# GPS Rally Computer — rallies that allow GPS odos

> Automobile rally computer for time-speed-distance navigation and computation. (iPhone/iPad app by MSYapps.)

- Source: https://appshunter.io/ios/app/gps-rally-computer/id1210193950 (this page in markdown: same URL + `.md`)
- Developer: [MSYapps](https://appshunter.io/developer/458482419)
- Category: Sports, Navigation
- Price: $24.99
- Rating: 3.80/5 from 5 App Store ratings
- Age rating: 4+
- Requires: iOS 12.4 · 2 MB
- Languages: American English
- Released: 2017-03-31
- Data updated: 2026-09-09
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/gps-rally-computer/id1210193950/reviews.md

## What is GPS Rally Computer?

GPS Rally Computer is a Universal app designed to simplify computations necessary to navigate a traditional time-speed-distance (TSD) automobile rally. The design and implementation is based on specifications outlined by Clarence Westburg and Rich Bireta, commonly known as the Simple Rally Computer or its acronym SRC. The User's Manual is available on the app detail page linked at http://www.msyapps.com.

A TSD rally is comprised of stages set along a route defined by written instructions. The first stage is the Odometer Check stage that allows you to calibrate your car’s odometer with that of the Rally Master’s odometer.

In later stages you will follow a course at a particular average speed that will change from time to time at places that are generally unknown in advance. 

In order to drive the course at the prescribed speeds. Odometer measurement is obtained from Apple’s GPS receiver or third-party devices via Bluetooth.

The GPS Rally Computer allows you to do all this and much, much more. For additional documentation, download the User’s Guide.

Features of the GPS Rally Computer:
 - Clock time in either minutes and seconds to tenths of a second or decimal minutes to thousandths of a minute
 - The clock is a 24-hour clock to simplify computations
 - Distance measurements in either miles or kilometers to either two- or three-digit precision
 - One button click to reset default conditions for starting a rally
 - The internal computer clock can be adjusted to match the official rally clock
- The distance between the GPS receiver and the position on the car where the rally measurements are taken (the front wheels, for example) can be added for improved distance precision
 - A "sprocket" button in the top menu bar allows access to the app settings from within the running application including settings for display of certain items
 - Calibrate the car's odometer to the official rally odometer on the odometer check stage via a popup
 - Change average speed (CAST) on a custom popup keypad
 - Preselect the next CAST to simplify the process of changing speed on each stage and setting CAST to zero for transit zones
 - As time passes and as the car's odometer is incremented, the actual speed over the course is compared with the expected speed. The difference in seconds or hundredths of a minute is displayed along with an indication to either “Early” or “Late” to stay on pace.
- Time errors may be displayed in either of two modes selectable in the app Settings
 - Pause or Gain time or take a Time Allowance on any leg or within a transit zone
 - Handle off-course corrections to time and distance with a Reverse button
 - Record "splits" of time and error at any time with a Split button
- Record "control" and reset time error and distance to zero and increment next starting time 5 minutes later (distance and time are modifiable) with a Control button.
 - Set next starting time for the Next CAST and have the time tick down on the master clock and autostart CAST, or override with a manual button click
- Optionally, use a Dual GPS receiver via Bluetooth to supplement or substitute for the Apple internal GPS
- Connects to TSD Remote app that serves as a driver's heads-up display connected via local network.

Note: Use of the GPS Rally Computer during any particular rally will be subject to the rules and instructions governing the rally and may also define your category or class among race participants. Some rallies may, in fact, prohibit use of this app.

This app has been tested with Bluetooth connectivity to a Dual XGPS150A Universal GPS Receiver.

Disclaimer: Continued use of GPS running in the background can dramatically decrease battery life.

## Key features

- Odometer calibration
- Precise speed tracking
- Real-time error correction
- Adjustable clock and distance units
- Customizable speed changes
- Time and distance recording


## Frequently asked questions about GPS Rally Computer

### What is GPS Rally Computer used for?

GPS Rally Computer is designed to simplify the computations needed for traditional time-speed-distance (TSD) automobile rallies. It helps users calibrate their odometer, track speed, and manage time errors to stay on pace during a rally.

### How accurate is the distance measurement in GPS Rally Computer?

Distance measurements can be taken from Apple's GPS receiver or third-party Bluetooth devices. The app also allows for the distance between the GPS receiver and the car's measurement point to be added for improved precision.

### Can I adjust the clock in GPS Rally Computer?

Yes, the internal computer clock can be adjusted to match the official rally clock. The clock displays in a 24-hour format and can show time in minutes and seconds to tenths of a second, or decimal minutes to thousandths of a minute.

### Does GPS Rally Computer support different units for distance?

Yes, distance measurements can be displayed in either miles or kilometers, with options for two- or three-digit precision. This flexibility caters to various rally formats and user preferences.

### How does GPS Rally Computer handle speed changes during a rally?

The app allows for changing average speeds (CAST) via a custom keypad and preselecting the next CAST. This simplifies the process of adjusting speed for different stages and transit zones.

### What are the pricing details for GPS Rally Computer?

GPS Rally Computer is a paid application priced at $24.99. There are no in-app purchases or subscription fees associated with its use.

### How often is GPS Rally Computer updated?

The app was last updated on February 7, 2024, indicating ongoing support and potential for future improvements. Version 5.3.1 is the latest release.

### Is GPS Rally Computer suitable for younger users?

GPS Rally Computer has an age rating of 4+, making it suitable for a wide range of users. Its functionality is geared towards rally participants of all ages.

## Version history (last 5 releases)

### 5.3.1 — 2024-02-07

- Updated info.plist file to improve peer-to-peer connectivity to the TSD Remote heads-up display app.

### 5.3 — 2023-09-09

- Fixed GUI display issue with iPad version.

### 5.2 — 2020-03-16

- Recalibrated filter rules to minimize distance creep while stopped or nearly stopped.
- Fixed bug in odometer correction factor routine and improved its functionality.
- Added 0 and 00 as allowable digits when initiating or editing odometer correction factor.
- Fixed bug that prevented Pause or Gain during a Transit Zone after adjusting the odometer with the "bump" feature.
- Improved the computation of distance estimates between GPS signals.
- Minor GUI changes.

### 5.1 — 2020-02-15

- The major code improvements and additions are designed to adjust the GPS coordinates of a moving vehicle owing to the time between reception of new GPS signals and to the time lag between the time the signal was generated from satellites and the time when processing actually occurs in the app.
- Users may now adjust the location coordinate by the distance between the GPS receiver in the car (either the iPhone or iPad or some third-party GPS receiver) and the position on the car where a rally may measure time or location at timed controls (sometimes this is the front of the car or the center of the front wheels). This optional adjustment is available in the Reset popup.
- All three of these potential errors in coordinate measurement are discussed at length in a 6-part thread in the Facebook "Road Rally Tech Talk" forum.
- If clock and GPS device distance adjustments are non-zero, an indication of the adjustments selected will be shown in the upper center of the display beneath the app title.
- If available to the app, compass coordinates are available to verify location when the car is stopped. The compass coordinates and bearing are available from a "compass" button on the "Map" popup. 
- The "gps" information display button and contents have been relocated to the "Map" popup. Also, there are two new pieces of information on the display: Time Lag, the difference between the time the GPS signal was generated and the time when the new GPS location is actually processed in the app; and Signal Interval, the time between each receipt of new GPS information from the GPS receiver, either Apple's internal receiver/processor or a third-party GPS receiver.
- Various improvements to the processing of information from the Dual 150 and 160 model GPS receivers.
- Changes to processing of Apple internal GPS signals to account for spurious readings when horizontal accuracy is poor or when the car is stopped or moving very slowly.
- Odometer synchronization has been removed from the "Odo" popup. Rather, you may use the "Adjust Odo" option to set, reset, or adjust the odometer as needed.
- Various, relatively minor GUI changes.
- Coding for displays has been reduced and simplified where possible.

### 5.0.67 — 2019-07-22

- For rallies where distance is measured in kilometers, CAST speed inputs can now be greater than 99.99.
- Various GUI modifications and code changes to accommodate this option.
- Distance measurement Setting of either miles or kilometers must be made before starting the rally or after a full reset to default conditions. In other words, the distance cannot be changed while the app is running during the rally.

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All apps by MSYapps: https://appshunter.io/developer/458482419

## Related topics

[simple rally](https://appshunter.io/ios/topics/simple-rally)

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