Aircraftformerly tasked with bringing food and supplies to troops behind enemy lines are now staying out of harm's way, thanks to a wirelessly networked, precision-guided aerial delivery system. The system is the Mosquito automated guidance unit from STA Technologies, and the wireless technology is provided by the WiPort-485 from Lantronix. The WiPort enables STAFF to remotely access and manage their guidance unit over a wireless network to configure target coordinates, transmit telemetry data remotely and deliver diagnostic data after the mission.

The Mosquito Tactical Resupply System is light enough to be delivered close to a target by means of an unmanned aerial vehicle (UAV). It has been used to deliver blood plasma, batteries, ammunition, ground-based sensors, and meals ready to eat (MRE) to Special Operations Forces and other troops on the battlefield (Fig. 1). Mosquito can navigate from drop altitudes of 1000 to 25,000 ft. and bring its load within 10 m of a target from a wireless control distance of 20 miles, for the protection of those navigating the supplies to their target drop. In a test conducted from a C-130 at 7000 ft. and 3 miles off the coast of France, the Mosquito guided its package within 9 m of the target. The Mosquito system is specified for accuracy of better than 30 m. In addition to guiding food and supplies, variants of the Mosquito system are available for dropping unattended ground sensors for gathering data behind enemy lines.

The Lantronix integrated wireless WiPort (Fig. 2) is a key part of the Mosquito system, according to Glen Bailey, STAFF 's Chief Engineer: "Lantronix' WiPort is and will continue to be a key component of our solution enabling the military to fly safely out of small arms range, while still delivering vital supplies, weapons, and technologies to our troops." The WiPort functions within the Mosquito to configure target coordinates prior to a mission, transmit telemetry data during the mission, and off load diagnostic data following the mission (package drop).

The WiPort-485 offers a simple means of adding wireless-local-area-network (WLAN) and Ethernet connectivity to a system. It can work with either an RS-422 or RS-485 wired connection and provides a logic-level (3.3-V) serial interface. The WiPort-485 integrates a fully developed TCP/IP network stack and operating system for access to a local network. It includes an embedded web server that can be used to remotely configure, monitor, or troubleshoot an attached device, and serves web pages to a browser when gathering information or communicating with other networked devices, such as sensors.

Its WLAN operation is based on the IEEE 802.11b/g standard at 2.412 to 2.484 GHz and enables data rates to 54 Mb/s. The WiPort-485's integrated circuit (IC) transceiver works with various modulation formats, including orthogonal- f requency-div isionmultiplexing (OFDM), direct-sequencespread- spectrum (DSSS), differentialbinary- phase-shift-keying (DBPSK), differential-quadrature-phase-shiftkeying (DQPSK), and complementarycode- keying (CCK) formats. It can handle receive levels to -10 dBm without overload and has receive sensitivity of -82 dBm for a data rate of 11 Mb/s, -87 dBm for 5.5 Mb/s, -89 dBm for 2 Mb/s, and -93 dBm for 1 Mb/s.

The WiPort-485 can work with or without a personal computer (PC). It can be configured locally through its serial port or remotely over a network, using Windows-based configuration software. The WiPort-485 includes 2 MB of flash memory for storing firrmware and web pages, with an option for 4 MB of flash memory and additional 1 MB of SRAM. The compact wireless solution employs a light-emitting diode (LED) to indicate WLAN activity, but consumes only 4 mA current for both the WLAN and the LED. Connections to the WiPort-485 are made by means of a 40-pin 1-mm microheader connector.