Patent Document ID: 9891325
Application ID: 14273120
Patent Flag: 1

Claim One:
1. A method for processing measurements in a global navigation satellite system comprising a first navigation receiver located in a rover and a second navigation receiver located in a base station, the method comprising the steps of: receiving a first plurality of measurements based on a first plurality of carrier signals received by the first navigation receiver from a plurality of global navigation satellites; receiving a second plurality of measurements based on a second plurality of carrier signals received by the second navigation receiver from the plurality of global navigation satellites, each carrier signal in the second plurality of carrier signals corresponding to a carrier signal in the first plurality of carrier signals, and each measurement in the second plurality of measurements corresponding to a measurement in the first plurality of measurements; calculating a first plurality of single differences based on the first plurality of measurements and the second plurality of measurements; determining a state vector based on a prescribed function using the first plurality of single differences, wherein the prescribed function is a Gauss-Newton method; calculating a second plurality of single differences based on an observation model represented by a prescribed mathematical model applicable to raw measurements for the global navigation satellite system, wherein the prescribed mathematical model is given by: 
 ρ r,k f,s =R r,k f,s +c (τ r,k +δτ r,k (ρ)f,s −τ k s )+ T r,k s +μ f/f ref ,s I r,k f ref ,s +ζ r,k (ρ)f,s 
 and 
 φ r,k f,s =R r,k f,s +c (τ r,k +δτ r,k (φ)f,s −τ k s )+ T r,k s +μ f/f ref ,s I r,k f ref ,s +λ f,s ( M r f,s +ψ r,k s )+ζ r,k (φ)f,s ; where: The set of index numbers r,k f,s refer to the following: f is the index number of the frequency band, s is the index number of a satellite, r is the index number of a receiver, k is the index number of a system time instant, ρ r,k f,s are line-of-sight pseudo-ranges (in meters) between satellite s and receiver r, φ r,k f,s are line-of-sight carrier phase measurements (in meters) between satellite s and receiver r, c is the speed of light (2.99792458×10 8 m/s), R r,k f,s =R(r r,k s +b r,k f,s ,r r,k s +c r,k f,s ) is the distance from the phase center of the transmitting antenna on satellite s to the phase center of the receiving antenna on receiver r, r=(x, y, z) T is the position vector, also referred to herein as the radius vector, in the World Geodetic System 84 (WGS 84) coordinate frame referenced to the center of the Earth, r r,k s is the radius vector of satellite s at the instant that the satellite signal is received at receiver r, b r,k f,s is the displacement vector of the phase center (for the frequency band f) of the receiving antenna on the receiver r relative to the antenna reference point; this vector depends on the direction of satellite s, c r,k f,s is the displacement vector of the phase center (for the frequency band f) of the transmitting antenna on the satellite s relative to the center-of-mass of the satellite, λ f,s is the wavelength of the carrier signal transmitted by satellite s on frequency band f, τ k s and τ r,k are the clock offsets of the satellite clock and the receiver clock, respectively, relative to the system time, δτ r,k (ρ)f,s and δτ r,k (φ)f,s are the code-measurement channel delay and phase-measurement channel delay, respectively, T r,k s is the troposphere delay, I r,k fref,s is the ionosphere delay caused by propagation of the satellite signal through the ionosphere, μ f / f ref , s = [ F f ref , s ] 2 [ F f , s ] 2 = ( λ f , s / λ f ref , s ) 2 is the ionosphere frequency ratio, where f ref is the index number of a reference frequency band, ψ r,k s =ψ r,k (⊥),s +ψ r,k (∥),s is the phase incursion (phase increment) due to change in mutual orientation of the antenna on satellite s and the antenna on receiver r. It includes a linear increment ψ r,k (⊥),s caused by turning the antennas in the plane of their dipole axes, and a nonlinear increment ψ r,k (∥),s caused by mutual deviation of axes normal to antenna dipoles from the line of sight, ζ r,k (ρ)f,s and ζ r,k (φ)f,s are code noise error (including DLL errors and multipath errors) and phase noise error (including PLL errors and multipath errors), respectively, calculating a plurality of residuals based on the first plurality of single differences and the second plurality of single differences; determining whether the first plurality of measurements and the second plurality of measurements are consistent with the observation model; and in response to determining that the first plurality of measurements and the second plurality of measurements are not consistent with the observation model, detecting anomalous measurements; and eliminating the detected anomalous measurements; determining whether the remaining measurements are sufficient for determining the state vector, and if the remaining measurements are sufficient for the determining of the state vector then calculating a position of the rover based on the remaining measurements.