF (s) |
Voltage (volts) |
Power Usage (mW) |
Features/Comments | Used in | ||
|
Tracking Contin. |
Trickle *** |
Average | |||||||||
| SiRF | SiRFstar I | 1997 | Motorola
MC68330 at 19.1 mhz |
0.60 | 60/40/8 | 5 | 1,700 | - | 1,700 |
- |
- Leadtek
Mouse 9531 - Royaltek Sapphire * |
| SiRF | SiRFstar I/LX |
Hitachi |
0.35 | 60/40/8 | 3.3 | 500 | 150 | 165 | - Sophisticated power
management - PDF (requires Acrobat Reader) |
- Pretec Compact GPS ** | |
| SiRF | SiRFstar IIe | 1999 | ARM7/TDMI 12.3 mhz |
50/38/8 | 2.7 | 500 | 150 | 165 | - Designed as a standalone
solution - Designed for GPS solutions where data throughput is more important than battery usage (built-in car systems, etc...) - WAAS, EGNOS, Beacon DGPS - PDF (requires Acrobat Reader) |
- Axiom CF GPS - Fortuna PocketTrack - Leadtek Mouse 9532 - Leadtek 9534 - Navman sleeve - Pharos CF GPS - PocketMap CF GPS - Teletype CF GPS - Transplant CF GPS - Billionton CF GPS |
|
| SiRF | SiRFstar IIe/lp | 2002 | ARM7/TDMI 12.3 (?) mhz |
? | 45/38/8 | 2.7 | 175 | 60 | 65 | - Designed as a standalone
solution - Designed for GPS solutions where battery usage is more important than data throughput (CF GPS, etc...) - WAAS, EGNOS, Beacon DGPS - PDF (requires Acrobat Reader) |
- Emtac
Bluetooth GPS - Holux GM-270 CF GPS - Transplant IGPSJ Sleeve |
| SiRF | SiRFstar IIt | 2002 | ARM7/TDMI 12.3 (?) mhz |
45/38/8 | 2.7 | 170 | 40 | 45 | - Designed to be integrated
in a host system with an existing powerful CPU (automobile navigation,
mobile computers) - WAAS, EGNOS, Beacon DGPS - PDF (requires Acrobat Reader) |
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* In some cases, manufacturer specs were not detailed enough to determine whether they were using the SiRFstar I or the SiRFstar IIe chip
** In some cases, manufacturer specs were not detailed enough to determine whether they were using the SiRFstar I/LX or the SiRFstar IIe chip*** "Trickle Mode"
"In TricklePower mode of operation the SiRFstar receiver initially starts up in continuous mode until it obtains the first fix. After that it transitions to TricklePower mode where it periodically performs a GPS fix and transitions to a standby state to conserve power. Just before it shuts itself off, the software programs the Real Time Clock when to wake up for the next position fix. At the prescribed time the RTC restarts the receiver. Upon startup, the receiver uses its fast re-acquisition capability to reacquire all visible satellites. Typically 200 ms after restarting, the receiver completes all the measurements required for computing a GPS position fix (tracking mode). Once the measurements are completed the software shuts down the signal processing sections of the receiver. The microprocessor continues running (CPU state) and computes and outputs the position fix. Finally, the software programs the RTC to wake up for the next fix and puts the microprocessor into a suspend state. Figure 2 shows the current consumption versus time for the three different states. Although user selectable, the receiver defaults to 200mS tracking time (and a 20% duty-cycle) which generates a one position update per second" from SiRF documentation.