<p>This is a good question! TL;DR, twisting/braiding the wires here <strong>should have little effect</strong> on the time to first GPS solution (<em>called TTFF in GPS parlance, for Time To First Fix</em>). It's recommended to help physically constrain the cable in the drone frame so it doesn't bump into things or get caught in the propellers, as twisting the wires stiffens/bulks up the wire bundle and shortens its length.</p>
<p>More generally, twisted-pair signal wires are useful for electromagnetically noisy environments (<em>such as a drone</em>). The act of twisting the signal wires together helps to ensure that any electromagnetic effects affect all the signal wires equally, and in some cases for special (<em>differential</em>) signaling protocols, automatically cancel out the effects.</p>
<p>The UART interface we're talking about here (<em>VCC, GND, TX, RX</em>) is not a differential signal protocol and doesn't benefit much from twisting the signal wires. The most likely effect of a noisy environment on a UART interface is an intermittent failure to communicate with the GPS module during flight, but I don't believe that's something you've been seeing.</p>
<p>To your other question:</p>
<blockquote>
<p>my module is an outdated one and thus more vulnerable to radio noise from other equipment of the same drone</p>
</blockquote>
<p>&quot;Hobby-grade&quot; GPS receivers are generally not all that great, especially in comparison to the integrated GPS/SoC chipsets in modern phones. There are several interesting reasons for this, including:</p>
<ul>
<li>Poor-quality receive antennas and EMI environment on a drone</li>
<li>Lack of <a href="https://en.wikipedia.org/wiki/Assisted_GNSS" rel="nofollow noreferrer">A-GPS</a> or other TTFF and accuracy improving strategies</li>
<li>Lack of support for other GNSS constellations other than GPS (<em>e.g. Galileo, GLONASS, BeiDou</em>)</li>
<li>Lack of knowledge of the current time (<em>i.e. no <a href="https://en.wikipedia.org/wiki/Real-time_clock" rel="nofollow noreferrer">RTC</a></em>)</li>
</ul>
<p>The easiest one of these to mitigate/improve without buying an expensive GPS receiver part is improving the antenna and/or moving it further from the motors. But the slow TTFF will always be present due to the lack of accurate time knowledge or A-GPS.</p>

CC BY-SA 4.0
2024-12-02T06:32:39.443Z
2024-12-02T06:32:39.443Z
ifconfig
<p>On my quad I have HGLRS M80 GPS module (for now I'm not going to upgrade it) and it takes quite a long time to find satellites and establish 3D fix. As far as I understand from reading the articles about it, one of the reasons is that my module is an outdated one and thus more vulnerable to radio noise from other equipment of the same drone.</p>
<p>I have quite a long wires connecting the module to the board (RX, TX, 5V, GND) twisted all together into one braid.</p>
<p><a href="https://i.sstatic.net/nSpRoR5P.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/nSpRoR5P.jpg" alt="GPS wires" /></a></p>
<p>What comes to my mind is the idea about</p>
<ol>
<li>making the wires shorter</li>
<li>splitting the braid in two: the first twisted pair for RX/TX and the second one for power supply</li>
</ol>
<p>Will this help me to reduce impact of radio noise and improve start-up time of my GPS module?</p>

<first-person-view><gps><wiring>
Should I separate signal wires from power ones and twist them?
Sergey Tsypanov
# Should I separate signal wires from power ones and twist them?

(Asked by: username_0 on 2024-11-28)

On my quad I have HGLRS M80 GPS module (for now I'm not going to upgrade it) and it takes quite a long time to find satellites and establish 3D fix. As far as I understand from reading the articles about it, one of the reasons is that my module is an outdated one and thus more vulnerable to radio noise from other equipment of the same drone.

I have quite a long wires connecting the module to the board (RX, TX, 5V, GND) twisted all together into one braid.

[![GPS wires](https://i.sstatic.net/nSpRoR5P.jpg)](https://i.sstatic.net/nSpRoR5P.jpg)

What comes to my mind is the idea about

1. making the wires shorter
2. splitting the braid in two: the first twisted pair for RX/TX and the second one for power supply

Will this help me to reduce impact of radio noise and improve start-up time of my GPS module?

**Tags:** first-person-view, gps, wiring

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## 1 answers

### Answer by username_1 on 2024-12-02. Score: 1 | Accepted answer

This is a good question! TL;DR, twisting/braiding the wires here **should have little effect** on the time to first GPS solution (*called TTFF in GPS parlance, for Time To First Fix*). It's recommended to help physically constrain the cable in the drone frame so it doesn't bump into things or get caught in the propellers, as twisting the wires stiffens/bulks up the wire bundle and shortens its length.

More generally, twisted-pair signal wires are useful for electromagnetically noisy environments (*such as a drone*). The act of twisting the signal wires together helps to ensure that any electromagnetic effects affect all the signal wires equally, and in some cases for special (*differential*) signaling protocols, automatically cancel out the effects.

The UART interface we're talking about here (*VCC, GND, TX, RX*) is not a differential signal protocol and doesn't benefit much from twisting the signal wires. The most likely effect of a noisy environment on a UART interface is an intermittent failure to communicate with the GPS module during flight, but I don't believe that's something you've been seeing.

To your other question:

> my module is an outdated one and thus more vulnerable to radio noise from other equipment of the same drone

"Hobby-grade" GPS receivers are generally not all that great, especially in comparison to the integrated GPS/SoC chipsets in modern phones. There are several interesting reasons for this, including:

* Poor-quality receive antennas and EMI environment on a drone
* Lack of [A-GPS](https://en.wikipedia.org/wiki/Assisted_GNSS) or other TTFF and accuracy improving strategies
* Lack of support for other GNSS constellations other than GPS (*e.g. Galileo, GLONASS, BeiDou*)
* Lack of knowledge of the current time (*i.e. no [RTC](https://en.wikipedia.org/wiki/Real-time_clock)*)

The easiest one of these to mitigate/improve without buying an expensive GPS receiver part is improving the antenna and/or moving it further from the motors. But the slow TTFF will always be present due to the lack of accurate time knowledge or A-GPS.


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