I have done some mapping with Reefmaster and Lowrance HDS7.
I would like a better horisontal accuracy.Therefore I will try to use an external rtk gps, and transmit to HDS7.

Equipment:
Lowrance HDS7 Gen2 Touch
Trimble GeoXH rtk gps receiver with an accuracy of 10 cm.

The Trimble transmit NMEA 0183 rs232.

HDS7 transmit/receive NMEA 0183 rs422.

I hope with this configuration to achive better maps and sidescans.
My problem is how to connect the HDS and Trimble together. I hope some of you guys maybe have a similar setup, and can give me some help here.

First of all: is this a possible setup? Will HDS7 accept external rtk gps data?
Is direct wiring possible rs232<>rs422?
Need of rs232/rs422 converter?
Need of nmea multiplexser?

Thanks

I feed NMEA0183 to my HDS Gen2 with heading and position using 38400, no problem there.
BUT the position is stored in a much lower resolution in the Lowrance unit (±1 meter) than the resolution you feed to the unit so you don't gain much with RTK compared to a GPS with SBAS once the position has been stored.

One thing that really helps the sidescan data if you are mapping in narrow areas with turns or has drift due to wind and current is a good heading! I use a GPS compass that supply true heading to the Lowrance unit with 10Hz.

/hakan

I have connect my rtk reciver with an AT10 adapter, feeding Simrad GO9 with cm accuray at 1hz. Should have got the "AT10 H" version that is 10Hz
community.emlid.com/t/the-rtk-boat-project/7095?u=tb_rtk