# US 10,768,264 B2 · Determination of a ground receiver position

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- Number: US 10,768,264 B2
- Document ID: US10768264B2
- Status: Granted
- Kind: B2
- Application number: 16/036,818
- Filed: 2018-07-16
- Published: 2018-11-15
- Granted: 2020-09-08
- Earliest claimed: 2014-09-26
- Assignees: Raytheon Company
- Applicants: Raytheon Company
- Inventors: Ian S. Robinson; Andrew M. Hautzik; Brandon Crow
- Web page: https://patentgrep.com/patent/US10768264B2

## CPC

- G01S 1/02: using radio waves (G01S19/00 takes precedence)
- G01S 19/10: providing dedicated supplementary positioning signals
- G01S 19/11: wherein the cooperating elements are pseudolites or satellite radio beacon positioning system signal repeaters
- G01S 19/21: Interference related issues {; Issues related to cross-correlation, spoofing or other methods of denial of service}
- G01S 19/215: {issues related to spoofing}
- G01S 19/38: Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
- G01S 19/396: {Determining accuracy or reliability of position or pseudorange measurements}
- G01S 19/48: by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES

## Abstract

Technology for determining a geographical location of a ground receiver is disclosed. A plurality of radio frequency (RF) signals from a plurality of RF signal carriers may be received at the ground receiver. The plurality of RF signal carriers may include satellites operated by a foreign entity or non-global positioning system (non-GPS) satellites. The ground receiver may measure a Doppler shift associated with each of the plurality of RF signals. The geographical location of the ground receiver may be determined in X, Y and Z coordinates based in part on the Doppler shift associated with each of the plurality of RF signals.

## Claims

### Claim 1

A ground receiver operable to determine a geographical location of the ground receiver, the ground receiver having computer circuitry configured to:
receive a plurality of radio frequency (RF) signals from a plurality of RF signal carriers at the ground receiver, wherein the plurality of RF signal carriers include at least one non-dedicated satellite, wherein the at least one non-dedicated satellite is a non-global positioning system (non-GPS) satellite;
measure a Doppler shift associated with each of the plurality of RF signals at the ground receiver, wherein the computer circuitry is further configured to:
measure frequencies for each of a plurality of non-spread spectrum RF signals;
compare the frequencies to known frequencies associated with the plurality of non-spread spectrum RF signals;
calculate a difference between the frequencies that are measured and the known frequencies in order to calculate the Doppler shift for each of the non-spread spectrum RF signals; and
determine the geographical location of the ground receiver in X, Y and Z coordinates based in part on the Doppler shift associated with each of the plurality of RF signals.

### Claim 2 (depends on 1)

The ground receiver of claim 1, wherein the RF signal carriers comprise at least one of low Earth orbit (LEO) satellites, medium Earth orbit (MEO) satellites or geostationary (GEO) satellites.

### Claim 3 (depends on 1)

The ground receiver of claim 1, wherein the RF signals comprise RF signals other than global positioning system (GPS) signals or ranging signals.

### Claim 4 (depends on 1)

The ground receiver of claim 1, wherein the computer circuitry of the ground receiver is further configure to determine an oscillator offset associated with the ground receiver, wherein the oscillator offset includes a frequency drift in a local oscillator of the ground receiver.

### Claim 5 (depends on 1)

The ground receiver of claim 1, wherein the computer circuitry of the ground receiver is further configure to determine, at the ground receiver, source locations associated with the plurality of RF signal carriers and the frequencies associated with the plurality of RF signals prior to determining the geographical location of the ground receiver.