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Colorado Springs, CO, United States

Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 150.00K | Year: 2014

ABSTRACT: The objective of this effort is to investigate designs and possible options for a PNT Flexible satellite for GPS to enhance position, navigation, and timing (PNT) capabilities at a low cost using small augmentation satellites with limited payload. A desired feature to help overcome GPS coverage issues due to terrain, spoofing, jamming and interference is to broadcast military signals at a higher power than the civilian signals. When operating using a saturated traveling wave tube amplifier (TWTA), for example, the behavior of this amplifier very nearly approaches an ideal limiting amplifier. Due to the suppression characteristics of the amplifier, input signals have to be amplitude-balanced in order to prevent the loss of signal on weaker signals. Under this SBIR effort we propose to develop an enhanced constant envelope modulation technology for flex-power operation that will provide improved power efficiency using a digital waveform generator and state of the art L-band high power amplifiers (HPA). We shall assemble a lab test environment including digital waveform generation, RF modulation with HPA and GPS UE signal reception to compare the flex-power performance and power savings of this enhanced modulation method with the conventional interplex modulation method currently used by the GPS satellites. BENEFIT: The ability to deliver configurable flex power to GPS signals on-board NavSat or similar GPS satellite vehicles would enable constellation managers the capability to serve the GPS user community with improved signal quality and navigation precision at a fraction of the cost compared to traditional solutions. The ability to adapt to changing requirements and situations with the flex power solution is a dramatic improvement over current capabilities. Due to the cost effectiveness of this solution and the significant improvements this capability would provide, it is anticipated that significant interest will be garnered for this technology and an accelerated transition path toward implementation on future GNSS satellites will be desired.


Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase II | Award Amount: 750.00K | Year: 2016

ABSTRACT:The objective of this effort is to investigate designs and possible options for a Position, Navigation, and Timing (PNT) flexible satellite for GPS to enhance PNT capabilities at a low cost. A desired feature to help overcome GPS coverage issues due to terrain, spoofing, jamming and interference is to broadcast military signals at higher power than the civilian signals. Under the Phase I SBIR effort we demonstrated a flexible digital signal modulation approach, termed FlexMod, which modulates large numbers of codes on a single carrier with flexible relative power levels while maintaining a constant envelope modulation output. Under Phase II, we shall implement a FlexMod firmware module and assemble a test set including a prototype Digital Waveform Generator (DWG), GPS constellation simulator and High Power Amplifiers (HPA) for testing with civil and military GPS receivers. This will be used to demonstrate the flex power performance of the enhanced FlexMod modulation method and evaluate the expected M-code power level that FlexMod could deliver with state of the art HPA technology to a GPS receiver through an earth coverage antenna in GPS III.BENEFIT:When combined with digital waveform generation and state of the art L-band high power amplifiers the FlexMod technology will allow for broadcast of multiple GPS codes (civil and legacy) and a high power M-code signal through a single antenna. This would allow for delivery of NavWar high power signals under A2/AD conditions without requiring a separate spot beam on future GPS III satellites. Due to the cost effectiveness of this solution and the significant improvements this capability would provide, it is anticipated that significant interest will be garnered for this technology for future GPS III satellites and payloads.


Grant
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase II | Award Amount: 750.00K | Year: 2014

Under the Phase I SBIR effort, we designed a Submersible GPS Enhancement and Playback System (SGEPS) to allow processing of the GPS signals after a submarine has submerged to reduce the time spent on surface for covert operations. This uses a Digital Storage Receiver (DSR) for capturing the GPS RF signals in the surface and a SAASM GPS receiver for the signal playback and processing after the submarine has submerged. The SGEPS data playback is designed to exploit both the anti-jam/anti-spoof signal processing capabilities of the SAASM receiver, combined with innovative anti-jam algorithms to detect and excise interfering signals to enhance the performance of the SGEP processing in a jammed environment. In the Phase II SBIR base effort, we propose designing, building, and testing a prototype SGEPS DSR system to demonstrate the reduced surface exposure and anti-jam performance of the system. In the Phase II option, we will integrate into the SGEPS processor anti-jam algorithms and demonstrate the ability to track GPS signals in a high jamming environment using these innovative anti-jam algorithms to excise the jammer signals and inertial aiding for ultra-tightly-coupled processing of the SAASM raw correlation output data to enhance signal detection in a high jamming environment.


Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 150.00K | Year: 2014

ABSTRACT: In the event that the GPS constellation was unavailable, none of the current back-up navigation and timing solutions in place today such as inertial navigation, geostationary augmentation systems or cellular positioning solutions would function, resulting in catastrophic effect on military and civil operations nationally and globally. To protect against this eventuality there is a need to develop a"Disruptive Navigation Architecture"that can provide the ability to rapidly reconstitute an equivalent capability in the event that GPS is not available. Under this SBIR effort we propose to design and demonstrate through prototyping and simulation an innovative Global Micro-Sat Positioning System (GMPS) to meet this need. We shall develop and identify the key functional performance parameters and system components needed to realize an alternate navigation solution in the absence of any GPS signals. The design for a GMPS Micro-Satellite will be developed based on existing Cubesat technology, to enable large numbers of microsats to be rapidly launched to reconstitute a global navigation and timing capability. The GMPS constellation coverage and geometry will be simulated in challenged environments and signal acquisition and tracking will be demonstrated using a Software Defined Radio (SDR) to show the expected GMPS PNT performance. BENEFIT: As both military and commercial operations have increasingly become reliant on GPS for position, navigation, and timing, the risk resulting from the loss of that capability has increased. Efforts to mitigate the effect of weak signals, jamming, and spoofing have been underway for some time, but the capability to address the complete loss of GPS remains a challenge due to the extreme cost of the existing GPS constellation and the logistics involved due to payload size and launch availability. It is anticipated that the cost effective and rapid replacement capabilities of the proposed technology will yield significant interest as a solution to the challenge of needing to rapidly deploy and reconstitute military GNSS.


Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase II | Award Amount: 750.00K | Year: 2015

ABSTRACT: The biggest demand on a military receiver has been from the time required to search and acquire for the military signals when an accurate internal time reference is not available. Prior research by NAVSYS into network assisted GPS approaches used the JTRS network itself to transfer time from another GPS receiver to reduce the initial time uncertainty and speed the acquisition time. This required at least one receiver on the network to have already acquired and tracked the GPS signals. Under this SBIR, we shall develop and implement methods to reduce the direct P(Y) acquisition time under situations where no unit on the network has yet acquired a GPS solution. The cooperative signal acquisition algorithms shall use shared data between network participants to speed direct P(Y) and direct M-code acquisition by distributing the search space between network participants reducing TTFF and allowing for longer correlation times for weak signal and high interference environments. This will be demonstrated under this effort using Software Defined Radio Testbeds to process the received GPS signals and also provide intra-network timing observations for the cooperative GPS signal processing. We shall use a combination of simulated and live satellite signals to show the improved performance. BENEFIT: The NAVSYS cooperative networked GPS signal acquisition technologies will provide reduced TTFF (Time to First Fix) initialization among a networked user groups as well as improved ability to acquire in weak signal or high interference environments. Military applications will be pursued in all major DoD branches by tailoring the implementation of this technology to their specific needs for assured PNT in their networked operations.

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