User's Manual

Heli-Coder 4 Transmitter Operation Manual | Doc. No. 6051452100 Rev. C
Broadcast Microwave Services, Inc. 16
7 BMS Geo-Point™ System
7.1 Geo-Point System Description
The Geo-Point System provides a method for ground personnel to instantly know the range and direction to the center
point of live video they are viewing. Using information received from the camera sensor or on-board moving map, the
CVIII+ hand-held receiver/monitor displays both real-time video and an easy to interpret compass “rose” that shows
direction and distance information. Unlike other tactical systems that rely on external processors, Geo-Point direction
information is developed within the handheld receiver.
The Plus model CVIII contains an integral compass and GPS receiver. Geo-Point software looks for a special word in
the NMEA 0183 data stream known as Target Lat Long (TLL). Using the TLL data received from the aircraft the
receiver displays direction and distance to where the airborne camera is pointed.
Geo-Point is a proprietary feature of BMS products.
7.2 Enabling Geo-Point™
A GPS receiver is built into the HC4. J4 (COM PORT) pins 5 and 6 accept NMEA 0183 serial data containing the
“stare point” (SP) information from an external source (usually the camera or a moving map). This function is enabled
all the time. The GPS source will be external if there is valid NMEA data on pins 5/6. If an input on pins 5/6 is missing
or corrupt, the HC4 will revert to its internal GPS source to maintain sync with the tracking sites. Lacking the SP
information the Geo-Point enabled device will report the aircraft range and position.
The SP info must be added to the NMEA stream in the TLL word (Target Lat/Long) position. The RX site will track by
reading the aircraft position LAT/LONG from the NMEA stream while Geo-Pont enabled display, (e.g. a BMS CVIII+, or
CVIII+-HD) will use the TLL info to develop the range/distance report for the Geo-Point display overlay. BMS has
worked with several manufacturers to assure compatibility and support for the Geo-Point function. The addition of the
TLL word to the GPS message is supported by several interfacing equipment manufactures or may involve a simple
set-up process.
To learn more about how adoption of Geo-Point can benefit your agency contact the BMS.