How to use the Network Earth Rotation Service

There are three levels of using the NERS:

Level 1: using your browser


Advantage of using NERS with a browser: you see what you get.

Disadvantage of using NERS client library: usually you need the Earth orientation parameters for computations.

Level 2: using at as Internet service

An Internet service is a request to a HTTP server with parameters. The server returns the answer upon receiving the request. Although An Internet service works with any browser, normally it used with a non-interactive client such as wget. Here are supported services:

UTC minus TAI: wget -q -O - ''
UT1 minus TAI: wget -q -O - ''
X pole coordinate: wget -q -O - ''
Y pole coordinate: wget -q -O - ''
Δψ nutation angle: wget -q -O - ''
Δε nutation angle: wget -q -O - ''
UT1 rate: wget -q -O - ''
X pole rate: wget -q -O - ''
Y pole rate: wget -q -O - ''
Length of day: wget -q -O - ''
Euler angle axis 1: wget -q -O - ''
Euler angle axis 2: wget -q -O - ''
Euler angle axis 3: wget -q -O - ''
Rotation matrix: wget -q -O - ''
Rotation matrix rate: wget -q -O - ''
Rotation matrix accl: wget -q -O - ''

Value of parameter req_date can be replaced to the date string that is ISO 8601 compatible, i.e. in format, for instance 20110.04.19T08:19:15.545

Advantage of using NERS as an Internet Service: you can include calls to internet service in your program

Disadvantage of using NERS as an Internet Service: Internet service is rather slow.

Level 3: using the client library NERS

Download and install NERS client library.

You nerd insert three calls to your program

  1. ners_init ( config_file, ners, time_tai_start, time_tai_stop, iuer ) — initialization of the ners object using configuration parameters from the config file, start and stop time.
  2. ners_get_eop ( ners, time_tai, cpar, m_par, l_par, pars, iuer ) — return an array of Earth orientation parameters cpar on the specified time.
  3. ners_quit ( code, ners ) — release dynamic memory allocated by ners.

Advantage of using NERS client library: it is very fast serve in your program.

Disadvantage of using NERS client library: you need to know how to program.

Back to the Network Earth Rotation Service

This page was prepared by Leonid Petrov ()
Last update: 2017.07.05_12:12:16