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This technical memorandum describes the algorithms used in computing a navigation fix from data provided by receivers of the 2-minute integrated doppler type designed to operate with the Navy Navigation Satellite System. The report covers the theoretical basis for calculating the change in range from the navigator to the satellite, the geometrical basis of the equations for obtaining a navigation fix, and the formatting and processing of the receiver data for the navigation solution. It also provides information on scaling for the navigation fix computations, on the calculations for a four-variable navigation solution, and on nonstandard numerical computation routines applicable to the navigation program.
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Copy No. 2K
o Technical Memorandum
PROGRAM REQUIREMENTS
FOR TWO-MINUTE INTEGRATED
DOPPLER SATELLITE
NAVIGATION SOLUTION
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Approved for puhlic releIas; dlstrlbutlon unlimited.
Reproducd by NATIONAL TECHNICAL INFORMATION spengfleW, Va.* 22101 SERVICE
Se'urilv Cn•a gc-atfir on DOCUMENT CONTROL DATA - R & D sve f ia vit' ,'iroiiratIon a1 flet, body of I b.fagm Ind Indedlnj annolhlvtfn mu- I br qisl rerd whe.n floe lY.,,I I r,.p,,f I I r l .40 ie.I) ,; % A t•NG A C I V I TV ( CVr p r aofe 0 1 1 1h 0 o r)0a 0 f) 0****. L O R I S CC U 141 I V C L A ' %I t I CA.gA 1 4 0, 0 The Johns Hopkins University Applied Physics Lab. ITnilAigified
Silver Spring, Md. 20910 (^1401 1141) t IILL
Prvoji'ain Requirements for Two-Minute Integrated Doppler Satellite Nivigntion Solution
"recnnic'nl Memorandum A, f "O- SI tF(I I vlflme, middle Initial, _IaI_* nu•menI
JK(iiterI by John B. Moffett
1. 9 011 I IAf TL Ia, TO T A L N O O F P A G t.b IT,. l'r1 6•. l .4f- September 1971 277 16 ,I "'Jll4AL OR GR4ANT NO. g9a ORIGINATOR'S IEPORT Nvdj•l•PERS N0001 7-62-C-
,.T; i s k Z 2 3 9.b OTmER IhNS repoal) REPORT NOIS) (Any other numbefx that may b"e Aksallned
',15111UT (^) OP STA (^) TEMENT (^) Approved (^) for (^) public (^) release; distribution (^) unlimited.
to I.JI'aFLI.MEt#TARY NOTES I•, SPONSORING MILITARY ACTIVITY Naval Electronic Systems Command Department of the^ Navy
- A f ,t ?ACI*
provided by receivers of the two-minute integrated doppler type designed to operate with the Navy Navigation Satellite System. The theoretical basis for calculating the change in range from the navigator to the satellite as a function of the integrated satellite doppler shift data is developed. The original receiver of the integratcd doppler type, the ANI SRN-9, is briefly described in its developmental versions, designed by APL, and its pro- duction versions, built by ITT. The Scripps/ONR 702CA receiver, built by Magnavox and used for oceanographic research applications of integrated doppler navigation, is also described. The geometrical basis of the equations for obtaining a navigation fix is developed. The formatting and processing of the receiver data for the navigation solution are de- scribed preparatory to a presentation of step-by-step procedures for computing a three- variable navigation fix. Procedures for calculating satellite alerts, using data from the navigation oolution, are also described. A representative FORTRAN program for ob- taining a navigation fix and for calculating alerts is presented.
Information is also provided on scaling for the navigation fix^ computations,^ on the calculations for a four-variable (velocity north) navigation solution, on the proce- dures for applying a correction for tropospheric refraction, on a computer program for geodetic coordinate transformation, and on nonstandard numerical computation routines applicable to the navigation program.
DD, o.ov^ ..^ l^^473 Seecurl UNC^ LASSIFIEI) ti~ty'|i~ficatoo.
ISEPTEMBER (^1971)
;• I
I |Technical Memorandum
:1 (^) PROGRAM REQUIREMENTS
FOR TWO-MINUTE INTEGRATED
i lDOPPLER SATELLITE
NAVIGATION SOLUTION
Edited by J. B. MOFFEIT
Approveid (^) for public release; distribution unlimniz,-i.
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4PPLIFn) THC^ J4NS* Pwyczr".^ "OPKINS (^) I^ IMNVERSlTY ARCPATO)RY I.LVao $"§G UARVLANV
I ABSTRACT
[ (^) This report describes the .:.lgorithms used in com- puting a navigation fix from data provided by receivers of the 2-minute integrated doppler type designed to operate Swith (^) the Navy Navigation Satellite System. The theoretical basis for calculating the change in range from the (^) naviga- tor to the satellite as a function of the integrated satellite doppler shift data is developed. The original receiver of the integrated doppler (^) type, the AN/SRN-9, is briefly de- scribed (^) in its developmental versions, designed by APL, I: and its production versions, built by ITT. The Scripps/ ONR 702CA receiver, built by Magnavox and used for oceanographic research (^) applicatione of integrated doppler L navigation, is also described.
The geometrical basis of the equations for obtain- j ing a navigation fix is developed. The formatting and pro- cessing of the receiver data for the navigation solution are described preparatory to a presentation of step-by-step L proceaures for computing a three-variable navigation fix. Procedures for calculating (^) satellite alerts, using data from the navigation (^) solution, are also described, A repre- sentative FORTRAN program for obtaining a navigation fix and for calculating (^) alerts is presented.
I• Information is also provided on scaling for the navigation fix computations, (^) on the calculations for a four- variable (velocity (^) north) navigation solution, on the pro- cedures for applying a correction for tropospheric refrac- tion, on a computer program for geodetic coordinate trans- formation, and on nonstandard numerical computation routines applicable to the navigation program.
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THE JOHNS HOPKINS UNIVmIISTY A 0 PLIED PHYSICS LABORATORY
The combined efforts of the following^ individuals are acknowledged for contributions to the preparation of this report: R. H. Bauer, J. W. Casey, J. G. Cusic, , IR. D. Faber, R. J. Finneran, G. C. Gutheim, H. S. Hopfield, M. 0. Marshall, G. W. Martin, C. E. Rehbein, V. Schwab, (^) and S. M. Yionoulis.
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THE,JOINS HO:KIN5: VI•TY T APPLIED SI$LV90^ PHYSICS^ ýt^ g^ WARTLAU3LABORATORY
List of Illustraticns xi
List of Tables xv
1 Navy Navigation Satellite^ System^ I 2 Integrated Doppler Measurement of Slant
3 Integrated (^) Doppler Tracking Equipment. 9
Developmental AN/SRN-9 Equipment. 9 .0 (^) Radio (^) Navigation Sets (^) AN/SRN- and AN/SRN-9A 23
Equations. 35 Coordinate Transformations 35
5 Data Types and Formats 51 A;. (^) Types of Data. (^). 51
. 6 Data Processing^65
Initialization. 67
Second Two-Minute Message 76 Third and Fourth Two-Minute
.1 Messages.. 82.
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APPLIED PHYSICS LABORATORY
(^1) [ ILLUSTRATIONS
1 Navy Navigation Satellite System 2 2 Block Diagram of AN/SRN- -• System .. 4
! -•4 Block Diagram of Satellite Integrated
Doppler Navigation Equipment, Single-Frequency System 10
5 Block Diagram of Satellite Integrated Doppler Navigation Equipment,
6 AN/SRN (XN-5) Receiving Equipment
7 Communication Link Modulation
8 AN/SRN-9 (XN-5) Refraction Channel Waveforms 18 9 AN/SRN-9 (XN-5) Control Group- Printer Configuration.. 20 10 AN/SRN-9 (XN-5) Doppler and Orbital
11 AN/SRN-9 Radio Navigation Set. 2.
12 AN/SRN-9A Radio Navigation Set. 25
13 AN/SRN-9 or^ AN/SRN-9A^ Two-Minute Doppler, Refraction, and Orbital Parameter Printout 28
14 Navigation Satellite Set 702CA. 32 15 702CA Doppler, Refraction, and Orbital Parameter Printout as
Obtained on HP 2115A Computer. 34
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TH[ JOHNS HOPKINS UNIVIERSITY PA"PLItI. IIYbICS LABORATORY* 51LV9* S^4kG MARYLAND*
ILLUSTRATIONS (cont'd)
16 XYZ and xyz Coordinate Systems 37
17 Orientation of Orbital Plane 38 - 18 x'y'z' Coordinate System 40
19 Relation Between x'y' and uv Planes 42 -- 20 Satellite Orbit^1 3 "i
21 Geoidal(Meters) Height (H) Contour.. Map 49 "
22 Data Format for AN/SRN- Equipment .. 58 ,
23 Data Format for Magnavox Equipment 59 24 Format of Doppler, Refraction, and Orbital Data Divided into Computer Words in the ITT and Magnavox Receivers 61 25 Receiver/ Computer Interface^ Timing Diagram 62 26 Status of Data Tables at - Iritialization 68
27 ID Code Sequence for ITT Receiver Data During a Two-Minute Message 71 28 Status of Data Tables and Pointer - Registers at End of First Two- Minute Message 77 29 Status of Data Tables and Pointer Registers after Subroutine UPTB in Second Two-Minute Message. 81 30 Status of Data Tables and Pointer Registers at End of Second Two- Minute Message 83 -'
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THE JOHNS* HOPCWKI UNIVZRS"Y APPLIED PHYSICS LABORATORY
ILLUSTRATIONS (cont'^ d)
A-18 Subroutine^ TTYT^
A-19 Subroutine^ CVTM^
A-20 Subroutines^ SATC^ and^ SXYZ^
A-21 Subroutine^ SOLVE^
A-22 Subroutines^ SLANT^ and EDIT^
A-23 Subroutine^ TYPE^
A-24 Subroutine^ ARCS^ and^ UCON^
A-25 Subroutines^ ALRT^ and^ AVIS^
C-i Velocity^ North^ Solution^ by^ Direct Search 2
-s
s-s
5.
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APPLIED ThE9JOHNS PHYSICS^ H4OPKINS LABORATORY UNIVERg.gry SILV" eUW WUA"rDtq
(I (^) TABLES
I
1 Variable Orbit Parameters in Navigation Message 52
2 Fixed Orbit Parameters in Navigation Message 53
3 Navigator's Estimates 55
4 Program Constants 56
5 Summary of Changes in Major Counters, Registers, Flags, and Switches During the First Two-Minute Message 78
Registers, Flags, and Switches During the Second Two-Minute Message 84 7 Interface Requirements Between Real-
Navigation Fix Program 124
C-i Number of Bit Errors Between any Two BCDX3 Digits 230
C-2 Number of Errors when Comparing Two Eight-D~git Sequences Made up of the Least Significant Digits of the BCDX Modulo 15 Time Sequence. 231 D-1 Height Parameters for Two-Quartic N Profile (kin) 235
Li• Times w 240
A
yEjotNS FrDIE p~4ySlrS #HOPipsUNSIVER*fyy LABOR~ATORY
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THE JOHNS "OpKINg U#4IVEOTy APPLIED PHYS•CS LABORATORY S#LV9 SPWMG MARYLAND*
from the satellites; a computing center where (^) future orbits,
orbital parameters, (^) and time corrections are computed; T and an injection station to transmit these new (^) orbital param- eters and time (^) corrections to the satellite. In addition, (^) the satellite time signals are comr.pared with Universal Time. This information is used in (^) the computing center for the time (^) correction computations. The U. S. Navy Astronautics Group, with headquarters at Point Mugu, California, is
Figure 2 shows a block (^) diagram of the AN/SRN- system. The purpose of this (^) report is to provide detailed information for (^) the navigation solution and alert computa- tions shown as part (^) of the computer programming. The
report are intended to provide background information only and are not a specification of any form.
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THE JOHNS HOPKINS UNIVERIITY RAPPLIED PHYSICS LABORATORY I ~S LVRRSPRING"A"Y"AD
Ii 2. INTEGRATED DOPPLER MEASUREMENT OF SLANT RANGE CHANGE
cept thatIntegrated the integral^ doppler of the^ navigation doppler shiftis^ based of the^ on satellite^ the^ con-
i "A satellite signal transmitted at^ time^ t^ k^ with^ slant range Sk will (^) be received by the navigator (^) at time tk + Sk/c. If the satellite is transmitting a stable signal at frequency (fo--) continuously between transmission of two^ time^ mark signals (transmitted at times tk and tk_1) the ground obser-- -."ver will count (fo-f)XT cycles for the interval between re- ceipt of the time markers (T = tk - tkl). The frequency of this received signal will be denoted fR(t) and the receiver reference frequency fo. A difference frequency therefore exists in the ground receiver of frequency fo-fR(t).^ The total number of cycles of this difference frequency between receipt of two satellite time marks^ is^ measured^ by^ count-
and tk + Sk/c. The apparent doppler count accumulation at a particular frequency (nominally f.) between receipt of P. two^ such^ successive time marks^ is^ therefore:
t +Sk Sk
"*I 1 Nk=/ (f- (^) 'RoR(t))dto f t -(f^ -T)T•^ (1)
fS k- 1 S k- 1
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THE JOHNS HOPiKINS^ UNIVERSITY APPLIED PHYSICS SILVEm SPIFNG^ MARYLAND LABORATORY
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SATELLITE
S , S 2 S3 S^4 S5^ S^6 S7^ se^ S^9 / •' I
NAVIGATOR D3 D4 D5 D6 7 t9 PATH
Fig. 3 SLANT^ RANGE^ MEASUREMENT^
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