Hybrid radio location system using a combination of satellite pseudoranges and radio pseudoranges

• US 6,430,416 B1
• Filed: 11/15/1999
• Issued: 08/06/2002
• Est. Priority Date: 11/15/1999
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Loomis, Peter Van Wyck
• Primary Examiner(s): Hunter, Daniel
• Assistant Examiner(s): Corsaro, Nick
• Application Number:
  US09/440,811
• Time in Patent Office: 995 Days
• Field of Search: 455/456, 455/457, 342/357.04, 342/357.09, 342/358, 342/450, 342/453, 342/357.02, 701/213, 701/214
• US Class Current: 455/456.1
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type

Abstract

A hybrid positioning system for locating an object using a combination of a GPS pseudoranges and local radio pseudoranges. The system includes one or more receptors coupled to a base station, and one or more location markers. The location markers are located with an object whose location is to be determined. Each of the location markers includes a GPS receiver for determining GPS pseudoranges and a radio transmitter for transmitting a radio signal including the GPS pseudoranges and information about the object. Each of the receptors passes the radio signal to the base station as an interface signal. The base station includes a radio pseudorange detector, a base GPS receiver, and a hybrid pseudorange processor. The radio pseudorange detector uses the times-of-arrival of the interface signals and the known interface signal transit times for determining radio pseudoranges from the location marker to the receptors. The base GPS receiver determines the locations-in-space of GPS satellites. The hybrid pseudorange processor uses a combination of the known locations of the receptors with the radio pseudoranges and the locations-in-space of the GPS satellites with the GPS pseudoranges for determining the location of the object.

Claims

1. A system for locating an object, comprising:

a first receptor for receiving radio signals and responsively issuing representative respective interface signals;

a second receptor for receiving radio signals and responsively issuing respective interface signals;

a first location marker located at said object, the first location marker including a GPS pseudorange detector for determining a first GPS pseudorange and a transmitter for transmitting a first of said radio signals including information for said first GPS pseudorange;

a second location marker located with the first receptor, the second location marker for transmitting a second of said radio signals; and

;

a base station for receiving a first of said interface signals issued by the first receptor in response to said first radio signal and a second of said interface signals issued by the second receptor in response to said second radio signal;

the base station including a radio pseudorange detector for using a time-of-arrival of said first interface signal for determining first radio pseudorange between the first location marker and the first receptor and determining a second radio pseudorange between the second location marker and the second receptor from a time-of-arrival of said second interface signal, and a hybrid pseudorange processor for using said first GPS pseudorange and said first and second radio pseudoranges in a determination of said location of said object.

2. The system of claim 1, wherein:

the second location marker is further for issuing a direct conducted signal to the first receptor;

the first receptor is further for issuing a representative third interface signal responsive to said direct signal;

said radio pseudorange detector is further for determining a third pseudorange between the second location marker and the first receptor from a time-of-arrival of said third interface signal; and

said hybrid pseudorange processor is further for using said third pseudorange for calculating said location of the first receptor.

3. A system for locating an object, comprising:

a first and a second receptor for receiving radio signals and issuing interface signals, said interface signals responsive respectively to said radio signals;

a first and a second location marker, the first location marker located at said object for transmitting a first of said radio signals, the second location marker located at said first receptor for transmitting a second of said radio signals; and

a base station for receiving a first of said interface signals issued by the first receptor in response to said first radio signal and a second said interface signal issued by the second receptor in response to said second radio signal, the base station including a radio pseudorange detector for using a time-of-arrival of said first interface signal for determining a first radio pseudorange between the first location marker and the first receptor and using a time-of-arrival of said second interface signal for determining a second radio pseudorange between the second location marker and the second receptor, and a pseudorange processor for using said second radio pseudorange for determining a location of the first receptor and using said location of the first receptor with said first radio pseudorange for determining said location of said object.

4. A method for locating an object, comprising steps of:

determining a first GPS pseudorange with a first location marker at a location of said object;

transmitting a first radio signal including information for said first GPS pseudorange from said first location marker;

receiving said first radio signal at a first receptor and responsively issuing a representative first interface signal;

transmitting a second radio signal from a second location marker at a location of said first receptor;

receiving said second radio signal at a second receptor and responsively issuing a representative second interface signal;

receiving said second interface signal at said base station;

determining a first radio pseudorange between said first location marker and said first receptor from a time-of-arrival of said first interface signal;

determining a second radio pseudorange between said second location marker and said second receptor from a time-of-arrival of said second interface signal; and

calculating said location of said object using said first GPS pseudorange and said first and second radio pseudoranges.

5. The method of claim 4, wherein:

issuing a direct conducted signal from said second location marker to said first receptor;

issuing a representative third interface signal responsive to said direct conducted signal from said first receptor to said base station;

determining a third pseudorange between said second location marker and said first receptor from a time-of-arrival of said third interface signal; and

calculating said location of said first receptor using said third pseudorange.

6. A method for locating an object, comprising steps of:

transmitting a first and a second radio signal from a first and a second location marker, respectively, said first location marker at said location of said object;

receiving said first radio signal at a first receptor and responsively issuing a representative first interface signal;

receiving said second radio signal at a second receptor and responsively issuing a second representative interface signal, said second receptor at a location of said first location marker;

receiving said first and said second interface signals at a base station;

determining a first radio pseudorange between the first location marker and the first receptor from a time-of-arrival of said first interface signal;

determining a second radio pseudorange between the second location marker and the second receptor from a time-of-arrival of said second interface signal;

using said second radio pseudorange for determining a location of said first receptor; and

using said location of said first receptor with said first radio pseudorange for determining said location of said object.