Fast acquisition of GPS signal corrupted by doppler or time delay effects
First Claim
1. A method of improving acquisition of GPS information received from an artillery munition comprising:
- inputting carrier Doppler compensation data into the GPS ground receiver;
inputting position estimating data for the munition into a GPS ground receiver;
inputting velocity estimating data into the GPS ground receiver or deriving velocity estimating data in the GPS ground receiver;
receiving in the artillery munition GPS navigation data, the GPS data having a first frequency;
shifting the frequency of the GPS data to a second frequency in the munition;
transmitting the frequency shifted data from the artillery munition to the GPS ground receiver;
converting the frequency shifted data back to the first frequency at the GPS ground receiver;
computing the position of the artillery munition from the first frequency data using GPS compensation software.
2 Assignments
0 Petitions
Accused Products
Abstract
An RF translator is placed on an artillery shell. The RF translator receives a GPS signal, converts the GPS signal to an S band signal, and then transmits the S band signal. The S band signal is received by a ground antenna and it is converted back to an L1 GPS signal. The transmission of the S band signal to a ground antenna induces two effects which make fast direct P(Y) acquisitions difficult. First, since the artillery shell is moving, a carrier Doppler is induced on the S band signal. Second, the time delay caused by the transmission of the S band signal affects the nominal code phase for acquisition. Acquisition of GPS signals corrupted by second frequency data effects require special compensation if fast direct P(Y) code acquisition is desired. A carrier Doppler and a code phase compensation term allow the GPS ground receiver software to focus its search window for the carrier frequency (code rate) and the code phase (time delay). By adding in these new compensation terms, small centered searches can be used and fast direct P(Y) code acquisition is possible.
54 Citations
32 Claims
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1. A method of improving acquisition of GPS information received from an artillery munition comprising:
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inputting carrier Doppler compensation data into the GPS ground receiver;
inputting position estimating data for the munition into a GPS ground receiver;
inputting velocity estimating data into the GPS ground receiver or deriving velocity estimating data in the GPS ground receiver;
receiving in the artillery munition GPS navigation data, the GPS data having a first frequency;
shifting the frequency of the GPS data to a second frequency in the munition;
transmitting the frequency shifted data from the artillery munition to the GPS ground receiver;
converting the frequency shifted data back to the first frequency at the GPS ground receiver;
computing the position of the artillery munition from the first frequency data using GPS compensation software. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of improving acquisition of GPS information received from an artillery munition comprising:
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inputting code phase compensation data into the GPS ground receiver;
inputting position estimating data for the munition into a GPS ground receiver;
inputting velocity estimating data into the GPS ground receiver or deriving velocity estimating data in the GPS ground receiver;
receiving in the artillery munition GPS navigation data, the GPS data having a first frequency;
shifting the frequency of the GPS data to a second frequency in the munition;
transmitting the frequency shifted data from the artillery munition to the GPS ground receiver;
converting the frequency shifted data back to the first frequency at the GPS ground receiver;
computing the position of the artillery munition from the first frequency data using GPS compensation software. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A device for improving acquisition of GPS signals from an artillery munition comprising:
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a munition with an RF translator for translating a GPS signal having a first frequency to a second frequency;
a GPS ground receiver for translating the second frequency to the first frequency;
the GPS ground receiver having a computer, the computer having a memory, the memory having software that compensates for carrier frequency Doppler effect. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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26. A device for improving acquisition of GPS signals from an artillery munition comprising:
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a munition with an RF translator, the translator receiving a GPS signal having a first frequency and transmitting a signal having a second frequency;
a GPS ground receiver for translating the second frequency to the first frequency;
the GPS ground receiver having a computer, the computer having a memory, the memory having software that compensates for time delay in the code phase. - View Dependent Claims (27, 28, 29, 30, 31, 32)
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Specification