| Acquisition Program: | PEO Soldier |
Objective: | To develop a field expedient prototype and design for wearable multi-function distributed antenna system for Land Warrior/Ground Soldier systems applications to be tested in a battalion unit for demonstration of network centric army operations. The work may leverage current ongoing army efforts as much as possible to expedite the realization of a prototype.
| Description: | Wearable electronics is of significant interest in military, police and commercial applications [1-4]. WLAN systems are a natural application for commercial use. For the military, possible applications include communication, surveillance (Blue Force tracking – e.g., L-band transceivers), and reconnaissance. Such systems require flexible antennas integrated onto a small area on the soldier (non-helmet area) and/or into the clothing of the soldier. Achieving a low profile, light weight antenna interface while sustaining a reliable link over a broad bandwidth, is the ultimate goal of such applications. Army’s short term needs require demonstrating such an antenna system integrated on the soldier platform. Woven printed antennas are a natural choice to satisfy these criteria in a relatively short time frame. A setback associated with such a solution is that these antennas may offer a much narrower bandwidth than needed for some of the multifunction operations. The ultimate goal for longer term applications is to mitigate the bandwidth problem, minimize size and space claim on a soldier, and maximize performance. A possible approach could be the use of fractal designs for these longer term applications. Initially, what is sought is a quick implementation of a GPS (L1 – 1.575 GHz & L2 – 1.227 GHz) AND a 5 Watt radio transceiver (420 MHz – 450 MHz) antenna (2 device connections – Radio & GPS interfaces) for soldier use providing optimum coverage, performance, and minimum weight/size on both sides of the soldier’s head.
Wearable antennas for military applications have been of interest for sometime. CERDEC is developing a suite of body wearable wideband antennas for incorporation into the Future Force Warrior Soldier Ensemble. The CERDEC schedule for delivery of these antennas to the FFW is in the FY06/07 timeframe. This solicitation focuses on an expeditious solution to demonstrate the feasibility of network centric operations in a battalion, and addresses the problems noted by warfighters with their practicality. Possible key issues to be considered are the positioning of the antenna over the soldier’s body in a battle situation. Due to the nature of mode of operation in a battlefield, this becomes very critical in terms of sustaining an uninterrupted link. A possible solution is to distribute the antenna system over the body and reconfigure it dynamically to obtain optimal performance. The reconfiguration involves weighted summation of the returns from all antenna components for optimized performance. The distributed antenna system can be used to enable for multi-band operations or from a spatial diversity standpoint to enhance link availability as the soldier changes positions. This could be potentially used for all United States Army Soldiers.
| | PHASE I: Develop a baseline design for a wearable distributed antenna system for GPS and comms net radio system (CNRS) [400-500 MHz – e.g., Enhanced Position Location Radio System (EPLRS) waveform] application and build an expedient proof of concept antenna element. The design should focus on a practical and quick solution and should consider operation on a dismounted ground soldier and attempt to meet low unintentional emissions and survive military & battlefield conditions
| | PHASE II: Build a prototype antenna system that meets Phase I applications. The prototype should provide optimal performance for different positions and sizes of the human platform and take into consideration soldier connections to both a GPS and a EPLRS CNRS system.
| | PHASE III: Leveraging other ongoing CERDEC efforts on the topic and from the experience gained in Phases I and II, advance the distributed antenna design to operate with the Joint Tactical Radio Waveform, spanning 2 MHz to 3000+ MHz and Selective Availability Anti Spoofing Module (SAASM) GPS Receiver. Incorporate broadband antenna components, (e.g., fractal antennas, etc.) in the design. Build a prototype and demonstrate performance. Extend the concept to WLAN applications where textile antennas can be worn by users for personal communications. Emergency responders could exploit such a system where GPS location and communications are critical. Examples, as diverse as coordinating a police unit in a SWAT scenario, firemen responding to an emergency such as a forest or residential fire, a ski patrol trying to locate victims after an avalanche, or emergency workers responding to a natural disaster such as a hurricane, earthquake or Tsunami. This list of applications is just a sample of the possible transitions to the private sector and illustrates the commercial potential of such a system. Plans for this technology would be for future consideration for incorporation as pre-planned product improvements to the Land Warrior Ensemble, Dismounted Battle Command System, and Mounted Warrior type programs.
| References: | 1) CERDEC Advanced Antennas ATO, “Body Wearable Antennas for the Future Force”
2) Lebaric, J. E., Adler, R. W., Gainor T. M. “Ultra-wideband radio frequency vest antenna.” MILCOM 2000 Proc., vol. 1, 22-25 Oct. 2000, pp. 588-590.
3) Massey P. J. “GSM fabric antenna for mobile telephones integrated within clothing,” IEEE AP-S Symp. Dig. Vol. 3, pp. 452-455, 2001.
4) Salonen P., Rantanen J. “A dual-band and wide-band antenna on flexible substrate for smart clothing,” IECON 2001, pp. 125-130.
5) Adams R. C. “Testing and integration of the COMWIN antenna system,” MILCOM 2002. Proceedings, Volume: 1, 7-10 Oct. 2002 pp. 637 - 641
| | Keywords: | body worn antenna, distributed system, GPS, multifunction, diversity, multiband, comms net radio, EPLRS, SAASM |
Questions and Answers: |
Q: 1. Should both the GPS and the CNRS antenna be assembled on the same substrate or should they be separated and actually be two separate antennas?
2. For this SBIR, is your requirement for the 30 Mhz band only? Or is it presently the 30 Mhz band, and later extend to the 100 Mhz band, hence more weight is given to a full 100 Mhz band antenna? Do you desire the full 100 Mhz bandwidth now?
3. Is a pop up antenna ok, can the antenna lay flat while unused, and very quickly pop up a very short distance while being used, then layed flat again?
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A: 1. Proposer discretion, remember the platform is the soldier so antenna placement is limited.
2. Read the proposal, it says CNRS is 100 MHz wide for phase I.
3. Proposer discretion but the remember title of the topic is for "Body Worn Platforms." |
Q: 1) 420-450 Mhz antenna, what polarization is needed? Should the antenna pattern and polarization be adjustable. Should the adjustments be manual, automatic or both?
2) antenna mechanical questions.
a) do you want the antenna to have a connector or cable output with connectors?
b) is the antenna stand alone, i.e. separate from the uniform, then added to the uniform, or does it have to be part of the uniform and we’ll work with the uniform manufacturer to embed the antenna in the production of the uniform?
c) Is there a location where you want the antenna located or a location to avoid. Location affects how the antenna must be shaped and designating a location changes the antenna design.
d) have you chosen a physical Length x Width size maximum?
e) What is the acceptable antenna thickness maximum for the 420-450 Mhz antenna, is one inch acceptable?
f) should the antenna be field replaceable or field repairable (connector primarily)
g) can you describe the radio’s used, or provide reference materials. I assume they are small, flat and fit inside the soldier uniform
3) 5 watt transmit power, is this peak or average. If this is average, then there is rf radiation concerns over time for the soldier. Minimizing exposure to the solder may require a very different design with larger ground plane. Please comment.
4) regarding other antennas on the uniform in addition to these, are there to be any others. If yes, that affects these antennas both in antenna pattern and EMI, please comment.
5) To create a very fast prototype, will you be supplying uniforms at the kickoff meeting. What quantity of prototypes are needed? Two, ten?
6) SBIR statement regarding “minimizing unwanted transmissions”, please explain if this is a switch on the antenna or effectively antenna filtering of above and below band emissions. If it’s filtering and you have requirements in mind, that would enable us to evaluate the performance of the antenna over frequency and determine the need for extra filtering.
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A: 1) The EPLRS MicroLight Radio is a currently a standard short (11 inches) whip antenna, so it is vertically polarized.
2)
a) Most likely a connector. Running of cables on the Land Warrior Ensemble will require some crafting.
b) It should be standalone and will be eventually attached to the Land Warrior load bearing vest (LBV) probably shoulder or epaulet area. The LBV carries the body armor and Land Warrior ensemble equipment and ammo, etc. Once a design is complete, modifications might be required for the LBV to support the new spatially diverse antennas.
c) Yes - Antenna should be associated with the upper body area of the Soldier and should avoid the helmet.
d) No. Signal performance is important, size and weight (Soldier Borne) must be as light as possible, with minimum volume.
e) No maximum has been specified. Protrusion from Soldier's body making him either a target or a visual obscuration for his line of sight should be factored in.
f) Depends on overall cost. Need to be able to replace easily if fails (swap out).
g) Target radio initially would be the Raytheon EPLRS MicroLight. Another possibility is Thales MBITR. Eventually, it will be a cluster 5 JTRS. For now the EPLRS MicroLight radio is small and attaches to the lower area of the Land Warrior LBV.
3) The EPLRS Microlight Radio has selectable transmit power out from about 100mW to 5Watts. 5 Watts would be a RMS / TDMA signal for now. "Average power" will probably be less than a Watt at maximum voice duty cycle and max power (more) more for any digital video transmission. Voice channel is 7.2 Kbps out of a total 468 Kbps channel bandwidth. Ground plane considerations need to be factored in for the Land Warrior Ensemble (LWE) as needed for proper transmission for combat net radio systems and for GPS signal reception. 5 Watts would be the PEAK average RMS transmit power.
4) Focus is on the LWE. Other antennas (in the future might be in the X, Ka or Ku bands for Soldier Radio Frequency (RF) Tags), and possibly near by L-Band direct SATCOM (~1.6 GHz) for the Dismounted Battle Command System (DBCS) for Leaders. EMI, EMC, and HAEMP (with system reset ok) are significant factors. Current system EMI is targeted to be about 15 to 20 dB below standard MIL-STD-461E requirements so as to NOT de-sense our radio receivers. This implies shielding of our entire system back to the batteries.
5) A minimum of two to allow communications between two systems, possibly three for one as a spare.
6) If antenna uses active gain circuitry, etc. and will need/require to connect to the Land Warrior centralized battery power, then appropriate shielding would be required so as not to generate emissions that would in turn de-sense our radio receivers. Additionally, when the Soldier is not transmitting, we do not want him/her to be an emitter on the battlefield with emissions.
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Q: Should this antenna be able to transmit as well as recieve signal from a GPS, or make the field soldier able to talk directly to one and other in a fire fight? |
A: The antennas will perform transmit and receive functions. The CNRS
system is line of sight. |