Iphone 4s gps chip: iPhone 4S — Technical Specifications

8 февраля, 2023

Did Apple degrade the accuracy of the iPhone 4S GPS compared to the iPhone 4



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I have done some extensive testing of my iPhone 4S compared to my iPhone 4 and found GPS accuracy has suffered substantially.

I’ve been using the 4 for about a year, riding a bicycle on a 3 mile loop park road several times a week. Typically, I’ll do about 6 laps or 18 miles. Using a great app called Cyclemeter, I save the track so I have a record of how fast and how far I rode. After I upgraded to the 4S I found the measured length of each lap varied widely and that ridiculously high speeds were being recorded.

Upon examination of the recorded track I find loops drawn out to points up to 100 feet from the actual course and back tracks heading the wrong direction. The net result is the iPhone 4S is off by around 20% on the measured distance from what I know it should be. Has anyone else looked carefully at their tracks and found similar results?

What is more likely: That I have a defective unit OR that Apple’s elimination of a dedicated GPS chip means less accurate information?

  • iphone
  • gps
  • hardware






6

My experience helping others with this problem seems to suggest a few things:

  • Apple’s been monkeying around with power conservation by trying to give «good enough» positioning results while idling the GPS for longer periods and relying on cell tower and wifi positioning more. Try turning off wifi for your next run to see if the GPS does better (and if your battery is drained more).
  • Application developers are decreasing the GPS resolution of their apps in order to have less impact on the battery due to user complaints. Check to see if the app you use can be configured for GPS update frequency and ask the app developer what they suggest regarding your problem.
  • Both the iPhone 4 and 4S seem to suffer from GPS degradation after awhile that can be fixed by doing a refresh of the device — in other words sometimes it’s a software issue that seems to fix itself after a hard reboot and system refresh. For some people a hard reboot is sufficient, but others have indicated that only a refresh will work for them. I think this started affecting some of my friend’s phones around the beginning of last summer. I’ve seen several of my friends have this issue, visit the store, have it refreshed and reset, and the problem disappear. Now they do the refresh themselves with iTunes when it gets annoying. I don’t have information on whether this is tied to a particular version of iOS or not, but I have seen it on both the 4 and 4S.

Of course you could also be experiencing a hardware problem, but you might consider some of the above actions before completely blaming the hardware.

Also be aware that GPS requires good line of sight to the sky. If you’ve changed your iOS device position recently, consider changing it back. If you’re wearing it, make sure your body isn’t between the device and the sky, and that your perspiration isn’t reaching the device.

I believe this is a hardware problem. I had an iPhone 4 using the RunKeeper app similar to Cyclemeter. It worked perfect for six months, then GPS accuracy degraded (says I ran a little over double my actual distance and the map shows data jumping all over about 250 yards off track). Behaves like signal blockage. Not caused by dropping, heat, power, etc. Per Genius suggestion, I tried disabling all other Locator apps as well as tricks you reported. Eventually, Apple replaced the iPhone under warranty with a new one which worked perfect for three months, and this week it began degrading as well (useless for running!). Since the original 1 year warranty is up, I’m stuck!
Apple Genius Knowledge Base does not address this issue. They say the GPS either works or it doesn’t, and it doesn’t degrade accuracy or get intermittent data points. They have no fix.






1

The iPhone 4s contains a GLONASS chip, in addition to the GPS chip (at least for units sold in North America and Russia). GLONASS is the Russian competitor to the GPS. Theoretically, it should improve accuracy, since iPhone samples both chips, but I don’t think that happened. In my case, the GPS seems 3-4 seconds behind what I am doing.

I am guessing this is new to Apple and all the problems get fixed in the next update.






3

geolocation — How accurate is the iPhone X location data?

How accurate is the GPS information that developers can get when using the iPhone X?

It’s a subjective question and the perceived accuracy of location data may differ based on usage, location and signal availability. While the real answer can only be obtained by actually capturing the data, I’ll try to share some information which can help you with your query.

iPhone X along with its contemporaries iPhone 8 and iPhone 8 Plus, are the first iPhones to include support for not one but four geolocation services:

A brief description of each one of them:

  1. GPS: Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Air Force.

  2. GLONASS: Globalnaya navigatsionnaya sputnikovaya sistema, or Global Navigation Satellite System, is a space-based satellite navigation system operating in the radionavigation-satellite service. It provides an alternative to GPS and is the second navigational system in operation with global coverage and of comparable precision.

  3. Galileo: Galileo is the global navigation satellite system (GNSS) that is being created by the European Union (EU) through the European GNSS Agency (GSA). One of the aims of Galileo is to provide an independent high-precision positioning system so European nations do not have to rely on the Russian GLONASS, Chinese BeiDou or US GPS systems, which could be disabled or degraded by their operators at any time. The use of basic (lower-precision) Galileo services will be free and open to everyone. The higher-precision capabilities will be available for paying commercial users. Galileo is intended to provide horizontal and vertical position measurements within 1-metre precision, and better positioning services at higher latitudes than other positioning systems.

  4. QZSS: The Quasi-Zenith Satellite System (QZSS) is a project of the Japanese government for the development of a four-satellite regional time transfer system and a satellite-based augmentation system for the United States operated Global Positioning System (GPS) to be receivable in the Asia-Oceania regions, with a focus on Japan. The goal of QZSS is to provide highly precise and stable positioning services in the Asia-Oceania region, compatible with GPS.

While GPS support has been available since iPhone 3G, GLONASS was added starting with iPhone 4S (ref: List of iOS devices).

Some references from the Web which back the claim that availability of multiple service support will lead to more accurate positioning data:

  • iPhone 8, 8 Plus, and X Support the Galileo Satellite System for Better GPS:

According to the European Global Navigation Satellite Systems Agency, Galileo support in the new iPhones will allow users to benefit from more precise positioning that’s able to combine GPS, GLONASS, and Galileo signals. Galileo, says the agency, has a modern signal structure that’s able to help users better maintain their position fix when navigating through cities worldwide.

Multi-satellite support also increases signal availability in urban areas where buildings can obstruct the sky and limit the number of visible satellites. Galileo has 15 operational satellites in orbit and three that are in testing, compared to 31 GPS satellites and 24 GLONASS satellites. By 2020, Galileo is expected to have 30 satellites operational.

  • The latest iPhone 8, iPhone 8 Plus, and iPhone X are Galileo-enabled:

Among the new features of the latest Apple offerings is the fact that the newest versions of the iPhone are Galileo-enabled. The resulting ‘multi-constellation’ capability means that users of the new iPhones will be able to benefit from more precise positioning that combines GPS, Glonass and Galileo signals. The use of multi-constellation increases signal availability, especially in urban environments, where buildings obstruct the sky and limit the number of satellites visible. In terms of accuracy, Galileo’s modern signal structure has better resistance to multipath, which helps users maintain their position fix when navigating in cities.

  • New iPhones better serve you in different parts of the world with support for Galileo and QZSS satellites

Combining GPS, GLONASS and Galileo signals lets new iPhones increase signal availability in urban environments where buildings obstruct the sky and limit the number of satellites visible.

In terms of accuracy, Galileo’s signal structure is said to provide better resistance to multipath, which helps iPhone users maintain their position fix when navigating in cities.

Where is the navigation chip in the smartphone? Part 2 / Habr

In the first part of the article, we remembered the good old days when one phone could be distinguished from another by a photograph. We got to the iPhone 4S and saw how the navigation receiver functions moved to the Qualcomm MDM-6610 communications chip. What was in the next iPhones?

iPhone 5, 5S, 5C

In the iPhone 5 (2012), the processing of navigation signals was left to the cellular modem, this time Qualcomm MDM9615 (gpsOneGen 8A).

The functions of the radio frequency unit were transferred to the Qualcomm RTR8600 chip — a multi-channel radio frequency unit (RF transceiver), containing, in addition to transmitting, 10 channels for receiving. Two of them are capable of transmitting GPS / GLONASS L1 signals, the rest are used for numerous cellular communication bands. The microcircuit is made according to the 65 nm technological process.

Qualcomm MDM9615 modem and Qualcomm RTR8600 RF transceiver on Apple iPhone 5 board (source ifixit.com)

The Qualcomm RTR8600 has been replaced by the new WTR1605L chip in the iPhone 5S and 5C. The chip size has been reduced by almost half by using a different packaging method and the number of channels has increased, which added support for Beidou.

Apple iPhone 5S board with Qualcomm MDM9615 modem and Qualcomm WTR1605L RF transceiver (right, source ifixit.com)

Model 5S was based on the new Apple A7 SNK. This is Apple’s first 64-bit SNK. In terms of navigation, it is notable for the fact that the M5 coprocessor is integrated into it. It is designed to process data from gyroscopes and accelerometers. nine0003

From iPhone 6 to iPhone 11

Subsequent iPhone models did not change the architecture in terms of navigation functions, but only developed chips.

Apple iPhone 6 board with Qualcomm MDM9625M modem (highlighted in orange, source ifixit. com)

The iPhone 6 went on sale in 2014, the modem in it was replaced with a Qualcomm MDM9625M, navigation technology was designated IZat gpsOneGen 8B.

Separate accelerometer and gyroscope chips were replaced with a single InvenSense MPU-6700 chip, an additional Bosch Sensortec BMA280 three-axis accelerometer chip was installed. The microcircuit from Bosch has the worst sensitivity and meager functionality, but at the same time it consumes three times less (130 μA). nine0003

Due to patent disputes between Apple and Qualcomm, the iPhone 7 (2016) was released in two versions. In most of the phones sold, instead of a modem from Qualcomm, an Intel PMB9943 chip (aka Intel XMM7360) is used paired with an analog Intel PMB5750s. They also take on the functions of processing GNSS signals.

Apple iPhone 7 board with Intel PMB9943 modem (to the left of the SIM card tray)

The situation with several modifications remains in the next two generations, iPhone 8 and X models have different versions with modems from Intel and Qualcomm. In the 2018 XR and XS models, Intel is already completely replacing Qualcomm: Intel PMB9 chips are used955 (XMM7560) supporting GPS, GLONASS, Galileo and Beidou.

In the fall of 2019, the iPhone 11 was released. An important innovation was the antenna and ultra-wideband (UWB) transceiver, which can be used for indoor navigation. Unfortunately, the use of this function in Russia is limited due to the peculiarities of licensing the frequency range.

One of the Apple iPhone 11 boards with Intel X927YD2Q modem (bottom center) and Intel 5765 P10 A15 08B13 RF transceiver (one position to the right, source ifixit.com)

For satellite navigation, the phone contains an Intel X927YD2Q modem paired with an Intel 5765 P10 A15 08B13 h2925 transceiver

iPhone 12, 13

In 2019, Intel sold most of its phone business to Apple. The deal included about 17,000 patents and 2,200 employees. Further development of modems, including GNSS receivers, is carried out in the California divisions of Apple. But the transition process after the merger takes some time. nine0003

In parallel, phones from Xiaomi and other competing brands began to appear on the market that support the L5 navigation range. Broadband signals are located in this frequency range. A wide bandwidth of the navigation signal can significantly reduce multipath errors and, as a result, improve positioning accuracy in urban environments. Experts have speculated about the appearance of similar solutions in the next generation of Apple products. nine0003

The third circumstance is the rapid development of 5G networks and the need to implement their support in flagship phones.

Together, the iPhone 12 and 13 are back to seeing chips from Qualcomm, the leader in 5G solutions.

Apple iPhone 12 board, Qualcomm SDR865 transceiver in yellow, Qualcomm X55M baseband processor in green (photo source — ifixit.com)

iPhone 12 communication and navigation functions are based on Qualcomm Snapdragon X55M and Qualcomm SDR865 transceiver. The phone contains two navigation antennas and processes signals from the navigation bands L1 and L5. nine0003 Apple iPhone 13 Pro board, blue highlights Qualcomm SDR865 transceiver, blue highlights Qualcomm X60M baseband processor. The 7 nm process technology was replaced by 5 nm, which had a positive effect on energy efficiency and heating.

Conclusion

If we try to identify trends, we see how the average navigation receiver has turned from a device into a function. nine0047 Secondary function communication modem. In the case of Apple, it is also implemented by the divisions on their own.

But not all modern receivers are «normally typical». Smartphones occupy more than 90% of the GNSS device market in terms of the number of units produced, but in monetary terms it is only 60%. What remains are telematics, automotive systems, geodetic and marine applications, aviation technology and rail transport, etc. Russian companies are represented in these sectors, have worthy solutions, and Russian engineers have an opportunity for self-realization. This does not cancel the trend towards integrating different systems in one SoC, which means that the work of a navigation engineer will continue to drift either towards the development of IP cores, software and firmware, or towards the use of foreign chips, modules and boards in their projects. nine0003

More pictures and details:

  • https://www.techinsights.com

  • https://ifixit.com

Link to the first part of the

GLONASS in iPhone

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Technics
Navigation

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    Support for GLONASS in their smartphones in 2011 was announced by several manufacturers at once, but few people know that these devices work differently with the signal of Russian satellites. Thus, the iPhone 4S prefers GPS as the main system, while the Samsung Galaxy Note «loves» GPS and GLONASS equally.

    In 2011, several manufacturers announced support for GLONASS in their smartphones: Samsung, Apple, Sony Ericsson (now just Sony), Motorola. CNews talked to the largest manufacturers of mobile microelectronics and found out how GLONASS works in smartphones based on their chipsets. nine0003

    iPhone 4S — GLONASS in reserve

    Luciano Splendorini (Luciano Splendorini), Qualcomm’s senior director of business development for Eastern Europe , told the publication that her company’s chips with support for two navigation systems use GPS as the main satellite system, and GLONASS as its «assistant».

    According to Splendorini, when starting navigation in a smartphone based on such a chip, the receiver integrated into it first tries to catch the signal of GPS satellites, and if it does not see enough of them at the moment or the signal level is weak, then in addition to them it connects the satellite signal GLONASS. nine0003

    “In our chipset, we try to minimize all possible energy costs, so initially it works with one navigation system, and only accesses the second when it is really needed — only in this case the signal from both systems is used simultaneously,” says Splendorini.

    It is worth noting that this is exactly how navigation works in the iPhone 4S: an autopsy of this smartphone, carried out by the iFixit portal, showed that it operates on the basis of the Qualcomm MDM6610 platform. nine0003


    iPhone 4S is the first Apple smartphone to support GLONASS

    GLONASS support in Qualcomm chips is provided by the GPS 8 navigation chip. It is supplied exclusively as part of the company’s ready-made mobile platforms, including CPU, GPU, APU, communication modules and a number of other components. GPS 8 is included in all Qualcomm Snapdragon platforms gen 2 and above. As part of the Qualcomm MSM 7230 platform, this microcircuit provided support for the Russian navigation satellite system in the world’s first GLONASS smartphone, which was released by the Chinese ZTE for MTS. nine0003

    In Samsung Galaxy Note — the first wins

    It is worth noting that Apple — as a client — Qualcomm lured away from its main competitor — Broadcom. The previous model iPhone 4, according to the same iFixit, used its navigation chip — BCM4750, which supports only GPS.

    Broadcom’s next generation navigation chip, the BCM4751, is capable of receiving and processing both GPS and GLONASS signals. Unlike GPS 8, a smartphone manufacturer can purchase it separately and integrate it into a mobile platform from another vendor, or together with the Broadcom platform. nine0003

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    As Richard Najarian, head of the Broadcom GPS direction, told CNews, BCM4751 is used in the Samsung Galaxy Note smartphone, being built into the mobile platform manufactured by Infineon (since 2011, a division of Intel). According to Najarian, it is currently the only smartphone model already available on the market that uses his company’s GLONASS-enabled chipset. GLONASS support is also announced in the new Samsung tablets — Galaxy Tab 10.1 and Galaxy Note 10.1, presented last week. nine0003

    Unlike the navigation chipset of Qualcomm, the Broadcom chipset does not give preference to GLONASS or GPS: when you start navigation in your smartphone, it starts to “seek out” and use the first available satellites, no matter what system they belong to.

    Could be even better

    Both companies note that their tests on dual-system chips show improvements in satellite signal availability and position accuracy. Adding a signal from other navigation systems could further improve these figures. nine0003

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    Qualcomm told CNews that they thought about adding to their chips and support for the Chinese satellite system COMPASS (BeiDou), but its specifications, available in the public domain, are not enough to implement this, the company says.

    What is required for GLONASS to work in a smartphone? nine0070

    It is worth noting that at the hardware level GLONASS is now supported by dozens of smartphones and tablets — in addition to Qualcomm and Broadcom, almost all major manufacturers of mobile microelectronics announced the release of GLONASS-enabled chips in 2010-2011. However, in order for the device to actually use the signal of both satellite systems, some refinement is necessary on the part of the smartphone manufacturer.

    Qualcomm says that the manufacturer needs a special antenna capable of receiving both systems (GPS signal of standard accuracy uses one frequency, while standard GLONASS signal uses a frequency range), additional signal filters, as well as setting up a software interface. nine0003

    According to representatives of Qualcomm, as a rule, the smartphone manufacturer conducts work on «turning on» GLONASS with the assistance of a microelectronics supplier. Subsequently, the company periodically releases software updates for its chipsets, which the smartphone manufacturer includes in new batches of devices.