APPLICATION OF PSEUDO-NOISE CORRELATION & BANDWIDTH SYNTHESIS TO ORBIT DETERMINATION

A TECHNIQUE WHICH COMBINES THE USE OF PSEUDO-NOISE (PN) CODECORRELATION AND MULTILATERATION WITH ANOTHER TECHNIQUE, TERMED "BANDWIDTH SYNTHESIS" (BWS), TO SIGNIFICANTLY ENHANCETHE ACCURACY OF SATELLITE ORBIT DETERMINATION IS THE FOCUS OF THIS PROJECT. FROM A THEORETICAL VIEWPOINT, BWS ALLOWS ONE TO CONSTRUCT A VERY WIDEBAND PN CORRELATION FUNCTION (E.G., REFLECTING MORE THAN 100 MHZ) BY EMPLOYING MULTIPLE PN CODES, EACH OF RELATIVELY NARROW-BANDWIDTH (E.G., LESS THAN 10 MHZ), WITH EACH OCCUPYING A DISJOINT FREQUENCY BAND.THIS BWS TECHNIQUE HAS BEEN APPLIED TO INTERFEROMETRY BUT APPARENTLY NOT TO PN CORRELATION/MULTILATERATION. THE GOALSOF THIS RESEARCH ARE: TO DEVELOP THE THEORETICAL BASIS FOR BWS/PN/MULTILATERATION (BWSPNM), CONSIDER HARDWARE AND SOFTWARE PROCESSING TECHNIQUES THAT MAY PROVIDE A CAPABILITYFOR NEAR-REAL-TIME ORBIT DETERMINATION, IDENTIFY ERROR SOURCES AND ASSESS THEIR POTENTIAL, AND ILLUSTRATE HOW BWSPNM MAY BE APPLIED VIA BOTH EXISTING SYSTEMS - SUCH AS TDRSS AND GPS - AND VIA FUTURE SYSTEMS. SIGNIFICANT BENEFITS OF BWSPNM RELATIVE TO OTHER TECHNIQUES, SUCH AS INTERFEROMETRY, ARE IDENTIFIED; POSSIBLE BENEFITS MIGHT BE REDUCTIONS IN REQUIREMENTS FOR FREQUENCY STANDARD STABILITY AND DATA TRANSFER.