| Q. |
Can the Jupiter 20 be used for GPS operation indoors? |
| A. |
You will find the unit may continue to track satellites inside a building, but will probably not obtain an initial fix or continue to generate a valid fix. A high sensitivity version using XTrac software will perform better in weak signal areas, however it is not guaranteed to work indoors since this is dependent upon the building construction material. |
| Q. |
Does the Jupiter 20 have Dead Reckoning capability? |
| A. |
There is a dedicated version of the module with all the interfaces for a DR system, including analogue gyro input, wheel pulse input and forward/reverse input. |
| Q. |
How long does the unit take to get a GPS fix? |
| A. |
The unit will normally get a GPS fix within 45 Seconds with a 95% probability from a cold start under stationary conditions with a good view of open sky. |
| Q. |
What is the format of the output data? |
| A. |
The Jupiter 20 default ASCII data protocol is NMEA 0183 at 9600 baud from port A, which is a standard protocol for marine electronics. Most GPS software applications use NMEA as their input.. |
| Q. |
What are the unused I/Os for? |
| A. |
The Jupiter 20 has built in functions that allow the customer to read and control these outputs using NMEA commands. These I/O connections can be used by customer specific software for their own applications. |
| Q. |
How does the active antenna get power? |
| A. |
The antenna connection of the Jupiter 20 can have DC power imposed upon it for power to the active antenna. |
| Q. |
Is the DC power to the antenna protected against short circuits? |
| A. |
The supply path to the antenna has NO short circuit protection. External current limiting should be added, limiting the current to 100mA. |
| Q. |
Do I need a multi-layer PCB to mount the Jupiter 20? |
| A. |
A double-sided board is sufficient to mount the Jupiter 20 module as long as the RF connections maintain a 50 Ohm impedance. It is also advisable to have a ground plane under the module. |
| Q. |
What antenna does Navman recommend? |
| A. |
Navman has performed testing using the ALPs model BSGW1-202A and has determined it is suitable for the Jupiter 20 GPS module. Other antennas are available from San Jose Navigation model MK-76. |
| Q. |
How do I manage the power consumption? |
| A. |
There are 2 power saving modes available on the GPS receiver:
- push to fix mode
- trickle power mode
Push to fix mode puts the GPS receiver into a dormant mode and can be re-initiated by pulling the reset pin low or by an internal software timer. Trickle power mode allows a reduction in power consumption by providing fixes at <1Hz. This mode is recommended for short durations only. |
| Q. |
What supply voltage must be used? |
| A. |
The Jupiter 20 can be operated from 2.9 to 3.6VDC. |