GLOBALSTAR PROPRIETARY AND CONFIDENTIAL INFORMATION
Use or disclosure of data contained on this sheet is subject to the restrictions in the Distribution Statements on the title page of this
document.
06/18/20
Subject to Change without Notice
P a g e | 10
Figure 2
LEO Constellation
Since the satellite position is constantly changing, simplex devices on the ground will transmit (with no knowledge of
any of the satellites locations) and the transmission may be received by one or more satellites. These satellites will then
relay the message to the nearest satellite gateway as shown below. Once received by the satellite gateway, the simplex
message will be delivered to the simplex gateway where redundant messages are discarded and the data from the
message is sent to the OEM via the Internet.
Figure 3
Simplex Messaging
Messages are composed of 1 or more 9-byte payloads. The user application may send a message via the Bluetooth Low
Energy interface to the ST100 board from 1 to 144 bytes in length. The ST100 board will break the message into 9 byte
packets. A 144 byte message would be broken into 16 packets.
INTERNET
T
Satellite Gateways
VAR, VAM
Simplex Transmitter
Simplex Gateway