Direct Initialization of Ultra-Tightly Coupled Weapons using a UTC Assisted Acquisition Process

Period of Performance: 01/01/2003 - 12/31/2003


Phase 1 SBIR

Recipient Firm

Navsys Corp.
14960 Woodcarver Road Array
Colorado Springs, CO 80921
Principal Investigator


Significant GPS anti-jam performance improvements for GPS-guided weapons can be achieved through the use of Ultra-Tightly-Coupled (UTC) GPS/inertial integrated systems. However, current UTC processing techniques use conventional code and carrier tracking loops to transition from direct signal acquisition to the UTC mode. This diminishes the benefits that can be achieved by UTC tracking in a jamming environment. Under this proposed SBIR effort we will develop a high A/J direct acquisition mode for UTC signal processing. Our proposed approach, termed UTC Assisted Acquisition, leverages aiding information that is provided to the weapon (Child) from the launch platform (Parent), to allow the weapon's GPS receiver to directly enter the UTC mode. The major innovation of the proposed approach is to use the Parent aiding data to reduce the UTC search space and leverage the UTC processing to use the combined set of satellite signals for acquisition for improved A/J protection. Under Phase I, we will define the parent-child 1760 bus data interfaces needed for Assisted Acquisition and will prototype and test the direct UTC acquisition mode under simulated jamming conditions. A design will be presented for a UTC GPS/inertial prototype system to be implemented and tested under the Phase II effort. The result of the development of the UTC-AA process will be a very robust GPS signal acquisition using direct initialization data from the launch platform as well as precision tracking capability for guided munitions in heavy jamming environments. The algorithm can be embedded within other manufacturers existing architectures. Honeywell, Northrop Grumman, Boeing Phantomworks, and others are developing systems that can greatly benefit from this innovative without major modifications to their current approach