<p>Pulsar, or X-ray navigation is being actively tested right now. Currently an X-ray telescope mounted on the International Space Station completed a test where a small navigation computer was able to solve for it's own position and orbit in space relying only timing information from X-rays produced by a group of pulsars.</p>
<p>I've written more about it in the question <a href="https://space.stackexchange.com/q/24448/12102">Is NICER/SEXTANT the first civilian “spacecraft” to determine it's own position in space without GPS or uplinked data?</a> Spoiler alert, hold your cursor over the box:</p>
<blockquote class="spoiler">
<p> <a href="https://space.stackexchange.com/a/24450/12102">Yes, it is the first</a></p>
</blockquote>
<p>You can also read about an investigation for X-ray communication in <a href="https://space.stackexchange.com/q/19882/12102">How will NavCube (actually) be important for the XCOM testing and demonstration?</a> I believe this will be a significantly longer term technology development path.</p>
<p><a href="https://www.nasa.gov/content/about-nicer" rel="nofollow noreferrer">NICER</a>, NASA’s Neutron star Interior Composition Explorer, will of course also be used for pure Astronomy research on neutron stars.</p>
<p>Will this replace GPS? Not really, No.</p>
<p>GPS serves the Earth's surface, and near Earth orbit (NEO) very nicely and efficiently. However, once you get a little farther, to MEO and GEO, it gets much more difficult to receive several simultaneous GPS signals because the satellites concentrate most of their power directly on to the Earth's disk, with only some side-lobes &quot;leaking&quot; past the terminator and into space.</p>
<p>See the questions and of course their answers:</p>
<ul>
<li><a href="https://space.stackexchange.com/q/14739/12102">Will Glonass, Galileo, or BeiDou-2 satellites provide better cis-lunar navigation than GPS?</a></li>
<li><a href="https://space.stackexchange.com/q/14737/12102">Has GPS been used beyond GEO? (duplicate)</a></li>
<li><a href="https://space.stackexchange.com/q/565/12102">How far up have satellites used a GNSS for positioning, and how does the precision degrade with altitude?</a></li>
</ul>
<p>So for spacecraft in farther Earth's orbits it may be possible to augment or replace GPS or GNSS in general, and for deep space, there is currently no way to autonomously navigate today, so it will be the first.</p>
<hr />
<p><a href="https://i.sstatic.net/V64w2.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/V64w2.jpg" alt="enter image description here" /></a></p>
<p><strong>above:</strong> NICER X-ray timing telescope/concentrator array, from <a href="https://www.nasa.gov/content/about-nicer" rel="nofollow noreferrer">About NICER</a>.</p>

CC BY-SA 3.0
2018-02-11T23:40:38.017Z
2018-02-11T23:47:50.653Z
2020-06-17T09:47:40.653Z
uhoh
<p>as a follow-up to my previous <a href="https://astronomy.stackexchange.com/questions/25012/thought-experiment-about-our-location-in-the-universe">question</a> I found out that the <a href="https://podolakvandysolarsystem.wordpress.com/2016/04/11/voyager-golden-record-reading-the-instructions/" rel="nofollow noreferrer">Voyager Golden record</a> uses a star map of pulsars to precisely show where our solar system is...</p>

<p>Is it possible/feasible to base a navigation system on pulsars in order to replace GPS?</p>

CC BY-SA 3.0
2018-02-11T23:20:50.057Z
The highest quality GPS-based positioning systems can locate position to [within centimeters](https://en.wikipedia.org/wiki/GNSS_enhancement#Carrier_phase_tracking_(surveying)).  These are survey systems, not commonly used GPS like a phone or camera or car might utilize.  Celestial navigation cannot come close to that accuracy.   And [locating a pulsar from the ground](https://www.quora.com/Are-there-any-pulsars-visible-to-the-naked-eye) would be quite difficult without specialist equipment that's quite impractical compared to the relatively compact (and cheap) GPS systems.
StephenG - Help Ukraine
CC BY-SA 3.0
2018-02-11T23:41:40.130Z
@StephenG GPS has very limited coverage for navigation near the Earth, and zero deep-space coverage of course.
uhoh
<pulsar><navigation>
Could pulsar navigation replace GPS
Our Man in Bananas
# Could pulsar navigation replace GPS

(Asked by: username_0 on 2018-02-11)

as a follow-up to my previous [question](https://astronomy.stackexchange.com/questions/25012/thought-experiment-about-our-location-in-the-universe) I found out that the [Voyager Golden record](https://podolakvandysolarsystem.wordpress.com/2016/04/11/voyager-golden-record-reading-the-instructions/) uses a star map of pulsars to precisely show where our solar system is...

Is it possible/feasible to base a navigation system on pulsars in order to replace GPS?

**Tags:** pulsar, navigation
> **Comments:**
> **username_1**: The highest quality GPS-based positioning systems can locate position to [within centimeters](https://en.wikipedia.org/wiki/GNSS_enhancement#Carrier_phase_tracking_(surveying)).  These are survey systems, not commonly used GPS like a phone or camera or car might utilize.  Celestial navigation cannot come close to that accuracy.   And [locating a pulsar from the ground](https://www.quora.com/Are-there-any-pulsars-visible-to-the-naked-eye) would be quite difficult without specialist equipment that's quite impractical compared to the relatively compact (and cheap) GPS systems.  
> **username_2**: @StephenG GPS has very limited coverage for navigation near the Earth, and zero deep-space coverage of course.  

---

## 1 answers

### Answer by username_2 on 2018-02-11. Score: 3 | Accepted answer

Pulsar, or X-ray navigation is being actively tested right now. Currently an X-ray telescope mounted on the International Space Station completed a test where a small navigation computer was able to solve for it's own position and orbit in space relying only timing information from X-rays produced by a group of pulsars.

I've written more about it in the question [Is NICER/SEXTANT the first civilian “spacecraft” to determine it's own position in space without GPS or uplinked data?](https://space.stackexchange.com/q/24448/12102) Spoiler alert, hold your cursor over the box:

> [Yes, it is the first](https://space.stackexchange.com/a/24450/12102)

You can also read about an investigation for X-ray communication in [How will NavCube (actually) be important for the XCOM testing and demonstration?](https://space.stackexchange.com/q/19882/12102) I believe this will be a significantly longer term technology development path.

[NICER](https://www.nasa.gov/content/about-nicer), NASA’s Neutron star Interior Composition Explorer, will of course also be used for pure Astronomy research on neutron stars.

Will this replace GPS? Not really, No.

GPS serves the Earth's surface, and near Earth orbit (NEO) very nicely and efficiently. However, once you get a little farther, to MEO and GEO, it gets much more difficult to receive several simultaneous GPS signals because the satellites concentrate most of their power directly on to the Earth's disk, with only some side-lobes "leaking" past the terminator and into space.

See the questions and of course their answers:

* [Will Glonass, Galileo, or BeiDou-2 satellites provide better cis-lunar navigation than GPS?](https://space.stackexchange.com/q/14739/12102)
* [Has GPS been used beyond GEO? (duplicate)](https://space.stackexchange.com/q/14737/12102)
* [How far up have satellites used a GNSS for positioning, and how does the precision degrade with altitude?](https://space.stackexchange.com/q/565/12102)

So for spacecraft in farther Earth's orbits it may be possible to augment or replace GPS or GNSS in general, and for deep space, there is currently no way to autonomously navigate today, so it will be the first.

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[![enter image description here](https://i.sstatic.net/V64w2.jpg)](https://i.sstatic.net/V64w2.jpg)

**above:** NICER X-ray timing telescope/concentrator array, from [About NICER](https://www.nasa.gov/content/about-nicer).


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