[phoggberg]

Does anyone know if there is a way to get the NMEA sentences out of the GPS receiver. Preferably via serial data at RS232. This is the raw data feed of GPS coordinates that is output from most recivers. Since I will have one onboard, no sense in adding another one unless I have to.

 

[HcRUL]

I've looked but haven't seen any information about directly accessing the GPS receiver in the Nav Unit. I did locate information that points to this data being available over the IBus.

After I get an IBus interface for my laptop I plan on using this data to generate my own NEMA sentences. The generated data could then be routed over a virtual serial port to mapping software on the laptop or broadcast over Bluetooth.

According to HackTheIBus Forum (MSG #3559):

B) Request Latitude/Longitude Information from NAV

C8 04 7F A1 00 12 (this has to be sent by your application !)

The NAV Unit will immediately return something like this:
7F 14 C8 A2 00 00 52 33 19 40 00 13 11 51 70 00 00 00 11 00 00 0B
in this case Latitude 52° 33' 19.4'' / Longitude 13° 11' 51.7''

Without requesting the lat/lon message comes twice per minute - CarX makes
use of this new request since version 2.4.9.h !

 

[CurtP]

Twice a minute isn't enough to use for routing - your application will have to constantly send requests for a position. Most setups get a broadcast once a second.

However, the solution HcRUL is working on sounds like it will be using an application to emulate NEMA broadcasts derived from the bus, not directly from the receiver. So the question remains - does the MINI receiver broadcast standard NEMA or something proprietary? I have serious doubts that the MINI receiver can broadcast to two devices simultaneously so even if you can tap into the receiver, more than likely you'll have to choose between either the MINI's satnav or the device you want to use. HcRUL's project is probably the best bet provided it is a solution that can work for you. Otherwise, you would probably be better served by installing a separate GPS receiver instead and there are several good places to mount one out of sight.

Deluo has a very nice "black box" permanent mount GPS receiver that includes a remote mount antenna with a very long cord. It broadcasts via Bluetooth and has a serial output on it as well (it does not include the serial cable though). It also records your vehicle movement as well. I just installed one in my new car and am pretty happy with it so far. More information can be found about it HERE.

 

[phoggberg]

Twice a minute isn't enough to use for routing - your application will have to constantly send requests for a position. Most setups get a broadcast once a second.However, the solution HcRUL is working on sounds like it will be using an application to emulate NEMA broadcasts derived from the bus, not directly from the receiver. So the question remains - does the MINI receiver broadcast standard NEMA or something proprietary? I have serious doubts that the MINI receiver can broadcast to two devices simultaneously so even if you can tap into the receiver, more than likely you'll have to choose between either the MINI's satnav or the device you want to use. HcRUL's project is probably the best bet provided it is a solution that can work for you.

I agree that 2 times a minute would not be good enough for position navigation, but it will work well enough for my purposes. Regarding talking to two devices, depending on the interface it is simply a function of buffering. Since my application only requires listening it is rather a simple matter to buffer the outputs to handle multiple inputs, so I would not have to choose between applications. Actually I have a solution, that uses a separate GPS receiver, but it requires the receiver to see the sky and I want to build this guy into the guts of the car. I expect to have completion of the self contained version done by the end of the month, time permitting.

However access to serial output of NEMA $GPRMC sentences direct or derived using the SatNav System's better antenna placement and higher front end sensitivity would give a higher reliability factor that I would prefer.

HcRUL's help has been appreciated, and I am also interested in his project as well.

 

[phoggberg]

Cracking the output

I've looked but haven't seen any information about directly accessing the GPS receiver in the Nav Unit. I did locate information that points to this data being available over the IBus.

After I get an IBus interface for my laptop I plan on using this data to generate my own NEMA sentences. The generated data could then be routed over a virtual serial port to mapping software on the laptop or broadcast over Bluetooth.

According to HackTheIBus Forum (MSG #3559):

B) Request Latitude/Longitude Information from NAV

C8 04 7F A1 00 12 (this has to be sent by your application !)

The NAV Unit will immediately return something like this:
7F 14 C8 A2 00 00 52 33 19 40 00 13 11 51 70 00 00 00 11 00 00 0B
in this case Latitude 52° 33' 19.4'' / Longitude 13° 11' 51.7''

Without requesting the lat/lon message comes twice per minute - CarX makes
use of this new request since version 2.4.9.h !

HcRule, Thnak you, I have done some work on this, and if you look at my message 3795 on the Hackthe IBUS site, I think I have found some more progress on the message formats. I have requested more data, lets see what transpires.

Thanks again for the leg up!!!