Additional Secondary Factor Research Articles

Primary Socialization Theory and a Bio/Psycho/Social/Spiritual Practice Model for Substance Use

This article supports primary socialization theory as a theory for practitioners to use in drug-user treatment and prevention interventions. Primary socialization theory is compatible with the bio/psycho/social/spiritual practice model and targeting the individual within his or her etiological domains/situation to initiate specific interventions. Governmental institutions are posited as an additional secondary socialization factor for primary socialization theory. Gender is stressed as important for primary socialization theory and is emphasized for carrying out interventions.

Integrated GPS/LORAN: Structures and Issues*

This paper summarizes the need for integrating GPS and LORAN-C (hereafter simply termed LORAN). Assuming that LORAN increasingly serves as a backup for GPS in the next 10 years, two scenarios for this new role of LORAN are presented. Improvements to LORAN for this new role are then outlined. Beginning with a comparison of existing accuracies of C/A-code GPS and LORAN, two Kalman filter-based integrated receiver structures are developed to exploit the advantages of both systems. Results of a proof-of-concept receiver in a fixed location, in a minivan on the highway, and aboard a Coast Guard vessel show significant improvement in both accuracy and availability. A newer receiver architecture is summarized. Improvements to LORAN to make it a better backup for GPS are revisited. Where additional secondary factor (ASF) values are not constant, high accuracy requires better propagation models or differential corrections. In addition, improved receiver technologies such as master-independent multichain operation are discussed.

Using GPS to calibrate Loran-C

Various techniques for using simultaneous Global Positioning System (GPS)/Loran data to estimate the propagation uncertainties that limit the absolute accuracy of Loran-C are discussed. Significant improvements in the absolute accuracy of Loran can be achieved with very simple calibrations. The absolute accuracy of Loran in the Gulf of Maine without calibration is presented. The maximum and RMS absolute errors are between 700 and 500 m, depending on the choice of land model. Simple calibrations greatly improve the absolute accuracy of Loran. As shown, if the land conductivities are fixed a priori and a single parameter is optimized, the maximum and RMS absolute errors fall to around 250 and 60 m, respectively. Alternatively, land can be treated as a single conductivity which can be adjusted to reduce offshore additional secondary phase factor errors. The performance of this practice is summarized in tables which show maximum and RMS errors of around 300 to 100 m, respectively. >

A Non-iterative Algorithm for Loran-C Position Determination

This paper presents a non-iterative algorithm for Loran-C position determination (from Loran-C stations in triplet configuration) that can be programmed for a handheld calculator or small computer. The algorithm can incorporate the Additional Secondary Factor (ASF) Correction, if known. Algorithms for computing the spheroid earth heading and distance between a fix and destination, for predicting the indicated time delays (ITD's) at a geographic position and for calibrating the fixing algorithm to a known position and ITD's are also presented.

DMAHTC Support to National Ocean Survey Loran-C Charting

The selection of Loran-C as the primary radionavigation system for the United States Coastal Confluence Zone (CCZ) requires, by joint agreement, that the Defense Mapping Agency Hydrographic/Topographic Center provide corrections to Loran-C lattices overprinted on National Ocean Survey (NOS) charts. Additional Secondary Factor (ASF) Corrections to warp the lattices are necessary if the system is to meet ¼ nautical mile or better positioning accuracy required by the Department of Transportation (DOT) and specified in the 1977 National Plan for Navigation. The Coast Guard, which has statutory responsibility for the Loran-C Radionavigation System, expects it to be the principal aid to navigation for civil use in the CCZ until the year 2000. For Department of Defense (DoD) purposes the system will be replaced eventually by the NAVSTAR Global Positioning System (GPS). This paper reviews future plans for refinement of the techniques to compute ASF corrections, as well as past and present computational methods. In addition, it examines the status of the Loran-C Radionavigation System and the status of NOS charts which support the system. The U.S. Coast Guard has surveyed critical areas in the CCZ to verify the accuracy of Loran-C NOS chart lattices. An example survey in the offshore area of the west coast is depicted and discussed.

The Preparation of Loran-C Lattices for Canadian Charts

An overview of what Loran-C is, how it works and how it is presented on a chart is given. Particular attention is given to the Additional Secondary Factor (ASF) and how the Canadian Hydrographic Service (CHS) incorporates it in its preparation of lattices. The method of prediction of Time Differences (TD) and the verification of both the propagation theory and of the TD values are done using Time of Arrival (TOA) measurements. The technique of computer controlled automated drafting of the Lines of Position (LOP) and how the ASF anomalies are accommodated in the lattices are outlined, so that the LOPs are in their true geographical location. The quality of the Loran-C signals has been surveyed by the CHS and this is reflected in its choice of lattices on a chart and the application of caution notes where necessary. The rationale of selection of lattices for various versions of charts is discussed.