Transmitting and receiving apparatus for full code correlation operation under encryption for satellite positioning system

• US 5,825,887 A
• Filed: 12/28/1995
• Issued: 10/20/1998
• Est. Priority Date: 12/28/1995
• Status: Expired due to Fees

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Lennen, Gary R.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Laufer, Pinchus M.
• Application Number:
  US08/580,353
• Time in Patent Office: 1,027 Days
• Field of Search: 364/449.7, 342/357, 342/352, 380/49, 380/34, 701/213, 701/214, 701/215
• US Class Current: 380/34
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/25 involving aiding data received from a cooperating element, e.g. assisted GPS
• CPC Class Codes: G01S 19/32 Multimode operation in a single same satellite system, e.g. GPS L1/L2

Abstract

The transmitting and receiving apparatus and method for full code correlation operation under encryption for the Satellite Positioning System (SATPS) are disclosed. The apparatus includes a central station designed to receive SATPS satellites encoded information using a high gain antenna and a delayed correlation receiver. The central station extracts the encrypted satellite information and transmits it to the delayed correlation receiver. The delayed correlation receiver receives the encrypted satellite information using the standard SATPS antenna and performs the full correlation with the encrypted information received from the central station without requiring the secret encryption keys.

Claims

1. A transmitting and receiving apparatus for full code correlation operation under encryption for a Satellite Positioning System (SATPS);

wherein a Y code replaces a known P-code when the anti spoofing (AS) is ON; and

wherein said Y-code is the modulo-two sum of an unknown W-code and said known P-code;

said apparatus comprising;

a CENTRAL STATION further comprising;

a W EXTRACTING RECEIVER further comprising;

at least one HIGH GAIN ANTENNA (HGA) for receiving the satellite signals from at least one SATPS satellite;

at least one DOWNCONVERTER AND SAMPLER for frequency translating, amplifying and digitally sampling the incoming L1 signals, wherein a first DOWNCONVERTER AND SAMPLER 1 is connected to a first HGA (1), wherein a second DOWNCONVERTER AND SAMPLER is connected to a second HGA (2), wherein an i-th DOWNCONVERTER AND SAMPLER is connected to an i-th HGA(i); and

wherein an N-th DOWNCONVERTER AND SAMPLER is connected to an N-th HGA (N);

i being an integer less or equal to N, N being a number of satellites being observed;

at least one DIGITAL CHANNEL PROCESSOR for further processing the digitally sampled satellite L1 signals, wherein a first DIGITAL CHANNEL PROCESSOR 1 is connected to a first DOWNCONVERTER AND SAMPLER 1, wherein a second DIGITAL CHANNEL PROCESSOR 2 is connected to a second DOWNCONVERTER AND SAMPLER 2, wherein an i-th DIGITAL CHANNEL PROCESSOR is connected to an i-th DOWNCONVERTER AND SAMPLER; and

wherein an N-th DIGITAL CHANNEL PROCESSOR is connected to an N-th DOWNCONVERTER AND SAMPLER;

a MASTER OSCILLATOR 1 block for providing the frequency source for the reference system;

a FREQUENCY SYNTHESIZER 1 block connected to said MASTER OSCILLATOR 1 block, wherein said FREQUENCY SYNTHESIZER 1 block uses said MASTER OSCILLATOR 1 block output signal for synthesizing local oscillator and clock signals; and

a MICROPROCESSOR SYSTEM 1 (μ

P SYSTEM

     1) connected to each said DIGITAL CHANNEL PROCESSOR for providing a CONTROL signal for each said DIGITAL CHANNEL PROCESSOR; and

a MODULATED W TRANSMITTER connected to said W EXTRACTING RECEIVER for resynchronizing, delaying, and combining the extracted W code for each said satellite being observed; and

for transmitting said combined, delayed and resynchronized W code;

a DELAYED W CORRELATION RECEIVER;

(a) for receiving the real time encrypted L1 and L2 satellite code signals;

(b) for storing the observed samples of received encrypted satellite L1 and L2 satellite signals;

(c) for receiving said extracted resynchronized, delayed and combined W bit information transmitted by said CENTRAL STATION;

(d) and for correlating its own observed encrypted L1 and L2 signals with the corresponding portions of said extracted resynchronized, delayed and combined W bit information; and

a COMMUNICATION LINK connecting said DELAYED W CORRELATION RECEIVER and said CENTRAL STATION;

wherein said DELAYED W CORRELATION RECEIVER can perform full correlation on L1 and L2 encrypted signals without requiring secret encryption keys.

2. The apparatus of claim 1, wherein said MODULATED W TRANSMITTER further comprises:

a RESYNCHRONIZING MEMORY 1 block, wherein each said i-th W code bit estimate is clocked into said RESYNCHRONIZING MEMORY 1 at the rate of said i-th W SYNC signal, i being an integer less or equal to N, wherein N is a number of satellites being observed, and wherein said RESYNCHRONIZING MEMORY 1 block generates an intermediate W code signal;

a CLOCK AND CARRIER SYNTHESIZER block connected to said RESYNCHRONIZING MEMORY 1 block for generating a resynchronizing clock, wherein said resynchronizing clock is used for formatting and clocking said intermediate W code bits at a different rate, and for adding a time tag to the transmission signal so that said DELAYED W CORRELATION RECEIVER can identify which GPS millisecond each reformatted W code section belongs to;

a MULTIPLIER for mixing said reformatted W code bits with a transmission carrier signal generated by said CLOCK AND CARRIER SYNTHESIZER block;

a BANDWIDTH FILTER AND AMPLIFIER connected to said MULTIPLIER for generating an output combined W code signal; and

an ANTENNA 1 connected to said BANDWIDTH FILTER AND AMPLIFIER for transmitting said combined output W code signal to said DELAYED W CORRELATION RECEIVER via said COMMUNICATION LINK.

3. The apparatus of claim 1, wherein said COMMUNICATION LINK further comprises:

a radiowave frequency band.

4. The apparatus of claim 1, wherein said COMMUNICATION LINK includes an infrared frequency band.

5. The apparatus of claim 1, wherein said COMMUNICATION LINK includes a microwave frequency band.

6. The apparatus of claim 1, wherein said COMMUNICATION LINK includes the ISM (industrial scientific medical) unlicensed operation band, and wherein the ISM band range is selected from a class of frequency range consisting of 900 MHz, 2.4 GHz, and 5.8 GHz.

7. The apparatus of claim 1, wherein said COMMUNICATION LINK includes a real time circuit switched communication link.

8. The apparatus of claim 1, wherein said COMMUNICATION LINK includes a 1.8 GHz band, wherein said 1.8 GHz band supports a personal communications services (PCS).

9. The apparatus of claim 1, wherein said COMMUNICATION LINK includes a Low Earth Orbiting Satellites (LEOS), wherein said LEOS is used to store and to forward digital packet data.

10. The apparatus of claim 1, wherein said COMMUNICATION LINK is selected from a class of radiowave communication means consisting of a cellular telephone communication means, paging signal receiving means, a wireless messaging services, a wireless application services, a wireless WAN/LAN station, and an Earth-satellite-Earth communication module that uses at least one satellite to relay a radiowave signal.

11. The apparatus of claim 1, wherein said COMMUNICATION LINK includes an Advanced Mobile Phone System (AMPS) including a modem, and wherein said modem is selected from a class consisting of a digital signal processor (DSP) modem, and a cellular digital packet data (CDPD) modem.

12. The apparatus of claim 1, wherein said COMMUNICATION LINK includes a digital cellular telephone communication means, and wherein said digital cellular telephone communication means includes a means of modulation of digital data over a radiolink selected from a class consisting of a time division multiple access (TDMA) system, and a code division multiple access (CDMA) system.

13. The apparatus of claim 1, wherein said i-th DOWNCONVERTER AND SAMPLER further comprises:

an i-th BANDPASS FILTER connected to said i-th HGA for filtering an i-th L1 signal generated by an i-th satellite;

an i-th LOW NOISE AMPLIFIER (LNA) connected to said i-th BANDPASS FILTER for amplifying said filtered i-th L1 signal;

an i-th MULTIPLIER connected to said i-th LOW NOISE FILTER for multiplying said i-th L1 signal with a first local oscillator signal, LO1, wherein an i-th mixed signal is produced;

an i-th BANDPASS FILTER connected to said i-th MULTIPLIER for filtering said i-th mixed signal;

an i-th AMPLIFIER connected to said i-th BANDPASS FILTER for amplifying said i-th filtered signal, wherein said i-th L1 signal is downconverted from the 1575.42 MHz frequency to a frequency of 175.42 MHz;

an i-th POWER SPLITTER connected to said i-th AMPLIFIER for power splitting said i-th L1 signal into two signals;

a first i-th MULTIPLIER for multiplying said i-th L1 signal with an inphase (I) version of a second local oscillator signal, LO2, to produce an i-th IL1 signal;

a second i-th MULTIPLIER for multiplying said i-th L1 signal with a quadrature (Q) version of said second local oscillator signal, LO2, to produce an i-th QL1 signal;

a first i-th LOWPASS FILTER connected to said first i-th MULTIPLIER for filtering said first i-th mixed signal;

a second i-th LOWPASS FILTER connected to said second i-th MULTIPLIER for filtering said second i-th mixed signal;

a first i-th AMPLIFIER connected to said first i-th LOWPASS FILTER for amplifying said i-th IL1 signal;

a second i-th AMPLIFIER connected to said second i-th LOWPASS FILTER for amplifying said i-th QL1 signal;

a first i-th one-bit analog-to-digital (A/D) CONVERTER connected to said first i-th AMPLIFIER for performing 1-bit quantization operation on said i-th IL1 signal;

a second i-th one-bit analog-to-digital (A/D) CONVERTER connected to said second i-th AMPLIFIER for performing 1-bit quantization operation on said i-th QL1 signal;

a first i-th FLIP-FLOP (FF1) connected to said first i-th one-bit A/D CONVERTER for sampling said i-th IL1 signal, wherein said sampling operation is performed by clocking said i-th IL1 signal through said i-th FF1 at sampling clock (SCLK) rate; and

a second i-th FLIP-FLOP (FF2) connected to said second i-th one-bit A/D CONVERTER for sampling said i-th QL1 signal, wherein said sampling operation is performed by clocking said i-th QL1 signal through said i-th FF2 at sampling clock (SCLK) rate.

14. The apparatus of claim 1, wherein said MASTER OSCILLATOR 1 block further includes:

a 10 MHz GENERATOR for generating a 10 MHz signal; and

a DIVIDE BY 2 block coupled to said 10 MHz GENERATOR block for dividing by 2 the 10 MHz signal generated by said 10 MHz GENERATOR block.

15. The apparatus of claim 1, wherein said FREQUENCY SYNTHESIZER 1 further comprises:

a PHASE DETECTOR for comparing phases of two signals, first said signal being an output signal from said MASTER OSCILLATOR 1 block, second said signal being generated by said FREQUENCY SYNTHESIZER 1 local reference signal, wherein minimum voltage output signal from said PHASE DETECTOR represents maximum phase alignment of said two signals;

a LOOP FILTER connected to said PHASE DETECTOR for filtering out high frequency voltage noise, wherein an output LOOP FILTER voltage signal includes a low frequency voltage noise;

a VOLTAGE CONTROLLED OSCILLATOR (VCO) connected to said LOOP FILTER, wherein a voltage signal at the input of said VCO causes frequency change in said VCO output signal, and wherein said VCO nominal output signal is locked to said reference signal; and

wherein said VCO nominal output signal is used as a first local oscillator signal, LO1;

a first DIVIDER connected to said VCO to divide said VCO output signal to obtain a second local oscillator signal, LO2;

a second DIVIDER connected to said first DIVIDER to divide said second oscillator signal, LO2, to obtain a sampling clock signal, SCLK; and

a third DIVIDER connected to said second DIVIDER to divide said sampling clock SCLK signal to obtain a MSEC reference signal.

16. The apparatus of claim 1, wherein said FREQUENCY SYNTHESIZER 1 further comprises:

a "Divide by 5" block;

a PHASE DETECTOR connected to said block "Divide by 5" for comparing 5 MHz output signal from said MASTER OSCILLATOR 1 with 5 MHz signal from said "Divide by 5" block, wherein minimum voltage output signal from said PHASE DETECTOR represents maximum phase alignment of two said 5 MHz signals;

a LOOP FILTER connected to said PHASE DETECTOR for filtering out high frequency voltage noise;

a VOLTAGE CONTROLLED OSCILLATOR (VCO) connected to said LOOP FILTER, wherein voltage signal at the input of said VCO causes frequency change in said VCO output signal, and wherein said VCO nominal output 1400 MHz signal is locked to said 5 MHz reference signal; and

wherein said 1400 MHz VCO output signal is used as a 1st local oscillator (LO1);

a "Divide by 8" block connected to said VCO to divide said 1400 MHz VCO output signal by 8 to obtain a 175 MHz signal used as a second local oscillator, LO2;

a "Divide by 7" block connected to said "Divide by 8" block to divide said 175 MHz signal by 7 to obtain a 25 MHz signal used as a sampling clock signal (SCLK); and

a "Divide by 25000" block connected to said "Divide by 7" block for dividing said sampling clock signal SCLK to obtain a 1 kHz reference signal, MSEC.

17. The apparatus of claim 1, wherein said i-th DIGITAL CHANNEL PROCESSOR further comprises:

an i-th carrier numerically controlled oscillator (CARRIER NCO

     1);

an i-th CARRIER MIXER 1 connected to said i-th CARRIER NCO 1 for multiplying i-th digitized inphase IL1 and i-th digitized inphase QL1 signals having carrier frequency with i-th inphase and i-th quadrature components of digital carrier;

wherein said i-th CARRIER MIXER 1 outputs i-th inphase IL1 and i-th quadrature Q L1 signals having zero carrier frequency;

an i-th CODE MIXER 1 connected to said i-th CARRIER MIXER 1 for code correlating said i-th inphase IL1 and said i-th quadrature Q L1 signals having zero carrier frequency with a locally generated replica of C/A code;

wherein when said i-th DIGITAL CHANNEL PROCESSOR'"'"'s carrier tracking loop is closed via said i-th CARRIER NCO 1 the i-th CARRIER MIXER 1'"'"'s input to said i-th CODE MIXER 1 represents an i-th satellite signal L1 C/A code; and

wherein said i-th CODE MIXER 1 performs said code correlation at 3 time points (early, punctual and late) on an i-th autocorrelation function graph creating an early, a punctual and a late sample of said i-th autocorrelation function;

an i-th block CORRELATORS 1 connected to said i-th CODE MIXER 1 for integrating said early, punctual and late samples of said i-th autocorrelation function over an integer number of i-th EPOCH signals;

wherein said i-th CORRELATORS 1 output signal is fed to said μ

P SYSTEM 1 at a rate of said i-th L1 C/A code EPOCH, and wherein said μ

P SYSTEM 1 uses said i-th CORRELATORS 1 output signal to develop feedback signals for an i-th L1 carrier tracking loop and for an i-th L1 code tracking loop;

an i-th CODE GENERATOR 1 connected to said i-th CORRELATORS 1 block for providing an i-th locally generated replica of C/A code, an i-th locally generated replica of P code, said i-th EPOCH signal, and an i-th W SYNC signal;

an i-th code numerically controlled oscillator (an i-th CODE NCO

     1) connected to said i-th block CORRELATORS 1 and connected to said i-th CODE GENERATOR 1 for driving said i-th CODE GENERATOR 1;

an i-th CODE MIXER 2 connected to said i-th CODE GENERATOR 1 for removing said i-th locally generated P code from said i-th incoming satellite Y code and for outputting an i-th L1 W code signal; and

an i-th W BIT EXTRACTOR 1 connected to said i-th CODE MIXER 2 and connected to said i-th CODE GENERATOR 1 for integrating said i-th L1 W code signal across an i-th W code bit period given by said i-th W SYNC signal, wherein the output of said i-th W BIT EXTRACTOR 1 provides an estimate W_i, `1` or `0`, of said i-th W code.

18. The apparatus of claim 17, wherein said i-th CODE GENERATOR 1 further comprises:

a first i-th DIVIDING CIRCUIT for dividing an input signal from said i-th CODE NCO to provide an i-th clock signal;

an i-th C/A CODE GENERATOR connected to said first i-th DIVIDING CIRCUIT for generating said i-th C/A code signal and said i-th EPOCH signal under said CONTROL signal of said μ

P SYSTEM 1, wherein said i-th C/A code signal is a locally generated i-th C/A code, and wherein an i-th EPOCH 1 signal is the repetition rate of said i-th C/A code, and wherein said i-th C/A CODE GENERATOR can be adjusted under said CONTROL signal to generate said i-th C/A code;

an i-th P CODE GENERATOR connected to said i-th CODE NCO 1, wherein said i-th P CODE GENERATOR is clocked by said i-th CODE NCO 1 signal under the CONTROL signal of said μ

P SYSTEM 1, and wherein said i-th P CODE GENERATOR generates said i-th P-code signal; and

an i-th DIVIDE BY 22 block connected to said i-th P CODE GENERATOR for dividing said i-th P code clock by 22, for synchronizing to said i-th C/A code EPOCH signal, and for outputting said i-th W SYNC signal;

wherein said i-th W SYNC signal acts as the i-th satellite W code bit synchronizer for extracting estimated i-th W code bits.

19. The apparatus of claim 17, wherein said i-th W BIT EXTRACTOR 1 further comprises:

an i-th ADDER;

a first i-th LATCH 1 connected to said i-th ADDER for accumulating the i-th L1 W signal across said i-th W bit period i-th W SYNC and for generating W_i bits; and

a second i-th LATCH 2 connected to said first i-th LATCH 1 for transferring to the output said W_i bits by clocking said i-th LATCH 2 at the rate of said i-th W SYNC signal.

20. The apparatus of claim 1, wherein said DELAYED W CORRELATION RECEIVER further comprises:

an ANTENNA 2 block for receiving real time L1 and L2 satellite signals from all N satellites being observed;

a DOWNCONVERTER AND IF PROCESSOR AND SAMPLING BLOCK connected to said ANTENNA 2 for frequency translating, amplifying, filtering, and sampling said received real time L1/L2 satellite signals;

at least one DELAYED CORRELATION PROCESSOR connected to said DOWNCONVERTER AND IF PROCESSOR AND SAMPLING BLOCK,

a COMMUNICATIONS RECEIVER for receiving said combined delayed output W signal transmitted from said MODULATED W TRANSMITTER via said COMMUNICATION LINK;

a RESYNCHRONIZING MEMORY 2 connected to said COMMUNICATIONS RECEIVER, wherein said RESYNCHRONIZING MEMORY 2 is configured to split said combined delayed output W signal into N delayed signals (W₁ ;

W₂ ;

. . . W_i. . . W_N) and into N synchronizing signals (W SYNC₁ ;

W SYNC₂ ;

. . . W SYNC_i ;

. . . W SYNC_N);

a μ

P SYSTEM 2 connected to each said DELAYED CORRELATION PROCESSOR for providing the CONTROL signal;

a FREQUENCY SYNTHESIZER 2 connected to each said DELAYED CORRELATED PROCESSOR; and

a MASTER OSCILLATOR 2 connected to said FREQUENCY SYNTHESIZER 2;

wherein said FREQUENCY SYNTHESIZER 2 and said MASTER OSCILLATOR 2 blocks supply the necessary clocking signals;

and wherein each said i-th DELAYED CORRELATION PROCESSOR is configured to correlate said real time signals i-th IL1 and i-th IL2 from said i-th satellite with said delayed signal W_i from said i-th satellite at said W SYNC_i rate.

21. The apparatus of claim 20, wherein said DOWNCONVERTER AND IF PROCESSOR AND SAMPLING BLOCK further comprises a DOWNCONVERTER block comprising:

a POWER SPLITTER 1 connected to said ANTENNA 2 for power splitting a single L1/L2 signal received by said ANTENNA 2 into two separate L1 and L2 signals;

a pair of two separate BANDPASS FILTER connected to said POWER SPLITTER 1 for filtering said L1 and L2 signals independently;

a POWER COMBINER connected to said pair of two separate BANDPASS FILTER for power combining said L1 and L2 signals into one combined signal L1/L2;

a LOW NOISE AMPLIFIER (LNA) connected to said POWER COMBINER for amplifying said filtered combined L1/L2 signal;

a POWER SPLITTER 2 connected to said FILTER /LNA and to said frequency/synthesizer for power splitting said L1/L2 signal into two signals;

a first MULTIPLIER connected to said POWER SPLITTER 2 for multiplying said L1 signal with said first local oscillator signal LO1 signal, wherein a first mixed signal is produced;

a second MULTIPLIER connected to said POWER SPLITTER for multiplying said L2 signal with said first local oscillator signal LO1 signal, wherein a second mixed signal is produced;

a first BANDPASS FILTER connected to said first MULTIPLIER for filtering said first mixed signal;

a second BANDPASS FILTER connected to said second MULTIPLIER for filtering said second mixed signal;

a first AMPLIFIER connected to said first BANDPASS FILTER for amplifying said first filtered signal; and

a second AMPLIFIER connected to said second BANDPASS FILTER for amplifying said second filtered signal.

22. The apparatus of claim 20, wherein said DOWNCONVERTER AND IF PROCESSOR AND SAMPLING BLOCK further comprises an IF PROCESSOR AND SAMPLING BLOCK further comprising:

a first POWER SPLITTER connected to said DOWNCONVERTER and to said FREQUENCY SYNTHESIZER 2 for power splitting said L1 signal into two signals;

a second POWER SPLITTER connected to said DOWNCONVERTER and to said FREQUENCY SYNTHESIZER 2 for power splitting said L2 signal into two signals;

a first MULTIPLIER for multiplying said L1 signal with an inphase (I) version of said second local oscillator signal LO2 signal to produce an IL1 signal;

a second MULTIPLIER for multiplying said L1 signal with a quadrature (Q) version of said second local oscillator signal LO2 signal to produce a QL1 signal;

a third MULTIPLIER for multiplying said L2 signal with an inphase (I) version of said second local oscillator signal LO2 signal to produce an IL2 signal;

a fourth MULTIPLIER for multiplying said L2 signal with a quadrature (Q) version of said second local oscillator signal LO2 signal to produce a QL2 signal;

a first FILTERING CIRCUIT connected to said first MULTIPLIER for filtering said IL1 signal;

a second FILTERING CIRCUIT connected to said second MULTIPLIER for filtering said QL1 signal;

a third FILTERING CIRCUIT connected to said third MULTIPLIER for filtering said IL2 signal;

a fourth FILTERING CIRCUIT connected to said fourth MULTIPLIER for filtering said QL2 signal;

a first AMPLIFIER connected to said first FILTERING CIRCUIT for amplifying said IL1 signal;

a second AMPLIFIER connected to said second FILTERING CIRCUIT for amplifying said QL1 signal;

a third AMPLIFIER connected to said third FILTERING CIRCUIT for amplifying said IL2 signal;

a fourth AMPLIFIER connected to said fourth FILTERING CIRCUIT for amplifying said QL2 signal;

a first one-bit analog-to-digital (A/D) CONVERTER connected to said first AMPLIFIER for performing 1-bit quantization operation on said IL1 signal;

a second one-bit analog-to-digital (A/D) CONVERTER connected to said second AMPLIFIER for performing 1-bit quantization operation on said QL1 signal;

a third one-bit analog-to-digital (A/D) CONVERTER connected to said third AMPLIFIER for performing 1-bit quantization operation on said IL2 signal;

a fourth one-bit analog-to-digital (A/D) CONVERTER connected to said fourth AMPLIFIER for performing 1-bit quantization operation on said QL2 signal;

a first FLIP-FLOP (FF1) connected to said first one-bit A/D CONVERTER for sampling said IL1 signal, wherein said sampling operation is performed by clocking said IL1 signal through said FF1 at sampling clock (SCLK) rate;

a second FLIP-FLOP (FF2) connected to said second one-bit A/D CONVERTER for sampling said QL1 signal, wherein said sampling operation is performed by clocking said QL1 signal through said FF2 at sampling clock (SCLK) rate;

a third FLIP-FLOP (FF

     3) connected to said third one-bit A/D CONVERTER for sampling said IL2 signal, wherein said sampling operation is performed by clocking said IL2 signal through said FF 3 at sampling clock (SCLK) rate; and

a fourth FLIP-FLOP (FF

     4) connected to said fourth one-bit A/D CONVERTER for sampling said QL2 signal, wherein said sampling operation is performed by clocking said QL2 signal through said FF 4 at sampling clock (SCLK) rate.

23. The apparatus of claim 20, wherein each said DELAYED CORRELATION PROCESSOR further comprises:

an L1 TRACKER for performing delayed correlation on the L1 Y code signal;

an L2 TRACKER connected to said L1 TRACKER for performing operations on the L2 Y code signal;

wherein said μ

P SYSTEM 2 is connected to said L1 TRACKER and to said L2 TRACKER; and

wherein said L1 TRACKER is fed by digitized inphase IL1 and quadrature QL1 of said real time L1 signal; and

wherein said L2 TRACKER is fed by digitized inphase IL2 and quadrature QL2 of said real time L2 signal; and

wherein said L1 TRACKER and said L2 TRACKER are being fed by each said delayed satellite signal W_i at said W SYNC_i rate from said RESYNCHRONIZING MEMORY block; and

wherein each said L1 and L2 TRACKER are synchronously clocked by said SCLK signal and synchronously referenced by said MSEC signal to local reference time;

said SCLK and said 1 kHz reference signal MSEC being outputted by said FREQUENCY SYNTHESIZER; and

wherein said μ

P SYSTEM 2 is fed by output signals from said L1 TRACKER and said L2 TRACKER; and

wherein said L1 TRACKER and said L2 TRACKER are fed by CONTROL signal from said μ

P SYSTEM 2.

24. The apparatus of claim 23, wherein said L1 TRACKER further comprises:

a carrier numerically controlled oscillator (CARRIER NCO

     2);

a CARRIER MIXER 2 connected to said CARRIER NCO 2 for multiplying said real time digitized inphase IL1 and Q L1 signals having carrier frequency with inphase and quadrature components of digital carrier;

wherein when tracking the L1 C/A code said CARRIER MIXER 2 outputs in its I channel a maximum of L1 C/A code signal power and outputs in its Q channel a maximum of L1 Y code signal power;

a CODE GENERATOR 2 for providing a locally generated replica of C/A code, P code, and clocking signal W SYNC;

a CODE MIXER 3 connected to said CARRIER MIXER 2, connected to said CODE GENERATOR 2, and connected to said CARRIER NCO 2 for code correlating the output signals from said CARRIER MIXER 2 with said locally generated replica of C/A code;

wherein, when said L1 TRACKER'"'"'s carrier tracking loop is closed via said CARRIER NCO 2, the input to said CODE MIXER 3 represents the satellite real time signal L1 C/A code; and

wherein said CODE MIXER 3 performs said code correlation at 3 time points (early, punctual and late) on the autocorrelation function graph creating an early, a punctual and a late sample of the autocorrelation function;

a block CORRELATORS 2 connected to said CODE MIXER 3 for integrating said early, punctual and late samples of said autocorrelation function;

wherein said CORRELATORS 2 output signal is fed to said μ

P SYSTEM 2 at a rate of L1 C/A code epoch, and wherein said μ

P SYSTEM 2 uses said CORRELATORS 2 output signal to develop feedback signals for the carrier tracking loop and for the code tracking loop;

a code numerically controlled oscillator (CODE NCO

     2) connected to said block CORRELATORS 2 and connected to said CODE GENERATOR 2 for providing a clocking signal at C/A code rate and for providing a clocking signal at P code rate;

said C/A code clocking signal and said P code clocking signal driving said CODE GENERATOR 2;

said CODE NCO 2 also providing a mechanism for aligning said locally generated replica of C/A code with said incoming satellite C/A code;

a CODE MIXER 4 connected to said CARRIER MIXER 2 and connected to said CODE GENERATOR 2, said CARRIER MIXER 2 outputting I and Q estimates of L1 Y code as an input to said CODE MIXER 4, said CODE GENERATOR 2 outputting said local replica of known L1 P code as input to said CODE MIXER 4, wherein said CODE MIXER 4 removes known L1 P code from said I and Q estimates of L1 Y code and outputs I and Q estimates of L1 W code;

a W BIT EXTRACTOR 2 connected to said CODE MIXER 4 for integrating the I and Q estimates of L1 W code across the period 22 P(Y) clocks;

a MEMORY 1 block connected to said W BIT EXTRACTOR 2 for storing the L1 W code bits outputted by said W BIT EXTRACTOR 2;

a CODE MIXER 5 connected to said MEMORY 1 block and connected to said RESYNCHRONIZING MEMORY 2 block for mixing the locally generated L1 W code estimates with the corresponding portion of said delayed combined estimate of W code signal; and

a block CORRELATORS 3 connected to said CODE MIXER 5 block and connected to said μ

P SYSTEM 2 for integrating the outputs of said CODE MIXER 5 block, wherein said CORRELATORS 3 are read by said μ

P SYSTEM 2 periodically to allow tracking of the L1 Y code signal and carrier tracking loops via said CODE NCO 2 and said CARRIER NCO 2 respectively.

25. The apparatus of claim 23, wherein said L2 TRACKER further comprises:

a carrier numerically controlled oscillator (CARRIER NCO

     3);

a CARRIER MIXER 3 connected to said CARRIER NCO 3 for multiplying said real time digitized inphase IL2 and Q L2 signals having carrier frequency with inphase and quadrature components of digital carrier;

a CODE GENERATOR 3 for providing a locally generated replica of P code and clocking signal W SYNC;

a code numerically controlled oscillator (CODE NCO

     3) connected to said CODE GENERATOR 3 for providing a clocking signal at P code rate for driving said CODE GENERATOR 3;

a CODE MIXER 6 connected to said CARRIER MIXER 3 and connected to said CODE GENERATOR 3, said CARRIER MIXER 3 outputting I and Q estimates of L2 Y code as an input to said CODE MIXER 6, said CODE GENERATOR 3 outputting said local replica of known L2 P code as input to said CODE MIXER 6, wherein said CODE MIXER 6 removes known L2 P code from said I and Q estimates of L2 Y code and outputs I and Q estimates of L2 W code;

a W BIT EXTRACTOR 3 connected to said CODE MIXER 6 for integrating the I and Q estimates of L2 W code outputted by said CODE MIXER 6 across the period 22 P(Y) clocks;

a MEMORY 2 block connected to said W BIT EXTRACTOR 3 for storing the L2 W code bits outputted by said W BIT EXTRACTOR 3;

a CODE MIXER 7 connected to said MEMORY 2 block and connected to said RESYNCHRONIZING MEMORY 2 block for mixing the locally generated L2 W code estimates with the corresponding portion of said delayed combined estimate of W code signal; and

a block CORRELATORS 4 connected to said CODE MIXER 7 block and connected to said μ

P SYSTEM 2 for integrating the outputs of said CODE MIXER 7 block, wherein said CORRELATORS 4 are read by said μ

P SYSTEM 2 periodically to allow tracking of the L2 Y code signal and carrier tracking loops via said CODE NCO 3 and said CARRIER NCO 3 respectively.

26. A method for performing a full correlation operation on encrypted satellite signals generated by a Satellite Positioning System (SATPS), said method comprising the steps of:

(a) receiving encrypted satellite signals from a first SATPS satellite by a first HIGH GAIN ANTENNA (HGA), from an i-th SATPS satellite by an i-th HIGH GAIN ANTENNA (HGA), from an N-th SATPS satellite by an N-th HIGH GAIN ANTENNA (HGA), i being an integer less or equal to N, N being a number of satellites being observed;

(b) extracting, resynchronizing, delaying and combining a W bit information from said received encrypted signals;

(c) transmitting said extracted delayed and combined W bit information;

wherein said steps (a) through (c) are performed by a CENTRAL STATION;

(d) receiving encrypted real time L1 and L2 satellite code signals;

(e) storing the observed samples of said received encrypted satellite L1 and L2 satellite signals;

(f) receiving said extracted delayed and combined W bit information transmitted by said CENTRAL STATION; and

(g) correlating said stored samples of said received encrypted L1 and L2 signals with the corresponding portions of said delayed and combined W bit information transmitted by said CENTRAL STATION;

wherein said steps (d) through (g) are performed by a DELAYED W CORRELATION RECEIVER.