DR or 5hz?

**Mad Jad** · 09-14-2006, 01:17 AM

I'm looking for a GPS solution that is ready to plug in to a serial port (and power) that will update faster than 1Hz. So I am looking at 5Hz such as the GPS 18 5Hz and GPS 16A from Garmin (roof mount preferred).

However, it is much more important to have DR, so does anyone know of a DR system that will send out serial updates at least 2Hz? I don't really care what the internal clock is and how accurate the points are, I just care about how often I can plot points in the software. That's why a 5hz solution is currently in the lead. <$300 preferred, $500 max. I have looked at products like racing loggers, but haven't found any that really stand out yet.

Ideally, the DR would be done inside the GPS unit and would consequently send out NMEA location sentences regardless of signal strength. However, with a 5hz race unit, I could potentially get accelerometer data as well and I could definitely use that to do all-software dead reckoning.

Ideas?

**theheel** · 09-14-2006, 01:51 AM

hope ur not gonna use iguidance.. because then its a waste.

In my newb stage i decided to pay an arm an a leg for a garmin 16a gps receiver thinking that using 5hz would be so fast updates, but i later found out that iguidance doesnt support anything faster than 1hz. I could have saved over 200+ dollars and gotton a 1hz gps reciever and gotton the same results.

**Mad Jad** · 09-14-2006, 02:21 AM

No definitely not using iguidance. You want to sell your 16A?

**Samboo** · 09-14-2006, 02:29 AM

all-software DR?

garmin gps 18 can be configured for dead reckoning using garmin's software already. u can set that in seconds. if it loses a signal it will still provide sentences and sort of "guess" where you're heading.

u will still need a good navigation software to continue "guessing" tho. i use gps 18 (with 30 sec DR) and NCK5 and they both do a good job.

edit: and u don't really need faster than 1hz if the software ur using simulates and updates fast. NCK5 updates smoothly with no jerking movement and i still use the normal cheap gps 18.

**Mad Jad** · 09-14-2006, 02:38 AM

I said all-software DR, but I meant to say that all corrections are done in software by the PC rather than being fed into the GPS module. That way, the corrections can interpolate data points between GPS sentences. Maybe I can get away with a cheap GPS unit and a serial accelerometer or gyro. That way I can do as many data points per second as I want (maxing out the gyro resolution).