yumaread

Reading data from the YUMA almanac file.

Library

EngeeNavigation

Syntax

Function call

data = yumaread(filename) — reads data from the YUMA almanac file specified by the argument filename, and returns the parameters of each corresponding satellite as tabular data data.

data = yumaread(filename,GPSWeekEpoch=refdate) — sets the starting date from which the YUMA almanac file counts the number of the week in the Global Positioning System (GPS).

Arguments

Input arguments

# filename is the name of the YUMA + almanac file line

Details

The name of the YUMA almanac file for reading data, set as a string. The file name can contain an absolute path, a relative path, or no path at all. The file name may also include an extension.

Типы данных

String

# GPSWeekEpoch — countdown date

+ "06-Jan-1980" | "21-Aug-1999" | "06-Apr-2019"

Details

The reference date set as a format string DateTime, from which the GPS number of the week is counted in the YUMA almanac file.

These dates are repeated every 1024 weeks, starting on January 6, 1980 at 00:00 (UTC). The default value is the date and time string, which matches the last date of the GPS week number transfer before the current day.

Типы данных

String

Output arguments

# data — parameters of each satellite

+ tabular data

Details

The parameters of each satellite returned as tabular data, where each row corresponds to a separate record, and each column corresponds to a parameter of this record.

Parameters Data type Description

Parameters	Data type	Description
`Time`	`DateTime`	The time according to the GPS clock, calculated using the parameters `Week` and `TimeOfApplicability`
`PRN`	`Float64`	The number of the satellite’s pseudorandom code
`Health`	`Float64`	Satellite status (serviceability) code
`Eccentricity`	`Float64`	The eccentricity of the orbit
`TimeOfApplicability`	`Float64`	The number of seconds since the beginning of the GPS week
`OrbitalInclination`	`Float64`	The angle of inclination of the orbit at the moment of reference, in radians
`RateOfRightAscen`	`Float64`	Rate of change of right ascension, in rad/s
`SQRTA`	`Float64`	The square root of the semimajor axis, in m^1/2
`RightAscenAtWeek`	`Float64`	Geographical longitude of the orbital plane at the beginning of the week, in radians
`ArgumentOfPerigee`	`Float64`	The angle from the equator to perigee, in radians
`MeanAnom`	`Float64`	The angular position of the satellite in orbit relative to perigee, in radians
`Af0`	`Float64`	Zero-order correction to satellite clock readings, in seconds
`Af1`	`Float64`	First-order correction to satellite clock readings, in seconds per second
`Week`	`Float64`	GPS week number. This is a continuous number, not `mod(1024)`

Time

DateTime

The time according to the GPS clock, calculated using the parameters Week and TimeOfApplicability

PRN

Float64

The number of the satellite’s pseudorandom code

Health

Float64

Satellite status (serviceability) code

Eccentricity

Float64

The eccentricity of the orbit

TimeOfApplicability

Float64

The number of seconds since the beginning of the GPS week

OrbitalInclination

Float64

The angle of inclination of the orbit at the moment of reference, in radians

RateOfRightAscen

Float64

Rate of change of right ascension, in rad/s

SQRTA

Float64

The square root of the semimajor axis, in m^1/2

RightAscenAtWeek

Float64

Geographical longitude of the orbital plane at the beginning of the week, in radians

ArgumentOfPerigee

Float64

The angle from the equator to perigee, in radians

MeanAnom

Float64

The angular position of the satellite in orbit relative to perigee, in radians

Af0

Float64

Zero-order correction to satellite clock readings, in seconds

Af1

Float64

First-order correction to satellite clock readings, in seconds per second

Week

Float64

GPS week number. This is a continuous number, not mod(1024)

Типы данных

DataFrame

Recommendations

To download the YUMA almanac files from the website NAVCEN for the current date, it is necessary to specify a date two days earlier than the current one, since the moment of GPS data applicability occurs approximately 70 hours after the transmission time of the almanac dataset.

Literature

Science Applications International Corporation. NAVSTAR GPS Space Segment/Navigation User Interfaces. IS-GPS-200M. Los Angeles, CA: United States Space Force Space Systems Command, approved May 21, 2021. https://www.navcen.uscg.gov/sites/default/files/pdf/gps/IS_GPS_200M.pdf.
Science Applications International Corporation. NAVSTAR GPS Space Segment/Navigation User Interfaces. ICD-GPS-240D. Los Angeles, CA: United States Space Force Space Systems Command, approved May 21, 2021. https://www.navcen.uscg.gov/sites/default/files/pdf/gps/ICD_GPS_240D.pdf.
United States Coast Guard. GPS Almanacs, NANUs, and OPS Advisories Archives. US Coast Guard Navigation Center. Accessed May 6, 2022. https://www.navcen.uscg.gov/archives.
Quasi-Zenith Satellite System(QZSS). Satellite Positioning, Navigation and Timing Service. Accessed September 20, 2022. https://qzss.go.jp/en/technical/download/pdf/ps-is-qzss/is-qzss-pnt-004.pdf.
QZSS almanac archives, Quasi-Zenith Satellite System(QZSS). QZSS (Quasi-Zenith Satellite System) - Cabinet Office (Japan) Accessed September 20, 2022. https://sys.qzss.go.jp/dod/en/archives/pnt.html.