Systems, Methods, Devices And Subassemblies For Rapid-Acquisition Access To High-Precision Positioning, Navigation And/Or Timing Solutions

Abstract

Position, navigation and/or timing (PNT) solutions may be provided with levels of precision that have previously and conventionally been associated with carrier phase differential GPS (CDGPS) techniques that employ a fixed terrestrial reference station or with GPS PPP techniques that employ fixed terrestrial stations and corrections distribution networks of generally limited terrestrial coverage. Using techniques described herein, high-precision PNT solutions may be provided without resort to a generally proximate, terrestrial ground station having a fixed and precisely known position. Instead, techniques described herein utilize a carrier phase model and measurements from plural satellites (typically 4 or more) wherein at least one is a low earth orbiting (LEO) satellite. For an Iridium LEO solution, particular techniques are described that allow extraction of an Iridium carrier phase observables, notwithstanding TDMA gaps and random phase rotations and biases inherent in the transmitted signals.

What is claimed is: 
     
         1 . A method comprising:
 receiving, by an augmentation subsystem, radio frequency (RF) data from a global navigation satellite system (GNSS) receiver;   receiving, by the augmentation subsystem and from the GNSS receiver, a first position, navigation and timing (PNT) solution;   receiving, by the augmentation subsystem and from the GNSS receiver, a query for low Earth orbit (LEO) satellite data;   computing, by the augmentation subsystem, LEO satellite carrier phase observables from the RF data;   computing, by the augmentation subsystem, a response to the query, wherein computing the response comprises eliminating random phase rotations from the computed LEO carrier phase observables based on the first PNT solution; and   providing, by the augmentation subsystem, the response to the GNSS receiver for estimating a second PNT solution.   
     
     
         2 . The method of  claim 1 , wherein the RF data is received by a frontend of the GNSS receiver and shared with the augmentation subsystem by the GNSS receiver. 
     
     
         3 . The method of  claim 1 , wherein eliminating the random phase rotations is further based on measurements from an inertial measurement unit (IMU) of the augmentation subsystem. 
     
     
         4 . The method of the  claim 1 , wherein the augmentation subsystem is implemented as an add-on card of the GNSS receiver. 
     
     
         5 . The method of  claim 1 , wherein the augmentation subsystem is implemented as a built-in component the GNSS receiver. 
     
     
         6 . A location system comprising:
 an augmentation subsystem including an inertial measurement unit (IMU); and   a global navigation satellite system (GNSS) receiver, wherein the augmentation subsystem is configured to perform operations comprising:
 receiving radio frequency (RF) data from the GNSS; 
 receiving, from the GNSS receiver, a first position, navigation and timing (PNT) solution; 
 receiving, from the GNSS receiver, a query for low Earth orbit (LEO) satellite data; 
 computing LEO satellite carrier phase observables from the RF data; 
 computing a response to the query, wherein computing the response comprises eliminating random phase rotations from the computed LEO carrier phase observables based on the first PNT solution; and 
 providing the response to the GNSS receiver for estimating a second PNT solution. 
   
     
     
         7 . The system of  claim 6 , wherein the RF data is received by a frontend of the GNSS receiver and shared with the augmentation subsystem by the GNSS receiver. 
     
     
         8 . The system of  claim 6 , wherein eliminating the random phase rotations is further based on measurements from an inertial measurement unit (IMU) of the augmentation subsystem. 
     
     
         9 . The system of the  claim 6 , wherein the augmentation subsystem is implemented as an add-on card of the GNSS receiver. 
     
     
         10 . The system of  claim 6 , wherein the augmentation subsystem is implemented as a built-in component the GNSS receiver. 
     
     
         11 . A non-transitory computer-readable medium storing instructions operable to cause an augmentation subsystem including an inertial measurement unit (IMU) to perform operations comprising:
 receiving radio frequency (RF) data from a global navigation satellite system (GNSS) receiver;   receiving, from the GNSS receiver, a first position, navigation and timing (PNT) solution;   receiving, from the GNSS receiver, a query for low Earth orbit (LEO) satellite data;   computing LEO satellite carrier phase observables from the RF data;   computing a response to the query, wherein computing the response comprises eliminating random phase rotations from the computed LEO carrier phase observables based on the first PNT solution; and   providing the response to the GNSS receiver for estimating a second PNT solution.   
     
     
         12 . The non-transitory computer-readable medium of  claim 11 , comprising a field-programmable gate array (FPGA). 
     
     
         13 . The non-transitory computer-readable medium of  claim 11 , wherein the RF data is received by a frontend of the GNSS receiver and shared with the augmentation subsystem by the GNSS receiver. 
     
     
         14 . The non-transitory computer-readable medium of  claim 11 , wherein eliminating the random phase rotations is further based on measurements from an inertial measurement unit (IMU) of the augmentation subsystem. 
     
     
         15 . The non-transitory computer-readable medium of the  claim 11 , wherein the augmentation subsystem is implemented as an add-on card of the GNSS receiver. 
     
     
         16 . The non-transitory computer-readable medium of  claim 11 , wherein the augmentation subsystem is implemented as a built-in component the GNSS receiver.